Device for recording and playing stream data

Time stamps are attached to packets output from stream data input section by a time stamp-attaching section in a HDD, and the packets are then recorded into a HDD main unit. A stream data-generating section removes the time stamps from the packets subsequent to a predetermined amount of packets last recorded into the HDD main unit and controls the timing of the packets according to the time stamps, and the packets are transferred to an HDD. In the HDD, time stamps start to be generated according to the last predetermined amount of packets, and to the packets transferred thereafter, time stamps are attached in a similar fashion as in the HDD, so that the packets are recorded into the HDD main unit.

BACKGROUND OF THE INVENTION

The present invention relates to techniques pertaining to stream data recording and playing devices that can record and play stream data for, for example, broadcasted programs, and more particularly to stream data recording and playing devices, stream data recording and playing controlling devices, and stream data recording and playing methods that can record and play long time, continuous stream data.

MPEG-2 transport stream format (hereafter referred to as MPEG-2TS) has been used for stream data for, for example, programs broadcasted from broadcast stations. (“MPEG” is an abbreviation of Motion Picture Expert Group. MPEG-2 is a standard specified by ISO/IEC and is documented in ISO/IEC 13818.) Stream data in such a format as described above are sent out from a broadcast station at a predetermined transmission rate, and the system time clock of the receiving side decoder is synchronized with that of the sending side encoder in order to produce images and sound at proper timing.

If the received stream data are recorded in a recording and playing device (a recording medium), such as a hard disk, as they are and thereafter the data are played back, it is difficult to present the images or sound as they are received from a broadcast station. This is due to the fact that in general, the speed of data recording into or reading from a hard disk or the like is not specifically controlled (i.e., accurate speed is not guaranteed), and therefore, stream data with proper timing cannot be obtained if the data that have been read out are output without any processing.

In view of this problem, a time stamp recording system is known in which, when received data are recorded, time stamps are attached to the received data in the units of packets or the like based on the system time clock that is synchronized with the sender side encoder or the like. With this system, when playing back the recorded data, data read out from a recording medium are output at timing corresponding to time stamps, and as a result, images and sound can be presented just like the data received from a broadcast station.

However, with the above-described conventional stream data recording and playing device, although stream data can be recorded with the use of time stamp recording system as described above, it is necessary that time stamps attached to a series of stream data have continuity and therefore such a series of stream data must be recorded in a single recording and playing device. For this reason, the conventional device has a drawback in that it is difficult to record and/or play stream data having an amount of data larger than (longer than) the storage capacity of a single recording and playing device. It should be noted that when data to be recorded do not require synchronization of data transmission, they can be handled in a similar way to character data and still image data even though the data are image data or the like, so there will be no problem if the data are divided and stored into a plurality of recording media, as disclosed in Japanese Unexamined Patent Publication No. 2000-349833. In contrast, when the data are stream data, it is difficult to divide and record them while their continuity is being maintained.

SUMMARY OF THE INVENTION

In view of the foregoing and other problems, it is an object of the present invention to record stream data for a longer time than the time corresponding to the storage capacity of a single stream data recording and playing device so that the data can be played back at proper timing, and to play the data at proper timing.

In order to accomplish the foregoing and other objects, the present invention provides, in a first aspect, a stream data-recording device for recording stream data into a recording medium, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, comprising: an analyzing means for analyzing the input stream data and extracting recording data to be recorded in the recording medium; a time stamp-attaching means for generating a time stamp that is synchronized with the time information contained in the recording data and attaching the time stamp to the recording data; a recording means for recording the recording data in the recording medium; and an output means for generating transfer stream data by removing the time stamp from the recording data that include last data of a predetermined amount of recording data to be recorded into the recording medium and data subsequent thereto, and outputting the generated transfer stream data to another stream data recording device at timing corresponding to the time stamp.

Accordingly, at the time when recording data to be recorded in the recording medium are once extracted, the accurate amount of the recording data can be detected, and the recording data to be recorded into the stream data recording device are distinguished from the recording data to be transferred and recorded into other stream data recording devices. Therefore, recording that leads to proper playback is possible and data overlap and data loss of the stream data are not caused over a plurality of stream data recording device, and consequently, no wasted recording space is created in the recording medium. Moreover, the data transfer to another stream data recording device is performed with stream data according to timing control using time stamps that are temporarily attached, and last data of a predetermined amount of recording data to be recorded in the stream data recording device are transferred in advance of the recording data to be recorded in the other stream data recording device. Consequently, for the other stream data recording device, it is easy to generate a time stamp that is continuous with a time stamp of the recording data to be recorded in the stream data recording device, and to attach the time stamp to the recording data when the data are recorded. Thus, recording that enables stream data to be played while maintaining their continuity can be easily performed. As a consequence, stream data can be recorded for a longer time than a time corresponding to the storage capacity of a single stream data recording device, and as continuous time stamps are attached to the stream data, the stream data can be played at proper timing with continuity.

In the foregoing device, it is possible that when the output means outputs the transferred stream data to further another stream data recording device subsequent to the other stream data recording device, the output means further outputs the transfer stream data generated based on the recording data that are to be recorded into the other stream data recording device and are subsequent to last data of a predetermined amount of recording data to the further another stream data recording device.

With this configuration, in the further another stream data recording device as well, the last data of a predetermined amount of recording data to be recorded in the other stream data recording device are transferred to the further another stream data recording device. Thus, in the further another stream data recording device, a time stamp can be easily generated that is continuous with the time stamp for the recording data to be recorded in the other stream data recording device, and the generated time stamps can be attached and recorded with the recording data. Therefore, recording that enables stream data to be played while maintaining their continuity can be easily performed with a further larger number of stream data recording devices.

The present invention also provides, in another aspect, stream data-recording device for recording stream data into a recording medium, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, comprising: an analyzing means for analyzing the stream data and extracting last data of a predetermined amount of recording data that are recorded in the recording medium in the other stream data recording device and recording data that are subsequent to the predetermined amount of recording data; a time stamp-attaching means for generating a time stamp that is synchronized with the time information contained in the recording data and attaching the time stamp to at least the recording data that are subsequent to the predetermined amount of recording data; and a recording means for recording the recording data that are subsequent to the predetermined amount of recording data.

With this configuration, the time stamp is generated based on the recording data that include the last data and data subsequent thereto of a predetermined amount of recording data to be recorded in a preceding stream data recording device such as described above, and therefore, a time stamp continuous with the time stamp of the recording data to be recorded in the preceding stream data recording device can be generated and attached to the recorded data. Thus, recording that enables stream data to be played while maintaining their continuity can be easily performed as described above.

It is possible that in the foregoing stream data recording device, an output means for generating transfer stream data by removing the time stamp from the recording data that include last data of a predetermined amount of recording data to be recorded into the recording medium and data subsequent thereto, and outputting the generated transfer stream data to further another stream data recording device at timing corresponding to the time stamp.

Thus, stream data transferred from one of the foregoing stream data recording devices are transferred to further another stream data recording device, and consequently, recording that enables stream data to be played while maintaining their continuity can be easily performed with a further larger number of stream data recording devices.

The present invention provides, in still another aspect, a stream data-recording device for recording stream data into a recording medium, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, comprising: an analyzing means for analyzing the input stream data and extracting recording data to be recorded in the recording medium and a recording medium of another stream data recording device; a time stamp-attaching means for generating a time stamp that is synchronized with the time information contained in the recording data and attaching the time stamp to the recording data; an output means for generating transfer stream data by removing the time stamp from the recording data to be recorded in the recording medium of the other stream data recording device and outputting the generated transfer stream data to the other stream data recording device at timing corresponding to the time stamp; and a recording means for recording, in the recording medium, recording data that are subsequent to the recording data to be recorded in the recording medium of the other stream data recording device.

Thus, with the transfer similar to the foregoing, recording has been first performed in the other stream data recording device, and thereafter, recording is performed in the stream data recording device. Therefore, recording can be performed while continuous time stamps are attached to the recording data, and recording that enables stream data to be played while maintaining their continuity can be easily performed.

The present invention provides, in yet another aspect, a stream data playing device for playing back continuous stream data from first and second recording data to which continuous time stamps are attached and which are respectively recorded in a first recording medium in the stream data playing device and in a second recording medium in another stream data playing device, comprising: a playing means for reading out the first recording data from the first recording medium and outputting the first recording data as first playback output data; an analyzing means for analyzing transfer stream data that are generated by the other stream data playing device by reading out the second recording data from the second recording medium and removing the time stamp therefrom, and are output from the other stream data playing device at timing corresponding to the time stamp, and for extracting second playback output data; a time stamp-attaching means for generating a time stamp synchronized with time information contained in the second playback output data and attaching the time stamp to the second playback output data; and an outputting means for generating playback stream data by removing the time stamps from the first playback output data and the second playback output data and sequentially outputting the generated playback stream data at timing corresponding to the time stamps.

With this configuration, the playback output data are extracted from the stream data transferred with timing control from the other stream data playing device based on the time stamps and the time stamps are attached. Thus, the same time stamp can be attached as that attached to the recording data recorded in the other stream data playing device, that is, the time stamp continuous with the recording data recorded in the stream data playing device can be attached. Therefore, stream data playback can be performed while continuity is maintained as in a similar manner to the case where all the recording data are recorded in the single stream data playing device.

It is preferable that in the foregoing stream data playing device, the outputting means outputs playback stream data generated from the first playback output data after playback stream data generated from the second playback output data have been output.

With this configuration, since it is relatively easy to read out the first recording data recorded in the stream data recording device at proper timing, it is possible to quickly output the playback stream data generated from the first playback output data easily after the playback stream data generated from the second playback output data are output, for example, while the capacity of the buffer is suppressed.

The present invention provides, in further another aspect, a stream data recording-controlling device for controlling recording of stream data into a recording medium of a stream data recording device, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, comprising: an analyzing means for analyzing the input stream data and extracting recording data to be recorded in the recording medium; a time stamp-attaching means for generating a time stamp that is synchronized with the time information contained in the recording data and attaching the time stamp to the recording data; and an output means for generating transfer stream data by removing the time stamp from the recording data, for outputting the generated transfer stream data at timing corresponding to the time stamp to the stream data recording device, and for outputting, prior to start of the outputting transfer stream data, predetermined stream data containing time information that is precedent to the transfer stream data at the start of the outputting to the stream data recording device.

With this configuration, according to a similar mechanism to that described for the foregoing first aspect of the invention, time stamps continuous with one another are easily generated in a plurality of stream data recording devices so that they can be attached to the recording data and are recorded. As a consequence, recording that enables stream data to be played while maintaining their continuity can be easily performed over a plurality of stream data recording devices. Consequently, stream data can be recorded for a longer time than a time corresponding to the storage capacity of a single stream data recording device, and moreover, playback can be performed at proper timing with continuity since continuous time stamps are attached to the stream data.

It is preferable that in the foregoing stream data recording-controlling device, when the output means outputs the transfer stream data to a stream data recording device subsequent to the second stream data recording device onward, the output means outputs, as the predetermined stream data containing time information, the transfer stream data that are to be output to a preceding stream data recording device also to a subsequent stream data recording device.

Thus, the transfer stream data to be output to the preceding stream data recording device are used as the predetermined stream data containing time information that precedes the transfer stream data at the start of the outputting when data are output from the stream data recording-controlling device to the stream data recording device, as described above. Therefore, the time stamps generated in the stream data recording devices can be easily synchronized with one another.

The present invention provides, in yet another aspect, a stream data playback-controlling device for controlling output of continuous playback stream data based on recording data to which continuous time stamps are attached and which are respectively recorded into a plurality of stream data playing device, comprising: an analyzing means for analyzing transfer stream data that are generated by each of the stream data playing devices by removing the time stamps from the recording data respectively recorded therein and outputting at timing corresponding to the time stamps, and for extracting playback output data; a time stamp-attaching means for generating a time stamp synchronized with the time information contained in the playback output data and attaching the time stamp to each of the playback output data; and an outputting means for generating playback stream data by removing the time stamp from each of the playback output data and sequentially outputting the generated playback stream data at timing corresponding to the time stamp.

With this configuration, according to a similar mechanism to that described in the foregoing, the same time stamps can be attached as those recorded in the plurality of stream data playing devices, that is, time stamps continuous with one another can be attached. Therefore, stream data playback can be performed while continuity is maintained as in a similar manner to the case where all the recording data are recorded through the single stream data playback-controlling device.

The present invention provides, in still another aspect, a stream data-recording method of recording stream data into a recording medium, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, wherein: continuous time stamps are attached to the stream data and the stream data are divided and recorded into a plurality of stream data recording devices so that the stream data do not overlap.

With this configuration, stream data are divided and recorded into a plurality of stream data recording devices, and consequently, the stream data can be recorded for a longer time than a time corresponding to the storage capacity of a single stream data recording device. In addition, since continuous time stamps are attached to the stream data, playback can be performed at proper timing while maintaining continuity. Moreover, no overlap occurs during recording, and therefore, wasteful recording space is not created.

The present invention provides, in another aspect, a stream data-recording method of recording stream data into a recording medium of a stream data recording device, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, comprising: a first extracting step of analyzing the input stream data and extracting recording data to be recorded in the recording medium; a first time stamp-attaching step of generating a time stamp synchronized with the time information contained in the recording data and attaching the time stamp to the recording data; an outputting step of dividing the recording data to which the time stamp is attached, generating transfer stream data by removing the time stamp from the divided recording data, and transferring the generated transfer stream data to the stream data recording device at timing corresponding to the time stamp; a second extracting step of, in the stream data recording device to which the transferred stream data are input, analyzing the input stream data and extracting recording data to be recorded in the recording medium of the stream data recording device; a second time stamp-attaching step of generating a time stamp synchronized with the time information contained in the recording data and attaching the time stamp to the recording data; and a recording step of recording the recording data to which the time stamp is attached into the recording medium.

With this configuration, according to a similar mechanism to that described for the foregoing first aspect of the invention, time stamps continuous with one another are easily generated in a plurality of stream data recording devices so that they can be attached to the recording data and are recorded. As a consequence, recording that enables stream data to be played while maintaining their continuity can be easily performed over a plurality of stream data recording devices. Consequently, stream data can be recorded for a longer time than a time corresponding to the storage capacity of a single stream data recording device, and moreover, playback can be performed at proper timing with continuity since continuous time stamps are attached to the stream data.

The present invention provides, in yet another aspect, a stream data playing method of playing continuous stream data from recording data to which continuous time stamps are attached and which are recorded into recording media of a plurality of stream data recording devices, comprising: a playing step of reading out the first recording data recorded in a recording medium of the first stream data recording device and outputting the data as the first playback output data; an outputting step of, in the second stream data recording device, reading out the second recording data recorded in the recording medium, and outputting transfer stream data generated by removing the time stamps at timing corresponding the time stamps; an extracting step of analyzing the transfer stream data that are output and extracting second playback output data; a time stamp-attaching step of generating a time stamp being synchronized with the time information contained in the second playback output data and continuous with a time stamp attached to the first playback output data, and attaching the generated time stamp to the second playback output data; and an outputting step of generating playback stream data by removing the time stamps from the first and the second playback output data to which the time stamps are attached, and sequentially outputting the generated playback stream data at timing corresponding to the time stamps.

The present invention provides, in further another aspect, a stream data playing method of playing continuous stream data from recording data to which continuous time stamps are attached and which are recorded into recording media of a plurality of stream data recording devices, comprising: an outputting step of reading out the recording data respectively recorded into the recording media in the plurality of stream data recording devices and outputting transfer stream data generated by removing the time stamps at timing corresponding to the time stamps; an extracting step of analyzing the transfer stream data that are output and extracting playback output data; a time stamp-attaching step of generating time stamps that are synchronized with the time information contained in the playback output data and are continuous between the playback output data corresponding to the plurality of stream data recording devices, and attaching the generated time stamps to the playback output data; and an outputting step of generating playback stream data by removing the time stamps from the playback output data to which the time stamps are attached, and sequentially outputting the generated playback stream data at timing corresponding to the time stamps.

With this configuration, according to a similar mechanism to that described in the foregoing, the same time stamps can be attached as those recorded in the plurality of stream data playing devices, that is, time stamps continuous with one another can be attached. Therefore, stream data playback can be performed while continuity is maintained as in a similar manner to the case where all the recording data are recorded through the single stream data playback-controlling device.

The present invention provides, in still another aspect, a stream data-recording device for recording stream data into a recording medium, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, comprising: an analyzing means for analyzing the input stream data and extracting recording data to be recorded in the recording medium or a recording medium in another stream data recording device; a time stamp-attaching means for generating a time stamp being controlled such that a time difference obtained by two pieces of time information contained in each of the recording data is equal to a difference between time stamps attached to the recording data that contain the two pieces of time information, and attaching the time stamp to the recording data; a recording means for recording a first recording data that is one of divided recording data into the recording medium; an output means for generating transfer stream data by removing the time stamp from a second recording data that is the other one of the divided recording data and is subsequent to the first recording data and outputting the generated transfer stream data to the other stream data recording device at timing corresponding to the time stamp; and a time stamp information-outputting means for outputting time stamp information corresponding to a relationship between the time stamp attached to the first recording data and the time stamp attached to the second recording data to the other stream data recording device.

It is preferable that in the foregoing stream data recording device, the time stamp information represents a difference between a time stamp attached to at least one of the head and the end of the first recording data and a time stamp attached to the head of the second recording data.

The present invention provides, in another aspect, a stream data-recording device for recording stream data into a recording medium, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, comprising: an analyzing means for analyzing the input stream data and extracting recording data to be recorded in the recording medium or a recording medium in another stream data recording device; a time stamp-attaching means for generating a time stamp being controlled such that a time difference obtained by two pieces of time information contained in each of the recording data is equal to a difference between time stamps attached to the recording data that contain the two pieces of time information, and attaching the time stamp to the recording data; an output means for generating transfer stream data by removing the time stamp from a first recording data that is one of divided recording data, and outputting the generated transfer stream data to the other stream data recording device at timing corresponding to the time stamp; a recording means for recording a second recording data that is the other one of the divided recording data and is subsequent to the first recording data into the recording medium; and a time stamp information-holding means for holding time stamp information corresponding to the time stamp attached to the first recording data.

The present invention provides, in another aspect, a stream data playing device for playing back continuous stream data from first and second recording data to which continuous time stamps are attached and which are respectively recorded in a first recording medium in the stream data playing device and in a second recording medium in another stream data playing device, comprising: a playing means for reading out the first recording data from the first recording medium and outputting the first recording data as first playback output data; an analyzing means for analyzing transfer stream data that are generated by the other stream data playing device by reading out the second recording data from the second recording medium and removing the time stamp therefrom, and are output from the other stream data playing device at timing corresponding to the time stamp, and for extracting second playback output data; a time stamp-attaching means for setting as an initial value a time stamp obtained based on the relationship between the time stamps attached to the first and the second recording data when continuous time stamps are attached to the first and the second recording data and based on the time stamp attached to the first recording data, and attaching to the second playback output data a time stamp that is continuous with the time stamp attached to the first recording data; and an outputting means for generating playback stream data by removing the time stamps from the first and the second playback output data, and sequentially outputting the generated playback stream data at timing corresponding to the time stamps.

The present invention provides, in another aspect, a stream data playing device for playing back continuous stream data from first and second recording data to which continuous time stamps are attached and which are respectively recorded in a first recording medium in the stream data playing device and in a second recording medium in another stream data playing device, comprising: a playing means for reading out the first recording data from the first recording medium and outputting the first recording data as first playback output data; an analyzing means for analyzing transfer stream data that are generated by the other stream data playing device by reading out the second recording data from the second recording medium and removing the time stamp therefrom, and are output from the other stream data playing device at timing corresponding to the time stamp, and for extracting second playback output data; a time stamp-attaching means for generating a time stamp corresponding to timing of receiving the second playback output data, or a time stamp being controlled such that a time difference obtained by two pieces of time information contained in each of the second playback output data is equal to a difference between time stamps attached to second playback output data that contain the two pieces of time information, and attaching the time stamp to the second playback output data; and an outputting means for generating playback stream data by removing the time stamps from the first and the second playback output data, sequentially outputting the generated playback stream data at timing corresponding to the time stamps, and controlling the timing from the time when an end of one of the first or the second playback stream data is output until a head of the other one is output to be such a timing corresponding to the difference between a time stamp attached to the end of one of the first or the second playback stream data and a time stamp attached to the head of the other one when continuous time stamps are attached to the first and the second recording data.

The present invention provides, in another aspect, the outputting means outputs the playback stream data generated from the first playback output data after the playback stream data generated from the second playback output data have been output.

The present invention provides, in another aspect, a stream data recording-controlling device for controlling recording of stream data into a recording medium of a stream data recording device, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, comprising: an analyzing means for analyzing the input stream data and extracting recording data to be recorded in the recording medium; a time stamp-attaching means for generating a time stamp being controlled such that a time difference obtained by two pieces of time information contained in each of the recording data is equal to a difference between time stamps attached to the recording data that contain the two pieces of time information, and attaching the time stamp to the recording data; an output means for generating transfer stream data by removing the time stamp from the recording data, and outputting the generated transfer stream data to the stream data recording device at timing corresponding to the time stamp; and a time stamp information-outputting means for outputting, to the stream data recording device, time stamp information corresponding to the relationship between a time stamp attached to the recording data for the transfer stream data and a time stamp attached to the recording data for transfer stream data that is continuous with the transfer stream data, or time stamp information corresponding to the time stamp attached to the recording data for the transfer stream data.

The present invention provides, in another aspect, a stream data playing method of playing continuous stream data from recording data to which continuous time stamps are attached and which are recorded into recording media of a plurality of stream data recording devices, comprising: a first extracting step of analyzing the input stream data and extracting recording data to be recorded in the recording medium; a first time stamp-attaching step of generating a time stamp being controlled such that a time difference obtained by two pieces of time information contained in each of the recording data is equal to a difference between time stamps attached to the recording data that contain the two pieces of time information, and attaching the time stamp to the recording data; an outputting step of dividing the recording data to which the time stamp is attached, generating transfer stream data by removing the time stamp from the divided recording data, and transferring the generated transfer stream data to the stream data recording device at timing corresponding to the time stamp; a time stamp information-acknowledging step of acknowledging, to the stream data recording devices, time stamp information corresponding to the relationship between time stamps attached to respective divided recording data, or corresponding to time stamps attached to respective recording data; a second extracting step of, in the stream data recording device to which the transferred stream data are input, analyzing the input stream data and extracting recording data to be recorded in the recording medium of the stream data recording device; a second time stamp-attaching step of generating a time stamp being controlled such that a time difference obtained by two pieces of time information contained in each of the recording data is equal to a difference between time stamps attached to the recording data that contain the two pieces of time information, and attaching the time stamp to the recording data; and a recording step of recording the recording data to which the time stamp is attached into the recording medium.

The present invention provides, in another aspect, a stream data playing method of playing continuous stream data from recording data to which continuous time stamps are attached and which are recorded into recording media of a plurality of stream data recording devices, comprising: a playing step of reading out the first recording data recorded in a recording medium of the first stream data recording device and outputting the data as the first playback output data; an outputting step of, in the second stream data recording device, reading out the second recording data recorded in the recording medium, and outputting transfer stream data generated by removing the time stamps at timing corresponding the time stamps; an extracting step of analyzing the transfer stream data that are output and extracting second playback output data; a time stamp-attaching step of setting as an initial value a time stamp obtained based on the relationship between the time stamps attached to the first and the second recording data when continuous time stamps are attached to the first and the second recording data and based on the time stamp attached to the first recording data, and attaching to the second playback output data a time stamp that is continuous with the time stamp attached to the first recording data; and an outputting step of generating playback stream data by removing the time stamps from the first and the second playback output data and sequentially outputting the generated playback stream data at timing corresponding to the time stamps.

The present invention provides, in another aspect, a stream data playing method of playing continuous stream data from recording data to which continuous time stamps are attached and which are recorded into recording media of a plurality of stream data recording devices, comprising: a playing step of reading out the first recording data recorded in a recording medium of the first stream data recording device and outputting the data as the first playback output data; an outputting step of, in the second stream data recording device, reading out the second recording data recorded in the recording medium, and outputting transfer stream data generated by removing the time stamps at timing corresponding the time stamps; an extracting step of analyzing the transfer stream data that are output and extracting second playback output data; a time stamp-attaching step of generating a time stamp corresponding to timing of receiving the second playback output data, or a time stamp being controlled such that a time difference obtained by two pieces of time information contained in each of the second playback output data is equal to a difference between time stamps attached to second playback output data that contain the two pieces of time information, and attaching the time stamp to the second playback output data; and an outputting step of generating playback stream data by removing the time stamps from the first and the second playback output data, sequentially outputting the generated playback stream data at timing corresponding to the time stamps, and controlling the timing from the time when an end of one of the first or the second playback stream data is output until a head of the other one is output to be such a timing corresponding to the difference between a time stamp attached to the end of one of the first or the second playback stream data and a time stamp attached to the head of the other one when continuous time stamps are attached to the first and the second recording data.

As described in these configurations, even when the time stamps attached during recording are not continuous, continuous time stamps can be attached to the transferred stream data or the output timing of the transferred stream data can be controlled, based on the already-attached time stamps during playback. Therefore, stream data can be played at proper timing while maintaining their continuity.

The present invention provides, in another aspect, a stream data-recording device for recording stream data into a recording medium, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, comprising: an analyzing means for analyzing the input stream data and extracting recording data to be recorded in the recording medium or a recording medium in another stream data recording device; a time stamp-attaching means for generating a time stamp being controlled such that a time difference obtained by two pieces of time information contained in each of the recording data is equal to a difference between time stamps attached to the recording data that contain the two pieces of time information, and attaching the time stamp to the recording data; a recording means for recording a first recording data that is one of divided recording data into the recording medium; an output means for generating transfer stream data by removing the time stamp from a second recording data that is one of divided recording data and outputting the generated transfer stream data at timing corresponding to the time stamp to the other stream data recording device; and a time stamp information-outputting means for outputting time stamp information corresponding to the time stamp attached to the head of the second recording data to the other stream data recording device.

The present invention provides, in another aspect, a stream data-recording device for recording stream data into a recording medium, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, comprising: an analyzing means for analyzing the stream data and extracting recording data to be recorded in the recording medium; a time stamp-attaching means for generating a time stamp being controlled such that a time difference obtained by two pieces of time information contained in each of the recording data is equal to a difference between time stamps attached to the recording data that contain the two pieces of time information, and attaching the time stamp to the recording data; a time stamp initial value-setting means for setting an initial value of the time stamp to be attached to the recording data by the time stamp-attaching means based on time stamp information corresponding to a predetermined time stamp; and a recording means for recording the recording data in the recording medium.

The present invention provides, in another aspect, a stream data recording-controlling device for controlling recording of stream data into a recording medium of a stream data recording device, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, comprising: an analyzing means for analyzing the input stream data and extracting recording data to be recorded in the recording medium; a time stamp-attaching means for generating a time stamp being controlled such that a time difference obtained by two pieces of time information contained in each of the recording data is equal to a difference between time stamps attached to the recording data that contain the two pieces of time information, and attaching the time stamp to the recording data; an output means for generating transfer stream data by removing the time stamp from the recording data, and outputting the generated transfer stream data to the stream data recording device at timing corresponding to the time stamp; and a time stamp information-outputting means for outputting, to the stream data recording device, time stamp information corresponding to a time stamp attached to the head of the recording data for the transfer stream data.

The present invention also provides, in further another aspect, a stream data-recording method of recording stream data into a recording medium of a stream data recording device, the stream data containing time information corresponding to reproduction timing and being input at timing corresponding to stream of reproduction time, comprising: a first extracting step of analyzing the input stream data and extracting recording data to be recorded in the recording medium; a first time stamp-attaching step of generating a time stamp being controlled such that a time difference obtained by two pieces of time information contained in each of the recording data is equal to a difference between time stamps attached to the recording data that contain the two pieces of time information, and attaching the time stamp to the recording data; an outputting step of dividing the recording data to which the time stamp is attached, generating transfer stream data by removing the time stamp from the divided recording data, and transferring the generated transfer stream data to the stream data recording device at timing corresponding to the time stamp; a time stamp information-acknowledging step for acknowledging, to the stream data recording device, time stamp information corresponding to a time stamp attached to the head of each of the divided recording data; a second extracting step of, in the stream data recording device to which the transferred stream data are input, analyzing the input stream data and extracting recording data to be recorded in the recording medium of the stream data recording device; a second time stamp-attaching step of generating a time stamp being controlled such that a time difference obtained by two pieces of time information contained in each of the recording data is equal to a difference between time stamps attached to the recording data that contain the two pieces of time information, and attaching the time stamp to the recording data; a time stamp initial value-setting step of setting an initial value of the time stamp to be attached to the recording data by the time stamp-attaching means based on the time stamp information; and a recording step of recording the recording data to which the time stamp is attached into the recording medium.

Thus, when stream data are transferred during recording, a time stamp attached prior to the transfer is acknowledged and set as an initial value when attaching a time stamp to the transferred stream data. Consequently, stream data to which continuous time stamps are attached can be recorded.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment according to the present invention is described below taking as an example a hard disk drive (hereafter abbreviated as “HDD”) that is a stream data recording and playing device, and a receiver recording and playing device that incorporates the stream data recording and playing device.

FIG. 1is a block diagram showing a primary portion of the configuration of a receiver recording and playing device101. The receiver recording and playing device101comprises a receiving section102to which a sound and image presenting device or the like is connected, and, for example, two HDDs103and104. The receiving section102and the HDDs103and104are connected to each other via the IEEE 1394 standard bus110to form a network, so that AV data (audio video data) are transferred in the form of stream data by isochronous communication and commands and the like are transmitted and received using asynchronous communication.

The receiving section102receives stream data of broadcast programs that are sent from broadcast stations or the like through broadcast radio waves, networks, or the like, and it outputs the data to the bus110through the IEEE 1394 standard interface. The format used for the stream data sent out from a broadcast station and the stream data transferred through the bus110is the MPEG-2TS format (MPEG-2 transport stream format). According to the MPEG-2TS format, as shown inFIG. 2, video data and audio data are transmitted in the units of 188-byte packets such as a video packet201and an audio packet202, for example, as time elapses. A plurality of broadcast programs can be multiplexed in these packets, and each of the broadcast programs or the like is discerned with the use of PIDs (packet identifier) or the like contained in the packets. The packets to be transmitted contain such packets as a PCR packet203(Program Clock Reference Packet), which contains time information (hour information) for synchronizing the system time clock with a system time clock of the sending side, and a data packet204.

The HDDs103and104have IEEE 1394 interfaces and are for recording and playing the stream data. They have the same configuration except that the later-described controlling sections308and309are different. Specifically, as shown inFIG. 3, each of the HDDs comprises, for example, a stream data input section301(analyzing means), a time stamp-generating section302(part of time stamp-attaching means), a time stamp-attaching section303(part of time stamp-attaching means), a buffer304, a HDD main unit305(recording means, playing means, and recording medium), a stream data-generating section306(output means, outputting means), a stream data-outputting section307(output means, outputting means), and a controlling section308or309.

The stream data input section301analyzes the packets of the stream data (AV bitstream) that are transferred in the form of the MPEG-2TS format through the bus110so that it extracts and outputs the packets to be recorded in the HDD103(for example, video packets, audio packets, PCR packets, and the like of a predetermined broadcast program).

The time stamp-generating section302constitutes a PLL (Phase Locked Loop) circuit, and generates, for example, a 6 byte time stamp indicating the reproduction timing of each packet to be recorded in the HDD main unit305, which is synchronized with the time information contained in the PCR packets that are output from the stream data input section301. More specifically, the time stamp-generating section302comprises a PCR time information-extracting section302a, a counter302b, a difference-computing section302c, a filter302d, and a VCO (Voltage Controlled Oscillator)302e. The PCR time information-extracting section302ais for extracting time information contained in the PCR packet. The counter302bis for counting reference clock inside the device with respect to an initial value that is the time information extracted initially (or at a predetermined timing) to output a time stamp. The difference-computing section302cis for computing the difference between the values output from the PCR time information-extracting section302aand the counter302b. The filter302dis for outputting a signal with a voltage corresponding to the difference that is output from the difference-computing section302c. The VCO302eis for generating the reference clock having a frequency corresponding to the signal output from the filter302d.

The time stamp-attaching section303attaches a time stamp that is generated by the time stamp-generating section302to each packet that is output from the stream data input section301.

The buffer304is for holding the packets that are output from, and to which a time stamp is attached by, the time stamp-attaching section303until they are written into the HDD main unit305, and for holding the packets that are read out from the HDD main unit305until they are output to the stream data-generating section306. In addition, the buffer304is so configured that it can output the packets that are output from the time stamp-attaching section303to the stream data-generating section306with or without writing the packets into the HDD main unit305.

The HDD main unit305is for magnetically holding recording data into a recording medium and for outputting them. In this HDD main unit305, the following information is also recorded, for example, as a HDD information section and a program information section, as needed.

HDD Information Section

(1) ID representing the HDD

(2) Free disk space

Program Information Section

For each entry corresponding to a program recorded:

(1) ID representing the program

(2) recorded location information of the program

(3) flag indicating that the recorded data is divided

(4) information indicating that the order of the data in the divided data

(5) ID of the HDD to which the divided data are stored

(6) difference value between the time stamp of the most leading packet and the time stamp to be attached to the most leading packet of the divided data

The stream data-generating section306is for outputting the packet held in the buffer304at the timing corresponding to the time stamp attached to the packet. More specifically, the stream data-generating section306comprises a time stamp-extracting section306a, a FIFO management section306c, a FIFO management section306c, a first time stamp memory306d, a second time stamp memory306e, a time stamp difference-computing section306f, a counter306g, a counter memory306h, a counter difference-computing section306i, and a difference-comparing section306j. The time stamp-extracting section306aextracts a time stamp from the packet output from the buffer304and outputs the packet from which the time stamp is removed. The FIFO306btemporarily holds the packet from which the time stamp is removed. The FIFO management section306ccontrols output timing of the packet from the buffer304to the time stamp-extracting section306aso that the FIFO306bdoes not overflow or underflow. The first time stamp memory306dand the second time stamp memory306esequentially hold the time stamp extracted by the time stamp-extracting section306a. The time stamp difference-computing section306fcomputes the difference between the time stamps held in the time stamp memory306dand306e. The counter306gcounts the reference clock that is output from the VCO302e. The counter memory306hholds the value of the counter306gat the time when the packet is output from the FIFO306b. The counter difference-computing section306icomputes the difference between the values held in the counter306gand the counter memory306h.

The difference-comparing section306jcompares the differences computed by the time stamp difference-computing section306fand the counter difference-computing section306i, and when they match, it instructs the FIFO306bto output the packet therefrom, the counter memory306hto bold the value that is output from the counter306g, and the time stamp memories306dand306eto update the time stamps that are output therefrom.

The stream data-outputting section307outputs the packets that are output from the FIFO306bof the stream data-generating section306to the bus110in the form of stream data in the MPEG-2 TS format through the IEEE 1394 standard interface.

The controlling sections308and309performs such operations as management of storage configuration (management of indexes, storage locations of entity data, or the like), management of available free storage space, and command processing with the receiving section102or the like; and at the same time, the controlling sections308and309controls split recording and playing across the HDDs103and104with data flow controls performed by the controlling sections shown inFIGS. 4 and 5, respectively.

The record controlling section308aand the record controlling section309ahave the same configuration, and so do the playback controlling section308cand the playback controlling section309d. The recording relay-controlling section308band the playback relay-controlling section309cperform relay control of stream data to the other HDD during recording and playing, respectively, and the relay operations itself are similar. It should be noted that the control operations as described above can be achieved by various means including, but not limited to a software, for example.

In the following, first, a normal recording and playback operation of the receiver recording and playing device101for only the HDD103is described.

Normal Recording Operation to HDD103

When the user carries out, for example, an instruction operation to record a desired broadcast program to the HDD103, the receiving section102outputs received stream data to the HDD103via the bus110. In the HDD103, the stream data input section301analyzes the packets of the stream data sent from the receiving section102and outputs only the packets that should be recorded according to the user instruction.

The time stamp-generating section302, first, starts to generate a time stamp according to time information indicated by the PCR packet that is output from the stream data input section301, which is a recording preparation operation (time stamp synchronization operation). At the time of the recording preparation operation, a time stamp is attached to the packet output from the stream data input section301and is stored in the buffer304, but recording into the HDD main unit305is not performed. Specifically, for example, false reading is performed by advancing a read pointer at the same time as the packets are written into the buffer304or at a predetermined timing. (It is possible that the time stamps are not attached, and it is also possible that the packets are not stored into the buffer304. It is also possible that overwriting is performed for the same region while the write pointer is being fixed so that writing is not performed consequently.)

Later, when an accurate time stamp synchronized with the time information of the PCR packet starts to be generated, recording to the HDD main unit305is started. Specifically, the time stamp-attaching section303attaches time stamps to the packets. output from the stream data input section301that change over time according to the output timing thereof (that is, timing at which the receiving section102receives broadcast), and lets the buffer304temporarily hold the packets. The packets to which time stamps are attached can control output timing during playback according to the time stamps, as will be described in the following section that explains the playback operation. Therefore, the packets held in the buffer304can be recorded into the HDD main unit305in asynchronous with the timing at which the packets of stream data are output from the stream data input section301.

Normal Playing Operation from HDD103

When the user carries out, for example, an instruction operation for playing the recorded contents or the like, the packets recorded in the HDD main unit305are read out, then temporarily held in the buffer304, and input to the time stamp-extracting section306a, by the control of the FIFO management section306c, at the timing such that the FIFO306bdoes not overflow or underflow. The time stamp-extracting section306aremoves the time stamps attached to the packets that are input and outputs the packets to FIFO306b, and it also extracts the time stamps and outputs the time stamps to the first time stamp memory306d. The first time stamp memory306dsequentially holds the time stamps that are output from the time stamp-extracting section306a, and it outputs the time stamp that has been attached to the packet that is to be output next. The second time stamp memory306etemporarily holds the time stamps that are output from the first time stamp memory306d, and it outputs the time stamp that has been attached to the packet that has been output from the FIFO306bmost recently. The time stamp difference-computing section306fcomputes the difference of two time stamps that are output from the time stamp memories306dand306e, which is the time difference from the time when the most recent packet is output until the next packet is output.

Meanwhile, the counter306gcounts the reference clock output from the VCO302e, and the counter memory306hholds the value of the counter306gat the time when the most recent packet is output from the FIFO306b. The counter difference-computing section306icomputes the difference between the value that is output from the counter306gand the value held in the counter memory306h, that is, the time elapsed from the time when the most recent packet has been output.

The difference-comparing section306jcompares the difference that is output from the time stamp difference-computing section306fand the difference that is output from the counter difference-computing section306i, and instructs the FIFO306bto output the next packet at the timing at which the differences match, that is, at the time when the time that is equal to the difference in the time stamps has elapsed from the time when the most recent packet is output. The difference-comparing section306jalso instructs the counter memory306hand the time stamp memories306dand306eto update the values that are held therein. The way of controlling the timing of outputting packets is not limited to the above-described manner in which the difference in the time stamps are used for the control. For example, it is also possible that the time stamp that is attached to the packet that is sent out first is assigned as the initial value of the counter306gand, subsequently, each time when the time stamp attached to a subsequent packet matches the value in the counter306g, the packet is output.

The stream data-outputting section307outputs the packets that are output from the FIFO306bto the bus110in the form of stream data in the MPEG-2 TS format through the IEEE 1394 standard interface. As described above, since the output timing is controlled according to time stamps, each packet of the stream data is output at the same timing as it is input into the stream data input section301. Therefore, images and sound are properly presented by the presenting device, which is not shown the drawings, through the receiving section102.

Separate Recording Operation to HDDs103and104

The following describes an operation in which stream data received by the receiving section102are divided and recorded into the HDD103and subsequently into the HDD104.

First, a summary is given. All the packets of the stream data that are output from the receiving section102are temporarily input into the HDD103, and then only the packets to be recorded are extracted and time stamps are attached thereto. Of the packets to which the time stamps are attached, some of the packets are recorded into the HDD main unit305of the HDD103. Regarding the remaining packets, the time stamps are removed therefrom, and they are output again as stream data at the timing according the time stamps, which are then sent to the HDD104and recorded into the HDD main unit305of the HDD104. Also, some of the last packets to be recorded into the HDD main unit305of the HDD103are sent to the HDD104as the packets for a recording preparation operation, and in the HDD104, and prior to the start of recording, a recording preparation operation is performed according to the packets for the recording preparation operation. This recording preparation operation ensures continuity of time stamps that are attached to the packets to be recorded into the HDDs103and104.

In other words, because all the packets are temporarily input into the HDD103and then only the packets to be recorded are extracted, it is possible to distinguish between the packets that can be recorded into a free space in the HDD103or a free space in a region that is reserved for recording in advance and the packets to be recorded into the HDD104. Thus, it is possible to divide and record the data without causing data overlapping or data loss. Moreover, because the packets to be recorded into the HDD104are sent from the HDD103to the HDD104in the form of stream data based on the time stamps, it is possible for the HDD104to attach time stamps data and record the data so that they can be played at proper timing, as in the case where the data are directly sent from the receiving section102. Furthermore, because the recording preparation operation ensures continuity of the time stamps, it is easy to carry out proper playback in which time continuity is maintained even at joints of the packets output from the HDDs103and104during playback.

In the following, specific operations of various portions are described. First, recording to the HDD main unit305of the HDD103is performed in a similar manner to the normal recording described above. Specifically, for example as shown inFIG. 6A, when a recording start command is issued from the receiving section102to the HDD103, time stamps are sequentially attached to the packets that are sent from the receiving section102thereafter and output from the stream data input section301. Then the packets are temporarily held in the buffer304and thereafter recorded into the HDD main unit305.

However, as shown inFIG. 7A, if the free space in the HDD main unit305becomes a predetermined amount, for example, the minimum recording unit amount or a predetermined amount of packets, data transfer for the recording preparation operation to the HDD104is started, as well as the recording into the HDD main unit305of HDD103. Specifically, first, as shown inFIG. 6B, a recording preparation operation start command is issued from the HDD103to the HDD104using asynchronous communication or the like. (It should be noted that it is possible that the receiving section102or the HDD103issue the recording preparation operation start command at the start of the recording into the HDD103or the like so that the HDD104becomes a stand-by state, if it is known in advance that data are to be divided and recorded into the HDDs103and104.) Thereafter, as shown inFIG. 7B, the predetermined amount of packets to be recorded last into the free space is output from the buffer304and recorded into the HDD main unit305, and at the same time, the packets are also output to the stream data-generating section306as the packet for the recording preparation operation of the HDD104. More specifically, the buffer304outputs the packets held therein to the HDD main unit305according to the read pointer for outputting for recording into the HDD main unit305, and at the same time, it also outputs the packets to the stream data-generating section306according to another read pointer to the pointer for recording at the timing controlled by the FIFO management section306cof the stream data-generating section306. Time stamps are removed from the packets that are input into the stream data-generating section306in a similar manner to the case of the foregoing normal playback operation, and according to the timing based on the time stamps, the packets are transferred in the form of stream data to the HDD104through the stream data-outputting section307. It should be noted that control of the timing at which the transfer is started is relatively easy if the transfer to the HDD104is started at the time when the free space of the HDD main unit305reaches a predetermined amount, as described above. However, it is not so limited, and it is sufficient as long as the transfer is started at the timing by which the buffer304does not cause an overflow or underflow.

In the HDD104, first, a recording preparation operation similar to the case of the above-described normal recording is performed for the predetermined amount of the packets for the recording preparation operation that are transferred from the HDD103and are output from the stream data input section301. Specifically, the time stamp-generating section302starts to generate time stamps based on the time information indicated by the PCR packet contained in the stream data from the HDD103, and the system time clock is synchronized with the HDD103so that the same time stamps are generated as those attached to the packets in the HDD103. At the time of this recording preparation operation, time stamps are attached to the packets that are output from the stream data input section301and the packets are stored in the buffer304(seeFIG. 7B), but the packets are not recorded in the HDD main unit305. (In this case as well, it is not essential to attach time stamps or store the packets into the buffer304, as described in the foregoing section where the recording operation is explained.) The difference from the recording preparation operation in the normal recording operation is that its recording preparation operation is performed corresponding accurately to the predetermined amount of packets for the recording preparation operation that are sent from the HDD103, and thereafter, the operation is performed such that the packets sent from the HDD103are actually recorded into the HDD main unit305. As a consequence, recording of continuous data free from data overlap and data loss is possible in the HDDs103and104. It should be noted that the “predetermined amount” of packets for the recording preparation operation is not particularly limited as long as it is a sufficient amount for the time stamp-generating section302to synchronize the system time clock (for example, an amount such that a PCR packet is always contained). However, it is necessary that the number of packets that are recorded in the HDD103and are output to the HDD104matches the number of packets that are used by the HDD104for the recording preparation operation but are not recorded therein. In order to achieve this, a certain predetermined amount may be determined in advance, or a predetermined amount may be acknowledged between HDDs103and104when starting up the device or at the time of starting the recording or the recording preparation operation. Or a predetermined amount may be set according to instruction from other devices such as the receiving section102or the like.

The HDD103continues only the transfer (relay) of packets as shown inFIG. 7Cafter recording of the predetermined amount of packets has been completed. The HDD104attaches time stamps to the packets transferred subsequent to the packets for recording preparation operation and temporarily stores them in the buffer304, as in the case of the normal recording operation. After a certain amount of packets are stored therein, the HDD104records the packets into the HDD main unit305one after another, as shown inFIG. 7D.

It should be noted that management of recorded contents that are split-recorded in the above-described manner can be easily performed by, although not limited thereto, providing managing information indicating relevance and sequence of recorded contents recorded into the HDDs103and104, for example. In addition, such management may be carried out by any of the receiving section102, HDDs103and/or104, and other controlling devices.

Linked Playing Operation from HDDs103and104

This section describes an operation in which the stream data split-recorded into the HDDs103and104are played back.

First, a summary is given. In this playback operation, the packets recorded in the HDD103go through the HDD104and are then output to the receiving section102(and subsequently to a presenting device or the like, which is not shown in the drawings). More specifically, first, the packets read out from the HDD main unit305of the HDD103are subjected to the removal of time stamps and the timing control according to the time stamps, and are temporarily transferred to the HDD104as stream data. To the transferred packets, time stamps are once again attached in the HDD104in a similar manner to that in the recording, then the packets are temporarily held in the buffer304and further subjected to removal of time stamps and timing control according to the timing stamps. Then, the packets are output and sent to the presenting device or the like through the receiving section102. Meanwhile, the packets recorded in the HDD main unit305of the HDD104are read out from the HDD main unit305subsequently to the packets that are transferred from the HDD103and held in the buffer304, are held in the buffer304, and are output under a similar timing control.

Thus, the packets recorded in the HDD103are transferred to the HDD104as stream data under the timing control according to the time stamps, and thereby, time stamps that are continuous with those of the packets recorded in the HDD104can be once again attached to the transferred packets. In other words, all the packets can be handled as if they are recorded in the HDD104, and therefore, they can be easily output as continuous stream data.

Now, specific operations of various portions are described below. For example, as shown inFIG. 8A, when a playback start command is issued from the receiving section102to the HDD103, first, the stream data recorded in the HDD103are played back, as in the case of the above-described normal playing operation. Specifically, as shown inFIG. 9A, the packets recorded in the HDD main unit305are read out and temporarily held in the buffer304.

As shown inFIG. 9B, the packets held in the buffer304are input into the stream data-generating section306, time stamps are removed therefrom, and the packets are output from the stream data-outputting section307at the timing based on the time stamps, in the form of stream data. It should be noted that the differences from the normal playback operation are that the output destination is the HDD104, not the receiving section102(AV data presenting device), that a relay start command is issued from the HDD103to the HDD104prior to the output, as also shown inFIG. 8A, and that at least one PCR packet is generated in the HDD103for synchronizing the system time clock between the HDDs103and104, for example, in the output. (It should be noted, however, that, if the HDD103has a configuration such that a PCR packet or the like, which is a packet containing time information, becomes the most leading packet during recording, the recorded packets may be output as they are.)

In the HDD104, first, time stamps start to be generated according to the PCR packet or the like as in a similar manner to that during recording, and then, the time stamps are sequentially attached to the packets that are transferred from the HDD103and are output from the stream data input section301, after which the packets are temporarily held in the buffer304. Here, the time stamps attached to the packets are the same time stamps as those attached when recorded in the HDD main unit305of the HDD103, as the packets are transferred from the HDD103in the form of stream data. The packets held in the buffer304are then output to the stream data-generating section306, and the time stamps are again removed therefrom. Then, they are output as stream data and sent to the presenting device or the like through the receiving section102.

Thereafter, as shown inFIG. 9C, the HDD103reads out packets from the HDD main unit305up to the last packet recorded in the HDD main unit305, and transfers them to the HDD104, which relays the transferred packets.

After that, when the transfer from the HDD103is completed, first, as shown inFIG. 8B, a playback completion notification (relay end/self-playback start command) is sent from the HDD103to the HDD104, for example, using asynchronous communication. The reason why the notification can be made using asynchronous communication is that the amount of data transferred from the HDD103to the HDD104is a multiple of the minimum recording unit of the HDD103, and therefore, if the notification can be made at timing within the range in which data of the minimum recording unit are transferred, the HDD104can detect the end of the transferred data. It should be noted that such a playback completion notification is described for illustrative purposes only. For example, it is possible that the HDD104is notified of the amount of data to be transferred from the HDD103in advance and the HDD104counts the amount of data that have actually been transferred. When the transfer from the HDD103is completed, the packets recorded in the HDD main unit305start to be read out in the HDD104, as shown inFIG. 9D, and the read packets are held in the buffer304.

Here, the time stamps of the packets that are transferred from the HDD103and held in the buffer304are, as described above, the same time stamps as those when recorded in the HDD main unit305of the HDD103, and therefore, the time stamp of the packet that is read out first from the HDD main unit305of the HDD104and held in the buffer304is continuous with the time stamp of the packet that is transferred last from the HDD103and held in the buffer304. As a consequence, the first packet recorded in the HDD104is output from the HDD104subsequently to the last packet recorded in the HDD103at proper timing, and thus, it is possible to present continuous stream data with a presenting device or the like.

Command Control

In the foregoing example, the commands issued from the receiving section102during the split recording and combined playing are the recording start command for the split recording or the playback start command for combined playing for the HDD103for convenience. However, it is possible that the receiving section102may issue the same recording start command or the playback start command as those for the normal recording or the normal playing and the HDD103side may voluntarily issue a recording preparation operation start command to the HDD104to start data transfer if available free space has been used up by the time the recording is instructed to stop, or the HDD103may voluntarily issue a relay start command or the like to the HDD104if the stream data that are instructed to play have been subject to the split recording. Insofar as the HDDs103and104having the above-described configuration are employed, the receiving section102may have the same configuration regardless of whether or not the split recording and the combined playing is performed.

The above-described example is not the only case where the receiving section102can perform a different operation from that during the normal recording and playing, (or the case where a controlling section or the like that performs command control is provided separately from the receiving section102). For example, the following is possible. For recording, as shown inFIG. 10, when the free space in the HDD103reaches a predetermined amount, a final recording start notification is issued from the HDD103to receiving section102and in response to this, the receiving section102issues a relay start command to the HDD103and a recording preparation operation start command to the HDD104. For playing, as shown inFIG. 11A, the receiving section102issues a playback start command to the HDD103and a relay start command to the HDD104at the start of playback, whereas, as shown inFIG. 11B, the HDD103issues a playback completion notification to the receiving section102when the HDD103completes playing, and in response to this, the receiving section102issues a playback start command to the HDD104.

The above-described example describes commands and notifications that control the operations of the HDDs103and104as a whole, but it is also possible to use combinations of commands that instruct operations of various portions thereof such as the buffer304. An example is as follows. When recording in the HDD104is started in the split recording, the HDD103performs a relay operation according to a storing command from the time stamp-attaching section303to the buffer304and a reading command from the buffer304to the stream data-generating section306while the HDD104performs a recording operation according to a storing command from the time stamp-attaching section303to the buffer304and a recording command from the buffer304to the HDD main unit305. When the control can be performed using such commands for buffer operation or the like, it is also possible to easily increase versatility and operation flexibility of the HDD103or the like.

A stream data recording and playing device according to Embodiment 2 is described with reference toFIG. 12. In this recording and playing device, time stamps attached to the packets that are recorded in the HDDs103and104are not continuous between the HDDs103and104unlike the foregoing example, but continuous stream data can be output because continuous time stamps are attached in the HDD that relays the packets during playback. It should be noted that in the following embodiments and variations, the parts and elements that have similar functions to those described in the foregoing Embodiment 1 and elsewhere are denoted by same reference characters, and are not further elaborated upon.

This stream data recording and playing device mainly differs from the configuration of the foregoing Embodiment 1 (FIG. 3) in that it comprises a PCR memory401, a PCR difference-computing section402, a counter memory403, a counter difference-computing section404, and a difference-comparing section405in place of the difference-computing section302c, and comprises a controlling section408in place of the controlling section308.

The PCR memory401holds time information contained in a PCR packet that is extracted by the PCR time information-extracting section302amost recently in order to compute the difference from time information contained in a PCR packet that is extracted next.

The PCR difference-computing section402computes the difference between the time information output from the PCR time information-extracting section302aand the time information output from the PCR memory401.

The counter memory403holds the value of the counter302bat the time when a PCR packet is extracted most recently in order to compute the difference from the value of the counter302bat the time when a PCR packet is extracted next.

The counter difference-computing section404computes the difference between the value that is output from the counter302bat the time when the next PCR packet is extracted and the value held in the counter memory403.

The difference-comparing section405outputs the difference between the difference output from the PCR difference-computing section402and the difference output from the counter difference-computing section404.

The controlling section408performs a control operation during recording and playing that is different from the operation performed by the foregoing controlling section308and so forth, which will be detailed later.

The counter302bis configured to output the holding value as a storing time stamp and hold a predetermined value as an initial time stamp value under the control of the controlling section408.

The stream data recording and playing device thus configured, the flow of packets during recording and playback is the same as that illustrated in the foregoingFIGS. 7 and 9, but handling of time stamps attached to the packets is different.

Specifically, when recording is performed, time information contained in the PCR packet and the value of the counter302bare not compared unlike the foregoing Embodiment 1. Instead, the difference between two pieces of time information contained in the successive PCR packets and the difference in the values of the counter302bat the time when these PCR packets are input into the time stamp-attaching section303are compared, and a PLL operation is performed so that those differences match. Accordingly, the initial value of the time stamp may be any values, and each time stamp value attached to each packet becomes independent from the time information indicated by the PCR packet as described above.

Specifically, for example as shown inFIG. 13A, in the HDD103, time stamps whose values are11S to11E are attached to the packets to be recorded in the HDD103, whereas time stamps whose values are12S to12E are attached to the packets to be recorded in the HDD104. These time stamps are continuous but independent of the time information of the PCR packet.

Also, when the time stamps are attached in the HDD103as described above, time stamp values11S and12S of the most leading packets that are respectively to be recorded in the HDDs103and104are read out from the counter302bby the controlling section408, and the difference therebetween (12S-11S) is held in the HDD main unit305together with, for example, a device ID, which indicates, for example, that the destination to be stored is the HDD104. The HDD104is notified of the held value during playing, as will be described later. (It is also possible that the notification may be made during recording and the value held in the HDD104, or that it may be temporarily held in a server device or the like and then the HDD104may be notified. The value to be notified of is not limited to the above-described example, but it is sufficient that it is substantially such information that the relationship of time stamps of the packets recorded in the HDDs103and104can be obtained.)

Meanwhile, time stamps are removed from the packets to which time stamp values12S to12E are temporarily attached in the HDD103, as in the foregoing Embodiment 1, and the packets are transferred to the HDD104at the timing corresponding to the time stamps. In the HDD104, for example, time stamp values22S to22E are attached to the packets as in a similar manner in the HDD103, as also shown inFIG. 13A, and the packets are recorded into the HDD main unit305. The time stamp values are also independent of the time information indicated by the PCR packet and of the time stamps attached in the HDD103.

Accordingly, there is no continuity between the time stamp values11S to11E and the time stamp values22S to22E that are respectively recorded into the HDDs103and104.

When playing back the stream data that are thus recorded, first, the HDD104is notified of the value (12S-11S) that is held in the HDD103as additional information to the relay command or the like. In the HDD104, a value22S-(12S-11S) based on the acknowledged value and the time stamp value22S of the most leading packet recorded in the HDD104is set in the counter302bas the initial time stamp value (at the timing at which it is attached to the most leading packet to be relayed). (When a value is set in the counter302bas described above, the difference from the value held in the counter difference-computing section404becomes indeterminate, and for this reason, it is preferable that the PLL operation (feedback operation) be temporarily stopped by, for example, fixing the output from the difference-comparing section405.) Then, as shown inFIG. 13B, when the packets recorded in the HDD103are relayed by the HDD104, time stamps are attached in the HDD104such that they are continuous with the packets recorded in the HDD104. More specifically, the difference between the time stamp attached to the packet last recorded in the HDD103and the time stamp attached to the packet first recorded in the HDD104becomes the same (12S-11E) during recording and during playback. Thus, by the stream data-generating section306of the HDD104, the packets are output in the form of stream data at timing according to the time stamps as described above, and therefore, the intervals between the end of the packet to be relayed and the head of the packet recorded in the HDD104is maintained to be the same as they were received by the HDD103during recording.

Here, the initial value of the time stamps at the time when packets start to be received during recording or playing may be any values, as mentioned above, and therefore, unlike Embodiment 1, it is not necessary that time information contained in the PCR be loaded to the counter302b. For this reason, it is not essential to perform a recording preparation operation for synchronizing the value of the counter302band the time information contained in the PCR packet, as is the case in Embodiment 1. However, it is necessary that the clock frequency that is output by the VCO302ehave a predetermined accuracy. For this purpose, it is possible to use a management packet for synchronizing the system time clock transmitted from one of the HDDs103and104, or from a server device or the like, or it is possible to use an oscillator that itself has high accuracy in order for the clock frequency to have a predetermined accuracy. Nevertheless, it is not impossible that proper recording and playback operations can be performed even when a recording preparation operation is performed as in Embodiment 1 so that time information contained in the PCR is loaded in the counter302bfor synchronization. (It should be noted that the clock may not always be used in common between the time stamp-generating section302and the stream data-generating section306, as described above, but independent clocks may be used for time stamp-generating section302and the stream data-generating section306.)

It also should be noted that the above-described configuration can be easily applied to cases where stream data are divided and recorded into three or more HDDs. If this is the case, the stream data that are output from the second HDD during playing are continuous stream data regardless of to which of the first or the second HDD the data were recorded, so it is sufficient that the initial time stamp value to be set in the counter302bin the third HDD be a value corresponding to the time stamp attached to the packet that is first recorded in the first HDD. Nevertheless, it is sufficient that the value (information) to be acknowledged to the third HDD be substantially a value such that the above-described value can be obtained. For example, it is possible to acknowledge such information indicating the relationship between the time stamps attached to the packets recorded in the first HDD and those attached to the packets recorded in the second HDD and the relationship between the time stamps attached to the packets recorded in the second HDD and those attached to the packets recorded in the third HDD. Alternatively, such information is acknowledged to the third HDD via the second HDD.

In the present embodiment as well, it is possible to employ a controlling device that does not have the HDD main unit305, or to transfer the stream data to the HDD104and thereafter record into the HDD103, as will be described later.

With reference toFIG. 14, another embodiment of the stream data recording and playing device is described in which continuous stream data can be output during playback even when time stamps attached to the packets respectively recorded in the HDDs103and104are not continuous between the HDDs103and104, as well as Embodiment 2. In this stream data recording and playing device, continuous stream data can be output even when time stamps are not continuous in the HDD104that relays the packets during playback, since output timing of the packets are properly controlled.

The basic configuration of the stream data recording and playing device is the same as the configuration of the device according to the foregoing Embodiment 2 (FIG. 12), except that, in the HDD104, a predetermined time stamp is set in the second time stamp memory306eof the stream data-generating section306under the control of a controlling section508during playback, in place of the setting of an initial time stamp value in the counter302bof the time stamp-generating section302.

In this example, for the operation during recording, time stamps that do not have continuity are attached to the packets that are recorded into the HDDs103and104, as in the case of Embodiment 2 above. (SeeFIG. 15A.) However, the controlling section508of the HDD103reads out a time stamp value11E that is attached to the last packet recorded in the HDD103and a time stamp value12S the most leading packet to be recorded in the HDD104from the counter302b, and it holds the difference (12S-11E) and notifies the HDD104of the difference.

On the other hand, in cases where the packets recorded in the HDD103are relayed by the HDD104during playback, the initial value of the counter302bis not particularly controlled. Thus, values21S to21E, which are irreverent to both time stamps attached in the HDD103and time stamps attached to the packets recorded in the HDD104, are attached to the packets that are input from the HDD103and are relayed by the HDD104, as shown inFIG. 15B, and these packets are output in the form of stream data at the timing according to the time stamps. Then, when the last packet that is relayed (the packet with a time stamp value of21E) is output from the stream data-generating section306, a value22S−(12S-11E) obtained from the value (12S-11E) acknowledged from the HDD103and the time stamp value22S of the most leading packet recorded in the HDD104is set into the second time stamp memory306e, not the above-described value21E. Thus, after the last packet to be relayed (the last packet recorded in the HDD103) is output from the stream data-generating section306, a time corresponding to the value (12S-11E) elapses, and then, the most leading packet recorded in the HDD104is output. That is, the interval between the end of the packet to be relayed and the head of the packet recorded in the HDD104is maintained to be the same as was received by the HDD103during recording, and thus continuous stream data are output.

Here, it is not impossible that proper recording and playback operations can be performed even when a recording preparation operation is performed as in Embodiment 1 so that time information contained in the PCR is loaded in the counter302bfor synchronization.

In place of setting the value22S−(12S-11E) in the second time stamp memory306eas described above, it is also possible that a value obtained by adding21E-22S+(12S-11E) to each time stamp may be set in the first time stamp memory306deach time the packet recorded in the HDD104is output.

Furthermore, when the stream data-generating section306is configured such that the time stamp attached to the packet that is first sent out is set as the initial value of the counter306g, and each subsequent packet is output each time the time stamp attached to each of the subsequent packets matches the value of the counter306g, as described in Embodiment 1 above, it is sufficient that when the last packet that is relayed is output from the stream data-generating section306, a value22S−(12S-11E) is set in the counter306g.

In the present embodiment as well, it is possible to use three or more HDDs. It is also possible to employ a controlling device that does not have the HDD main unit305, or to transfer the stream data to the HDD104and thereafter record into the HDD103.

With reference toFIG. 16, another embodiment of the stream data recording and playing device is described in which continuous time stamps are attached at the time of recording, as well as Embodiment 1. The configuration of this device is basically the same as that of Embodiment 1 (FIG. 3), except that the counter302bof the time stamp-generating section302can output its held value as a storing time stamp or hold a predetermined value as a initial time stamp value under the control of a controlling section608.

In this stream data recording and playing device, time stamps are attached in synchronization with PCR during recording, as in a similar manner to Embodiment 1. However, the time stamp to be attached to the most leading packet in the HDD104is not performed by the PCR itself but according to notification from the HDD103. Specifically, the HDD103notifies the HDD104of a value to be held in the counter302bwhen a time stamp is attached to the most leading packet to be recorded in the HDD104. The HDD104sets the acknowledged value as the initial time stamp value in the counter302b, and attaches time stamps that are continuous with the time stamps attached to the packets recorded in the HDD103, to the packets to be recorded in the HDD104. That is, the HDD104is notified of the initial time stamp value during the time in which, after a time stamp is attached in the HDD103to the most leading packet to be recorded in the HDD104, the packet is transferred to the HDD104through the buffer304, the stream data-generating section306, and so forth and a time stamp is attached by the time stamp-attaching section303in the HDD104; therefore, continuous time stamps can be attached to the packets recorded in the HDDs103and104.

In addition, also during playing, the HDD104is notified of the time stamp value attached to the most leading packet recorded in the HDD103in advance, and the time stamp value is set in the HDD104as the initial time stamp value in the counter302b; therefore, time stamps that are continuous with the time stamps that are attached to the packets recorded in the HDD104are attached to the packets that are output from the HDD103, and thus, continuous stream data can be played back. (It should be noted that because the time stamps attached to the recorded packets consequently become the same as in Embodiment 1, it is possible to use the device described in Embodiment 1 to play the data.)

A described above, because the notification of time stamp values and the control of initial values are carried out, it is not always necessary to perform the recording preparation operation as described in Embodiment 1 insofar as the clock frequency output by the VCO302ehas a predetermined accuracy at the time when packets start to be received during recording or playing due to the clock frequency control as explained in Embodiment 2.

It is also possible that the notification of an initial time stamp value as described above by generating a packet containing time information when starting to transfer stream data to output the packet as the initial packet.

In the foregoing, time stamps are described to be synchronized with time information contained in the PCR packet, but it is also possible that the difference between time stamps may be synchronized with the difference in the two pieces of time information contained in the PCR packets, as in the case of Embodiment 2.

In the present embodiment as well, it is possible to use three or more HDDs. It is also possible to employ a controlling device that does not have the HDD main unit305, or to transfer the stream data to the HDD104and thereafter record into the HDD103.

Variations

The foregoing embodiments have illustrated examples in which stream data are first recorded into the HDD103and thereafter recorded into the HDD104, but recording can be started from either of the HDDs by providing a controlling section having the functions of the controlling sections308and309, in place of the controlling sections308and309.

The foregoing examples show that split recording is performed into two HDDs103and104, but recording into three or more HDDs can be easily accomplished. Specifically, for example as shown inFIG. 17A, in addition to the HDD103and the HDD104, a HDD105may be provided that has a function of recording stream data that are relayed, as the HDD104, and a function of relaying the stream data to the HDD104at the end of recording, as the HDD103, in order that the packets sent from the receiving section102to the HDD103are relayed to the HDD104through the HDD103and HDD105. It is also possible that as shown inFIG. 17B, in addition to the HDD103and the HDD104, a HDD104′ having substantially the same functions as the HDD104may be provided such that when the free space in the HDD104′ reaches a predetermined amount, the HDD104′ issues a final recording start notification to the HDD103, and in response to this, the HDD103issues a recording preparation operation start command to the HDD104and performs data transfer. Alternatively, if the HDD103can detect that the free space in a given HDD reaches a predetermined amount by counting the amount of data relayed to the HDDs, it is sufficient that simply a plurality of the HDDs104are provided.

On the other hand, in cases where stream data are played back from three HDDs103to105, for example as shown inFIG. 18A, it is possible that the packets output from the HDD105(104′) are input to the HDD104and then from the HDD104to the receiving section102(thus a presenting device or the like, which is not shown in the drawings). (In this case, for example, the playback completion notification is sent from the HDD103to HDD105(the HDD104′) and likewise is sent from the HDD105(the HDD104′) to the HDD104.) Alternatively, as shown inFIG. 18B, it is possible that packets may be transferred directly from each of the HDDs103and105(the HDD104′) to the HDD104. (In this case, the playback completion notification is sent from the HDD103to the HDD104directly or via the HDD105(the HDD104′).) Here, in the case ofFIG. 18A, it is necessary that, at the start of playback, proper time stamps be generated between the HDDs105and104as well as between the HDDs103and105with a PCR packet or the like. Specifically, in the cases of Embodiments 2 to 4, it is necessary that the difference between the time stamps be equal to the difference between two pieces of time information contained in the successive PCR packets. In the case of Embodiment 1, it is necessary that the time stamp be synchronized with the time information.

In addition, in cases where three or more HDDs are provided as well, as shown inFIGS. 10 and 11, the recording and playback operations may be controlled by commands from the receiving section102or the like.

It is also possible that a HDD that does not have the split recording or combined playing functions may be provided together and connected to the bus110.

The foregoing embodiments illustrated the examples in which stream data from the receiving section102are input into the HDD103and are recorded in sequence from the HDD103to the HDD104, but it is possible that recording may be performed from the HDD104first. This is achieved if, as shown inFIG. 19A, the HDD103transfers stream data input form the receiving section102to the HDD104, and after free space in the HDD104runs out, as shown inFIG. 19B, recording into the HDD103is performed. In this case, proper time stamps can be generated in the HDDs103and104by sending stream data containing time information, such as a PCR packet, from the HDD103to the HDD104prior to recording into the HDD104. In order to control the timing of starting recording into to the HDD103, information indicating that available free space in the HDD104is running out can be sent from the HDD104to the HDD103, or the HDD103can confirm available free space in the HDD104in advance and count the amount of data to be transferred to the HDD104.

Likewise, the sequence for the playback may be reversed. The foregoing embodiments illustrated the examples in which stream data played back from the HDD103are transferred first to the HDD104, and then from the HDD104(via the receiving section102) to a presenting device or the like. However, for example, it is possible that as shown inFIG. 20A, data are first output from the HDD103to (via the receiving section102) directly to the presenting device or the like, and thereafter, as shown inFIG. 20B, stream data played back from the HDD104are transferred to the HDD103. It should be noted, however, that it is necessary that data transfer from the HDD104are performed at such timing that the output from the HDD103has not finished and the buffer304does not overflow.

In addition, for example as shown inFIGS. 21 to 23, it is possible to eliminate the HDD main unit, and a controlling section310may be provided and a controlling device106may be used that mainly performs relay of stream data and control for HDDs. This configuration is similar to the cases where the recording amount itself of the HDD103illustrated inFIG. 17Bor the HDD104inFIG. 18Bis 0. Thus, split recording and combined playing of stream data can be properly performed, and moreover, a simple configuration is achieved since the controlling sections308and309in the HDDs103and104do not require the recording relay-controlling section308bor the playback relay-controlling section309c. In addition, the receiving section102may be provided with the function of the controlling device106.

Further, the foregoing PLL operation as described above is not essential to synchronize the difference between the time stamps with two pieces of time information contained in the PCR packet as in Embodiment 2, but instead, it is possible that, for example, the clock frequency may have a predetermined accuracy. The foregoing PLL operation as described above is also not essential to synchronize the time stamp with time information contained in the PCR packet as in Embodiment 1, but instead, it is possible that, for example, the clock frequency may have a predetermined accuracy and the initial value of the time stamp may be the time information.

The foregoing embodiments illustrated that PCR packet is used as a packet containing time information, but this is for illustrative purposes only. For example, a user packet containing time information may also be used instead.

The foregoing embodiments illustrated that an IEEE 1394 standard bus is used for the bus110. However, the bus110is not so limited, and insofar as the interface can transmit stream data synchronized with reproduction timing and can configure a network, additional HDDs can be easily installed by merely connecting the HDDs with the network to perform split recording and combined playing of stream data. Also, the format of stream data is not limited to the MPEG-2 TS format. When stream data transmission that are similar to those output from the receiving section102is performed between the HDDs103and104, split recording and combined playing as described above can be performed, and it is not necessary to use exclusive signal lines or special packet formats. Therefore, it is possible to use various transmission systems and data formats with synchronization characteristics.

As has been described thus far, in the present invention, data to be recorded or played are extracted from input stream data; temporary time stamps are attached thereto and then removed therefrom; and the data are transferred to another recording and playing device at timing according to the time stamps. As a consequence, it is possible to record stream data for a longer time than a time corresponding to the storage capacity of a single stream data recording and playing device so that they can be played back at proper timing, and to play back at proper timing.