Abstract:
A reproducing apparatus which comprises a reproducing part having a first reproducing mode and a second reproducing mode different from the first reproducing mode and arranged to reproduce a signal recorded on a recording medium, a detection part for detecting a recording time of the signal recorded on the recording medium, and a control part for switching the reproducing part between the first reproducing mode and the second reproducing mode according to the recording time detected by the detection part.

Description:
This is a continuation application under 37 CFR 1.62 of prior application Ser. No. 08/425,143, filed Apr. 19, 1995 abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a reproducing apparatus that reproduces signals recorded on a recording medium. 
     2. Description of the Related Art 
     It is a general practice to use a video tape recorder (VTR) using a ½-inch or 8-mm width magnetic tape in recording video signals and audio signals in the form of analog signals. 
     FIG. 5 is a block diagram showing the configuration of a conventional VTR. Referring to FIG. 5, a recording-review function of checking what is being video-taped will be explained. A video image picked up by a camera  51  and a sound picked up by a microphone  52  are processed for recording by a video signal processing circuit  53  and an audio signal processing circuit  54  and combined by an adder  55  into one signal which is then sent to a recording head  56 . When a shooting start command is issued through an input key  57 , a system control circuit  58  sends a record command to a servo circuit  59 , which controls a capstan motor  60  and a drum motor  61  so as to rotate them at rotational frequencies for recording. The recording head  56  attached to a drum  62  records received signals representing a video image and sound onto a magnetic tape  63 . 
     When a user stops shooting by pressing the input key  57 , the system control circuit  58 , in response to the command from the input key  57 , sends a recording review command to the servo circuit  59 . The servo circuit  59  stops the two motors  60 ,  61  to stop the recording operation and then reverses the capstan motor  60 . At this time, the drum motor  61  is controlled to match the relative speed of a reproducing head  64  on the drum  62  so that signals recorded on the magnetic tape  63  can be reproduced. The signals reproduced by the reproducing head  64  are converted by a video signal processing circuit  65  into video signals and by an audio signal processing circuit  66  into audio signals. The video signals are displayed on a viewfinder  67  and the audio signal is sent to a headphone terminal  68 . 
     The servo circuit  59  counts the pulses (CFG) that are output each time the capstan motor  60  rotates and rewinds the magnetic tape  63  to a position where video-taping is started. Then, the servo circuit  59  controls the capstan motor  60  and the drum motor  61  so as to rotate in the same direction and at the same speed as those during the recording, and performs reproduction to a position of the magnetic tape  63  where the video-taping is stopped. The user monitors the video image being reproduced on the viewfinder  67 . 
     The above-mentioned VTR, however, has a drawback that it takes a rather long time to rewind the recorded magnetic tape in order to perform the recording-review and it takes a very long time to reproduce the tape in a normal reproducing mode. 
     SUMMARY OF THE INVENTION 
     An object of this invention is to provide a reproducing apparatus capable of reproducing recorded signals efficiently and reliably. 
     Another object of this invention is to provide a reproducing apparatus capable of reproducing recorded signals in a short time. 
     Still another object of this invention is to provide a reproducing apparatus capable of reproducing recorded signals in a fixed time. 
     To achieve the above object, a reproducing apparatus of one embodiment of this invention comprises reproducing means having a first reproducing mode and a second reproducing mode different from the first reproducing mode and for reproducing a signal recorded on a recording medium, detection means for detecting a recording time of the signal recorded on the recording medium, and control means for switching the reproducing means between the first reproducing mode and the second reproducing mode according to the recording time detected by the detect ion means. Because of this configuration, it is possible to perform tape reproduction in an appropriate reproducing mode according to the recording time of the signal recorded on a recording medium. 
     According to another embodiment of this invention, a reproducing apparatus comprises reproducing means having a first reproducing mode and a second reproducing mode different from the first reproducing mode and for reproducing a signal recorded on a recording medium, detection means for detecting an amount of information of the signal recorded on the recording medium, and control means for switching the reproducing means between the first reproducing mode and the second reproducing mode according to the amount of information detected by the detection means. Because of this configuration, it is possible to perform tape reproduction in an appropriate reproducing mode according to the amount of information of the signal recorded on a recording medium. 
     According to still another embodiment of this invention, a reproducing apparatus comprises reproducing means for reproducing a signal recorded on a recording medium, and control means for performing control in such a way as to make a reproducing time taken by the reproducing means constant irrespective of a recording time of the signal recorded on the recording medium. Because of this configuration, it is possible to always reproduce a signal recorded on a recording medium in a fixed time irrespective of the recording time of the signal. 
     According to a further embodiment of this invention, a reproducing apparatus comprises reproducing means for reproducing a signal recorded on a recording medium, and control means for performing control in such a way as to make a reproducing time taken by the reproducing means constant irrespective of an amount of information of the signal recorded on the recording medium. Because of this configuration, it is possible to always reproduce a signal recorded on a recording medium in a fixed time irrespective of the amount of information of the signal. 
     Other objectives and features of the present invention will become apparent from the following description-in this specification and the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram showing the configuration of a video camera of one embodiment of this invention; 
     FIG. 2 is a diagram showing the structure of a solid-state memory used in the embodiment; 
     FIG. 3 is a flowchart of the invention; 
     FIG. 4 is a flowchart of the invention; and 
     FIG. 5 is a block diagram showing the configuration of a conventional video camera. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     One embodiment of this invention will be described, referring to the accompanying drawings. 
     FIG. 1 is a configuration block diagram of a video camera of an embodiment of this invention. In FIG. 1, recording operation will be explained. Left (L) and right (R) channel stereophonic audio signals are fed from a stereo microphone  1  and converted into digital audio signals (audio data) by A/D converters  3 ,  4 . The digital audio signals are subjected to various processings such as noise removal and limitation on dynamic range by audio signal processing circuits  5 ,  6 . 
     A video signal fed from a camera  7  is converted into a digital video signal (video data) by an A/D converter  8  capable of processing faster than the A/D converters  3 ,  4  and the noise is removed by a video signal processing circuit  9 . 
     Next, ID data generated by an ID signal generating circuit  10 , the audio data and video data are combined by a data combining circuit  11  and stored in a main memory  12 . The memory address, write and read of the main memory  12  are controlled by a memory controller  13 . Further, the memory controller  13  is controlled by a system controller  14  to perform the overall control of the apparatus including the operation mode switching. The system controller  14 , in response to a command to perform record/reproduction/search entered through an operation key  15 , controls the memory controller  13  and at the same time displays on a display part  16  information such as time codes representing the operation status and the recording/reproducing times. There are two kinds of time codes. One represents the elapsed time from the start of a recording medium or a video program, and the accumulated time of camera shooting. The other represents the date (year, month and day of the month) and the time (hour, minute and second) when recording or camera shooting was done and the time of frames. To generate the latter time code, the apparatus has a calendar clock generating circuit  17 . Based on the information from the system controller  14 , the ID signal generating circuit  10  generates an:ID signal representing time code, picture quality, audio mode selection. The data combining circuit  11  combines video data and audio data-into a data block for every ID signal. 
     Next, FIG. 2 shows an example of data storage in the main memory  12  formed of a solid-state memory. In FIG. 2, video data, audio data and ID data form one data block to which an address representing the location in the memory where they are stored is assigned. pne data block has a fixed amount of data. If, for example, one data block is formed for one field of an NTSC signal in corformity with the CCIR recommendation 601 studio digital encoding standards, the one data block consists of 1.42848 Mbits of video data, 23.52 Kbits of audio data and 10 bits of ID data. That is, the address number is updated for every total of these bits, as shown in FIG.  2 . 
     The main memory  12  stores video data and audio data according to this data processing. It is also possible to expand the main memory and to use an interchargeable memory such as IC cards. 
     When a command to stop the recording is issued by the operation key  15 , the system controller  14  stops the recording in the main memory  12 . In FIG. 2, the recording (shooting) starts from the top and stops at an address number n. After this, to automatically start the recording-review, the system controller  14  displays on the display part  16  a message to the effect that the recording-review is being performed, and causes the memory controller  13  to control the memory address and read/write operation to read information signals stored in the main memory  12  by the recording operation. 
     The memory controller  13  starts reading from the address number  1  of FIG. 2, the recording (shooting) start address, and then increases the address number one by one. The increment of the address number by one results in that all the information is reproduced, so that this reproduction requires the same length of time as that of the recording. To shorten the reproducing time, the address number is increased by two, thus performing a double-speed reproduction. For example, only data blocks having the address number  1 ,  3 ,  5  . . . , n are reproduced. Still faster reproduction can be realized by increasing the increment by which the address number is increased. 
     The above-mentioned operation of the memory controller  13  is shown in the flow chart of FIG.  3 . In FIG. 3, the recording is started at step S 1 , the operation moves to step S 2  where the memory controller  13  writes in an address counter the memory address from which the data is recorded. In this example, the recording starts from the address number  1 , the first address in the memory. Then, each time one data block is recorded at step S 3 , the address number in the address counter is increased by one at step S 4 . The value in the address counter, representing the end of shooting, is written in an END register. When the shooting is ended at step S 5 , the address counter is reset to the shooting start address number (in this case, “1”) at step S 6 . At step S 7 , data block located at the address number indicated by the address counter is reproduced. Then, at step S 8 , the memory controller  13  increases the number in the address counter by two and reproduces the corresponding data block until the number in the address counter is larger than the value of the END register. At step S 9 , when the number in the address counter becomes larger than the value of the END register, the recording-review is ended. 
     Next, the reproduction will be explained referring to FIG.  1 . The reproduced signal read-from the main memory  12  is in the form of serial data consisting of three kinds of data: ID data, video data and audio data, and is supplied to a data distributing circuit  18 . Data fed to the data distributing circuit  18  is distributed as follows. 
     The video data is inputted into a data selecting circuit  19 , which supplies an analog video signal for video image monitor to an adder  20  and at the same time sends the video data to a digital output terminal  21 . 
     For the ID data information for every ID signal is detected by a search information reproducing circuit  22 , display information for monitoring is generated by a display information generating circuit  23 , the display information generated by the display information generating circuit  23  and the video information recovered by the data selecting circuit  19  are combined together by the adder  20 , the combined signal is converted into an analog signal by a D/A converter  24 , and this analog signal is displayed on a viewfinder  25 . 
     For the audio data, the data selecting circuit  19  sends it to a D/A converter  27  for generating an audio signal for a headphone terminal  26  and also feeds the audio data to a digital output terminal  28 . 
     Here, the video data and audio data are output from the data selecting circuit  19  in synchronism with the information from the display information generating circuit  23  to correct, by using the ID signal, the deviation between the video data and the audio data caused by the delay required to process the reproduced signal. 
     In this embodiment, recording-review starts automatically just after the shooting is ended, it is possible to start the recording-review operation only when the operator presses a recording-review key provided for this purpose in the operation key  15 . Further, although this embodiment uses a solid-state memory for the recording medium, a magnetic tape may also be used instead. It is possible to perform reproduction in the reverse direction. 
     In this way, immediately after finishing the shooting, the operator can review the video image by fast-feed reproduction and thereby decide whether to start the shoot of the next sceen or reshoot the same scene that he or she just shot. When a solid-state memory is used, it is possible to produce, with a simple configuration, a video image of good quality with no noise even when the image is reproduced at high speed. 
     As mentioned above, the recording-review is performed in the fast-feed reproduction, if the speed of the fast-feed is constant, the reproduction finishes in a short time when the recording time is short. Conversely, when the recording time is long, the double-speed reproduction takes a great deal of time until it finishes. 
     Thus, the increment by which the address number is increased is made variable according to the shooting or recording time. That is, it is made small when the recording time is short and large when it is long. This control is carried out by the memory controller  13  for counting the address number and, according to the counter value, the value to be added to the address number is changed. The operation of the memory controller  13  is shown in the flowchart of FIG.  4  and will be explained referring to the FIG.  4 . 
     In FIG. 4, recording is started at step S 41 , the operation of the memory controller  13  proceeds to step S 42 , where it writes in the address counter the memory address from which recording is started. In this example, recording is started from the address number  1 , the first address of the memory, as shown in FIG.  2 . Each time one data block is recorded at step S 43 , the address number in the address counter is increased by one at step S 44 . Then, in the END register the address counter value representing the end of recording is written. 
     When the shooting is ended at step S 45  and the address counter value of the END register is greater than a fixed value K at step S 46 , the memory controller  13  goes to step S 47  where it sets a value “4” to be added to the address counter X. If at step S 46  the address counter value of the END register is smaller than the fixed value K, the memory controller  13  moves to step S 48  where it sets the add value X to “2”. Then at step S 49 , the memory controller  13  resets the address counter value to the recording start address number (in this example, “1”) and at step S 50  reproduces the data block specified by the address number of the address counter. 
     Then, the value of the address counter is increased by two or four at step S 51  while the reproduction continues until the value of the address counter becomes larger than the END register value. Then, when the address counter becomes greater than the END register value at step S 52 , the recording-review is ended. 
     As described above, by changing the value to be added to the address counter X, i.e., the reproduction step according to the END register value representing the recording time, it is possible to change the speed of fast-feed reproduction according to the recording time. If the reproducing time is made constant irrespective of the recording time, it is possible to always perform the recording-review operation in a fixed time. Likewise, by monitoring the value of the address counter, it is possible to change the speed of fast-feed reproduction as the reproduction address approaches the recording end address. 
     While in this embodiment the video signal is taken as an example of the object of recording-review, signals other than the video signal may be subjected to the recording-review. That is, by changing the increment step of reading according to the recording time, the contents of the recorded signal can be reviewed in a short period of time.