Video and audio editing system

Abstract: A video and audio editing system includes a start time table (FIG. 7) and an end time table (FIG. 7) for storing a processing start time and a processing end time, respectively, for each scene to be fetched, a time lag inputting apparatus (7; 23) For inputting time lags in fetching of an external apparatus (20) and an audio board (17), a table updating apparatus (4) for updating contents of the start and end time tables (FIG. 7) based on the inputted time lags, and a controller (2) for referring to the contents of the start and end time tables (FIG. 7) to control fetching start and end times of video data and audio data or control reading start and end times from the storage medium ((15)) and fetching or reading out the audio data skipping silence data corresponding to the time lags.

Description: This invention relates to a video and audio editing system, and more particularly to an editing system for controlling an external apparatus by means of a personal computer (PC) to select video and audio materials of a required scene and store them as data for a multimedia application. A system which employs, for example, an application software program "Vidcap.exe" which operates on the operation system "Windows 3.1" offered by Microsoft, United States, is known as an editing system which controls an external apparatus by means of a personal computer to select video and audio materials of a required scene and input, compress and store data of them to, by and in the personal computer. FIG. 10 shows in block diagram a construction of the system mentioned above. Referring to FIG. 10, the system shown includes a personal computer (PC) 102 including a CPU (Central Processing Unit) 100 and a ROM 101 and an external apparatus 103 connected to the personal computer 102 via a transmission line 104 and an RS232C interface 105. The system further includes an instruction inputting apparatus 106 such as a keyboard or a pointing device for being operated by an operator to input an instruction, a video board 107 and an audio board 108 for fetching video data and audio data from the external apparatus 103 into the personal computer 102 via transmission lines 104, a memory 109 for being used to compress fetched data, a hard disk drive unit (HDD) 110 for storing the compressed data, a program 111 for being developed on the memory in the personal computer 102 to cause the personal computer 102 to operate, a display unit 112 for displaying image data before and after the data are fetched into the personal computer 102, and an outputting apparatus 113 for outputting audio data. The video board 107 is a hardware element for receiving video data inputted from the external apparatus 103 and storing the received data into a memory area which can be accessed by the personal computer 102. The program 111 controls, if start and end times of a scene to be fetched are set by an operator and then an execution instruction is issued, the external apparatus 103 to first shift the read point to the start time and then successively fetch video data successively feeding the frame and compress and store the fetched video data until the end time comes. Then, in order to fetch analog audio data, the read point is shifted to the start time again and then a reproduction instruction is issued to the external apparatus 103, whereafter a recording instruction is issued to the audio board 108 so that fetched data are temporarily stored onto a storage medium until the end time comes. Then, after the fetching is completed, reading in, compression and storage are performed again. Thereafter, the tops of the video and audio data after compressed are adjusted to each other to establish a relation between them in terms of time. Problems of the conventional video and audio editing system described above will be described below with reference to a time chart for fetching processing of analog audio data of FIGS. 11(a) and 11(b). FIG. 11(a) illustrates analog audio data fetching processing when reproduction is performed subsequently to recording while FIG. 11(b) illustrates analog audio data fetching processing when recording is performed subsequently to reproduction. Each arrow mark in FIGS. 11(a) and 11(b) represents a route of issuance of an instruction, and the axis of abscissa represents the time. Referring first to FIG. 11(a), when a recording instruction is first issued to the audio board 108 and then a reproduction instruction is issued to the external apparatus 103 based on the program 111, the following time lags 1 ○, 2 ○, 3 ○ and 4 ○ must be taken into consideration: 1 ○ a time lag after a recording instruction is issued based on the program 111 until the audio board 108 receives the instruction; 2 ○ another time lag after the audio board 103 receives the instruction until it operates, 3 ○ a further time lag after a reproduction instruction is issued based on the program 111 until the external apparatus 103 receives the instruction; and 4 ○ a still further time lag after the external receives 103 receives the instruction until it operates. Due to the time lags, the time at which the audio board 108 actually starts recording is later at a time A than the set start time; the time at which data are inputted to the audio board 108 is later at a time B than the start time; and the time at which recording is ended is later at a time C delayed from the set end time. Consequently, the audio board 108 fails to fetch the audio data from the start time to the time A, and the audio data from the time A to the time B exhibit silence (absence of sound). As a result, when the video and audio data after compressed are reproduced simultaneously, the sound is reproduced earlier than the image. EP-A-0 176 324 discloses a system synchronizing apparatus, wherein a system synchronizing apparatus obtains from a digital audio system reproduced audio signals which are synchronized with a reproduced video signal from a video system, by comparing a first time code which is reproduced in a first recording and reproducing apparatus which constitutes the video system and employs a first television system with a second time code which is reproduced from a second recording and reproducing apparatus which constitutes the digital audio system together with a digital audio processor and employs a second television system. The system synchronizing apparatus at least controls the second recording and reproducing apparatus responsive to a difference in the time codes so that phases of the time codes coincide for every predetermined frame address of one of the two time codes and controls the first and second recording and reproducing apparatuses according to the needs so that starting points of the first and second time codes coincide. Further, EP-A.0 438 299 discloses an offline editing system wherein a post production offline editing system is capable of storing unedited video takes in a random access memory such as a set of laser video disc players, displaying selected takes (or individual frames from selected takes), and generating an edit list which defines an edited video programme. The system includes a computer programmed with software providing an integrated software environment which enables a user conveniently to log unedited takes into the system, and to generate an edit list suitable for use in a subsequent online editing operation. The system software provides global access to a variety of video post production environments at any point during an offline editing operation. The system software presents menus to the user including icons or mnemonic text in windows which may be conveniently selected by the user using a mouse. The system may include a video special effects unit capable of processing the stored takes to simulate various video transitions between scenes (such as dissolves, fades, and wipes), to enable the user to view a show defined by an edit list which specifies such transitions, the user interface may include means for jogging (and shuttling) the laser disc players using the mouse. It is an object of the present invention to provide a video and audio editing system which eliminates such a phenomenon that video or audio data fail to be fetched, the top of audio data exhibits silence, or when video data and audio data after compressed are reproduced simultaneously, the image and the sound are not reproduced synchronously. Present invention is defined in independent claim 1. Preferred embodiments are described in the depending claims. In order to attain the object described above, according to an aspect of the present invention, there is provided a video and audio editing system wherein video data and audio data are fetched from an external apparatus onto a computer via a video board and an audio board, respectively, and stored onto a storage medium, the video and audio editing system comprising, where the video and audio editing system is constructed such that operations from fetching to storage cannot be performed on the real time basis, a start time table and an end time table for storing a processing start time and a processing end time, respectively, for each scene to be fetched, time lag inputting means for inputting time lags in fetching of the external apparatus and the audio board, table updating means for updating contents of the start time table and the end time table based on the inputted time lags, and control means for referring to the contents of the start time table and the end time table to control a reading start time and a reading end time from the storage medium and reading out the audio data from the storage medium skipping silence data corresponding to the time lags. According to an aspect of the present invention, there is provided a video and audio editing system wherein video data and audio data are fetched from an external apparatus onto a computer via a video board and an audio board, respectively, and stored onto a storage medium, the video and audio editing system comprising, where the video and audio editing system is constructed such that operations from fetching to storage cannot be performed on the real time basis, a start time table and an end time table for storing a processing start time and a processing end time, respectively, for each scene to be fetched, time lag inputting means for inputting time lags in fetching of the external apparatus and the audio board, table updating means for updating contents of the start time table and the end time table based on the inputted time lags, and control means for referring to the contents of the start time table and the end time table to control fetching start times and fetching end times of video data and audio data and fetching the audio data skipping silence data corresponding to the time lags. In both of the video and audio editing systems described above, the time lag inputting means may include means for acquiring a first time lag which is a time by which audio data are fetched later or earlier than the fetching start time designated by an operator and means for acquiring a second time lag which is a time by which the fetched audio data exhibit silence beginning with the top thereof, and the table updating means may update the contents of the start time table and the end time table based on the fetched first and second time lags. Or, the time lag inputting means may be an instruction inputting apparatus for being manually operated by an operator to arbitrarily input a time lag. In both of the video and audio editing systems described above, the contents of the start and end time tables are updated based on the time lags inputted by the time lag inputting means, and the fetched audio data are read skipping silence data beginning with the top thereof. Consequently, such a situation that data cannot be fetched successfully or silence is present at the top of data or else synchronism is not established when video and audio data after compression are reproduced simultaneously can be eliminated. The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings in which like parts or elements are denoted by like reference characters. FIG. 1 is a block diagram of a video and audio editing system showing a preferred embodiment of the present invention; FIG. 2 is a flow chart illustrating video data fetching processing of the video and audio editing system of FIG. 1; FIG. 3 is a flow chart illustrating audio data fetching processing of the video and audio editing system of FIG. 1 where the system is constructed such that fetching and storage of audio data cannot be performed on the real time basis; FIG. 4 is a flow chart illustrating processing for acquiring a time lag in the video and audio editing system of FIG. 1 when a reproduction instruction is issued subsequently to a recording instruction; FIG. 5 is a flow chart illustrating processing for acquiring a time lag in the video and audio editing system of FIG. 1 when a recording instruction is issued subsequently to a reproduction instruction; FIG. 6 is a flow chart illustrating processing for producing a table in the video and audio editing system of FIG. 1; FIG. 7 is a view showing a table produced by the processing illustrated in FIG. 6; FIG. 8 is a flow chart illustrating processing for skipping silence data in the video and audio editing system of FIG. 1; FIG. 9 is a flow chart illustrating audio data fetching processing of the video and audio editing system of FIG. 1 where the system is constructed such that fetching and storage of audio data can be performed on the real time basis; FIG. 10 is a block diagram showing a construction of a conventional video and audio editing system; FIGS. 11(a) and 11(b) are time charts illustrating fetching processing for analog audio data in the conventional video and audio editing system of FIG. 10; and FIGS. 12(a) and 12(b) are time charts illustrating fetching processing for analog audio data in the video and audio editing system of FIG. 1. Referring to FIG. 1, there is shown in block diagram a video and audio editing system to which the present invention is applied. The video and audio editing system shown includes a personal computer (PC) 11 and an external apparatus 20 connected to each other by a transmission line 19 and an interface box 18. The interface box 18 includes an interface for bidirectional communications such as, for example, an RS232C interface so that the personal computer 11 and the external apparatus 20 can communicate instructions with each other via the interface box 18 so as to allow the personal computer 11 to utilize all functions prepared by the external apparatus 20 such as reproduction, stopping and pause. A CPU 12 in the personal computer 11 operates in accordance with a BIOS (Basic Input Output System) stored in a ROM 13 and a program 1 developed on a memory 14. Video data sent from the external apparatus 20 are inputted to a memory in a video board 16 and outputted as they are to a display unit 21 and simultaneously transferred, based on an instruction of the program 1, to the memory 14 in the personal computer 11 and a hard disk drive unit (HDD) 15. Then, the video data are compressed and recorded onto a storage medium such as a hard disk. Similarly, analog audio data from the external apparatus 20 are inputted to a memory in an audio board 17 and outputted as they are to an outputting apparatus 22 and simultaneously transferred, based on an instruction of the program 1, to the memory 14 in the personal computer 11 and the hard disk drive unit 15. Then, the audio data are compressed and recorded onto the storage medium such as a hard disk. An operator will input an instruction using an instruction inputting apparatus 23 such as a keyboard or a pointing device. The program 1 has functions as an initial setting section 3 for initializing the video board 16 and the audio board 17 and establishing a working area in the memory 14, a table production section 4 including a table production sub-section for producing a start time table and an end time table for storing processing start times and processing end times of a video material and an audio material to be fetched in response to an instruction of an operator and a table updating sub-section for updating contents of the tables based on time lags, an external apparatus control section 5 for controlling the external apparatus 20 based on the contents of the tables, a board control section 6 for controlling the video board 16 and the audio board 17, a time lag acquisition section 7 including a sub-section for acquiring a time (first time lag) by which audio data are to be fetched later or earlier than the fetching start time designated by the operator and another sub-section for acquiring another time (second time lag) by which silence successively appears in fetched audio data beginning with the top of the same, a data control section 8 including a sub-section for skipping, when data temporarily on a storage medium are read in, silence data beginning with the top of the audio data and another sub-section for skipping, when data are transferred from the audio board 17 to a memory area of the personal computer 11, silence data beginning with the top of the audio data, a video and audio compression section 9 for compressing fetched video and audio data, a video and audio decompression section 10 for restoring video data and audio data in order to confirm the data after stored, and a main control section 2 for controlling all of the other sections or modules. FIG. 2 is a flow chart illustrating data fetching processing by the video and audio editing system shown in FIG. 1. Referring to FIG. 2, after the program 1 is started in response to an instruction of an operator (step S1), the video board 16 and the audio board 17 are initialized (step S2) and areas necessary for storage and compression of data are established on the memory 14 in the personal computer 11 (step S3), whereafter the external apparatus 20 connected to the system is started (step S4). Then, if the operator controls the external apparatus 20 via the instruction inputting apparatus 23 to input fetching start and end times of a required scene (step S5), it is recognized whether or not time lags are set in advance (step S6). If time lags are not set, then time lags are acquired by the time lag acquisition section 7 (step S7), and such tables as illustrated in FIG. 7 are produced by the table production section 4 (step S8). The acquisition of time lags is performed before video and audio data are actually fetched effectively, but upon the acquisition, fetching of video data is not performed. In this instance, the operator will select a location of audio data of a scene to be fetched at which the top of the audio data represents presence of sound without fail. FIG. 4 is a flow chart illustrating processing by the time lag acquisition section 7 for acquiring a time lag in advance before video data and audio data are fetched actually while FIG. 5 is a flow chart illustrating processing by the time lag acquisition section 7 different from the processing illustrated in FIG. 4, and FIGS. 12(a) and 12(b) are time charts illustrating fetching processing for analog audio data by the video and audio editing system of FIG. 1. In FIGS. 4 and 5, a request for interruption is notified from the audio board 17 to the program 1 when the audio board 17 enters into an input waiting state. Processing when a reproduction instruction is issued subsequently to a recording instruction will be described with reference to FIGS. 4 and 12(a). If the operator controls the external apparatus 20 using the instruction inputting apparatus 23 to input fetching start and end times (step S100), then the board control section 6 notifies an interrupt address to the audio board 17 (step S101), and the time lag acquisition section 7 starts a timer thereof (step S102). Then, a recording instruction is issued to the audio board (step S103), and then a reproduction instruction is issued to the external apparatus 20 (step S104). If a response instruction to the reproduction instruction is received from the audio board 17, then the current time is acquired from the system (step S105) and stored into a variable t1 (step S106). Then, when a request for interruption is received from the audio board 17, the current time is acquired from the system (step S107) and stored into another variable t2 (step S108). The board control section 6 controls the audio board 17 to start fetching (step S109) and transfers data inputted to the audio board 17 to the memory 14 in the personal computer 11 (step S110). After the fetching is completed, the time lag acquisition section 7 reads the data developed in the memory 14 beginning with the top of the same for one sample (used as a unit of sampling) (step S111) and discriminates, from the amplitude of the data, whether or not the data are silence data (representing absence of sound or silence) (step S112). When the data are silence data, the processing in steps S111 and S112 is repeated, but when the data are sound data (representing presence of sound), a time interval of the silence data (time from A to B) is calculated from the amount of data read in (step S113). Further, another time interval by which data have been fetched earlier or later than the designated start time is calculated from the variables t2 - t1 (step S114). Then, the former time interval thus calculated is stored as the time lag 2 and the latter time interval is stored as the time lag 1 in units of a frame of video data (step S115). Subsequently, processing when a recording instruction is issued subsequently to a reproduction instruction will be described with reference to FIGS. 5 and 12(b). If the operator controls the external apparatus 20 using the instruction inputting apparatus 23 to input fetching start and end times (step S116), then the board control section 6 notifies an interrupt address to the audio board 17 (step S117) and the time lag acquisition section 7 acquires the current time from the system (step S118) and stores it into a variable t3 (step S119). Then, a reproduction instruction is issued to the external apparatus 20 (step S121), and then a recording instruction is issued to the audio board 17 (step S122). Then, if a request for interruption is received, then the current time is acquired from the system (step S123) and stored into a variable t4 (step S124). The board control section 6 controls the audio board 17 to start fetching (step S125) and transfers data inputted to the memory of the audio board 17 to the memory 14 in the personal computer 11 (step S126). After the fetching is completed, the time lag acquisition section 7 reads the data for one sample developed in the memory 14 beginning with the top of the same (step S127) and discriminates, from the amplitude of the data, whether or not the data are silence data (step S128). When the data are silence data, the processing in steps S127 and S128 is repeated, but when the data are sound data, a time interval of the silence data (time from A to B) is calculated from the amount of data read in (step S129). Then, another time interval by which data are fetched later than the designated start position is calculated from t4 - t3 (step S130). The former time interval thus calculated is stored as the time lag 2 and the latter time interval is stored as the time lag 1 in units of a frame (step S131). FIG. 6 is a flow chart of processing by the table production section 4 for producing tables. Referring to FIG. 6, the table production section 4 converts start and end times of a scene inputted by an operator in units of a frame (step S43) and produces a start time table and an end time table (step S44). When video data are to be fetched, the tables are referred to. Thereafter, from the time lags 1 and 2 calculated in such a manner as described above, an audio start time and an audio end time for fetching of audio data are calculated (step S45), and an audio start time table and an audio end time table are produced (step S46). The audio start time and the audio end time are calculated using the following equations. audio start time = video start time - time lag 1 audio end time = video end time - time lag 1 Referring back to FIG. 2, when video data and audio data are to be actually fetched effectively, an instruction to execute compression will be developed by the operator (step S9). In response to the instruction, the external apparatus control section 5 refers to the start time tables and the end time tables and controls the external apparatus 20 to return the read point to the video start time T1 the first scene (step S10) and then to temporarily stop (step S11). Then, the board control section 6 transfers data for one frame inputted to the memory of the video board 16 to the memory area 14 in the personal computer 11 (step S12). The video compression section 9 compresses the transferred data (step S13) and the hard disk drive unit 15 stores the compressed data onto the storage medium (step S14). Then in step S15, the start time table and the end time table are referred to to confirm whether or not the video end time of the first scene has come, and when the video end time has not come as yet, the video data are fed by one frame (step S16) so that the processing in steps S11 to S16 is repeated successively feeding the frames one by one until the video end time comes. When the video end time of the first scene comes, it is confirmed whether or not there remains another table set (step S17), and if there remains another table set, fast feeding is performed to the video start time of the second scene (step S18), and the processing in steps S11 to S16 is repeated until the video end time of the second scene comes. It is to be noted that, while it is illustrated in FIG. 7 that tables can be set for up to 20 scenes, the number of scenes is not specifically limited to 20. After fetching of the video data is completed, fetching of audio data is started. In this instance, where the video and audio editing system is constructed such that the operations from fetching to storage of audio data cannot be performed on the real time basis, when data stored on the storage medium are to be read in, data fetched prior to fetching of actual data beginning with the audio data are skipped. This processing will be described below. FIG. 3 is a flow chart of audio data fetching processing. Referring to FIG. 3, the external apparatus control section 5 controls the external apparatus 20 to return the read point to the audio start time of the first scene (step S19) and issues a reproduction instruction to the external apparatus 20 (step S20). Then, the board control section 6 starts fetching of the audio board 17 (step S21), transfers data inputted to the audio board 17 to the memory 14 in the personal computer 11 (step S22) and writes the data onto the storage medium by means of the hard disk drive unit 15 (step S23). Then in step S24, the timer of the personal computer 11 is supervised by the main control section 2 (step S24), and when the audio end time of the first scene is exceeded, a stopping instruction is issued to the external apparatus 20 (step S25) and fetching of data by the audio board 17 is ended (step S26). Then, writing onto the storage medium is ended (step S27), and the timer is stopped (step S28). Thereafter, it is confirmed in step S29 whether or not there remains no set table, and if there remains a set table, fast feeding is performed until the audio start time of the second scene is reached (step S30) and then the processing in steps S20 to S29 is repeated. On the contrary if there remains no set table, the data acquisition section 8 reads the stored data skipping silence data beginning with the top of the stored data (step S31), and the video and audio compression section 9 compresses the data (step S32) and the compressed data are stored onto the storage medium by the hard disk drive unit 15 (step S33). Thereafter, synchronism in time between the compressed video data and audio data is established (step S34). FIG. 8 is a flow chart illustrating processing for skipping silence data. Referring to FIG. 8, the data acquisition section 8 opens a file temporarily stored on the storage medium (step S49) and refers to the contents of the tables to calculate the data amount within the silence time (time lag 2) (step S50). Then, the data read point is shifted by the data amount of the silence time from the top of the file (step S51), and the data of the file beginning with the shifted position are read out into the working area established in the memory 14 (step S52). On the other hand, where the video and audio editing system is constructed such that the operations from fetching to storage of audio data can be performed on the real time basis, processing for eliminating a phenomenon wherein the top of audio data exhibits silence by fetching, when the external apparatus 20 is controlled to select video and audio materials of a required scene to fetch data of them into the personal computer 11, the audio data skipping silence data beginning with the top of the audio data proceeds in the following manner. In this instance, the program 1 is started, and the processing in steps S1 to S18 shown in the flow chart of FIG. 2 is performed until fetching of audio data is completed. Referring to FIG. 9. The external apparatus control section 5 controls the external apparatus 20 to shift the data read point back to the audio start time of the first scene (step S53) and issues a reproduction instruction to the external apparatus 20 (step S54), and the board control section 6 starts fetching of the audio board 17 (step S55) and refers to the contents of the tables to calculate the data amount within a silence time (time lag 2) (step S56). After data are inputted to the audio board 17, the read point is shifted by the data amount of the silence time from the top of the memory area of the audio board 17 (step S57) and transfers, beginning with the shifted position, the data to the memory 14 in the personal computer 11 (step S58). Then, the video and audio compression section 9 compresses the data (step S59) and stores the data onto the storage medium (step S60). The timer of the personal computer 11 is supervised by the main control section 2, and when the audio end time is exceeded, a stopping instruction is issued to the external apparatus 20 (step S61) and the fetching of audio data is ended (step S62). Then, the writing of the audio data onto the storage medium is ended (step S63) and the timer is stopped (step S64). Then, it is confirmed whether or not there remains a table set (step S65), and if a set table remains, the read point is shifted to the audio start time of the second scene (step S66) and the processing in steps S54 to S65 is performed. If no set table remains, then synchronism in time between the compressed video and audio data is established (step S67). Having now fully described the invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit and scope of the invention as set forth herein.

Claims: A video and audio editing system wherein video data and audio data are fetched from an external apparatus (20) onto a computer (11) via a video board (16) and an audio board (17), respectively, and stored onto a storage medium ((15)), characterized in that it comprises: a start time table (FIG. 7) and an end time table (FIG. 7) for storing a processing start time and a processing end time, respectively, for each scene to be fetched; time lag inputting means (7; 23) for inputting time lags in fetching of said external apparatus (20) and said audio board (17); table updating means (4) for updating contents of said start time table (FIG. 7) and said end time table (FIG. 7) based on the inputted time lags; and control means (2) for referring to the contents of said start time table (FIG. 7) and said end time table (FIG. 7) to control reading-in start times and reading-in end times of video data and audio data to said storage medium ((15)) and reading-out the audio data from said storage medium ((15)) skipping silence data corresponding to the time lags, after the reading-in is completed. A video and audio editing system as set forth in claim 1, characterized in that said time lag inputting means (7) includes means for acquiring a first time lag which is a time by which audio data are fetched later or earlier than the fetching start time designated by an operator and means for acquiring a second time lag which is a time by which the fetched audio data exhibit silence beginning with the top thereof, and said table updating means (4) updates the contents of said start time table (FIG. 7) and said end time table (FIG. 7) based on the fetched first and second time lags. A video and audio editing system as set forth in claim 1, characterized in that said time lag inputting means (23) is an instruction inputting apparatus for being manually operated by an operator to arbitrarily input a time lag.

Inventors: KIKUCHI TSUNEYUKI, SAMESHIMA TAKASHI, KIKUCHI, TSUNEYUKI, SAMESHIMA, TAKASHI, Kikuchi, Tsuneyuki, c/o NEC Techno-Systems, Ltd., Sameshima, Takashi, c/o NEC Corp.
Applicants: NIPPON ELECTRIC CO, NEC CORPORATION
Application year: 1996
Main classification: G11B27
IPC codes: G11B27, G06F17, H04N5