JPH0946642A - Method for establishing initial synchronization in image and audio data compressing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an output of data after compression synchronization even when a start command for compression processing is made in an optional timing in image and audio data compressing device. SOLUTION: After a compression start command from a user I/F 9, a CPU 109 is interrupted by a 1st frame pulse of a frame pulse generating circuit 8 and the CPU 10 starts the compression of a audio compression circuit 6 after an interrupt reply and compression audio data are stored in a buffer memory 7. Furthermore, the CPU 10 sets a moving image compression circuit 4 to an operation ready state after the interrupt reply time and a 2nd frame pulse is used to start compression processing for image data. When an output of compression image data is obtained from the motion image compression circuit 4 by the CPU 10, compression audio data are outputted from the buffer memory 7 corresponding to the 2nd frame pulse to establish initial synchronization relating to an output of the compression data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for establishing initial synchronization in a compression apparatus for image and audio data, and when encoding and compressing image data and audio data and recording them on a recording medium such as a CD-ROM or a hard disk, Alternatively, the present invention relates to a method for outputting each compressed data in accurate synchronization even when the compression processing is instructed at an arbitrary timing in the case of highly efficient transmission.

[0002]

2. Description of the Related Art Recently, with the advent of the full-scale multimedia era, a wide variety of image data and audio data compression / expansion processing technologies have been developed for the purpose of saving storage media capacity and improving data transmission efficiency. Although it is being developed, the amount of image data and the amount of audio data differ greatly, and since each has unique characteristics, it is necessary to perform compression processing on each data while maintaining a time-series correspondence. Causes various problems.

Specifically, image data and audio data are compressed by independent data compression devices based on their respective encoding algorithms, but the processing speed of image data becomes slower than that of audio data, and each data is compressed. Even if both are input to each compression device at the same time, the timing at which the compressed image data is output is delayed from the timing at which the compressed audio data is output. There is a sense of discomfort due to the mismatch between the image and the sound.

In order to solve the problem, for example, in an image and audio data compression processing device in which a buffer memory is provided on the output side of the image data compression system, variable delay means is provided on the output side of the audio data compression system. In addition, a method has been proposed in which the output of the compressed audio data is delayed by the variable delay means by an amount corresponding to the delay amount from the start of writing the compressed image data to the buffer memory to the start of the reading (Japanese Patent Laid-Open No. HEI 5). -304642).

Also, in an apparatus for compressing image data and audio data frame by frame, the numbers of the image frame and audio frame currently being processed are compared, and if the audio frame number is greater than the image frame number, the image is processed. Since the data compression processing is delayed, the method of interrupting the image compression processing of the compared image frame and shifting to the compression processing of the image data of the next frame to adjust the synchronization is also proposed ( JP-A-6-121276).

[0006]

By the way, when the image data and the audio data are compressed and recorded on the recording medium, for example, the moving image data and the audio data read from the VTR are displayed on the monitor device. While displaying
In many cases, only moving images and audio data in a required time zone are selectively compressed and recorded. In that case, the start of the compression process is instructed by the key operation of the user interface (I / F), but since the instruction input is made at any time selected by the operator, one frame of image data is compressed. In most cases, an instruction is input during the processing intermediate time zone. Therefore, when the start of the compression process is instructed at an arbitrary time point, the compressed audio data is output in association with the compressed image data in the initial state after the instruction, that is, the synchronization of each compressed data is performed. The issue is how to establish it.

In the method of the above-mentioned Japanese Patent Laid-Open No. 5-304642, the delay time that occurs in the compressed image data due to the delay of the capacity of the buffer memory and the line transmission rate is the starting time and the writing time of the buffer memory in the initial state. Since the difference appears at the start, the time difference is given as the delay amount for the variable delay means. This method seems to provide a solution to the above problem, but when the start instruction of the compression process is given at an arbitrary timing, the compressed data of the first frame is incomplete for the image and audio. In addition, since a buffer memory for measuring the delay amount is provided on the image data compression system side where the compression process is originally delayed, and the audio data compression system is subordinate to that system,
Overall throughput is reduced. Incidentally, JP-A-6-12
The method of No. 1276 realizes the synchronization adjustment during the compression operation, and does not provide the synchronization establishment when the start instruction of the compression processing is given at an arbitrary timing as described above, and the method does not use the voice. When the frame number becomes larger than the image frame number, the loss of compressed image data occurs.

Therefore, according to the present invention, in the case where a compression processing start instruction is given at an arbitrary timing while receiving multimedia data in which image data and audio data are associated in time series with a sync signal, The purpose is to provide a method for establishing the synchronization of the initial output of the compressed image data and the compressed audio data, and to compress the image data and the audio data in a desired time zone so that they can always be recorded and transmitted in synchronization with each other. Was created as.

[0009]

According to the present invention, multimedia data in which image data and audio data are associated in time series with a sync signal is transmitted, and the image data is processed by an image compression processing means. In an image and audio data compression apparatus that compresses data by audio compression processing means and outputs each compressed data in a time series correspondence, compression instructing means for instructing to start compression processing of the multimedia data; Frame signal generation means for generating a frame start signal of image data using a synchronization signal, first control means for controlling the operation start of the image compression processing means and the audio compression processing means, and compression by the audio compression processing means. Buffer means for accumulating the audio data and second control means for controlling the reading of the compressed audio data accumulated in the buffer means are provided. When there is an instruction input from the compression instruction means, the first control means controls the audio compression processing means based on the first frame start signal generated by the frame signal generation means after the instruction input. At the same time as starting the operation, the image compression processing means is set to the operation ready mode, and the compression operation of the image compression processing means is started based on the next second frame start signal. An image characterized in that, when the data is delayed and output, the second control means reads out and outputs compressed audio data corresponding to the audio data after the second frame start signal stored in the buffer means. And an initial synchronization establishing method in a voice data compression apparatus.

In the present invention, the output timing of the compressed audio data is subordinated to the output timing of the compressed image data that has been compressed in frame units. Then, in order to manage the procedure, the frame signal generation means uses a frame start signal generated by using a synchronization signal included in the input multimedia data (for example, a vertical synchronization signal or a horizontal synchronization signal of image data). . An instruction is input from the compression instructing means at an arbitrary timing, but the first control means monitors the output of the frame signal generating means from the time when the instruction is input, and starts the first frame after the instruction input. The input audio data is compressed by the audio compression processing means based on the signal, and the compressed audio data is stored in the buffer means. It should be noted that the timing of the first frame start signal does not always coincide with the start timing of the compression operation by the audio compression processing means, and if interrupt processing or the like is involved, the audio compression processing means is delayed by the response time thereof. Since the processing speed of is relatively high, the audio compression processing means outputs the compressed audio data by the time the second frame start signal is output.

On the other hand, with respect to the input image data, the first control means merely sets the image compression processing means in the operation ready mode based on the first frame start signal and does not start the compression operation. The image compression processing means is operated based on the second frame start signal to start the compression processing of the input image data. In this case, since the image compression processing means is in the operation ready mode in advance by the interrupt processing by the first frame start signal, the image compression processing means can immediately shift to the compression operation and the first image data corresponding to the second frame start signal. Data compression can be started from. Here, the reason why the compression process is not started by the first frame start signal is that if the response time due to the interrupt process or the like intervenes, the data compression cannot be performed from the beginning of the frame and the synchronization cannot be achieved in frame units.

After the image compression processing means starts the compression processing of the input image data by the second frame start signal, the compressed image data is output when a fixed compression output delay time elapses. On the other hand, the buffer means stores the compressed audio data compressed by the audio compression processing means after the first frame start signal is received and the response time due to the interrupt processing or the like elapses. Compressed audio data after the start signal is also stored. Also,
Since the compression speed of the audio data is faster than the compression speed of the image data, the compression of the audio data related to the same frame is completed by the time the compression of the image data corresponding to the second frame start signal is completed.

Therefore, when the image compression processing means delays the output of the compressed image data, the second control means causes the compressed audio data in the buffer means to start from a predetermined address position corresponding to the data after the second frame start signal. Read and output in synchronization with compressed image data. Therefore, mutually corresponding compressed image data and compressed audio data are simultaneously output in a state where the initial synchronization is accurately established. Further, since the initial synchronization is established, thereafter, the output synchronization of each compressed data can be continuously maintained while using the frame start signal.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of "a method for establishing initial synchronization in a compression apparatus for image and audio data" of the present invention will be described in detail below with reference to the drawings. First, FIG. 1 shows a block circuit diagram of a multimedia data compression apparatus connected to a VTR and a data recording apparatus. In the figure, 1 is VT
R, VIDEO output terminal, AUDIO output terminal, SYNC (sync signal; vertical sync signal of image data in this case) output terminal
The COMMAND input terminal is connected to the compressor 2 side. The compression device 2 includes an A / D converter 3 that quantizes an analog moving image signal obtained from the VIDEO output terminal of the VTR 1, and a moving image compression circuit that compresses the moving image data quantized by the A / D converter 3. 4, an A / D converter 5 for quantizing an analog audio signal obtained from the AUDIO output terminal of the VTR 1, an audio compression circuit 4 for compressing the audio data quantized by the A / D converter 5, and a compression process. A ring buffer memory 7 for storing the reproduced audio data by a FIFO method, a frame pulse generation circuit 8 for generating a frame start pulse based on a synchronization signal obtained from a SYNC output terminal of VTR1, an operation control of VTR1 and a data compression Based on the user I / F 9 that gives a start instruction and the frame start pulse generated by the frame pulse generation circuit 8, the operation control of the moving image compression circuit 4 and the audio compression circuit 6 and the data from the ring buffer memory 7 are performed. Consisting CPU10 Metropolitan perform read control. The moving picture compression circuit 4 and the audio compression circuit 4 execute data compression using the sync signal of VTR1.

When using the compression device 2,
The monitor device 21 is connected to the VTR 1, the operation of the VTR 1 is controlled, and the user I / F 9 gives an instruction to start the compression process while monitoring the moving image and sound recorded on the magnetic tape, and the desired time period The compressed data of the moving image and the sound of is recorded on the recording medium (CD-ROM) 22a of the data recording device 22 connected to the output of the moving image compression circuit 4 of the compression device 2 and the ring buffer memory 7.

In the above configuration, the compressed data of the moving image and the audio in the desired time zone is recorded on the recording medium 22a of the data recording device 22.
The procedure for establishing the initial synchronization when recording is performed on the recording medium will be described with reference to the timing chart of FIG. First, user I /
From F9, a start instruction is given to the VTR1 to cause the monitor device 21 to reproduce and output the moving image and the sound, and the start and end of the moving image to be edited and recorded on the recording medium 22a are confirmed, and the magnetic tape is placed before the moving image. Rewind to give a start instruction again. Then, when the moving image to be edited and recorded is confirmed, the user I / F 9 gives an instruction to start the compression process.

Here, the frame pulse generation circuit 8 uses the VT
One frame start pulse is output every time two vertical sync signals are obtained from the SYNC output terminal of R1, but the CPU that received the compression start signal from the user I / F9
10 is monitoring the output of the frame pulse generation circuit 8,
An interrupt occurs when the first frame start pulse after the instruction is detected. When the interrupt response time has elapsed, the CPU 10 immediately starts the compression operation of the audio compression circuit 6, and the audio compression circuit 6 compresses the audio data obtained from the A / D converter 5. Therefore, the voice data is compressed immediately after the interrupt response time elapses, and the compressed voice data is sequentially transferred and accumulated in the ring buffer memory 7.

Further, the CPU 10 outputs a compression processing start signal to the moving picture compression circuit 4 after the interrupt response time has elapsed, and sets the moving picture compression circuit 4 in the ready mode. Then, the moving image compression circuit 4 is caused to start the compression processing by the second frame start pulse obtained from the frame pulse generation circuit 8. Therefore, for the moving picture compression circuit 4, A /
Although moving image data is continuously input from the D converter 3, after the compression start instruction is input by the user I / F 9,
The compression process is not executed until two frame start pulses are detected, and when the second frame start pulse is detected, the moving image data corresponding to the frame start pulse (first field data ) Will start the compression process.

By the way, the compressed moving image data is not output immediately from the time when the moving image compression circuit 4 starts the compression process, but naturally there is a delay time required for the data compression, and thereafter the compressed moving image data Output is started.
Therefore, the CPU 10 monitors whether the data output start state is set after the moving picture compression circuit 4 starts the compression operation, and immediately when the data output start state is set, the compressed audio data from the ring buffer memory 7 Start reading.

At that stage, the ring buffer memory 7 is
As described above, the compressed audio data after the time point at which the interrupt response time has elapsed after the first frame start pulse is detected is stored, but the CPU 10 also stores the address of the ring buffer memory 7 in parallel with the above control. Manage. Then, the CPU 10 confirms the address position of the compressed audio data at the time when the second frame start pulse is detected, and when starting the reading of the compressed audio data from the ring buffer memory 7, the address position after the address position is detected. Ring buffer memory 7 so that only data is read
Read control is executed.

As a result, the compressed audio data is output from the ring buffer memory 7 at a timing substantially coincident with the timing at which the compressed moving image data is output from the moving image compression circuit 4, and these data start the second frame. The compressed moving image data (first field data) of the frame indicated by the pulse and the compressed audio data corresponding to the compressed moving image data are provided in the state where the initial synchronization is established based on the compression start instruction from the user I / F 9. Compressed data will be output. Moreover, the establishment of the initial synchronization is performed by the user I.
It always holds even if the compression start instruction from / F9 is input at any timing.

When the initial synchronization is established as described above, since the moving image signal and the audio signal output from the VTR 1 are associated with each other, the frame pulse generation is also performed for the following moving image data and audio data. If the compression process is performed on a frame-by-frame basis based on the frame start pulse of the circuit 8, the compressed moving image data and the compressed audio data can be output in a constantly synchronized state. If the user I / F 9 gives an instruction to end the compression process when the moving image to be edited and recorded ends while checking the monitor device 21, the output of the compressed data is stopped and the desired moving image and audio are compressed. Only the data is recorded on the CD-RO by the data recording device 22.
It will be recorded in M22a. The data recording device 22
CD-RO each compressed data in the specified format
Although it is recorded in M22a, since each compressed data of moving image and sound is recorded in synchronization from the beginning, it is properly expanded / decompressed.
Naturally, when reproduced, a natural reproduction result can be obtained in which there is no time difference between the moving image and the sound.

[0023]

The "initial synchronization establishing method in the image and audio data compression apparatus" of the present invention has the above-mentioned configuration, and therefore has the following effects. In the image and audio data compression device, even when the compression instruction is given from the compression instruction means at an arbitrary timing, it is possible to output the compressed image data and the compressed audio data in a nearly perfect synchronization relationship. . In particular, an optimum compression device is realized when only data in a desired time zone is compressed and recorded on a recording medium while monitoring image and sound data of VTR or the like, or when transmitted through a communication line.

[Brief description of drawings]

FIG. 1 is a block circuit diagram (connected to a VTR and a data recording device) of a multimedia data compression device according to an embodiment of an “initial synchronization establishment method in a video and audio data compression device” of the present invention. .

FIG. 2 is a timing chart showing an operation of establishing initial synchronization in the compression apparatus of the embodiment.

[Explanation of symbols]

1 ... VTR, 2 ... compression device (compression device for image and audio data), 3,5 ... A / D converter, 4 ... moving image compression circuit (image compression processing means), 6 ... audio compression circuit (audio compression processing) Means), 7 ...
Ring buffer memory (buffer means), 8 ... Frame pulse generation circuit, 9 ... User I / F (compression instruction means), 10 ... C
PU (first control means, second control means), 21 ... Monitor device, 2
2 ... Data recording device, 22a ... Recording medium.

Front page continuation (72) Inventor Hatano Sakuma 3-12 Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Victor Company of Japan, Ltd. (72) Inventor Masaaki Tako 3-12 Moriya-cho, Kanagawa-ku, Yokohama Within Victor Company of Japan, Ltd.

Claims (1)

[Claims] 1. When receiving multimedia data in which image data and audio data are associated in time series with a synchronization signal, the image data is processed by the image compression processing means and the audio data is processed by the audio compression processing means. In a compression device for image and audio data that compresses and outputs each compressed data in time series correspondence, a compression instructing means for instructing to start a compression process of the multimedia data, and an image data of the image data using the synchronization signal. Frame signal generation means for generating a frame start signal, first control means for controlling the operation start of the image compression processing means and the audio compression processing means, and a buffer means for accumulating compressed audio data by the audio compression processing means. , Second control means for controlling reading of the compressed audio data stored in the buffer means is provided, and a command is issued from the compression instruction means. When there is an instruction input, the first control means starts the operation of the audio compression processing means based on the first frame start signal generated by the frame signal generation means after the instruction input, and The image compression processing means is set to the operation ready mode, the compression operation of the image compression processing means is started based on the next second frame start signal, and the image compression processing means delays and outputs the compressed image data. At this time, the second control means reads out and outputs compressed audio data corresponding to the audio data after the second frame start signal stored in the buffer means, and outputs the compressed audio data. Initial synchronization establishment method in.