JP2001086460A - Method and device for accelerating transcoding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable high speed division of a program file and to perform transcoding processing at high speed. SOLUTION: A program file 101 from a storage device is divided by a dividing circuit 105, transcoding processing is simultaneously performed by plural transcoding devices 102a and 102b and the divided program files are coupled by a coupling circuit 106 so that a transcoded program file can be generated. As a divided length of the program file, setting information (temporarily divided length) greater than the code length of one GOP is used and the program file is divided at the position of (n) multiple (n=0, 1...), namely, at the position of the first GOP and the position of the first GOP after the length is divided temporarily. The position of the GOP can be detected at high speed only by reading out a code stream until detecting the GOP from the position of temporarily divided length ×(n) (n=0, 1) inside a storage device where the program file is stored.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to transcoding, and more particularly, to a video disc recorder, a set disc,
The present invention relates to a method and an apparatus for speeding up transcoding for recompressing encoded audio and video which can be applied to or incorporated in electronic equipment such as a top box and a video server.

[0002]

2. Description of the Related Art A transcoding device comprises a decoding device and an encoding device, and is used for the purpose of increasing the free space of a storage device by recompressing a recorded program file. By using the transcoding device, it becomes possible to store another program file using the free space.

[0003]

However, a normal transcoding device requires the same processing time as the reproduction time of a program file. Therefore, even when transcoding is performed without reproducing the program file to make free space in the storage device, it takes the same time as when reproducing the program file, and there is a problem in terms of efficiency. For this reason, a method of performing processing in parallel using a plurality of transcoding devices (JP-A-7-123270 and JP-A-11-155128) is considered. It is difficult to divide a file (code stream) to be supplied to the apparatus and to perform synchronization processing between transcoding apparatuses.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is an object of the present invention to provide a transcoding speed-up method capable of speeding up file division for a plurality of transcoding devices. And a device.

Another object of the present invention is to provide a code stream dividing apparatus suitable for parallel processing of transcoding.

[0006]

According to the present invention, there is provided a transcoding method for reading a code stream from a storage device in which a code stream in GOP units is stored as a file and performing re-encoding for code compression. In the high-speed method, the code stream is read from a storage location corresponding to n times (n is zero and a positive integer) the setting information on the division length of the file (the code length of one GOP unit or more), and each of the read code streams is read. The position of the first GOP in the code stream is detected, the code stream in the divided range is read out independently from the detected storage position of each GOP, and re-encoding is performed in parallel by different transcoding devices. . Further, the detection of the GOP position from the storage position corresponding to n times the setting information is performed in time series from the head of the file.

The high-speed transcoding device of the present invention
In a high-speed transcoding device that reads a code stream from a storage device in which a code stream in units of P is stored as a file and performs re-encoding by code compression, the setting information regarding the division length of a file (a code length of 1 GOP unit or more) is obtained. a code stream reading unit that reads a code stream from storage locations corresponding to n times (n is a zero and a positive integer), a GOP detection unit that detects the position of the first GOP from each read code stream, An actual division position storage unit for storing the storage positions of the respective GOPs, a file reading unit for reading out the code streams in the respective division ranges from the storage positions of the stored GOPs, and re-encoding the read code streams. A plurality of transcoding devices and each re-encoded code stream And having a file writing unit for storing in the storage device as over arm. Also,
The code stream reading unit detects a GOP position from a storage position corresponding to n times the setting information in a time-series manner from the beginning of a file.

A code stream dividing apparatus for parallel processing of transcode according to the present invention reads a code stream from a storage device in which a code stream in units of GOPs is stored as a file and performs code compression re-encoding. Splitting device (1G)
A code stream reading unit that reads a code stream from a storage position corresponding to n times (n is a zero and a positive integer) of setting information related to setting information related to an OP unit or more, and a first GOP from each read code stream. GOP detection unit for detecting the position of each GOP, and each detected GOP
And a file reading unit that reads a code stream in a division range from the storage position of the stored GOP.
Further, the code stream reading unit detects a GOP position from a storage position corresponding to n times the setting information in a time series from the head of the file.

(Operation) Using a plurality of transcoding devices, a file is divided at GOP (Group of Picture) breaks, and transcoding is performed in units of code streams in a division range of about a designated size. The setting information (provisional division length) related to the division length equal to or longer than the code length of 1 GOP is used for dividing the code stream, and n times (n = 0, 1,...)
That is, the code stream is divided at the position of the first GOP, the position of the first GOP after the provisional division length, the position of the first GOP after the double provisional division length, and so on, and is coded by the number of transcoders corresponding to the number of divisions. Is performed in parallel. Detecting the position of a GOP only requires reading a code stream from the storage from the temporary division length × n (n = 0, 1,...) Position until the first GOP is detected. do not do.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a transcoding apparatus according to the present invention;

(Description of Configuration) FIG. 1 is a configuration diagram showing an embodiment of a transcoding device according to the present invention. 1
Circuit 105 which receives two program files 101 as input
And two transcoding devices 102a and 102b that receive the program file divided by the division circuit 105 as input.
And a combination circuit 106 that receives each output of the transcoding devices 102a and 102b as input and forms one transcoded program file 103.

The dividing circuit 105 inputs one program file 1 and outputs the program file 101 to the transcoding device 102a and the transcoding device 102b, for example, as two files separated into the first half and the second half of the file. I do. Transcoding device 102a,
At 102b, only the respective files are transcoded, and the transcoded files are combined by the combining circuit 106.
Respectively. The combining circuit 106 combines the files from the transcoding device 102a and the file from the transcoding device 102b, outputs the combined one program file 103, and stores it in the storage device.

Transcoding devices 102a, 102b
For example, since the first half and the second half of the file are simultaneously transcoded in parallel, the processing time is approximately 1 /
2 and high-speed transcoding is realized.

Next, a processing method for dividing one file and transcoding simultaneously will be described in more detail. First, a method of dividing a program file will be described with reference to FIGS.

FIG. 2 is a diagram showing a processing block for detecting a division position of a program file. A storage device 203 in which a program file is stored, and a provisional division length instructing unit 20 in which a provisional division length corresponding to a division length for dividing the program file is stored.
1, a code stream reading unit 202 that reads a file from the storage device 203, skips the file to a position (such as an address of data) specified by the provisional division length designating unit 201, and outputs a subsequent code stream; A GOP detection unit 204 that analyzes the code stream of the file output from the reading unit 202 and detects the start position (eg, data address) of the GOP;
Actual division position storage section 20 for recording the output of P detection section 204
And 5.

(Explanation of Operation) FIG. 3 is a view showing a flowchart relating to the file dividing process in the block diagram shown in FIG. The actual storage position information of the GOP of the program file is detected based on the file division length setting information from the temporary division length instructing unit 201, and the actual division position storage unit 20 is detected.
5 shows a procedure for storing the information in the storage unit 5. The position information stored in the actual division position storage unit 205 is used for dividing a program file to be supplied to each of a plurality of transcoder devices.

First, an initial value of the file division is set to the control variable n, and 1 is substituted for n in order to detect the position information of the first GOP of the file (step S31). Subsequently, the code stream reading unit 202
File 3 is opened, and the file pointer (file pointer) is advanced from the temporary division position designating unit 201 to a position obtained by multiplying the value of the setting information (temporary division length) regarding the file division length by (n-1). (Step S32).

It is checked whether or not the position of the file pointer has reached the end position (final position) of the file (step S33). If the position has been reached, the entire process ends, and if not, the process proceeds to step S34. . In step S34, a file is read from the position of the current file pointer, the read code stream is sent to the GOP detection unit 204, and the head position of the first GOP of the code stream is detected (step S35). It is checked whether the head position of the GOP has been detected (step S36),
If not detected, the process ends. If the head position of the GOP can be detected, the head file position of the detected GOP (for example, the address of a storage device or data) is stored in the actual division position storage means 205 (step S37).
Next, n + 1 is substituted for the control variable n (step S3).
8) Return to step S32 and repeat the same processing as above.

With the above processing operation, the actual division position storage unit 205 stores the start position information which is the GOP break of the file. The length of the file divided by the head position information of this GOP is
It becomes a value close to the provisional division length specified from 1. The temporary division length can be, for example, approximately half the length of all the files. In this case, the length of the division file is divided by the GOP at substantially the center of all the files. When the temporary division length is divided into a plurality of files of three or more, the temporary division length is approximately 1 / M of all files (M is, for example, an integer of three or more).
It can be.

Next, a method of simultaneously transcoding a plurality of divided files will be described with reference to an example in which a program file is divided into a first half and a second half. When using the two transcoding devices shown in FIG.
Uses the first head position information of the GOP stored in the real division position storage unit 205, supplies a code stream obtained by reading a program file in a storage device (not shown) from the position of the first GOP to the transcoding device 102a,
Using the head position information of the GOP in the middle of the program file, the code stream read from the position of the GOP is supplied to the transcoding device 102b, and transcoding is performed. The combining circuit 106 combines the coded output of the transcoding device. Also, a transcoded program is stored by storing the re-encoded output using the GOP head position information stored in the actual division position storage unit 205 in a storage device (not shown) as one program file. A file is generated.

In the program file division processing in the above processing, the file pointer performs an operation of skipping near a desired GOP position in accordance with an instruction from the temporary division position instructing unit 201, and it is necessary to trace all files. Therefore, it can be executed in a very short time as compared with the total reproduction time of the program file or the transcoding operation time, and the processing itself does not cause a processing delay that affects the entire transcoding.

(Other Embodiments) Next, another embodiment of the method and apparatus for speeding up transcoding according to the present invention will be described with reference to FIGS.

FIG. 4 is a configuration diagram showing a transcoding device according to the present embodiment. This embodiment includes a storage device 403 in which a file is stored, a file reading unit 411 that reads a file from the storage device 403,
412, 413 and transcoding units 421, 422, 423 for compressing the read encoded information again
And file write units 431, 432, and 433 for writing the re-encoded data to the storage device 403, respectively.
And a transcoding control unit 40 for instructing the transcoding units 421, 422, and 423 to start / end.
4 and an actual division position storage unit 405.

The transcode control unit 404 reads the head position information of the GOP from the real division position storage unit 405,
File reading unit 411 and transcoding unit 42
1 instructs transcoding. File reading unit 4
Reference numeral 11 reads a file in the storage device 403 from the position of the corresponding GOP and sends the file to the transcoding unit 421. The transcoding unit 421 sequentially recompresses the transmitted files and sends the files to the file writing unit 431. The file writing unit 431 writes the recompressed data to the storage device 403 based on the position of the GOP. The same operation as described above is performed simultaneously for the transcode units 422 and 423, and the recompressed data is stored in the storage device 403.

In the above embodiment, regarding the recompression ratio, the transcoding control section 44 sends the recompression rate (for example, 0.8) to the transcoding sections 421 to 423.
May be notified, or the recompression ratio may be stored in advance in each of the transcode units 421 to 423.

For the processing of the recompressed data, a temporary file may be written once and replaced with the original file after the end of transcoding.
Once recompressed data becomes smaller than the data amount of the original file, it may be overwritten on the read file. In this case, the files are merged when all the transcoding is completed, and a transcoded file is created.

FIG. 5 is a block diagram showing a transcoding device according to an embodiment using N transcoding devices. In this embodiment, the program files 501 to the N transcoding devices 502a to 502n are input by dividing one program file 501 into N files. Also, the N transcoding devices 502a to 502a-5
02n is output as one program file 503 by the combining circuit 105. The transcoding operation speeds up according to the number of transcoding devices.

FIG. 6 is a diagram showing an overall processing block diagram in the case where a program file is divided into N files and transcoding processing is performed. A storage device 603, a code stream reading unit 602 including a temporary division position indicating unit 601 and arithmetic units 606 and 607, and a GOP detecting unit 604.
, An actual division position storage unit 605, a transcode control unit 608, and a parallel transcode processing unit 609.

The temporary division position designating section 601 sets the value a of the division length, and the arithmetic section 606 sets a × (n-1) =
0 is calculated, the head position of the file is indicated as a file pointer related to the address of the storage device 603, reading is started from the position of the file pointer in the storage device 603, and a code stream is output. GOP detector 604
Detects the first GOP from the codestream,
The storage position information of the GOP is notified to the real division position storage unit 605, and the calculation unit 607 is instructed to calculate the GOP detection for the next file division. The actual division position storage unit 605 stores the storage position information, and the calculation unit 607 stores n
= N + 1 = 1, and the calculation unit 606 points to the file pointer a × 1, and repeats the same processing as described above. By repeating the above processing, the actual division position storage unit 605 stores the position information of the first GOP to be divided.

The transcode control unit 608 controls the storage device 603 and the parallel transcode processing unit 609 based on the GOP position information stored in the real division position storage unit 605 by the above processing, and stores the data by N transcode devices. The program files in the device 603 are read out in parallel and encoded, and are stored again in the storage device 603 as code-compressed program files.

FIG. 7 is a diagram showing another embodiment for acquiring the position information of the first GOP for dividing the program file into N files. Storage device 703, division position instructing section 701, and GOP detecting sections 704-1 to 704-N
702, an actual division position storage unit 705, and operation units 708-1 to 708-N.

In the present embodiment, a temporary division position instructing section 701
, A × 1... A × (n−1) based on the provisional division length a from
1 to 707-N, and outputs a code stream in parallel from each file pointer position.
In 4-1 to 704-N, the position information of the first GOP is detected and stored in the actual division position storage unit 705, and the detection of the position information to be divided is further accelerated by parallel processing. Is done.

[0033]

According to the present invention, the program file division for performing the transcoding parallel processing can be executed at high speed and reliably, so that the processing time of the entire transcoding can be sufficiently reduced. Further, since the reading position from the storage device for the transcoding process is clearly demarcated by the GOP position information, the synchronization operation between the plurality of transcoding devices is facilitated.

Further, according to the code stream dividing apparatus for parallel processing of transcode of the present invention, setting information (provisional division length) equal to or more than the code length of 1 GOP is used as the division length of the code stream, and n times as large. (N = 0, 1, 2,...), Ie, the first GOP position, the first GOP after the provisional division length
, The position of the first GOP after the provisional division length × 2,..., The position of the GOP is detected by the provisional division length × n
(N = 0, 1, 2,...) Since the code stream from the position to the detection of the GOP is merely read from the storage device, the processing is completed in a very short time, and even if the number of divisions of the program file increases, the It can be ignored for code processing time.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a transcoding speed-up method and apparatus according to the present invention.

FIG. 2 is a configuration diagram of file division position detection according to the present embodiment.

FIG. 3 is a flowchart illustrating a file dividing process according to the embodiment.

FIG. 4 is a diagram showing another embodiment of a transcoding speed-up method and apparatus according to the present invention.

FIG. 5 is a block diagram showing an operation of performing transcoding processing by dividing the file into N files.

6 is a diagram showing an overall processing block diagram when the transcoding process shown in FIG. 5 is performed.

FIG. 7 is a diagram showing another embodiment for acquiring GOP position information.

[Explanation of symbols]

101, 501 program files 102a, 102b, 102c, 502a, 502b,
502n Transcoding device 103, 503 Transcoded program file 105, 505 Dividing circuit 106, 506 Coupling circuit 201, 601, 701 Temporary division position instructing section 202, 602, 702 Code stream reading section 203, 503, 603, 703 Storage Apparatus 204, 604, 704-1, 704-2, 704-N
GOP detection unit 205, 405, 605, 705 Real division position storage unit 411, 412, 413 File read unit 404, 608 Transcode control unit 421, 422, 423 Transcode unit 431, 432, 433 File write unit 606, 607, 707-1, 707-2, 707-N
Operation unit 609 Parallel transcode processing unit

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Claims (6)

[Claims] 1. A transcoding speed-up method for reading a code stream from a storage device in which a code stream in units of GOP is stored as a file and performing re-encoding for code compression. The code streams are read from storage locations corresponding to n times (n is zero and a positive integer) the setting information about the length of the code stream, and the position of the first GOP of each read code stream is detected. A transcoding speed-up method characterized by independently reading a code stream in a divided range from a storage position of each GOP and performing re-encoding in parallel by different transcoding devices. 2. The method according to claim 1, wherein the detection of the position of the GOP from the storage position corresponding to n times the setting information is performed in chronological order from the beginning of the file. 3. A high-speed transcoding device that reads a code stream from a storage device in which a code stream in GOP units is stored as a file and performs re-encoding for code compression. ), And a GOP for detecting the position of the first GOP from each of the read code streams from a code stream reading unit that reads a code stream from a storage position corresponding to n times (n is zero or a positive integer) the setting information. A detection unit, a real division position storage unit that stores the storage position of each detected GOP, a file reading unit that reads a code stream in a division range from the storage position of the stored GOP, and a readout of each code stream And a plurality of transcoding devices for re-encoding Fast transcoding apparatus characterized by having a file writing unit for storing in the storage device as one code stream. 4. The high-speed encoding apparatus according to claim 3, wherein the code stream reading unit detects a GOP position from a storage position corresponding to n times the setting information in a time-series manner from the beginning of the file. Transcoding device. 5. A code stream division apparatus for parallel processing of transcode for reading a code stream from a storage device in which a code stream in GOP units is stored as a file and performing re-encoding for code compression. A code stream reading unit that reads a code stream from a storage position corresponding to n times (n is a zero or a positive integer) the setting information related to the length (a code length of one GOP unit or more); A GOP detecting unit for detecting the position of the GOP, an actual division position storing unit for storing the storage position of each detected GOP, and a file reading unit for reading a code stream of the division range from the stored storage position of the GOP. Code stream division apparatus for parallel processing of transcode characterized by having 6. The code according to claim 5, wherein the code stream reading unit detects the position of the GOP from a storage position corresponding to n times the setting information in a time series from the head of the file. Stream splitting device.