JP4286061B2 - Video data format conversion system and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a video data format conversion system for re-encoding video data encoded in one format in another format.
[0002]
[Prior art]
In recent years, original video data is divided and assigned to a plurality of computers (nodes), format conversion (transcoding) is performed in parallel, and the transcoded data is finally combined to increase the processing speed. Distributed transcoding is being studied.
In addition, in a system having a plurality of computers, there is a system in which jobs are assigned to a plurality of computers and distributedly processed. (For example, refer to Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-166958 (page 3, FIG. 1)
[0004]
[Problems to be solved by the invention]
However, in the conventional distributed transcoding system for processing video data, after the format conversion is completed and combined, the image quality of the video is checked. For this reason, when the image quality has deteriorated in the converted video, it is necessary to transcode the entire original video again, and the processing efficiency cannot be said to be good.
[0005]
The present invention has been made in view of the above circumstances, and an object thereof is to provide a video data format conversion system and method that can further improve the processing efficiency of video data format conversion.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a video data format conversion system according to the first aspect of the present invention provides:
A server, a first computer that divides video data into a plurality of segments, a plurality of second computers that transcode the divided segments, and a third computer that combines the transcoded segments, A video data format conversion system for performing video data format conversion using distributed processing,
The server
Schedule generating means for generating schedule data indicating a schedule relating to video data allocation to each of the second computers based on the transcoding speed and data transfer speed of each of the second computers;
Division transfer instruction means for transmitting an instruction to divide and transfer video data based on the allocation schedule to the first computer,
The first computer includes means for dividing video data in accordance with an instruction from the server and sequentially transferring the video data to each of the second computers,
Each said second computer is
Means for sequentially receiving segments from the first computer;
Means for sequentially transcoding the received segments;
Image quality deterioration detection means for detecting image quality deterioration according to a predetermined criterion in segment transcoding;
Means for transmitting an image quality deterioration detection notification including information identifying the segment to the server when image quality deterioration is detected by the image quality deterioration detecting means during the transcoding process of one segment;
The server, in response to receiving the image quality degradation detection notification, re-segmentation instruction means for transmitting a segment division and transfer instruction for which image quality degradation has been detected to the first computer; Means for transmitting to each transcoding node encoding parameters used to re-encode the detected segments;
It is characterized by that.
[0007]
According to such a configuration, degradation in image quality is detected on a segment basis and the transcoding process is retried only for that segment, so that the overall processing time can be shortened and the processing efficiency can be improved.
[0008]
The schedule data created by the schedule creation means of the server may indicate at least a transfer start time and a transcoding start scheduled time of each segment assigned to each of the second computers,
The server subdivision instructing means refers to the schedule data, and with respect to the second computer that has detected the degradation of image quality during the transcoding process of one segment, the scheduled transcoding start time of the next segment Means for instructing the first computer to divide and transfer again the one segment by a data length that can be processed by the process, and to transfer the remaining divided part of the one segment to all the second segments And a means for transmitting to the first computer an instruction to perform redistribution to the computer after the division and transfer processing of the video data instructed by the division transfer instruction means.
[0009]
As a result, when image quality degradation is detected in one segment, reassignment of the segment can be instructed with little influence on the original schedule.
[0010]
The schedule creation means includes
In order to create a schedule for the first round of data transfer to a plurality of second computers, a segment having a predetermined length is assigned to the computer having the last data transfer order among the plurality of second computers, and the segment is transcoded. Time and transfer time are calculated, and the time obtained by adding the calculated transcoding time and transfer time is determined as the transcoding time of the computer whose data transfer order is one before, and the transcoding time is determined within the determined transcoding time. The transfer time of data with a codeable data length is calculated, and the time obtained by adding the determined transcoding time and the transfer time calculated based on the transcoding time is one order before the data transfer order. Computer transcoding time By repeating the process of determining and means for determining a data length and a data transfer time and transfer data transcoding time in the data transfer of the first cycle,
In order to create a schedule for the N-th data transfer (N is a positive number of 2 or more) for a plurality of second computers, the transfer order is transferred to the last computer in the (N-1) -th data transfer. The data length that can be transmitted with the determined transfer time is determined as the data transfer time of each second computer in the N-th data transfer by dividing the transcoding time of the segment to be divided by the total number of the second computers Is calculated from the data transfer rate of the second computer, and the transcoding time of each second computer in the N-th data transfer is determined from the calculated data length and the transcoding rate of the second computer. The data length, data transfer time, and transfer data transcoding time of the round data transfer Means for constant may be provided.
[0011]
Thus, for example, when the second computer performs transfer processing in the background during transcoding, and the data transfer rate of the second computer is sufficiently faster than the transcoding rate, the video to each second computer When creating a schedule relating to data allocation, an optimal schedule can be created from the viewpoint of both processing time and image quality of transferred data.
[0012]
A video data format conversion method according to the second aspect of the present invention is as follows:
A first computer dividing video data into a plurality of segments, a plurality of second computers transcoding the divided segments, and a third computer combining the transcoded segments; A video data format conversion method for performing video data format conversion using distributed processing,
A schedule generation step in which a server generates schedule data indicating a schedule relating to video data allocation to each of the second computers based on a transcoding speed and a data transfer speed of each of the second computers;
A division transfer instruction step in which the server transmits an instruction to divide and transfer video data based on the allocation schedule to the first computer;
The first computer dividing the video data in accordance with an instruction from the server and sequentially transferring the divided video data to the second computers;
The second computer receiving segments from the first computer and sequentially transcoding the received segments;
When the second computer detects image quality degradation based on a predetermined standard during the transcoding process of one segment, the image quality degradation detection notification including information specifying the segment is transmitted to the server;
In response to receiving the image quality degradation detection notification, the server transmits an instruction to divide and transfer a segment in which image quality degradation is detected to the first computer; and
Sending the encoding parameters used by the server to re-encode the segment in which the degradation of image quality is detected to each transcoding node;
It is characterized by providing.
[0013]
According to such a configuration, degradation in image quality is detected on a segment basis and the transcoding process is retried only for that segment, so that the overall processing time can be shortened and the processing efficiency can be improved.
[0014]
The schedule data created by the schedule generation step may indicate at least a transfer start time and a scheduled transcoding start time of each segment assigned to each of the second computers,
The re-segmentation instructing step refers to the schedule data, with respect to the second computer that has detected the degradation of image quality during the transcoding process of one segment, by the scheduled transcoding start time of the next segment. Instructing the first computer to divide and transfer the one segment by a processable data length, and to transfer the remaining divided portion of the one segment to all the second computers. A step of transmitting to the first computer an instruction to perform the redistribution processing after the division and transfer processing of the video data instructed by the division transfer instruction step.
[0015]
As a result, when image quality degradation is detected in one segment, reassignment of the segment can be instructed with little influence on the original schedule.
[0016]
The schedule creation step includes:
In order to create a schedule for the first round of data transfer to a plurality of second computers, a segment having a predetermined length is assigned to the computer having the last data transfer order among the plurality of second computers, and the segment is transcoded. Time and transfer time are calculated, and the time obtained by adding the calculated transcoding time and transfer time is determined as the transcoding time of the computer whose data transfer order is one before, and the transcoding time is determined within the determined transcoding time. The transfer time of data with a codeable data length is calculated, and the time obtained by adding the determined transcoding time and the transfer time calculated based on the transcoding time is one order before the data transfer order. Computer transcoding time By repeating the process of determining by the steps of determining a data length and data transfer transcoding time time and transfer data in the data transfer of the first cycle,
In order to create a schedule for the N-th data transfer (N is a positive number of 2 or more) for a plurality of second computers, the transfer order is transferred to the last computer in the (N-1) -th data transfer. The data length that can be transmitted with the determined transfer time is determined as the data transfer time of each second computer in the N-th data transfer by dividing the transcoding time of the segment to be divided by the total number of the second computers Is calculated from the data transfer rate of the second computer, and the transcoding time of each second computer in the N-th data transfer is determined from the calculated data length and the transcoding rate of the second computer. The data length, data transfer time, and transfer data transcoding time of the round data transfer A step of constant, may be provided.
[0017]
According to such a configuration, degradation in image quality is detected on a segment basis and the transcoding process is retried only for that segment, so that the overall processing time can be shortened and the processing efficiency can be improved.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings as a format conversion system for converting the format of video data encoded in a predetermined format into another format.
[0019]
FIG. 1 is a diagram showing the configuration of a format conversion system according to an embodiment of the present invention.
As shown in FIG. 1, the format conversion system includes a server computer (hereinafter referred to as a server) 1 and a plurality of computers (nodes), which are connected to each other via a network 10. The node includes a source node 21, a plurality of transcoding nodes 22, and a destination node 23.
[0020]
The server 1 includes a computer that includes a control unit, a storage unit, and a communication control unit. The storage unit stores operation programs executed by the control unit and various data necessary for processing (data transfer rate, transcoding rate, etc. of each transcoding node 22), and the control unit is stored in the storage unit. The scheduling unit 1a, the node control unit 1b, and the like are logically realized by executing the operation program and the like.
[0021]
The scheduling unit 1 a performs an initial scheduling process for assigning video data to be processed to each transcoding node 22.
In this initial scheduling process, on the basis of the segment transfer rate and transcoding rate of each transcoding node 22, the method of allocating each segment obtained by dividing the source (video data) to be processed to each transcoding node 22, Schedule data indicating the scheduled transfer start time of each segment for each transcoding node 22 and the scheduled transcoding start time of each segment in each transcoding node 22 is created. Each transcoding node 22 in the present system receives the next segment in the background during segment transcoding, and the schedule created here is also based on this.
[0022]
The initial scheduling process will be specifically described with reference to FIG. In the first round of data transfer, the scheduling unit 1a first transfers a segment sequentially to a plurality of transcoding nodes 22 (nodes 1 to 4 in the illustrated example). In the example, data of the minimum segmentable segment length is assigned to the node 4). Then, the transcoding time of the allocated data is calculated using the transcoding speed of the transcoding node 22, and a time obtained by adding the data transfer time of the data of the minimum slicable segment length to the transcoding time is obtained, The time is defined as the transcoding time of the node in the previous transfer order (node 3 in the example in the figure), the segment length data that can be transferred at that time is obtained from the data transfer rate of the transcoding node 22, The process assigned to the node (node 3) is sequentially performed for each node (node 2 and node 1). For example, for the node 2, the data transfer time allocated to the node 3 is calculated from the data transfer rate, and the sum of the calculated node 3 data transfer time and the node 3 transcoding time is the node 2 transcoding time. A segment having a data length that can be transcoded within that time is allocated. For node 1, the data transfer time allocated to node 2 is calculated from the data transfer rate, and the time obtained by adding the calculated data transfer time of node 2 and the transcoding time of node 2 is the transcoding time of node 1. Allocate a segment of data length that can be transcoded within that time. Thereby, the data length, transfer time, transcoding time, etc. of the segment assigned to each node in the first round of data transfer are determined.
[0023]
Next, for the data transfer in the Nth cycle (after the second cycle), in the data transfer in the (N-1) th cycle, the data assigned to the last node in the transfer order (node 4 in FIG. 2) The transcoding time is equally divided by the total number of transcoding nodes 22, the data length that can be transferred in the equally divided time is obtained using the data transfer rate of the transcoding node 22, and assigned to each node in the N-th data transfer. The data length. The data transcoding time is calculated from the data length and the node transcoding speed. Then, in the last round of data transfer (phase M in the example shown in the figure), if there are no sources left to allocate the determined data length segment to each node, for example, the remaining source portion is equally divided. Thus, the segment length assigned to each node is determined. Thereby, the data length, transfer time, transcoding time, etc. of the segment assigned to each node are determined in the Nth round of data transfer.
[0024]
Then, for example, the scheduling unit 1a adds each segment sequentially transferred to each node by sequentially adding the initial transfer time of the segment and the transcoding time of each subsequent segment with reference to a predetermined scheduled transfer start time. The transfer start time, the scheduled transcoding start time, and the like are obtained and stored in the storage unit as schedule data.
In general, since the data transfer rate of the transcoding node 22 is sufficiently higher than the transcoding rate, the data length of the segment allocated to each node as described above gradually increases. This makes it easy to control the bit rate, suppresses variations in image quality, and improves the image quality when combined.
[0025]
In addition, the scheduling unit 1a responds to a notification (degradation of image quality detection) that the image quality degradation is detected from the transcoding node 22, and rescheduling processing for reassigning the corresponding segment to each transcoding node 22 I do. The image quality degradation detection notification from the transcoding node 22 includes, for example, information for identifying a segment in which image quality degradation is detected (image quality degradation detection segment), information on the quantization step used for encoding the segment, and the like.
[0026]
The rescheduling process will be described with reference to FIG. First, the scheduling unit 1a obtains a time Ta from the time when the image quality deterioration is detected until the transcoding of the next segment starts at the node (image quality deterioration detection node) where the image quality deterioration is detected. Specifically, when the time when image quality degradation is detected is tc [s] and the scheduled transcoding start time of the segment following the image quality degradation is tn [s], time Ta [s] is It is calculated | required by the formula shown.
[0027]
[Expression 1]
Ta [s] = tn−tc
[0028]
Note that the information on the time tc [s] at which the image quality degradation is detected may be included in the image quality degradation detection notification to the server 1 by the image quality degradation detection node, or the server 1 detects the image quality degradation from the node. The time when the notification is received may be acquired from an internal timer, and the time may be assumed to be the time when the image quality deterioration is detected.
[0029]
Next, the scheduling unit 1a obtains the data length Lc that can be transcoded during the time Ta by using the equation shown in Equation 2 with the node transcoding speed V [bit / s]. Then, this data length Lc is the length of the portion to be reassigned to the node that has detected the image quality deterioration in the image quality deterioration detection segment.
[0030]
[Expression 2]
Lc [bit] = Ta / V
[0031]
In addition, the scheduling unit 1a sets the total length of the image quality degradation detection segment to L [bit], and calculates the data length Lr of the remaining portion that is not transcoded at the time Ta among the segments in which the image quality degradation has been detected by the equation (3) .
[0032]
[Equation 3]
Lr [bit] = L−Lc
[0033]
The data length to be allocated to each node is determined by, for example, equally dividing the remaining data length Lr [bit] by all the transcoding nodes 22.
For example, for data redistributed to each transcoding node 22, for example, a transcoding time or the like is obtained and added to the end of the original schedule data.
[0034]
The node control unit 1b performs a process of transmitting various instructions to each node (source node 21, transcoding node 22, and destination node 23).
For example, the node control unit 1b transmits to the source node 21 a division / transfer instruction that instructs the source to be divided into segments of a predetermined length and transferred to each node. The source to be processed may be transmitted in advance, or may be transmitted together with the division / transfer instruction. This division / transfer instruction instructs to divide the source into segments of a predetermined segment length based on the schedule data generated by the initial scheduling process, and transfer it to each transcoding node 22, for example, Includes information such as the data length of the transfer segment to each node in the first round, the data length of the transfer segment to each node in the second round, ..., the transfer segment data length to each node in the Mth round . Further, information on the scheduled transfer start time and the scheduled transcoding start time for each segment may be included.
[0035]
In addition, the node control unit 1b transmits to the source node 21 a subdivision / transfer instruction for retrying transcoding for the image quality degradation detection segment. The re-division / transfer instruction is an instruction to divide the image quality detection segment into predetermined length parts and immediately transfer them to the image quality deterioration detection node, and to redistribute the remaining divided parts to the transcoding nodes 22. And an instruction to perform the processing after the division of the source and the transfer of each segment designated by the division / transfer instruction. The previous instruction includes, for example, information for identifying an image quality degradation detection node (for example, node ID, address, etc.), information for identifying an image quality degradation detection segment (for example, segment number, etc.) based on a calculation result by rescheduling processing, etc. ), Information such as the length Lc of the segment portion to be immediately reassigned to the image quality degradation detection node. The subsequent instruction includes information such as the length obtained by dividing the data length Lr of the remaining portion when the length Lc portion is divided from the image quality deterioration detection segment by the total number of nodes.
[0036]
In addition, the node control unit 1 b transmits a transcoding instruction for the transferred segment to the transcoding node 22.
In addition, the node control unit 1b supplies the encoding parameter information used when re-encoding the divided data of the image quality deterioration detection segment together with information (segment number or the like) for specifying the image quality deterioration detection segment to each transcoding node 22. Send. This encoding parameter is a parameter used for processing for improving the image quality of the image quality degradation segment in each transcoding node 22. The content of the process for improving the image quality is arbitrary. For example, when improving the image quality by applying a noise removal or smoothing filter as a pre-process for the reassigned data, the encoding parameter is the preceding parameter. Indicates parameters used in processing. In addition, when the image quality is improved by encoding the target segment by increasing the bit rate, the encoding parameter indicates the value of the bit rate.
[0037]
In addition, the node control unit 1b transmits an instruction to combine the accumulated segments to the destination node 23 in response to, for example, receiving a notification that the transcoding of the segments has been completed from all the transcoding nodes 22. To do.
[0038]
The source node 21 includes a computer that includes a control unit, a storage unit, and a communication control unit. The storage unit stores the operation program executed by the control unit and various data necessary for the processing. The control unit executes the operation program stored in the storage unit, thereby logically dividing the dividing unit 21a and the like. Realize.
The dividing unit 21 a divides the video data into a plurality of segments having a predetermined segment length in accordance with a division / transfer instruction from the server 1, and performs a process of sequentially transferring the divided segments to the transcoding nodes 22.
Further, the dividing unit 21a divides the segment having the image quality degradation into the data length Lc and the data length Lr in accordance with the re-division / transfer instruction from the server 1, and detects the data quality Lc data degradation. Transfer to the selected node immediately. Then, data having a data length obtained by dividing the remaining data length Lr by the number of nodes is added to the end of the transfer schedule to each node.
[0039]
The transcoding node 22 includes a computer that includes a control unit, a storage unit, and a communication control unit. The storage unit stores an operation program executed by the control unit and various data necessary for processing. The control unit executes the operation program stored in the storage unit, thereby converting the conversion control unit 22a, encoding / decoding. The unit 22b and the image quality deterioration detection unit 22c are logically realized.
[0040]
The conversion control unit 22a controls the entire transcoding node 22 in accordance with an instruction from the server 1 or the like. The conversion control unit 22a stores the segment received sequentially from the source node 21 in the storage unit, processes the transcoding instruction from the server 1 to the encoding / decoding unit 22b, and the data encoded by the encoding / decoding unit 22b. Processing for transferring (encoded data) to the destination node 23, processing for notifying the server 1 when the encoding / decoding unit 22b detects deterioration in image quality and stopping the encoding processing, and dividing the image quality deterioration segment A process of receiving and storing an encoding parameter to be used for data from the server 1, a process of notifying the server 1 that the transcoding of the allocated segment is completed, and the like are performed.
[0041]
The encode / decode unit 22b reads and decodes data of a predetermined segment stored in the storage unit in accordance with an instruction from the server 1, and performs a process of encoding in another predetermined format. Further, the encoding / decoding unit 22b stops the encoding process upon receiving a notification of the occurrence of image quality degradation from the image quality degradation detection unit 22c.
In addition, the encoding / decoding unit 22b increases predetermined processing (for example, noise removal, filtering by a smoothing filter, and bit rate) to improve the image quality when encoding the reassigned data for the image quality degradation segment. Encoding). In this predetermined process, the encoding parameter received from the server 1 is used.
[0042]
The image quality deterioration detection unit 22c performs image quality deterioration detection processing for detecting that image quality deterioration has occurred in the encoding processing by the encoding / decoding unit 22b. In this image quality deterioration detection process, for example, the value of the quantization step used in the encoding process by the encoding / decoding unit 22b is monitored from the log, and it is considered that the image quality has deteriorated when a predetermined limit value is exceeded. When the image quality deterioration detection unit 22c detects the image quality deterioration, the image quality deterioration detection unit 22c notifies the encoding / decoding unit 22b to that effect.
[0043]
The destination node 23 includes a computer that includes a control unit, a storage unit, and a communication control unit. The storage unit stores an operation program executed by the control unit and various data necessary for processing, and the control unit executes the operation program stored in the storage unit to logically realize the coupling unit 23a. To do.
The combining unit 23a receives each segment after the conversion process from each transcoding node 22, accumulates and stores it in the storage unit, sequentially combines the accumulated segments according to a combination instruction from the server 1, After completion of the joining process, a joining completion signal is transmitted to the server 1.
[0044]
Next, the overall processing flow in the format conversion system of the present invention will be described with reference to FIG.
First, the server 1 performs initial scheduling processing, creates schedule data for assigning a source to each transcoding node 22 (step S1), and transmits a division / transfer instruction to the source node 21 (step S2). The source node 21 divides the source into segments having a specified segment length in accordance with the division / transfer instruction from the server 1, and transfers the segment to each transcoding node 22 (step S3).
Further, the server 1 transmits a transcoding instruction for the transferred segment to each transcoding node 22 (step S4).
[0045]
Each transcoding node 22 receives the segment transferred from the source node 21 and stores it in the storage unit. Also, segment transcoding is executed in accordance with the transcoding instruction from the server 1 (step S5). Transcoding node 22 receives and stores the next segment in the background while performing segment transcoding. The transcoding node 22 also performs processing for detecting degradation of image quality by monitoring the quantization step in the log in the transcoding processing (step S6). The segments for which transcoding has been completed are sequentially transmitted to the destination node 23 (or may be batch transmission).
[0046]
When no transcoding node 22 detects any deterioration in image quality during the transcoding process (step S7: No), each transcoding node 22 notifies the server 1 of the end of transcoding ( Step S11).
When the server 1 receives the notification that the transcoding is completed from all the transcoding nodes 22, the server 1 transmits a segment combination instruction to the destination node 23 (step S12).
In response to this, the destination node 23 combines the accumulated segments and transmits a combination completion signal to the server 1 (steps S13 and S14).
[0047]
Further, in step S7, for example, when image quality degradation is detected in any of the transcoding nodes 22, the transcoding node 22 stops the transcoding process (step S8), and notifies the image quality degradation detection notification to the server. 1 (step S9).
The server 1 that has received the image quality deterioration detection notification performs rescheduling processing, and the data length that does not affect the transcoding schedule of the subsequent segment in the image quality deterioration detection node, that is, the subsequent segment A data length Lc that can be transcoded before the scheduled transcoding start time is obtained. Further, the remaining data Lr is obtained based on the data length Lc, and the data length assigned to each node is determined by equally dividing the number of nodes (step S10).
[0048]
Then, the server 1 transmits to the source node 21 an instruction (subdivision / transfer instruction) for instructing subdivision and transfer for the image quality deterioration detection segment (step S2). In addition, the server 1 transmits, to each transcoding node 22, an encoding parameter used in encoding processing of the reassignment data of the segment in which the image quality deterioration is detected, together with information for specifying the image quality deterioration segment.
[0049]
The source node 21 that has received the re-division / transfer instruction divides the designated segment (image quality degradation segment) into the designated data length Lc and the remaining portion. Then, the data of the data length Lc is transferred to the image quality deterioration detection node for the image quality deterioration segment, and the remaining part is divided into the specified length, and the transfer schedule is added to the end of the transfer schedule for each node. (Step S3).
In addition, the server 1 transmits a transcoding instruction for the retransmitted segment to each transcoding node 22 (step S4).
[0050]
When each transcoding node 22 successfully completes the transcoding for all the segments transferred from the node (the segments for the original transfer schedule and the segments reassigned by the detection of the image quality deterioration), the notification is made. Is transmitted to the server 1 (steps S5 to 8, 11).
In response to this, the server 1 transmits a segment combination instruction to the destination node 23 (step S12), combines the segments in which the destination node 23 is integrated, and transmits a combination completion signal to the server 1 (step S12). S13, S14).
[0051]
As described above, according to the present invention, degradation in image quality is detected on a segment basis and the transcoding process is retried only for that segment, thereby reducing the overall processing time and improving the processing efficiency. Can do.
In addition, for the image quality degradation detection segment, the segment is divided and reassigned to a length that can be processed within the originally scheduled processing time, and the remaining part is additionally redistributed to each node. The work schedule can be hardly affected.
[0052]
In the above description, the image quality deterioration detection unit 22c detects the deterioration of the image quality by detecting the abnormality of the quantization step. However, the present invention is not limited to this, and various other methods can be adopted. For example, the deterioration of the image quality may be detected by checking whether the S / N ratio (signal to noise ratio) output from the encoding / decoding unit 22b is below a threshold value.
[0053]
The above system configuration is an example. For example, the function of one computer may be realized by a plurality of computers, and the functions of a plurality of computers may be realized by a single computer. .
For example, there may be a plurality of source nodes 21, and the plurality of source nodes 21 may share the above-described processing related to source division / transfer.
Further, at least one of the source node 21 and the destination node 23 may also serve as the transcoding node 22.
[0054]
The system of the present invention can be realized using a normal computer system, not a dedicated system. For example, a program for executing the above operation is stored in a computer-readable recording medium (FD, CD-ROM, DVD, etc.) and distributed, and the program is installed in the computer to execute the above processing. A server 1, a source node 21, a plurality of transcoding nodes 22, a destination node 23, and the like may be configured. Further, it may be stored in a disk device included in a server device on a network such as the Internet, and may be downloaded onto a computer, for example, superimposed on a carrier wave.
Further, when the OS realizes the above functions by sharing the OS or jointly with the OS and the application, only the part other than the OS may be stored and distributed in a medium, or may be superimposed on a carrier wave to a computer. You may download it.
[0055]
【The invention's effect】
According to such a configuration, it is possible to shorten the overall processing time and improve the processing efficiency in the video data format conversion processing.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a format conversion system according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining initial scheduling processing;
FIG. 3 is a diagram for explaining rescheduling processing;
4 is a diagram for explaining an overall processing flow in the format conversion system of FIG. 1; FIG.
[Explanation of symbols]
1 server
1a Scheduling part
1b Node control unit
2 nodes
10 network
21 Source node
21a Dividing part
22 Transcoding node
22a Conversion control unit
22b Encoding / decoding part
22c Image quality deterioration detection unit
23 Destination node
23a joint

Claims (6)

A server, a first computer that divides video data into a plurality of segments, a plurality of second computers that transcode the divided segments, and a third computer that combines the transcoded segments, A video data format conversion system for performing video data format conversion using distributed processing,
The server
Schedule generating means for generating schedule data indicating a schedule relating to video data allocation to each of the second computers based on the transcoding speed and data transfer speed of each of the second computers;
Division transfer instruction means for transmitting an instruction to divide and transfer video data based on the allocation schedule to the first computer,
The first computer includes means for dividing video data in accordance with an instruction from the server and sequentially transferring the video data to each of the second computers,
Each said second computer is
Means for sequentially receiving segments from the first computer;
Means for sequentially transcoding the received segments;
Image quality deterioration detection means for detecting image quality deterioration according to a predetermined criterion in segment transcoding;
Means for transmitting an image quality deterioration detection notification including information identifying the segment to the server when image quality deterioration is detected by the image quality deterioration detecting means during the transcoding process of one segment;
The server, in response to receiving the image quality degradation detection notification, re-segmentation instruction means for transmitting a segment division and transfer instruction for which image quality degradation has been detected to the first computer; Means for transmitting to each transcoding node encoding parameters used to re-encode the detected segments;
A video data format conversion system characterized by that. The schedule data created by the schedule generating means of the server indicates at least the transfer start time and the transcoding start scheduled time of each segment allocated to each of the second computers,
The server subdivision instructing means refers to the schedule data, and with respect to the second computer that has detected the degradation of image quality during the transcoding process of one segment, the scheduled transcoding start time of the next segment Means for instructing the first computer to divide and transfer again the one segment by a data length that can be processed by the process, and to transfer the remaining divided part of the one segment to all the second segments Means for transmitting, to the first computer, an instruction to perform redistribution to the computer after the division and transfer processing of the video data instructed by the division transfer instruction means.
The video data format conversion system according to claim 1, wherein: The schedule creation means includes
In order to create a schedule for the first round of data transfer to a plurality of second computers, a segment having a predetermined length is assigned to the computer having the last data transfer order among the plurality of second computers, and the segment is transcoded. Time and transfer time are calculated, and the time obtained by adding the calculated transcoding time and transfer time is determined as the transcoding time of the computer whose data transfer order is one before, and the transcoding time is determined within the determined transcoding time. The transfer time of data with a codeable data length is calculated, and the time obtained by adding the determined transcoding time and the transfer time calculated based on the transcoding time is one order before the data transfer order. Computer transcoding time By repeating the process of determining and means for determining a data length and a data transfer time and transfer data transcoding time in the data transfer of the first cycle,
In order to create a schedule for the N-th data transfer (N is a positive number of 2 or more) for a plurality of second computers, the transfer order is transferred to the last computer in the (N-1) -th data transfer. The data length that can be transmitted with the determined transfer time is determined as the data transfer time of each second computer in the N-th data transfer by dividing the transcoding time of the segment to be divided by the total number of the second computers Is calculated from the data transfer rate of the second computer, and the transcoding time of each second computer in the N-th data transfer is determined from the calculated data length and the transcoding rate of the second computer. The data length, data transfer time, and transfer data transcoding time of the round data transfer And means for constant, a
3. The video data format conversion system according to claim 1, wherein the video data format conversion system is a video data format conversion system. A first computer dividing video data into a plurality of segments, a plurality of second computers transcoding the divided segments, and a third computer combining the transcoded segments; A video data format conversion method for performing video data format conversion using distributed processing,
A schedule generation step in which a server generates schedule data indicating a schedule relating to video data allocation to each of the second computers based on a transcoding speed and a data transfer speed of each of the second computers;
A division transfer instruction step in which the server transmits an instruction to divide and transfer video data based on the allocation schedule to the first computer;
The first computer dividing the video data in accordance with an instruction from the server and sequentially transferring the divided video data to the second computers;
The second computer receiving segments from the first computer and sequentially transcoding the received segments;
When the second computer detects image quality degradation based on a predetermined standard during the transcoding process of one segment, the image quality degradation detection notification including information specifying the segment is transmitted to the server;
In response to receiving the image quality degradation detection notification, the server transmits an instruction to divide and transfer a segment in which image quality degradation is detected to the first computer; and
Sending the encoding parameters used by the server to re-encode the segment in which the degradation of image quality is detected to each transcoding node;
A video data format conversion method comprising: The schedule data created by the schedule generation step indicates at least a transfer start time and a transcoding start scheduled time of each segment assigned to each of the second computers,
The re-segmentation instructing step refers to the schedule data, with respect to the second computer that has detected the degradation of image quality during the transcoding process of one segment, by the scheduled transcoding start time of the next segment. Instructing the first computer to divide and transfer the one segment by a processable data length, and to transfer the remaining divided portion of the one segment to all the second computers. Transmitting to the first computer an instruction to perform the redistribution processing after the division and transfer processing of the video data instructed by the division transfer instruction step.
The video data format conversion method according to claim 4, wherein: The schedule creation step includes:
In order to create a schedule for the first round of data transfer to a plurality of second computers, a segment having a predetermined length is assigned to the computer having the last data transfer order among the plurality of second computers, and the segment is transcoded. Time and transfer time are calculated, and the time obtained by adding the calculated transcoding time and transfer time is determined as the transcoding time of the computer whose data transfer order is one before, and the transcoding time is determined within the determined transcoding time. The transfer time of data with a codeable data length is calculated, and the time obtained by adding the determined transcoding time and the transfer time calculated based on the transcoding time is one order before the data transfer order. Computer transcoding time By repeating the process of determining by the steps of determining a data length and data transfer transcoding time time and transfer data in the data transfer of the first cycle,
In order to create a schedule for the N-th data transfer (N is a positive number of 2 or more) for a plurality of second computers, the transfer order is transferred to the last computer in the (N-1) -th data transfer. The data length that can be transmitted with the determined transfer time is determined as the data transfer time of each second computer in the N-th data transfer by dividing the transcoding time of the segment to be divided by the total number of the second computers Is calculated from the data transfer rate of the second computer, and the transcoding time of each second computer in the N-th data transfer is determined from the calculated data length and the transcoding rate of the second computer. The data length, data transfer time, and transfer data transcoding time of the round data transfer Comprising the steps of: a constant, a,
6. The video data format conversion method according to claim 4, wherein the video data format is converted.

Images