JP2021166342A - Distribution device and distribution method - Google Patents

Abstract

To provide a distribution device and a distribution method that can seamlessly switch contents.SOLUTION: The distribution device has a processor provided with a decryption unit, a detection unit, an insertion unit, a correction unit, and a distribution unit. The decryption unit decrypts time data of a first stream file and time data of a second stream file different from the first stream file. The detection unit detects, based on a result of decryption, overlapping of playback timings of pictures when the first stream file is switched for playback to the second stream file. When the overlapping is detected, the insertion unit inserts dummy data into the first stream file to resolve the overlapping. The correction unit corrects the time data of the first stream into which the dummy data is inserted. The distribution unit distributes the first stream file whose time data is corrected and the second stream file.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to a distribution device and a distribution method.

An IP rebroadcast system is known that rebroadcasts the digital broadcast of an MPEG (Moving Picture Experts Group) -2 system via an IP (Internet Protocol) network. Using this type of system, a service for distributing video / audio of specific content such as promotional content for sales promotion to a user terminal is provided. The user terminal repeatedly plays back the delivered content (loop playback).

Special Table 2005-537708 Japanese Unexamined Patent Publication No. 2011-2500 Special Table 2009-521164

Promotional content is for promotional purposes and is therefore replaced at any time or on a regular basis. At that time, if the content A being played is simply switched to the next content B, the continuity of the time data contained in the TS (Transport Stream) file is lost, and the user terminal (Set Top Box: STB) causes an error. There was something. The time information includes, for example, PCR (Program Clock reference), PTS (Presentation Time Stamp), DTS (Decoding Time Stamp), and the like.

To avoid this, there is a method of performing MPEG editing at the joint between contents and re-stamping PCR, PTS, DTS to ensure continuity, but editing only the end and the beginning between the two contents to be played in a loop. It is difficult to do so, and in the first place, it is not possible to perform MPEG editing in advance in the operation of deciding the sales promotion content to be played next time according to the situation. If the playback rates of the contents are different, but if the playback rates are the same, it is desired to prevent a shock when switching the contents so that the contents can be switched seamlessly.

Therefore, an object of the present invention is to provide a distribution device and a distribution method capable of seamlessly switching contents.

According to the embodiment, the distribution device distributes a stream file including a plurality of picture data including the encoded picture and time data that defines the reproduction timing for each picture. The distribution device includes a decoding unit, a detection unit, an insertion unit, a correction unit, and a distribution unit. The decoding unit decodes the time data of the first stream file and the time data of the second stream file different from the first stream file. Based on the result of decoding, the detection unit detects the overlap of the reproduction timings of the pictures when switching from the first stream file to the second stream file and reproducing the files. When an overlap is detected, the insertion unit inserts dummy data into the first stream file in order to eliminate the overlap. The correction unit corrects the time data of the first stream file in which the dummy data is inserted. The distribution unit distributes the first stream file and the second stream file in which the time data is modified.

FIG. 1 is a system diagram showing an example of a content distribution system according to an embodiment. FIG. 2 is a diagram for explaining a stream structure in an MPEG2-system. FIG. 3 is a diagram for explaining an error during switching reproduction. FIG. 4 is a flowchart showing an example of the processing procedure of the distribution device 4 in the embodiment. FIG. 5 is a diagram for explaining that the STB error is eliminated.

Next, an embodiment of the present invention will be described. In the embodiment, a content distribution system that conforms to the MPEG-2 system and distributes a TS (Transport Stream) file as a stream file is assumed.

FIG. 1 is a system diagram showing an example of a content distribution system according to an embodiment. The system of the present embodiment distributes, for example, video (including audio) of promotional content to a plurality of terminal devices by IP multicast. The promotion content is, for example, video content such as an advertisement / advertisement for sales promotion of a telecommunications carrier or a business operator such as BS digital broadcasting. Of course, the specific video content is not limited to the promotional content.

In FIG. 1, the distribution device 4 is connected to, for example, a personal computer (PC) 2 located at an editing base via a LAN (Local Area network) 3. The PC 2 creates a stream file for loop playback and transfers it to the distribution device 4 via the LAN 2.

The distribution device 4 acquires the stream file from the PC 2 and stores it in the storage unit 42. In the embodiment, the storage unit 42 stores the first stream file 42a, the second stream file 42b, and the modified first stream file 42a'. The first stream file 42a, the second stream file 42b, and the modified first stream file 42a'contain the time data Ta, Tb, and Ta', respectively. Here, the time data is information that defines the reproduction timing of the MPEG2-TS picture, and is, for example, PCR, PTS, or DTS. The structure of MPEG2-TS will be described later (Fig. 2).

The modified first stream file 42a'is played at the delivery destination immediately before the second stream file 42a. The second stream file 42b is switched and played from the modified first stream file 42a'at the delivery destination. The modified first stream file 42a'inserts the NULL TS of the required length into the first stream file 42a, and modifies the time data Ta so as to be consistent with the insertion of the NULL TS (time data (time data ( Modification) Ta'), the generated stream file. Details will be described later.

The processor 41 of the distribution device 4 processes the first stream file 42a. The distribution unit 43 reads the first stream file 42a from the storage unit 42 and distributes it to STB22-1 to 22-n via the network 5. Further, when the timing of switching reproduction comes, the distribution unit 43 reads the modified first stream file 42a'and the second stream file 42b from the storage unit 42 and distributes them to STB22-1 to 22-n. Here, the network 5 is, for example, an IP network.

Each of STB22-1 to 22-n is a dedicated terminal device (receiver) installed in a store or the like by a business operator contracted with a service business operator. Alternatively, STB22-1 to 22-n are installed in the home of a user who has a contract with a business operator such as BS digital broadcasting. Each of STB22-1 to 22-n is connected to, for example, a digital television receiver or a display device, and receives TS delivered by IP multicast via network 5. The STBs 22-1 to 22-n execute a reproduction process (including a decoding process) for the received TS, and output the video signal after the reproduction process to a digital television receiver or a display device.

The distribution device 4 is a computer, and includes a processor 41 such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit), and a memory as a storage unit 42. Here, the stream structure in the MPEG2-system will be described.

FIG. 2 is a diagram for explaining a stream structure in an MPEG2-system. The TS file has a hierarchical structure and stores an ES (Elementary Stream) including a plurality of picture data including encoded pictures. The ES includes a PTS (Presentation Time Stamp) field that defines the display timing of each picture and a DTS (Decoding Time Stamp) field that defines the decoding timing. PTS and DTS are time data that define the reproduction timing for each picture.

The ES is given a PH (PES Header) to become a PES (Packetized Elementary Stream) packet, and is further given a TH (TS Header) and multiplexed to generate a TS. The TS may be TTS (Time-stamped Transport Stream).

The ES includes, for example, an I picture, a B picture, and a P picture, and the display (reproduction) timing of each picture is defined by DTS and PTS. Here, if the DTS and PTS are inconsistent between different stream files, the picture cannot be played back at the timing specified by the DTS and PTS.

It will be described back to FIG. The processor 41 includes a decoding unit 41a, a detection unit 41b, an insertion unit 41c, and a correction unit 41d as processing functions according to the embodiment. These functional blocks can be understood as a process generated by the processor 41 executing arithmetic processing as the program stored in the storage unit 42 progresses.

The decoding unit 41a analyzes the PH of the first stream file 42a and extracts at least the last PTS and DTS. Then, the contents of these PTS and DTS are deciphered. The decoding unit 41a also analyzes the PH of the second stream file 42b and extracts at least the last PTS and DTS. Then, the contents of these PTS and DTS are deciphered. The decoded result is temporarily stored in the storage unit 42.

Based on the result of decoding by the decoding unit 41a, the detection unit 41b detects the overlap of the reproduction timings of the pictures of the respective stream files when the first stream file 42a is switched to the second stream file 42b for reproduction.

When the overlap of the reproduction timings of the pictures is detected, the insertion unit 41c adds NULL TS as dummy data to the end of the first stream file 42a in order to eliminate the overlap.

The correction unit 41d performs PCR re-stamping processing of the first stream file 42a to which the NULL TS is added. That is, the correction unit 41d corrects the PTS and DTS. As a result, the modified first stream file 42a'is generated. The modified first stream file 42a'is distributed via the network 5.

As shown in FIG. 3, when different stream files are simply switched and played back, an error may occur at the joint between the end and the beginning of the stream files that are back and forth in time. For example, the B21 picture at the beginning of the first stream file 42b may be interrupted between the P11 picture at the end of the first stream file 42a and the I11 picture. In this case, the STB cannot decide whether to display the P11 picture or the B22 picture. That is, inconsistencies occur in the display timings of a plurality of pictures, and as a result, playback becomes impossible (STB error).

As described above, the values of PCR, PTS, and DTS at the end of the content currently being played have nothing to do with the values of PCR, PTS, and DTS at the beginning of the content to be played next. That is, there is no continuity of time data (counter value) at the joint of switching playback. Despite this, STB synchronizes with the PCR before switching, and the display timing is determined by PTS and the decoding timing is determined by DTS, so it is necessary to resynchronize with the new PCR when switching to the next content. Instead, the playback was temporarily interrupted. The operation of the distribution device 4 capable of eliminating such a problem will be described below.

FIG. 4 is a flowchart showing an example of the processing procedure of the distribution device 4 in the embodiment. In FIG. 4, the distribution device 4 analyzes the PH of the TS file (first stream file) currently being played back, and detects the last PCR, PTS, and DTS (step S11). The detected PCR, PTS, and DTS are stored in the storage unit 42 as time data.

Next, the distribution device 4 determines whether or not the display timing of the last picture based on the detected PTS and DTS overlaps with the display timing of the first picture of the next reproduction (step S12). If there is an overlap (YES in step S12), the distribution device 4 inserts a NULL TS having a minimum time width that does not overlap with the picture at the beginning of the next reproduction (step S13).

Next, the distribution device 4 performs PCR re-stamping processing (step S14), further performs PTS and DTS re-stamping processing (step S15), and transmits a TS (TTS) packet (step S16). The procedure of steps S14 to S16 is repeated until the end of the loop reproduction (YES in step S17). The transmitted TS (TTS) packet is received at STB22-1 to 22-n. STB22-1 to 22-n restores ES from PES based on the PCR of the received TS (TTS) packet, and decodes and displays each picture based on PTS and DTS of ES.

Here, it is assumed that the content switching is performed (YES in step S18). Then, the distribution device 4 analyzes the PH of the TS file (second stream file) to be reproduced next time, and detects the leading PTS and DTS (step S21). Further, the distribution device 4 acquires the PTS and DTS at the end of the first stream file currently being played back from the storage unit 42 (step S22).

Next, the distribution device 4 collates the PTS and DTS at the beginning of the second stream file with the PTS and DTS at the end of the first stream file (step S23). When the PTS and DTS of the second stream file overlap with the last PTS and DTS currently being played (YES), the distribution device 4 sets the FULL TS having the minimum time width that does not overlap with the next playback start PTS and DTS. , Is inserted at the end of the first stream file (step S24).

Next, the distribution device 4 re-stamps the PCR of the second stream file so as to maintain continuity with the PCR currently being reproduced (step S25). Further, the distribution device 4 performs PTS and DTS restamping processing of the second stream file so that the relationship between the restamped PCR and the PTS and DTS values is the same as the relationship between the PCR and PTS and DTS before restamping (step S26). ).

Then, the distribution device 4 seamlessly sends out the second stream file (step S28) in synchronization with the end of the content currently being played (step S27). A separate buffer or the like may be provided to buffer the second stream file before the end of the content currently being played, and the transmission data of the content switching section may be prepared in advance.

In the second and subsequent rounds of loop playback after switching playback, the distribution device 4 performs NULL TS with a minimum time width in which the last PTS and DTS of the content currently being played and the first PTS and DTS of the next playback do not overlap. Insert and re-stamp and send PCR, PTS, DTS.

By inserting the NULL TS at the end of the stream file, as shown in FIG. 5, PCR is maintained at all stages of PES, ES, decoding, and display. That is, the display timings between the pictures do not overlap. As a result, STBs 22-1 to 22-n can continue to operate with minimal shock and without error. That is, even when the contents are replaced, the STB error at the joint of the loop playback is reduced, and the viewing can be performed smoothly.

As described above, in the embodiment, for discontinuous PCR, PTS, and DTS between contents that are not related to each other, the overlap of PTS and DTS at the joint of the contents is eliminated, and the continuity of PCR, PTS, and DTS is maintained. I made it. That is, the PCR is automatically re-stamped so as to maintain the continuity between the PCR at the end of the content currently being played and the PCR at the beginning of the content to be played next time between two different contents. In addition, by inserting FULL TS between the end of the content currently being played and the beginning of the content scheduled to be played next time, the PTS and DTS at the end of the content currently being played and the beginning of the content to be played next time are inserted. The overlap of PTS and DTS was eliminated.

As described above, according to the embodiment, it is possible to prevent an STB error at the joint of switching playback without preparing a separate MPEG editing device. Therefore, according to the embodiment, it is possible to provide a distribution device and a distribution method capable of seamlessly switching contents.

The present invention is not limited to the above embodiment. For example, the technique described in the embodiment is not limited to the switching playback in the case of loop playback of a single content, and can be similarly applied to the loop playback of a plurality of contents. Here, the loop reproduction of a plurality of contents is a form in which a reproduction order is determined in advance for a plurality of contents having the same reproduction rate, and the loop reproduction is performed from the end to the beginning of the reproduction order.

Although embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. This novel embodiment can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

2 ... personal computer (PC), 4 ... distribution device, 5 ... network, 41 ... processor, 41a ... decoding unit, 41b ... detection unit, 41c ... insertion unit, 41d ... correction unit, 42 ... storage unit, 42a ... first Stream file, 42b ... 2nd stream file, 42a'... modified 1st stream file, Ta, Tb ... time data, Ta'... time data (correction), 43 ... distribution unit.

Claims (6)

In a distribution device that distributes a stream file containing a plurality of picture data including encoded pictures and time data that defines a playback timing for each picture.
A decoding unit that decodes the time data of the first stream file and the time data of the second stream file different from the first stream file.
Based on the result of the decoding, the detection unit that detects the overlap of the reproduction timings of the pictures when switching from the first stream file to the second stream file and reproducing the files.
When the overlap is detected, an insertion part that inserts dummy data into the first stream file in order to eliminate the overlap, and an insertion portion.
A correction unit that corrects the time data of the first stream file into which the dummy data is inserted, and a correction unit that corrects the time data.
A distribution device including a distribution unit that distributes a first stream file in which the time data is modified and a distribution unit that distributes the second stream file. The first stream file and the second stream file are TS (Transport Stream) files of the MPEG (Moving Picture Experts Group) -2 system.
The distribution device according to claim 1, wherein the decoding unit decodes a PTS (Presentation Time Stamp) field and a DTS (Decoding Time Stamp) field of at least the last PES (Packetized Elementary Stream) packet of the TS file. The distribution device according to claim 2, wherein the insertion unit adds a NULL TS to the end of the first stream file. The distribution device according to claim 3, wherein the insertion portion adds a null TS having a minimum length for eliminating the overlap. The distribution device according to claim 2, wherein the correction unit re-stamps the PCR (Program Clock Reference) of the first stream file. In a distribution method for distributing a stream file containing a plurality of picture data including an encoded picture and time data that defines a playback timing for each picture.
A process in which a computer decodes the time data of the first stream file and the time data of the second stream file different from the first stream file.
Based on the result of the decoding, the computer detects the overlap of the reproduction timings of the pictures when switching from the first stream file to the second stream file and reproducing the files.
When the computer detects the overlap, the process of inserting dummy data into the first stream file in order to eliminate the overlap, and
The process in which the computer corrects the time data of the first stream file into which the dummy data is inserted, and
A distribution method comprising a process in which the computer distributes a first stream file in which the time data is modified and the second stream file.

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