CN102480634B - The method, apparatus and system that in Mobile Multimedia Broadcasting, classified service is synchronous - Google Patents
The method, apparatus and system that in Mobile Multimedia Broadcasting, classified service is synchronous Download PDFInfo
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- CN102480634B CN102480634B CN201010557758.7A CN201010557758A CN102480634B CN 102480634 B CN102480634 B CN 102480634B CN 201010557758 A CN201010557758 A CN 201010557758A CN 102480634 B CN102480634 B CN 102480634B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
- H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
- H04N21/234—Processing of video elementary streams, e.g. splicing of video streams, manipulating MPEG-4 scene graphs
- H04N21/2343—Processing of video elementary streams, e.g. splicing of video streams, manipulating MPEG-4 scene graphs involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements
- H04N21/234327—Processing of video elementary streams, e.g. splicing of video streams, manipulating MPEG-4 scene graphs involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements by decomposing into layers, e.g. base layer and one or more enhancement layers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
- H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
- H04N21/242—Synchronization processes, e.g. processing of PCR [Program Clock References]
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/60—Network structure or processes for video distribution between server and client or between remote clients; Control signalling between clients, server and network components; Transmission of management data between server and client, e.g. sending from server to client commands for recording incoming content stream; Communication details between server and client
- H04N21/61—Network physical structure; Signal processing
- H04N21/6106—Network physical structure; Signal processing specially adapted to the downstream path of the transmission network
- H04N21/6131—Network physical structure; Signal processing specially adapted to the downstream path of the transmission network involving transmission via a mobile phone network
Abstract
The present invention relates to the method, apparatus and system that in a kind of Mobile Multimedia Broadcasting, classified service is synchronous, when each layer bit stream of the classified service in MPEG-2TS code stream is transmitted by CMMB, by unified timestamp, synchronous between each layer bit stream (that is: each individual-layer data) ensureing classified service, thus ensure the normal enforcement of classified service in CMMB.
Description
Technical field
The present invention relates to mobile communication technology field, specifically a kind of mobile multimedia broadcast system (CMMB, when transmitting MPEG-2TS stream classified service ChinaMobileMultimediaBroadcasting), realize the method and system of the multiple hierarchical synchronization of classified service.
Background technology
Along with the development of the communication technology, the application of China mobile multi-media broadcasting technology is more and more wider.At present, China Mobile multimedia broadcasting system (is called for short: CMMB) standard defines in broadcasting service frequency range, the frame structure, Channel Coding and Modulation etc. of mobile multimedia broadcast system broadcast channel transmission signal.Specify in CMMB standard, adopt multiplexed sub frame to carry out the stream medium data such as encapsulate video, audio frequency, transmit.
Classified service refers to that encoder is encoded to content source, produce the code stream of many levels, Primary layer code stream can be decoded separately, and enhancement layer bitstream comprises the additional information for improving low-lever code current mass, needs to decode together with the low layer code stream comprising Primary layer.Classified service can realize other differentiated service in poor service, realize the ability of various terminal adaptation, and have plurality of advantages, therefore, in CMMB system, transmit classified service is necessary.
In classified service, terminal is when frame data receive, and code stream can be encoded in multiple layering.In end side, need the code stream by different layering to merge, as multiple layerings of same frame of video are combined, then carry out video decode and represent.When merging, must be synchronous between each layer bit stream, what guarantee participated in merging is same access unit code stream, ensure the success merged, merge successful guarantee subsequent decoding and represent successfully.
In prior art, each layer bit stream of classified service in being flowed by MPEG-2TS is not provided to be transmitted by CMMB, and the synchronous technology between each layer bit stream ensureing above-mentioned multiple classified service.
Summary of the invention
Main purpose of the present invention is to provide the method, apparatus and system that in a kind of Mobile Multimedia Broadcasting, classified service is synchronous, each layer bit stream of classified service in being flowed by MPEG-2TS is transmitted by CMMB, and synchronous between each layer bit stream ensureing above-mentioned multiple classified service.
The technical solution adopted for the present invention to solve the technical problems is:
In Mobile Multimedia Broadcasting, classified service sends a synchronous method, and it comprises:
The MPEG-2TS code stream that front end transmitting apparatus received code equipment sends;
From described MPEG-2TS code stream, extract packaged media data, obtain each layer bit stream: Primary layer code stream and enhancement layer bitstream;
Described each layer bit stream is packaged in respectively by the layer belonging to it in different multiplexed sub frames in broadcast channel frame and the multiplexed sub frame positional information at described each layer bit stream place is packaged in described broadcast channel frame;
The CMMB airtime that the PTS timestamp of described each layer bit stream of described media data converts under uniform time reference is stabbed, controls synchronous on the CMMB airtime stabs of described each layer bit stream;
Broadcast transmission is stabbed together with the CMMB airtime of described each layer bit stream of this media data by needing the media data sent.
Preferably, the CMMB airtime that the described PTS timestamp by described each layer bit stream of described media data converts under uniform time reference stabs, and controls synchronous on the CMMB airtime stabs of described each layer bit stream; Specifically comprise:
According to the PCR time of the described each layer bit stream of PCR temporal information calculating that the PTS information in the PES bag at described each layer bit stream place and PES are wrapped;
Then the PCR time of this layer bit stream is multiplied by CMMB time scale divided by the clock scale of PCR, obtains the CMMB timestamp of this layer bit stream.
The present invention also provides classified service in a kind of Mobile Multimedia Broadcasting to receive synchronous method, and it comprises:
The multiplexed sub frame positional information at each layer bit stream place described in terminal receiving equipment listening broadcast channel frame;
Receive the Primary layer code stream in described each layer bit stream according to described positional information and the disposal ability of self, or receive the enhancement layer bitstream of described Primary layer code stream and correspondence;
By described each layer bit stream by the CMMB airtime stab alignment, synchronous after merge;
Described each layer bit stream is carried out decoding represent.
Preferably, describedly described each layer bit stream is pressed the CMMB airtime and stabs alignment, synchronous, specifically comprise:
Received described each layer bit stream is put into buffering area together with the CMMB timestamp of its correspondence by described terminal receiving equipment;
When frame data receive, get code stream to be combined from described buffering area and carry out alignment merging.
Preferably, described when frame data receive, get code stream to be combined from described buffering area and carry out alignment merging, specifically comprise:
The Primary layer code stream belonging to an access unit got by described terminal receiving equipment, with the timestamp of Primary layer code stream for benchmark, takes out the enhancement layer bitstream corresponding with Primary layer code stream timestamp, it can be used as the code stream of same access unit to merge.
The present invention also provides a kind of front end transmitting apparatus, and it comprises:
Code stream receiving element, for the MPEG-2TS code stream that received code equipment sends;
Data extracting unit, for extracting packaged media data from described MPEG-2TS code stream, obtains each layer bit stream: Primary layer code stream and enhancement layer bitstream;
Code stream encapsulation unit, for being packaged in described each layer bit stream by the layer belonging to it in the different multiplexed sub frames in broadcast channel frame respectively and being packaged in described broadcast channel frame by the multiplexed sub frame positional information at described each layer bit stream place;
Code stream lock unit, the CMMB airtime that the PTS timestamp for the described each layer bit stream by described media data converts under uniform time reference stabs, and controls synchronous on the CMMB airtime stabs of described each layer bit stream;
Code stream transmitting element, for needing the media data sent to stab broadcast transmission together with the CMMB airtime of described each layer bit stream of this media data.
Preferably, described code stream lock unit, comprising:
Time Calculation subelement, for calculating the PCR time of described each layer bit stream according to the PCR temporal information of the PTS information in the PES bag at described each layer bit stream place and PES bag;
Timestamp computation subunit, for then the PCR time of this layer bit stream is multiplied by CMMB time scale divided by the clock scale of PCR, obtains the CMMB timestamp of this layer bit stream.
The present invention also provides a kind of terminal receiving equipment, and it comprises:
Position monitoring unit, for the multiplexed sub frame positional information at layer bit stream place each described in listening broadcast channel frame;
Code stream receiving element, for receiving the Primary layer code stream in described each layer bit stream according to described positional information and the disposal ability of self, or receives the enhancement layer bitstream of described Primary layer code stream and correspondence;
Code stream merge cells, for by described each layer bit stream by the CMMB airtime stab alignment, synchronous after merge;
Code stream represents unit, represents for described each layer bit stream is carried out decoding.
Preferably, described code stream merge cells comprises:
Buffer sublayer unit, for putting into buffering area by received described each layer bit stream together with the CMMB timestamp of its correspondence;
Code stream alignment subelement, for when frame data receive, gets code stream to be combined and carries out alignment merging from described buffering area.
Preferably, described code stream alignment subelement, for getting the Primary layer code stream belonging to an access unit, with the timestamp of Primary layer code stream for benchmark, take out the enhancement layer bitstream corresponding with Primary layer code stream timestamp, it can be used as the code stream of same access unit to merge.
The present invention also provides the system that in a kind of Mobile Multimedia Broadcasting, classified service is synchronous, and it comprises:
Encoding device, sends after the code stream of the multiple layerings generated of encoding is encapsulated as MPEG-2TS code stream;
Front end transmitting apparatus, for receiving the MPEG-2TS code stream that described encoding device sends, packaged media data is extracted from described MPEG-2TS code stream, obtain each layer bit stream: Primary layer code stream and enhancement layer bitstream, described each layer bit stream is packaged in respectively by the layer belonging to it in different multiplexed sub frames in broadcast channel frame and the multiplexed sub frame positional information at described each layer bit stream place is packaged in described broadcast channel frame, the CMMB airtime that the PTS timestamp of described each layer bit stream of described media data converts under uniform time reference is stabbed, control synchronous on the CMMB airtime stabs of described each layer bit stream, broadcast transmission is stabbed together with the CMMB airtime of described each layer bit stream of this media data by needing the media data sent,
Terminal receiving equipment, for the multiplexed sub frame positional information at layer bit stream place each described in listening broadcast channel frame, the Primary layer code stream in described each layer bit stream is received according to described positional information and the disposal ability of self, or receive the enhancement layer bitstream of described Primary layer code stream and correspondence, by described each layer bit stream by the CMMB airtime stab alignment, synchronous after merge, described each layer bit stream is carried out decoding and represents.
Preferably, described front end transmitting apparatus, for calculating the PCR time of described each layer bit stream according to the PCR temporal information of the PTS information in the PES bag at described each layer bit stream place and PES bag, then the PCR time of this layer bit stream is multiplied by CMMB time scale divided by the clock scale of PCR, obtains the CMMB timestamp of this layer bit stream.
Preferably, described terminal receiving equipment, also for received described each layer bit stream is put into buffering area together with the CMMB timestamp of its correspondence, when frame data receive, gets code stream to be combined and carries out alignment merging from described buffering area.
Preferably, described terminal receiving equipment, also for getting the Primary layer code stream belonging to an access unit, with the timestamp of Primary layer code stream for benchmark, take out the enhancement layer bitstream corresponding with Primary layer code stream timestamp, it can be used as the code stream of same access unit to merge.
Implement technical scheme of the present invention, there is following beneficial effect: the method, apparatus and system that in Mobile Multimedia Broadcasting provided by the invention, classified service is synchronous, when each layer bit stream of the classified service in MPEG-2TS code stream is transmitted by CMMB, by unified timestamp, synchronous between each layer bit stream (that is: each individual-layer data) ensureing classified service, thus ensure the normal enforcement of classified service in CMMB.
Accompanying drawing explanation
In the Mobile Multimedia Broadcasting that Fig. 1 provides for the embodiment of the present invention, classified service sends the flow chart of synchronous method;
Fig. 2 is the particular flow sheet of the step S140 of Fig. 1;
In the Mobile Multimedia Broadcasting that Fig. 3 provides for the embodiment of the present invention, classified service receives the flow chart of synchronous method;
Fig. 4 is the particular flow sheet of the step S230 of Fig. 3;
The structural representation of the front end transmitting apparatus that Fig. 5 provides for the embodiment of the present invention;
Fig. 6 is the concrete structure schematic diagram of code stream lock unit in Fig. 5;
The structural representation of the terminal receiving equipment that Fig. 7 provides for the embodiment of the present invention;
Fig. 8 is the structural representation of the code stream merge cells in Fig. 7;
The structural representation of the system that Fig. 9 provides for the embodiment of the present invention;
The composition structural representation of the broadcast channel frame that Figure 10 provides for application examples of the present invention.
The realization of the object of the invention, functional characteristics and advantage will in conjunction with the embodiments, are described further with reference to accompanying drawing.
Embodiment
In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.
The embodiment of the present invention provides classified service in a kind of Mobile Multimedia Broadcasting to send synchronous method, and as shown in Figure 1, the method comprising the steps of:
MPEG (the MovingPicturesExpertsGroup/MotinPicturesExpertsGroup that S110, front end transmitting apparatus received code equipment send, dynamic image expert group)-2TS (TransportStream, transport stream) code stream; Each layer bit stream has the PCR time, and the described PCR time ensures that base layer data in same sampling instant, enhancement data are synchronously temporal at PCR
S120, front end transmitting apparatus extract packaged media data from described MPEG-2TS code stream, obtain each layer bit stream: Primary layer code stream and enhancement layer bitstream;
Described each layer bit stream is packaged in by the layer belonging to it in different multiplexed sub frames in broadcast channel frame and is packaged in described broadcast channel frame by the multiplexed sub frame positional information at described each layer bit stream place by S130, front end transmitting apparatus respectively;
S140, front end transmitting apparatus are by the PTS (Presentationtimestamp of described each layer bit stream of described media data, representing time stamp) CMMB airtime of converting under uniform time reference of timestamp stabs, and controls synchronous on the CMMB airtime stabs of described each layer bit stream; In the present embodiment, as shown in Figure 2, this step S140 specifically comprises step:
S141, front end transmitting apparatus are according to the PTS information in the PES bag at described each layer bit stream place and PES (PacketizedElementaryStream, the basic stream of grouping) the PCR temporal information of wrapping calculates PCR (ProgramClockReference, program clock reference) time of described each layer bit stream;
Then the PCR time of this layer bit stream is multiplied by CMMB time scale divided by the clock scale of PCR by S142, front end transmitting apparatus, obtains the CMMB timestamp of this layer bit stream.
S150, front end transmitting apparatus stab broadcast transmission by needing the media data sent together with the CMMB airtime of described each layer bit stream of this media data.
The method that this embodiment provides converses CMMB timestamp corresponding to layered code stream by being multiplied by CMMB time scale with the PCR time of each layer bit stream, determine the CMMB timestamp initial value of business with the PCR time of the ground floor code stream in handled first multiplexed sub frame, and determined the CMMB timestamp of subsequent layers code stream by this conversion method.Ensure the unification of each layer bit stream on same PCR time point at CMMB timestamp, thus synchronous between each layer bit stream ensureing different layered service.
The embodiment of the present invention also provides classified service in a kind of Mobile Multimedia Broadcasting to receive synchronous method, and the method that the method that this embodiment provides and above-described embodiment provide matches, and as shown in Figure 3, the method comprising the steps of:
The multiplexed sub frame positional information at each layer bit stream place described in S210, terminal receiving equipment listening broadcast channel frame;
S220, described terminal receiving equipment receive the Primary layer code stream in described each layer bit stream according to described positional information and the disposal ability of self, or receive the enhancement layer bitstream of described Primary layer code stream and correspondence;
S230, described terminal receiving equipment by described each layer bit stream by the CMMB airtime stab alignment, synchronous after merge; In the present embodiment, as shown in Figure 4, this step S230 more specifically comprises:
Received described each layer bit stream is put into buffering area together with the CMMB timestamp of its correspondence by S231, described terminal receiving equipment;
Moment that S232, described terminal receiving equipment receive at frame data (, get code stream to be combined from described buffering area and carry out alignment and merge.In the present embodiment, this step S232 specifically comprises: the Primary layer code stream belonging to an access unit got by described terminal receiving equipment, with the timestamp of Primary layer code stream for benchmark, take out the enhancement layer bitstream corresponding with Primary layer code stream timestamp, it can be used as the code stream of same access unit to merge.
Described each layer bit stream is carried out decoding and represents by S240, described terminal receiving equipment.
In the Mobile Multimedia Broadcasting that above-described embodiment provides, classified service sends and receives synchronous method, when each layer bit stream of the classified service in MPEG-2TS code stream is transmitted by CMMB, by unified timestamp, synchronous between each layer bit stream (that is: each individual-layer data) ensureing classified service, thus ensure the normal enforcement of classified service in CMMB.
The embodiment of the present invention provides a kind of front end transmitting apparatus, and as shown in Figure 5, this front end transmitting apparatus comprises:
Code stream receiving element 510, for the MPEG-2TS code stream that received code equipment sends;
Data extracting unit 520, for extracting packaged media data from described MPEG-2TS code stream, obtains each layer bit stream: Primary layer code stream and enhancement layer bitstream;
Code stream encapsulation unit 530, for being packaged in described each layer bit stream by the layer belonging to it in the different multiplexed sub frames in broadcast channel frame respectively and being packaged in described broadcast channel frame by the multiplexed sub frame positional information at described each layer bit stream place;
Code stream lock unit 540, the CMMB airtime that the PTS timestamp for the described each layer bit stream by described media data converts under uniform time reference stabs, and controls synchronous on the CMMB airtime stabs of described each layer bit stream;
Code stream transmitting element 550, for needing the media data sent to stab broadcast transmission together with the CMMB airtime of described each layer bit stream of this media data.
In more specifically embodiment, as shown in Figure 6, described code stream lock unit 540 comprises:
Time Calculation subelement 541, for calculating the PCR time of described each layer bit stream according to the PCR temporal information of the PTS information in the PES bag at described each layer bit stream place and PES bag;
Timestamp computation subunit 542, for then the PCR time of this layer bit stream is multiplied by CMMB time scale divided by the clock scale of PCR, obtains the CMMB timestamp of this layer bit stream.
The embodiment of the present invention also provides a kind of terminal receiving equipment, and as shown in Figure 7, this terminal receiving equipment comprises:
Position monitoring unit 710, for the multiplexed sub frame positional information at layer bit stream place each described in listening broadcast channel frame;
Code stream receiving element 720, for receiving the Primary layer code stream in described each layer bit stream according to described positional information and the disposal ability of self, or receives the enhancement layer bitstream of described Primary layer code stream and correspondence;
Code stream merge cells 730, for by described each layer bit stream by the CMMB airtime stab alignment, synchronous after merge;
Code stream represents unit 740, represents for described each layer bit stream is carried out decoding.
In more specifically embodiment, as shown in Figure 8, described code stream merge cells 730 comprises:
Buffer sublayer unit 731, for putting into buffering area by received described each layer bit stream together with the CMMB timestamp of its correspondence;
Code stream alignment subelement 732, for when frame data receive, gets code stream to be combined and carries out alignment merging from described buffering area.In other examples, more specifically, described code stream alignment subelement 732, for getting the Primary layer code stream belonging to an access unit, with the timestamp of Primary layer code stream for benchmark, take out the enhancement layer bitstream corresponding with Primary layer code stream timestamp, it can be used as the code stream of same access unit to merge.
The embodiment of the present invention also provides the system that in a kind of Mobile Multimedia Broadcasting, classified service is synchronous, and as shown in Figure 9, this system comprises:
Encoding device 810, sends after the code stream of the multiple layerings generated of encoding is encapsulated as MPEG-2TS code stream;
In the present embodiment, source of media is encoded to Primary layer code stream and at least one enhancement layer bitstream by encoding device 810, Primary layer code stream can be decoded separately, and enhancement layer bitstream comprises the additional information for improving low-lever code current mass, needs to decode together with comprising the low layer of Primary layer code stream.On the time line, layered code stream take access unit as base unit, and typical access unit is as a frame frame of video.Under the mode of hierarchical coding, an access unit on particular point in time can be encoded as the data of multiple layer bit stream, and the data of this multiple layer bit stream can be divided into multichannel and transmit; Terminal receiving equipment (as: mobile terminal such as mobile phone) as required, can receive the data of multiplex multiple layers simultaneously, and it merged by affiliated access unit, decoding represents.
Front end transmitting apparatus 820, for receiving the MPEG-2TS code stream that described encoding device sends, packaged media data is extracted from described MPEG-2TS code stream, obtain each layer bit stream: Primary layer code stream and enhancement layer bitstream, described each layer bit stream is packaged in respectively by the layer belonging to it in different multiplexed sub frames in broadcast channel frame and the multiplexed sub frame positional information at described each layer bit stream place is packaged in described broadcast channel frame, the CMMB airtime that the PTS timestamp of described each layer bit stream of described media data converts under uniform time reference is stabbed, control synchronous on the CMMB airtime stabs of described each layer bit stream, broadcast transmission is stabbed together with the CMMB airtime of described each layer bit stream of this media data by needing the media data sent,
Terminal receiving equipment 830, for the multiplexed sub frame positional information at layer bit stream place each described in listening broadcast channel frame, the Primary layer code stream in described each layer bit stream is received according to described positional information and the disposal ability of self, or receive the enhancement layer bitstream of described Primary layer code stream and correspondence, by described each layer bit stream by the CMMB airtime stab alignment, synchronous after merge, described each layer bit stream is carried out decoding and represents.
The system that above-described embodiment provides, when each layer bit stream of the classified service in MPEG-2TS code stream is transmitted by CMMB, by unified timestamp, synchronous between each layer bit stream (that is: each individual-layer data) ensureing classified service, thus ensure the normal enforcement of classified service in CMMB.
In more specifically embodiment, described front end transmitting apparatus 820, also for calculating the PCR time of described each layer bit stream according to the PCR temporal information of the PTS information in the PES bag at described each layer bit stream place and PES bag, then the PCR time of this layer bit stream is multiplied by CMMB time scale divided by the clock scale of PCR, obtains the CMMB timestamp of this layer bit stream.Be multiplied by CMMB time scale with the PCR time of each layer bit stream and converse CMMB timestamp corresponding to layered code stream, determine the CMMB timestamp initial value of business with the PCR time of the ground floor code stream in handled first multiplexed sub frame, and determined the CMMB timestamp of subsequent layers code stream by this conversion method.Ensure the unification of each layer bit stream on same PCR time point at CMMB timestamp, thus synchronous between each layer bit stream ensureing different layered service.
In more specifically embodiment, described terminal receiving equipment, for received described each layer bit stream is put into buffering area together with the CMMB timestamp of its correspondence, when frame data receive, get code stream to be combined from described buffering area and carry out alignment merging.More specifically in embodiment, described terminal receiving equipment 830, also for getting the Primary layer code stream belonging to an access unit, with the timestamp of Primary layer code stream for benchmark, take out the enhancement layer bitstream corresponding with Primary layer code stream timestamp, it can be used as the code stream of same access unit to merge.
The application examples of above-described embodiment is provided below:
Should be H264SVC (extendible Video coding) encoder with encoding device in use-case be example, its encoded output video data elementary cell is NALU (NetworkAbstractionLayer, network abstraction layer unit), the some NALU on same time point form an access unit.
In this application examples, SVC video and a road audio frequency is contained for broadcasting service, SVC video adopts space delamination pattern, be encoded as a road QVGA (QuarterVGA, 320 × 240 pixel images) elementary stream and a road VGA (VideoGraphicArray, a kind of video transmission standard, video image 640X480 pixel image) augmented video code stream, audio frequency is encoded as a road voice data code stream.It should be noted that, the method equipment that above-described embodiment provides and system are equally applicable to the situation of multichannel enhanced flow and other hierarchical coding pattern.
Send after the SVC elementary stream that coding generates by encoding device, SVC enhancing code stream and voice data code stream are divided into multiple program multiplexing to be encapsulated as a road MPEG-2TS code stream.For the PTS timestamp in the PES code stream of each road program not mandatory requirement interdepend, ensured by PCR the SVC elementary stream in same sampling instant, SVC strengthen code stream and voice data code stream synchronously temporal at PCR.
The MPEG-2TS code stream that front end transmitting apparatus received code equipment sends, packaged SVC media data is extracted from MPEG-2TS code stream, SVC Primary layer code stream and SVC enhancement layer bitstream are packaged in respectively by the layer belonging to it in different multiplexed sub frames in broadcast channel frame, the multiplexed sub frame positional information at each for described video flowing layer bit stream place are packaged in described broadcast channel frame simultaneously.
The composition structural representation of the broadcast channel frame that Figure 10 provides for application examples of the present invention.As shown in Figure 10, certain frequency F has 40 time slots, wherein time slot 0 (multiplexed frame 0) is for communicating control information, and time slot 1 to time slot 39 is for transport service information.Video Primary layer code stream, audio frequency and data message in video traffic S is configured to, in multiplexed frame 1, take time slot 1 to time slot 4 by front end transmitting apparatus, and multiplexed sub frame number is 1.Video source modeling layer bit stream is configured to multiplexed frame 2, takies time slot 5 to time slot 6, and multiplexed sub frame number is 1.Other business are no longer transmitted in multiplexed frame 1 and multiplexed frame 2.At control information and the electron service instruction (ElectronicServiceGuide of business, ESG) the multiplexed frame positional information of carrying each layer (each enhancement layer bitstream of Primary layer code stream and correspondence thereof) code stream is added in information, this descriptor indicates that video traffic S comprises two multiplexed sub frames: the multiplexed sub frame 1 of multiplexed frame 1 is business Primary layer bit stream data, and the multiplexed sub frame 1 of multiplexed frame 2 is enhancement layer bitstream data.
Front end transmitting apparatus obtains the Primary layer code stream V1 of video traffic S, is encapsulated in the multiplexed sub frame 1 of multiplexed frame 1, obtains the enhancement layer bitstream V2 of video traffic S, is encapsulated in the multiplexed sub frame 1 of multiplexed frame 2.Front end transmitting apparatus obtains voice data code stream and the data segment information of video traffic S, adds in the multiplexed sub frame 1 of multiplexed frame 1, is namely carried in same multiplexed sub frame together with Primary layer code stream.Carry the multiplexed frame positional information of each layer bit stream, be carried in the multiplexed frame 0 in broadcast channel frame, to indicate the multiplexed frame positional information of each layer bit stream of receiving terminal, to facilitate its receiver, video business S.
Time voice data code stream, stream of video data are encapsulated into and go in multiplexed sub frame, encapsulate in units of audio or video unit one by one.For each audio unit or video unit, have the CMMB timestamp that corresponding, according to CMMB standard, this timestamp is that the relative reproduction time that the initial reproduction time in multiplexed sub frame is corresponding with each unit combines.The relative reproduction time that initial reproduction time is corresponding with each unit is also encapsulated in multiplexed sub frame, together sends with media data.
On the transmitting apparatus of front end, needing the PCR timestamp of received media data to convert to the CMMB airtime stabs, in the process synchronous on the CMMB airtime stabs of each layered service of control SVC.
On the transmitting apparatus of front end, synchronous on the CMMB airtime stabs of each layered service of SVC, carries out by the following method:
For each multiplexed sub frame corresponding to each layering of SVC,
A, receive input MPEG-2TS code stream, for each video unit, take out its place PES wrap PTS timestamp, in conjunction with its place program code stream corresponding to PCR information about events, calculate the PCR time of this video unit;
The PCR time of B, direct video unit is multiplied by CMMB time scale, obtains the CMMB timestamp of this SVC video unit.To multiplexed sub frame, get an initial reproduction time, the CMMB timestamp of video unit is decomposed into relative reproduction time two parts that initial reproduction time is corresponding with each unit, relative reproduction time corresponding to initial reproduction time and each unit is encapsulated in multiplexed sub frame and goes.
In steps A, the calculating of the PCR time of video unit can adopt following methods:
(1) TS in parsing MPEG-2TS code stream wraps, until the TS be resolved to PCR wraps, using this PCR as with reference to PCR timestamp, resolves PES bag in this TS bag, using the PTS in PES bag as reference PTS timestamp.
(2) for each video unit follow-up, take out the PTS timestamp that its place PES wraps, if with PCR in this TS bag, then upgrade with reference to PCR timestamp, upgrade with reference to PTS timestamp simultaneously.If this TS does not have PCR in wrapping, then calculate the PCR of this video unit;
(3) go with the PTS timestamp in PES bag and do difference with reference to PTS timestamp, then adding with reference to PCR timestamp by this difference, just obtaining the PCR time that PES bag is corresponding, that is the PCR time that video unit is corresponding.
PCR time=| PTS timestamp-reference PTS timestamp |+with reference to PCR timestamp formula (1)
The time scale of CMMB described in step B, represents the CMMB chronomere number of generation per second, is 22500 according to CMMB standard " Mobile Multimedia Broadcasting part 2: multiplexing ".
Multiplexed frame 0 in the upper receiving terminal listening broadcast channel frame of terminal receiving equipment (as: mobile phone, net book etc.), receiving control information and ESG information, with correct receiving multimedia broadcast business, listen to simultaneously, also comprise the multiplexed sub frame positional information at each layer bit stream place in scalable video business.Terminal receiving equipment also according to self needs, as its video flow processing ability or Internet Transmission situation, determines to receive Primary layer code stream, or receives the enhancement layer bitstream of Primary layer code stream and correspondence.In this application examples, this terminal receiving equipment can process the net book of VGA video for one, needs the enhancing code stream of the elementary stream and VGA simultaneously receiving QVGA to process, and decoding represents VGA video.After receiving the elementary stream and enhancing code stream transmitted from different multiplexed sub frame, video unit extracts by net book from multiplexed sub frame, parse H264 basic coding unit NALU, the NALU belonging to different layered service is stabbed alignment, synchronous by the CMMB airtime, afterwards the NALU belonging to same access unit is merged, then carry out video decode and represent.
On terminal receiving equipment (as: net book), the synchronous of each layered service of SVC carries out by the following method:
A, each video unit, have corresponding CMMB timestamp, this timestamp is that the relative reproduction time that the initial reproduction time in multiplexed sub frame is corresponding with each unit combines.The NALU data comprised by video unit put into buffering area together with the timestamp of its correspondence, and buffering area can be Primary layer or enhancement layer, and this Primary layer, enhancement layer are all separately independently.
B, every a Fixed Time Interval, net book just gets a video access unit from aforementioned buffering area, after being merged by the NALU alignment of data of different for video access unit layering, sends into decoder.First get the NALU data of the SVC Primary layer code stream belonging to a video access unit, with the timestamp of SVC Primary layer code stream for benchmark, take out the NALU data of the enhancement layer bitstream corresponding with Primary layer code stream timestamp, it can be used as the data of same video access unit, merge with the NALU data of Primary layer code stream, using the NALU data after merging as a complete access unit, send into decoders decode.
These are only preferred embodiment of the present invention, not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.
Claims (11)
1. in Mobile Multimedia Broadcasting, classified service sends a synchronous method, it is characterized in that, comprising:
The MPEG-2TS code stream that front end transmitting apparatus received code equipment sends;
From described MPEG-2TS code stream, extract packaged media data, obtain each layer bit stream with the PCR time: Primary layer code stream and enhancement layer bitstream;
Described each layer bit stream is packaged in respectively by the layer belonging to it in different multiplexed sub frames in broadcast channel frame and the multiplexed sub frame positional information at described each layer bit stream place is packaged in described broadcast channel frame;
The CMMB airtime that the PTS timestamp of described each layer bit stream of described media data converts under uniform time reference is stabbed, controls synchronous on the CMMB airtime stabs of described each layer bit stream;
Broadcast transmission is stabbed together with the CMMB airtime of described each layer bit stream of this media data by needing the media data sent;
Wherein, the CMMB airtime that the described PTS timestamp by described each layer bit stream of described media data converts under uniform time reference stabs, and controls synchronous on the CMMB airtime stabs of described each layer bit stream; Specifically comprise:
According to the PCR time of the described each layer bit stream of PCR temporal information calculating that the PTS information in the PES bag at described each layer bit stream place and PES are wrapped;
Then the PCR time of this layer bit stream is multiplied by CMMB time scale divided by the clock scale of PCR, and the CMMB airtime obtaining this layer bit stream stabs.
2. in Mobile Multimedia Broadcasting, classified service receives a synchronous method, it is characterized in that, comprising:
The multiplexed sub frame positional information at each layer bit stream place in terminal receiving equipment listening broadcast channel frame;
Receive the Primary layer code stream in described each layer bit stream according to described positional information and the disposal ability of self, or receive the enhancement layer bitstream of described Primary layer code stream and correspondence;
By described each layer bit stream by the CMMB airtime stab alignment, synchronous after merge;
Described each layer bit stream is carried out decoding represent;
It is converted to by the PTS timestamp of described each layer bit stream under uniform time reference that the described CMMB airtime stabs, and is specially:
According to the PCR time of the described each layer bit stream of PCR temporal information calculating that the PTS information in the PES bag at described each layer bit stream place and PES are wrapped;
Then the PCR time of this layer bit stream is multiplied by CMMB time scale divided by the clock scale of PCR, and the CMMB airtime obtaining this layer bit stream stabs.
3. method as claimed in claim 2, is characterized in that, describedly described each layer bit stream is pressed the CMMB airtime and stabs alignment, synchronous, specifically comprises:
Received described each layer bit stream stabs together with CMMB airtime of its correspondence and puts into buffering area by described terminal receiving equipment;
When frame data receive, get code stream to be combined from described buffering area and carry out alignment merging.
4. method as claimed in claim 3, is characterized in that, described when frame data receive, and gets code stream to be combined and carries out alignment and merge, specifically comprise from described buffering area:
The Primary layer code stream belonging to an access unit got by described terminal receiving equipment, with the timestamp of Primary layer code stream for benchmark, takes out the enhancement layer bitstream corresponding with Primary layer code stream timestamp, it can be used as the code stream of same access unit to merge.
5. a front end transmitting apparatus, is characterized in that, comprising:
Code stream receiving element, for the MPEG-2TS code stream that received code equipment sends;
Data extracting unit, for extracting packaged media data from described MPEG-2TS code stream, obtains each layer bit stream: Primary layer code stream and enhancement layer bitstream;
Code stream encapsulation unit, for being packaged in described each layer bit stream by the layer belonging to it in the different multiplexed sub frames in broadcast channel frame respectively and being packaged in described broadcast channel frame by the multiplexed sub frame positional information at described each layer bit stream place;
Code stream lock unit, the CMMB airtime that the PTS timestamp for the described each layer bit stream by described media data converts under uniform time reference stabs, and controls synchronous on the CMMB airtime stabs of described each layer bit stream;
Code stream transmitting element, for needing the media data sent to stab broadcast transmission together with the CMMB airtime of described each layer bit stream of this media data;
Wherein, described code stream lock unit, comprising:
Time Calculation subelement, for calculating the PCR time of described each layer bit stream according to the PCR temporal information of the PTS information in the PES bag at described each layer bit stream place and PES bag;
Timestamp computation subunit, for then the PCR time of this layer bit stream is multiplied by CMMB time scale divided by the clock scale of PCR, the CMMB airtime obtaining this layer bit stream stabs.
6. a terminal receiving equipment, is characterized in that, comprising:
Position monitoring unit, for the multiplexed sub frame positional information at layer bit stream place each in listening broadcast channel frame;
Code stream receiving element, for receiving the Primary layer code stream in described each layer bit stream according to described positional information and the disposal ability of self, or receives the enhancement layer bitstream of described Primary layer code stream and correspondence;
Code stream merge cells, for by described each layer bit stream by the CMMB airtime stab alignment, synchronous after merge;
Code stream represents unit, represents for described each layer bit stream is carried out decoding;
It is converted to by the PTS timestamp of described each layer bit stream under uniform time reference that the described CMMB airtime stabs, and is specially:
According to the PCR time of the described each layer bit stream of PCR temporal information calculating that the PTS information in the PES bag at described each layer bit stream place and PES are wrapped;
Then the PCR time of this layer bit stream is multiplied by CMMB time scale divided by the clock scale of PCR, and the CMMB airtime obtaining this layer bit stream stabs.
7. terminal receiving equipment as claimed in claim 6, it is characterized in that, described code stream merge cells comprises:
Buffer sublayer unit, puts into buffering area for being stabbed together with CMMB airtime of its correspondence by received described each layer bit stream;
Code stream alignment subelement, for when frame data receive, gets code stream to be combined and carries out alignment merging from described buffering area.
8. terminal receiving equipment as claimed in claim 7, it is characterized in that, described code stream alignment subelement, for getting the Primary layer code stream belonging to an access unit, with the timestamp of Primary layer code stream for benchmark, take out the enhancement layer bitstream corresponding with Primary layer code stream timestamp, it can be used as the code stream of same access unit to merge.
9. the system that in Mobile Multimedia Broadcasting, classified service is synchronous, is characterized in that, comprising:
Encoding device, sends after the code stream of the multiple layerings generated of encoding is encapsulated as MPEG-2TS code stream;
Front end transmitting apparatus, for receiving the MPEG-2TS code stream that described encoding device sends, packaged media data is extracted from described MPEG-2TS code stream, obtain each layer bit stream: Primary layer code stream and enhancement layer bitstream, described each layer bit stream is packaged in respectively by the layer belonging to it in different multiplexed sub frames in broadcast channel frame and the multiplexed sub frame positional information at described each layer bit stream place is packaged in described broadcast channel frame, the CMMB airtime that the PTS timestamp of described each layer bit stream of described media data converts under uniform time reference is stabbed, control synchronous on the CMMB airtime stabs of described each layer bit stream, broadcast transmission is stabbed together with the CMMB airtime of described each layer bit stream of this media data by needing the media data sent,
Terminal receiving equipment, for the multiplexed sub frame positional information at layer bit stream place each described in listening broadcast channel frame, the Primary layer code stream in described each layer bit stream is received according to described positional information and the disposal ability of self, or receive the enhancement layer bitstream of described Primary layer code stream and correspondence, by described each layer bit stream by the CMMB airtime stab alignment, synchronous after merge, described each layer bit stream is carried out decoding and represents;
Wherein, described front end transmitting apparatus, for calculating the PCR time of described each layer bit stream according to the PCR temporal information of the PTS information in the PES bag at described each layer bit stream place and PES bag, then the PCR time of this layer bit stream is multiplied by CMMB time scale divided by the clock scale of PCR, and the CMMB airtime obtaining this layer bit stream stabs.
10. system as claimed in claim 9, it is characterized in that, described terminal receiving equipment, also put into buffering area for being stabbed together with CMMB airtime of its correspondence by received described each layer bit stream, when frame data receive, get code stream to be combined from described buffering area and carry out alignment merging.
11. systems as claimed in claim 10, it is characterized in that, described terminal receiving equipment, also for getting the Primary layer code stream belonging to an access unit, with the timestamp of Primary layer code stream for benchmark, take out the enhancement layer bitstream corresponding with Primary layer code stream timestamp, it can be used as the code stream of same access unit to merge.
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| CN201010557758.7A CN102480634B (en) | 2010-11-24 | 2010-11-24 | The method, apparatus and system that in Mobile Multimedia Broadcasting, classified service is synchronous |
| PCT/CN2011/077591 WO2012068898A1 (en) | 2010-11-24 | 2011-07-25 | Method, apparatus and system for synchronizing tiered service in mobile multimedia broadcasting |
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| CN201010557758.7A CN102480634B (en) | 2010-11-24 | 2010-11-24 | The method, apparatus and system that in Mobile Multimedia Broadcasting, classified service is synchronous |
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| EP3378235A4 (en) | 2015-11-20 | 2019-05-01 | Genetec Inc. | Media streaming |
| US11716520B2 (en) * | 2021-06-25 | 2023-08-01 | Netflix, Inc. | Systems and methods for providing optimized time scales and accurate presentation time stamps |
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| CN101273627A (en) * | 2005-09-27 | 2008-09-24 | 韩国电子通信研究院 | Apparatus for transmitting and receiving digital multimedia broadcasting for high-quality video service |
| CN101282482A (en) * | 2008-05-04 | 2008-10-08 | 中兴通讯股份有限公司 | Apparatus, system and method for synchronously playing video data and audio data |
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| KR20050088448A (en) * | 2002-12-20 | 2005-09-06 | 코닌클리케 필립스 일렉트로닉스 엔.브이. | Method and apparatus for handling layered media data |
| JP2009267573A (en) * | 2008-04-23 | 2009-11-12 | Victor Co Of Japan Ltd | Moving picture hierarchical encoder, moving picture hierarchical decoder, moving picture hierarchical encoding method, moving picture hierarchical decoding method, moving picture hierarchical encoding program, and hierarchical decoding program |
| CN101951506B (en) * | 2010-09-17 | 2014-03-12 | 中兴通讯股份有限公司 | System and method for realizing synchronous transmitting and receiving of scalable video coding service |
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| CN101273627A (en) * | 2005-09-27 | 2008-09-24 | 韩国电子通信研究院 | Apparatus for transmitting and receiving digital multimedia broadcasting for high-quality video service |
| CN101690200A (en) * | 2007-05-04 | 2010-03-31 | 韩国电子通信研究院 | Method and apparatus for providing high-quality multimedia service in dmb system |
| CN101282482A (en) * | 2008-05-04 | 2008-10-08 | 中兴通讯股份有限公司 | Apparatus, system and method for synchronously playing video data and audio data |
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