Detailed description of the invention
Here will illustrate exemplary embodiment in detail, its example represents in the accompanying drawings.Explained below relates toDuring accompanying drawing, unless otherwise indicated, the same numbers in different accompanying drawings represents same or analogous key element.Following exemplary embodimentDescribed in embodiment do not represent all embodiments consistent with the present invention.On the contrary, they are only with the most appendedThe example of the apparatus and method that some aspects that described in detail in claims, the present invention are consistent.
The audio and video data streams being sent to set top box side by time-shifted service device end is after encoded device carries out compression codingData stream, be sent to the audio and video data streams of set top box side after decoder is decoded, extract audio and video data streamsIn audio/video frames, and play out successively.Having a system clock in audio/video coder, system clock is a 27MHzClock, the sampling of signal, process all based on this clock, this clock is used for producing the correct display of instruction audio frequency and videoTimestamp with decoding.Wherein, PCR is by the counter status sampling triggering system clock pulse, is placed on TS bagTransmitting in adaptation field of head.PCR accounts for 6Bytes altogether, and wherein 6bits reserves, 42bits significance bit.The PCR of 42bits is divided into twoThe PCR_Ext of PCR_Base and 9bits of part: 33bits.PCR_Base be by 27MHz pulse through 300 frequency dividing after 90kHzPulse-triggered enumerator, then be sampled counter status obtaining.PCR_Ext is by the direct flip-flop number of 27MHz pulseDevice, then be sampled counter status obtaining.
Owing to PCR value is the sampling to the counter status that system clock pulse triggers, so PCR value represents its place TSThe encoder-side system time that audio, video data in bag is corresponding, so, in time shift program, when can be calculated by PCR valueMove the relative time that program is play, thus realize the renewal of time shift temporal information in time shift program.Specific as follows:
Fig. 1 is the flow chart according to a kind of time shift time obtaining method shown in an exemplary embodiment.
Fig. 2 is the application scenarios schematic diagram of this method.
Step S100, receives reference note video data stream and benchmark that time-shifted service device sends according to time shifting broadcasting requestTime shift temporal information.
Understand in conjunction with Fig. 2, when intelligent television 2 receives the time shifting broadcasting request from remote control under live state, intelligenceTime shifting broadcasting request can be sent to Set Top Box 4 by TV 2, Set Top Box 4 time shifting broadcasting request is sent to time-shifted service device 1,The request of described time shifting broadcasting includes suspending or fast rewinding request.Such as, when intelligent television 2 is just in certain TV programme live, now byCan press Pause key in being busy with other things, the program that intelligent television 2 is play is switched to time shift program by programme televised live, waits to finishPlay button can be pressed after thing play from local continuation the just now suspended；Or, for live joint during viewing is liveMesh is thought again to watch, and now, can realize reviewing by falling back on certain time point soon.During viewing time shift program, needThe video window interface 3 of intelligent television 2 shows that time shift temporal information, time shift temporal information include current time shifting broadcasting time, a left sideBoundary time and right margin time.
Being seamless switching between programme televised live and time shift program, the broadcasting of beholder imperceptible rear player is cutChange, such as, when pressing Pause key during watching programme televised live, now picture suspends, when recovering to play after a whileTime, the local continuation that TV programme can then be suspended is play.It is understood that programme televised live is real-time, also cannot suspend,So programme televised live to be realized and the seamless switching of time shift program, it is necessary to record broadcasting of a period of time at time-shifted service device endPutting program to be cached at server end, when being switched to time shift program by programme televised live, Set Top Box directly obtains from time shift addressTake audio, video data, and send to intelligent television.
The data of time-shifted service device end caching, with buffer time as unit of account, generally cache the sound of hourVideo stream data, the data of caching are the audio, video datas of previous hour of current live time, so, server end cachingAudio, video data is dynamically change, and changes along with the change of live time.
When benchmark time shift temporal information includes benchmark current time shifting broadcasting time, benchmark left margin time and benchmark right marginBetween.The benchmark current time shifting broadcasting time refers to the time point play in current time shift program, benchmark left margin time and baseThe quasi-right margin time is the time shift time range in video window interface display.Generally, the benchmark left margin time is to work asThe previous hour corresponding time point of front live time, the benchmark right margin time is the current live time, if current time shiftWhen reproduction time and right margin time consistency, actual program is switched to programme televised live by time shift program.
When time shift server receives time shifting broadcasting request, time-shifted service device sends reference note according to time shifting broadcasting requestVideo flowing and benchmark time shift temporal information, so, time shifting broadcasting request includes obtaining audio and video data streams and obtaining base simultaneouslyThe request instruction of punctual shift time information, obtains audio and video data streams request equal with acquisition benchmark time shift temporal information request instructionSent by RTSP agreement.Wherein, benchmark time shift temporal information is corresponding with reference note video flowing, and includes that the current time shift of benchmark is broadcastPut time, benchmark left margin time and benchmark right margin time.When time shift server receives time shifting broadcasting request, time shift takesBusiness device sends audio and video data streams by breakpoint or rewind point to Set Top Box, wherein, in audio and video data streams firstThe individual audio and video data streams with PCR value is reference note video data stream, and benchmark time shift temporal information is and reference note video countsAccording to the time shift temporal information that stream is corresponding.
Step S200, receives the current audio, video data that time-shifted service device issues after reference note video data stream automaticallyStream.
When time-shifted service device receives time shifting broadcasting request, time-shifted service device can send ensuing sound from trend Set Top BoxVideo data stream, meanwhile, Set Top Box also can constantly receive the audio and video data streams that time-shifted service device sends.It is to say, work asWhen time-shifted service device receives time shifting broadcasting request, the audio and video data streams play of caching is sent to machine by time-shifted service deviceIn top box, during sending, first being gone out by reference note video stream, the sound after retransmiting reference note video flowing subsequently regardsFrequency stream, and Set Top Box also can receive and parse through audio frequency and video number according to the order of the audio and video data streams that time-shifted service device sends successivelyAccording to stream.
After receiving current audio and video data streams, extract PCR value from the current audio and video data streams, and according to extractingPCR value carries out the calculating of time difference.Step S300, determines that the PCR value that current audio and video data streams extracts regards with reference noteThe time difference of the PCR value extracted in frequency data stream.
When receiving reference note video data stream, from reference note video data stream, extract PCR value.I.e. regard from reference noteFrequency data stream obtains TCP bag, and from TCP bag, extracts TS bag successively, it is judged that whether current TS bag includes PCR value, whenWhen including PCR value, extraction PCR value is as benchmark PCR value, if not including PCR value in current TS bag, obtains next TSBag continues to determine whether to include PCR value, until extracting benchmark PCR value.
According to the PCR extracted in the PCR value extracted from current audio and video data streams and reference note video data streamValue calculates time difference, owing to PCR value is the sampling of the timing to 27MHz system clock, therefore, from current audio and video data streamsThe PCR value extracted current audio and video data streams the most corresponding with the time difference of benchmark PCR value and reference note video data streamTime difference, so, by calculating the time difference of PCR value and the benchmark PCR value extracted from current audio and video data streamsJust can the real-time update current time shifting broadcasting time.
The method calculating time difference with benchmark PCR value according to the PCR value extracted from current audio and video data streams, ginsengSee Fig. 3, a kind of step S300 schematic flow sheet provided for the embodiment of the present invention.
Step S301, is converted into time value by PCR value and benchmark PCR value respectively.
From the foregoing, it can be understood that PCR is by the counter status sampling triggering system clock pulse, it is placed on TS packet headerIn adaptation field transmit.PCR accounts for 6Bytes altogether, and wherein 6bits reserves, 42bits significance bit.The PCR of 42bits is divided into twoPoint: the PCR_Ext of PCR_Base and 9bits of 33bits.PCR_Base be by 27MHz pulse through 300 frequency dividing after 90kHz arteries and veinsRush flip-flop number, then be sampled counter status obtaining.PCR_Ext is by the direct flip-flop number of 27MHz pulse,It is sampled counter status again obtaining.Formula is as follows:
PCR_Time=PCR_Base × 300+PCR_Ext；
PCR_Ext=(system_clock_frequence) × T；
The effect of PCR_Base is when switching program, it is provided that the initial value to decoder PCR enumerator, it is ensured that Set Top BoxEnd audio-visual synchronization, the effect of PCR_Ext is the system clock of the phase-locked loop circuit revised decoding device by decoder end.ThisIn the method that bright embodiment provides, calculate the current PCR value and the benchmark PCR value that extract from current audio and video data streams timeBetween difference time, extract the PCR_Base in PCR value field.
Such as: System Clock time 07:12:45.56 is by the 27MHz pulse calculating of field value after 300 frequency dividings.
Time 07:12:45.56 is converted into the calculating of second:
(7 × 60+12) × 60+45.56=3285.56；
As shown from the above formula, by PCR value divided by 90000, PCR value can be converted into time value, described time valueUnit is the second.
According to above-mentioned computing formula, the PCR value extracted from current audio and video data streams and benchmark PCR value are removed respectivelyIt is converted into corresponding time value after 90000.
Step S302, makees difference by the time value that time value corresponding for PCR value is corresponding with benchmark PCR value, obtains time differenceValue.
By the current PCR value that extracts in current audio and video data streams divided by the time value after 90000, deduct benchmark PCR valueDivided by the time value after 90000, obtain time difference, described time difference be extract from current audio and video data streams work asThe time difference of the TS bag TS bag corresponding with benchmark PCR value that front PCR value is corresponding.
Such as, the PCR_Base=295700400 of benchmark PCR value, then the time value that benchmark PCR value is corresponding is3285.56s；
The PCR_Base=296410500 of the PCR value extracted from current audio and video data streams, by PCR_Base divided byAfter 90000, the time value obtaining the PCR value that extracts corresponding is 3293.45s.
Time value corresponding for the PCR value extracted in current audio and video data streams is deducted the time that benchmark PCR value is correspondingValue, it may be assumed that 3293.45-3285.56=7.89s, so the TS bag that the PCR value that extracts from current audio and video data streams is correspondingThe time difference of TS bag corresponding with benchmark PCR value is 7.89s.
If it is corresponding that the time value that the current PCR value extracted in current audio and video data streams is corresponding deducts benchmark PCR valueTime value for, time negative, illustrating that current time shift program is in fast reverse play state.
After obtaining time difference, in step S400, according to time difference and benchmark time shift temporal information, determine currentTime shift temporal information.
After calculating the time difference between the PCR value extracted in benchmark PCR value and current audio and video data streams, by baseThe punctual reproduction time that moves is the current time shifting broadcasting time plus described time difference, because of on the basis of PCR value broadcast with benchmark time shiftThe time that puts is corresponding, so the current time shifting broadcasting time calculated according to time difference extracts in current audio and video data streamsPCR value corresponding.
Same, the benchmark left margin time obtains the current left margin time plus time difference, and the benchmark right margin time addsUpper described time difference obtains the current right margin time.Principle is identical with the calculating of current time shifting broadcasting time, the most superfluous at thisState.
Detailed description of the invention, sees Fig. 4, the step S400 schematic flow sheet provided for the embodiment of the present invention.
Step S401, when adding benchmark time shifting broadcasting time, benchmark left margin time and benchmark right margin time respectivelyBetween difference, obtain current time shifting broadcasting time to be determined, left margin time to be determined and right margin time to be determined.
By benchmark time shifting broadcasting time, benchmark left margin time and benchmark right margin time plus time difference, in theoryCurrent time shifting broadcasting time, left margin time and right margin time can be obtained, but, if time shift program is in F.F. or fastWhen moving back state, the time difference of fast forward and fast reverse, more than the time schedule under current live state, therefore can cause current time shiftReproduction time, current left margin time and current live time to be considered when updating current right margin time.So, first willBenchmark time shifting broadcasting time, benchmark left margin time and benchmark right margin time are defined as treating plus the value after described time differenceDetermine current time shifting broadcasting time, left margin time to be determined and right margin time to be determined.
Step S402, during according to current time shifting broadcasting time to be determined, left margin time to be determined and right margin to be determinedBetween, determine current time shift temporal information, wherein, current time shift temporal information includes current time shifting broadcasting time, current left marginTime and current right margin time.
After determining current time shifting broadcasting time to be determined, left margin time to be determined and right margin time to be determined, logicalCross following step and determine current time shifting broadcasting time, current left margin time and current right margin time, see Fig. 5, for thisThe step S402 schematic flow sheet that bright embodiment provides, specific as follows:
Step S4021, receives the present system time to set-top-box system acquisition request.
Set Top Box is after each plug-in, automatically real by NTP (Newwork Time Protocol, NTP)Clock time in existing Set Top Box is synchronization with the local network time, and the local network time is system time.When Set Top BoxAfter time and system time synchronization, directly can obtain present system time to the clock request of Set Top Box, due to currentlyThe live time is present system time, it is therefore not necessary to the time-shifted service device acquisition request current live time.
Step S4022, it is judged that whether the right margin time to be determined is equal to or more than present system time.
Due under time-shift playing state, when speed F.F., the time difference of current time shifting broadcasting time each F.F. is relativelyGreatly, therefore, the current right margin time carries out F.F. as well as time difference described in the time, and the speed ratio current live of F.F.Time speed is big, if the current right margin time is fast-forward to overlap with the current live time, the current right margin time is the most notCan be updated further according to the right margin time to be determined.
Step S4023, when the right margin time to be determined equals to or more than the current system live time, determines current the rightBoundary's time is the current system live time.
When the right margin time to be determined equals to or more than the current live time, according to the described right margin time to be determined moreDuring current right margin time of new video window interface, the current right margin time alreadys more than the audio frequency and video of time-shifted service device cachingThe right margin time of data, so, when the right margin time to be determined equals to or more than the current live time, when determining right marginBetween be the current live time.
Step S4024, it is judged that whether the current time shifting broadcasting time to be determined is equal to or more than present system time.
Boundary's time is equal under current live time state on the right, when speed F.F., the current time shifting broadcasting time along withSpeed F.F. can exceed the right margin time, accordingly, it would be desirable to judge that whether the current time shifting broadcasting time to be determined is equal to or more than the right sideBoundary time.
Step S4025, when the current time shifting broadcasting time to be determined equals to or more than present system time, when determining currentShifting reproduction time is present system time.
If the time shifting broadcasting time to be determined equal to or more than the current right margin time, illustrate if actual program byTime-shift playing state is switched to live state, is now defined as the current live time i.e. the current time shifting broadcasting time to be determinedCan.
Step S4026, it is judged that whether the left margin time to be determined caches audio, video data less than or equal to time-shifted service deviceThe left margin time.
The length of the audio, video data time of time-shifted service device end caching determines according to the internal memory of time-shifted service device, typicallyIn the case of audio, video data when caching the least.In the method that the present embodiment provides, during the time shift of video window interface displayBetween scope be one hour, but time-shifted service device caching more than one hour of audio, video data time, such as, by time shift takeIn business device, the audio, video data set of time of caching is two hours, now, presets in the left margin time that video clip showsFor previous hour of current live time.
The left margin time of time-shifted service device caching audio, video data is by the time of time-shifted service device caching audio, video dataAnd present system time has relation, it is two hours when the audio, video data time of time shift server buffer, the most current systemThe system time is Beijing time 9::00, then, the left margin time of time-shifted service device caching audio, video data is present system timeDraw back two hours, i.e. the left margin time of time shift server buffer audio, video data is Beijing time 7:00.
Under time-shift playing state, when speed rewind, the meeting speed rewind of left margin time, fall back on soon when the left margin timeWhen time-shifted service device caches the left margin time of audio, video data, when the current left margin time cannot update than minimum left marginBetween less.
Step S4027, when the left margin time to be determined is less than or equal to the left side of time-shifted service device caching audio, video dataDuring boundary time, determine the left margin time that the current left margin time is time-shifted service device caching audio, video data.
When the left margin time to be determined caches the left margin time of audio, video data less than or equal to time-shifted service device, thisTime the left margin time to be determined beyond the time range that the audio, video data of caching in time-shifted service device is corresponding, so, will treatDetermine that the left margin time is defined as the left margin time of time-shifted service device caching audio, video data.
Such as, the left margin time of time-shifted service device caching audio, video data is Beijing time 7:00, when benchmark left marginWhen time is Beijing time 6:58:50 plus the time value after time deviation, illustrate that the current left margin time after updating cannotUpdate to Beijing time 6:58:50, so, the current left margin time of video window interface display can be updated to north by Set Top BoxCapital time 7:00.
From the foregoing, under time-shift playing state, the audio, video data cached is sent to machine top by time-shifted service deviceIn box, the time period of the audio, video data cached in time-shifted service device is generally one hour, it is also possible to be two or moreHour, the data cached time period is determined by the internal memory of time-shifted service device.When the data time section of time shift server buffer is twoThe when of individual hour, wherein, the right margin time of time-shifted service device relief area is the current live time, along with live carrying out,Time-shifted service device then can cache on the basis of the audio, video data of caching, is similar to buffer circle, so time-shifted serviceThe left margin time of the audio, video data of device relief area and right margin time are also as live and change, but at video windowOn mouthful interface display time shift scope be one hour, therefore, in time shift program playing process, along with speed F.F. or fastMove back, need in real time by with left margin time of the audio, video data of caching in time-shifted service device and right margin time carry out rightRatio, determines current time shifting broadcasting time, current left margin time and current right margin time.
See Fig. 6, the another kind of time shift time obtaining method schematic flow sheet provided for the embodiment of the present invention.
As shown in FIG., before step S300, also include step S500, from current audio and video data streams, extract PCRValue.After receiving current audio and video data streams, from current audio and video data streams, extract PCR value, according to the PCR value extractedTime difference is calculated with the PCR value extracted in reference note video data stream.Certainly, constantly sending out along with audio and video data streamsSend, from audio and video data streams, extract PCR value successively.
From current audio and video data streams, extract the idiographic flow of PCR value, see Fig. 7, provide for the embodiment of the present inventionStep S500 schematic flow sheet, specific as follows:
Audio, video data is in the encoded post package of encoder-side in TS bag, and PCR value is to sample system clockAfter be inserted into the TS bag binary field from adaptation field.
TS bag be the packet header by 4 bytes and 184 bytes from adaptation field and count off according to constituting, PCR value be inserted in fromIn adaptation field, including PCR labelling and PCR value from adaptation field, wherein, PCR labelling identifies in TS bag whether comprise PCRValue, when PCR is labeled as 1, represents in TS bag and there is PCR value, when PCR is labeled as 0, represents in TS bag and there is not PCR value, thisTime just need not from TS bag extract PCR value.PCR value is the Optional Field in TS bag, say, that be not in each TS bagAll comprise PCR value.
PCR value is made up of the binary field of 42bits, wherein, PCR_Base be by 27MHz pulse through 300 divide after90kHz pulse-triggered enumerator, then be sampled counter status obtaining.PCR_Ext is directly to be touched by 27MHz pulseSend out enumerator, then be sampled counter status obtaining.
Step S501, obtains the TCP bag in current audio and video data streams, and TCP bag comprises multiple TS bag.
Time shifting broadcasting request is sent in time-shifted service by RTSP agreement, and RTSP agreement is application layer protocol, soTS bag is that Transmission Control Protocol based on application layer is transmitted, so, TS wraps in and can be encapsulated as TCP bag when application layer is transmitted, oneTCP bag includes multiple TS bag, and in the method that the present embodiment provides, a TCP bag includes 7 TS bags.The transmission frequency of TCP bagRate and interval are controlled by time-shifted service device, to ensure the fluency of audio and video playing.Therefore, need first to obtain before extracting PCR valueTake the TCP bag in audio and video data streams.
Step S502, extracts PCR value from all TS bags of TCP bag.
TCP bag in the method that the embodiment of the present invention provides includes 7 TS bags, when obtaining from audio and video data streamsAfter TCP bag, from TCP bag, decode 7 TS bags, from 7 TS bags, then extract PCR value.When extracting PCR value, permissibleExtract the PCR value in all TS bags, it is also possible to only extract the PCR value in one of them TS bag.In order to improve PCR value in TS bagAnalyzing efficiency, a PCR value can be extracted in a TCP bag.Owing to PCR value is the sampling to system clock, instituteWith, general each regular hour just can be extracted a PCR value and be inserted in TS bag, certainly, between adjacent two PCR value timeBetween according to coding rule depending on.Therefore, all of TS bag may all there is PCR value in a TCP bag, it is also possible to a PCR valueDo not have yet.
The method extracting PCR value from TCP bag, referring specifically to Fig. 8, the step S502 flow process provided for the embodiment of the present inventionSchematic diagram.
Step S5021, obtains the TS bag in TCP bag successively.
After getting the TCP bag in current audio and video data streams, according in TCP bag TS bag ordering order or inverted orderObtain TS bag successively, and resolve TS bag successively.Such as, TS is extracted the most successively according to putting in order of TS bag in TCP bagBag, when extracting first TS bag, resolves first TS bag.
Step S5022, it is judged that whether include PCR value in TS bag.
It has been noted that include PCR labelling in adaptation field at TS bag in above-mentioned literary composition, it is used for representing in TS bag whether wrapContaining PCR value.So, when this step judges whether include PCR value in TS bag, by resolving the PCR labelling in TS bag, sentenceDisconnected PCR marks whether to be 1, when PCR is labeled as 1, includes PCR value in described TS bag, now, extracts in described TS bagPCR value.
Step S5023, when including PCR value in TS bag, determines and extracts PCR value from arbitrary TS bag of TCP bag.
In order to improve the analyzing efficiency of TS bag, improve the calculating speed of current time shift information, from TCP bag in this method simultaneouslyIn extract a PCR value.Preferably, when resolving the TS bag in TCP bag, when extracting PCR value for the first time, the most trueIt is scheduled in arbitrary TS bag of TCP bag and extracts PCR value, and determine that the PCR value extracted is current PCR value.Extract for the first timePCR value be in resolving TS bag successively, for the first time PCR value of appearance in TS bag.
Step S5024, when not including PCR value in TS bag, it is judged that whether TS bag is last TS in TCP bagBag.
If current TS bag does not include PCR value, it is judged that whether current TS bag is last TS in TCP bagBag.During TS bag in obtaining TCP bag successively, often obtain a TS bag will judge whether be surrounded by PCR in the TS bag extractedValue, if there being PCR value, then the PCR value in follow-up TS bag is not involved in the calculating of time difference, if in the TS bag extracted notInclude PCR value, then judge whether the TS bag extracted is last bag in TCP bag.
Step S5025, when TS bag is not for last the TS bag in TCP bag, the next TS bag of acquisition TS bag, and fromThe next TS bag of TS bag extracts PCR value, until extracting PCR value.
When the TS bag extracted is not last bag in TCP bag, then, suitable according to the arrangement of TS bag in TCP bagSequence obtains next TS bag, and performs above-mentioned steps, judges whether to include PCR value, if comprised from the TS bag extractedThere is PCR value, extract in PCR value, and the TS bag extracted after this TS bag without determining whether PCR value again.By above-mentionedStep obtains TS bag successively, until extracting PCR value.
Step S5026, when TS bag is for last the TS bag in TCP bag, determines from all TS bags of TCP bag the most notExtract PCR value.
If during the TS bag extracted during last TS bag of TCP bag, determining and all not carrying from all TS bags of TCP bagGet PCR value.It is to say, when 7 the TS bags resolved successively in TCP bag, all do not extract PCR value from 7 TS bags.
From the foregoing, the step that Fig. 8 provides is that circulation obtains TS bag and extracts the process of PCR value in TCP bag, carryingDuring taking PCR value, each TS bag may all there is PCR value, it is also possible to only have in second and the 5th TS bag and have PCRValue, but when this method calculates current time shift temporal information, from TCP bag, only extract a PCR value calculate, if itsHis TS bag also has PCR value, then the PCR value in other TS bags is not involved in the calculating of time difference.
The mode extracting PCR value provided in the embodiment of the present invention is that the PCR value extracted for the first time from TCP bag is carried outCalculate, but the manner is not intended as the restriction of scope, extracts the mode of PCR value from TCP bag, can be byThe last value extracted from TCP bag carries out the modes such as calculating.
Step S503, when extracting PCR value from arbitrary TS bag of TCP bag, determines and carries from all TS bags of TCP bagTake out PCR value.
In step shown in Fig. 8, it is described in detail for extracting PCR value from TCP bag, in step S3023, has worked as instituteState time TS bag includes PCR value, determine and extract PCR value from arbitrary TS bag of described TCP bag, when determining from TCP bagWhen arbitrary TS bag extracts PCR value, determine and extract PCR value from all TS bags of described TCP bag.
It is to say, when extracting PCR value from TCP bag, extract the TS bag in TCP bag successively and extract from TS bagPCR value, when extracting PCR value from any one TS bag, and determines and extracts PCR value from TCP bag, now, at TCP bagMiddle subsequent extracted to PCR value be no longer participate in the calculating of time difference.
Step S504, when all not extracting PCR value from all TS bags of TCP bag, receives current audio and video data streamsNext audio and video data streams, and from the next audio and video data streams of current audio and video data streams extract PCR value, untilExtract PCR value.
In above-mentioned steps S5026, when last TS bag during TS bag is described TCP bag, determine the institute from TCP bagHave in TS bag and all do not extract PCR value.Extract the TS bag in TCP bag successively, and analyze whether by PCR value in TS bag, when TCP bagIn when there is not PCR value in all of TS bag, determine to be from TCP bag and extract PCR value, then obtain next sound and regardTCP bag in frequency data stream, continues to extract successively TS bag, and extracts PCR value from TS bag.
From the above-mentioned description to Fig. 7 and Fig. 8, Fig. 7 and Fig. 8 specifically describes extraction PCR from audio and video data streamsThe process of value, the process extracting PCR value from audio and video data streams is as follows:
When receiving current audio and video data streams, from audio and video data streams, obtain TCP bag, owing to TCP bag comprisingThere is multiple TS bag, and PCR value is present in TS bag, so needing to extract PCR value, the side that the embodiment of the present invention provides from TS bagIn method, TCP bag includes 7 TS bags.Obtain the TS bag in TCP bag successively, and by judging the PCR labelling in TS bag, sentenceWhether disconnected TS bag includes PCR value, when PCR is labeled as 1, illustrates current TS bag includes PCR value, extract current TSPCR value in bag, and participate in the calculating of time shift difference, still need when the TS after current TS bag wraps in playing audio-video to continueParsing audio, video data therein, simply the PCR value in the TS bag after current TS bag is no longer participate in the calculating of time shift difference.
If the PCR in current TS bag is labeled as 0, illustrate current TS bag does not include PCR value, then, obtain nextLower TS bag, and continue to resolve in next TS bag whether include PCR value, the rest may be inferred, until extracting the PCR participating in calculatingValue.After often having analyzed a TCP bag, just obtain next audio and video data streams, and extract from next audio and video data streamsPCR value.
Seen from the above description, when extracting the calculating that PCR value participates in time difference from TCP bag, only need to be from TCP bagExtract a PCR value, time like this without resolving TS bag every time, from TS bag, all extract PCR value, decrease extractionNumber of times, the most less number of times calculated.Further, due between two the most adjacent TS bags interval time the most micro-at millisecondSecond level, so, calculate time difference when only extracting a PCR value from TCP bag, and do not extract the PCR value participation in other bagsCalculating, the time deviation causing the renewal of current time shift temporal information is also millisecond even microsecond pole, therefore, the time causedError is negligible.
When carrying out speed fast forward and fast reverse under time-shift playing state, due to the processing accuracy of server end PCR value, justWhen often playing, itself there is discordance in PCR coding, if the most still with the benchmark extracted from reference note video data streamThe calculating of time difference is carried out on the basis of PCR value, if, calculate the error that time difference exists 0.1ms each time, then along withThe repeatedly calculating of time difference, and when being updated according to described time difference, bigger time deviation will be caused.For understandingCertainly the problems referred to above, the embodiment of the present invention also introduces alignment mechanism, specifically comprises the following steps that
See Fig. 9, another the time shift time obtaining method schematic flow sheet provided for the embodiment of the present invention.
Step S601, it may be judged whether receive time-shifted service device and ask to send out according to the speed fast forward and fast reverse playback of Set Top BoxThe audio frequency and video number stream sent, the transfer rate of audio and video data streams is corresponding with the request of described speed fast forward and fast reverse playback.
When speed fast forward and fast reverse, PCR value easily occurs inconsistent, therefore, is receiving speed F.F. or fast operatingTime, starting correction mechanism, the correction mechanism that the embodiment of the present invention provides is to carry out a synchronous calibration with time-shifted service device.When connecingWhen receiving the audio and video data streams that time-shifted service device sends according to the request of speed fast forward and fast reverse playback, time-shifted service device is according to againSpeed fast forward and fast reverse request sends audio and video data streams to Set Top Box, and such as, speed rewind or fast reverse play request are fast for twiceEntering playing request, now, time-shifted service device sends audio and video data streams with twice transfer rate to Set Top Box.
Step S602, moves the sound that server asks according to the speed fast forward and fast reverse playback of Set Top Box to send when receivedDuring video counts stream, whether real-time judge audio and video data streams transfer rate is recovered to default regular transmission rate.
During speed transmission audio and video data streams, whether real-time judge audio video transmission speed is recovered to normal transmissionSpeed.The transfer rate of current audio and video data streams is obtained by RTSP agreement, and the transfer rate of acquisition is normal with defaultTransfer rate contrasts.Aforesaid way be applicable to time-shifted service device connect often receive a speed rewind or F.F. request, becomeCarry out a speed fast forward and fast reverse operation, corresponding to user when using remote controller to carry out speed F.F. or fast operating, oftenBy a speed fast forward and fast reverse button, just carry out a speed fast forward and fast reverse action；Another kind of situation is, when user pressesDuring speed fast forward and fast reverse button, when pressing play button, time shift program just can normal play.For above-mentioned the second situation, sentenceThe disconnected normal play that whether receives is asked, and when receiving normal play request, then calibrates.
Step S603, when audio and video data streams transfer rate is recovered to when presetting regular transmission rate, again when describedMove server and send time shifting broadcasting request.
For the first situation of speed fast forward and fast reverse, when audio and video data streams transfer rate is recovered to presetting normal biographyDuring defeated speed, again send time shifting broadcasting request to time-shifted service device, thus again accept reference note video data stream and benchmarkTime shift temporal information, carries out the calculating of time deviation on the basis of the benchmark PCR value again extracted.
For the second situation of speed fast forward and fast reverse, when receiving normal play request, again to time-shifted serviceDevice sends time shifting broadcasting and asks, and ensuing process is described above.
Another kind of alignment mechanism is in the case of normal play, such as, in the time that time shift program is play with normal speedTime longer, it is also possible to there is time offset issue, now can also carry out synchronous calibration with server.
Idiographic flow sees Figure 10, another the time shift time obtaining method provided for the embodiment of the present invention.
Step S604, it is judged that time difference is the poorest equal to Preset Time.
The computational methods of time difference are mentioned above, the playing process of time shift program update according to time difference currentTime shift temporal information, time difference refers to the time difference between current audio and video data streams and reference note video data stream, alsoThat is current difference between time shifting broadcasting time and benchmark current time shifting broadcasting time.The increase of difference over time, timeMove program current time shift time also constantly update.
Arranging Preset Time in set-top-box system poor, Preset Time difference can be 15 minutes, 20 minutes or 30 minutes etc.,The time value of Preset Time difference is not as the restriction of scope.
Step S605, when time difference is equal to Preset Time difference, sends time shifting broadcasting request to time-shifted service device again.
Such as, Preset Time difference is 20 minutes, when time difference was equal to 20 minutes, resends to time-shifted service deviceTime shifting broadcasting is asked, and again extracts benchmark PCR value, and reacquires the benchmark time shifting broadcasting time.
Certainly, there is time difference in actual applications and be not up to 20 minutes integer values, when therefore, it can arrange defaultBetween difference scope, if in the range of time difference is positioned at Preset Time difference, again to time-shifted service device send time shifting broadcasting request.
From the foregoing, the time shift time obtaining method that the embodiment of the present invention provides, updating current time shift temporal informationTime, it is not necessary to frequently obtain current time shift temporal information to time-shifted service device, only need to send time shifting broadcasting request to time-shifted service device, time shifting broadcasting request send or, receive reference note video data stream and corresponding with reference note video data stream simultaneouslyBenchmark time shift temporal information.By the benchmark PCR value extracted from reference note video data stream, and from subsequently received soundThe PCR value extracted in video data stream carries out mathematic interpolation, obtains current audio and video data streams and reference note video data streamTime difference, thus the benchmark current time shifting broadcasting time be the current time shifting broadcasting time plus described time difference.Same,Current left margin time and current right margin time are updated also dependent on time difference.By in audio and video data streamsTime difference between PCR value and benchmark PCR value determines current time shift temporal information, it is not necessary to travel frequently over RTSP protocol instructions toThe request of time-shifted service device updates time shift time range and current time shifting broadcasting time, thus alleviates the load of time-shifted service device, timeMove the load reduction of server, just decrease time-shifted service device information and return the phenomenon postponed, and then strengthen video window interfaceThe real-time that time refreshes.
The embodiment of the invention also discloses a kind of Set Top Box, affiliated Set Top Box includes processor and can for storing processorPerform the memorizer of instruction.
Processor for control receive time-shifted service device send reference note video data stream, benchmark time shift temporal information withAnd current audio and video data streams, after receiving reference note video data stream, control to extract the PCR in reference note video data streamValue, and be stored in memorizer as benchmark PCR value, the benchmark time shift temporal information received storage is made in memory simultaneouslyOn the basis of.
Processor continues to control to extract PCR value from current audio and video data streams, and by the PCR value extracted and benchmarkPCR value carries out mathematic interpolation, calculates time difference, and during calculating, processor is first by the PCR value extracted and benchmarkPCR value is converted into time value, then does mathematic interpolation.The benchmark current time shifting broadcasting time in benchmark time shift temporal information is addedUpper described time difference obtains the current time shifting broadcasting time.Meanwhile, benchmark left margin time and benchmark right margin time are plus instituteState time difference and obtain left margin time and right margin time.
The concrete mode performing operation about Set Top Box has been described in detail in the embodiment of method,This will be not set forth in detail explanation.
Figure 11 is the block diagram according to a kind of Set Top Box shown in exemplary embodiment.
The terminal that the Set Top Box that the embodiment of the present invention provides controls is intelligent television, when Set Top Box is according to disclosed by the inventionWhen method calculates current time shift temporal information, current time shift temporal information is sent to time showing flow process by Set Top Box, andThe video display interface of intelligent television is updated to current time shift temporal information.
Processor 401 control the video of terminal realize, video rewind or F.F., program switching and time shifting state switching etc.Operation, is processing including the disparate modules completing aforesaid operations, to facilitate the interaction between Set Top Box and intelligent television.
Memorizer 402 is configured to store various types of data to support the operation in terminal.The example of these dataIncluding any application program for operating on intelligent television or the instruction of method, computational methods etc..Memorizer 402 can be byAny kind of volatibility or non-volatile memory device or combinations thereof realize, such as static RAM(SRAM), Electrically Erasable Read Only Memory (EEPROM), Erasable Programmable Read Only Memory EPROM (EPROM), able to programmeRead only memory (PROM), read only memory (ROM), magnetic memory, flash memory, disk or CD.
The various assemblies that power supply module 403 is Set Top Box provide electric power, and power supply module 403 can include power management systemSystem, one or more power supplys, and other with for Set Top Box generation, manage and distribute the assembly that electric power is associated.
Multimedia groupware 404 is included between Set Top Box and user the output interface screen provided.In certain embodiments,Screen can include display screen or touch panel.If screen includes that touch panel, screen can be implemented as touch screen, to receiveInput signal from user.Touch panel includes that one or more touch sensor touches with sensing, slides and touch panelOn gesture.Described touch sensor can not only sense touch or the border of sliding action, but also detects and described touchOr slide relevant persistent period and pressure.Set Top Box can also be provided with button, and user can be saved by buttonThe functions such as mesh switching, speed fast forward and fast reverse, Volume Up or reduction.
Input/output interface 405 provides interface for processing between assembly and peripheral interface module, communications component 406 is joinedIt is set to be easy to the communication of wired or wireless mode between Set Top Box and time-shifted service device.Set Top Box can access based on communication standardWireless network, such as WiFi, 2G or 3G, or combinations thereof.In one exemplary embodiment, communications component 406 is via extensivelyBroadcast channel and receive the broadcast singal from external broadcasting management system or broadcast related information.In one exemplary embodiment,Described communications component 406 also includes near-field communication (NFC) module, to promote junction service.Such as, can be based on penetrating in NFC moduleFrequency identifies (RFID) technology, Infrared Data Association (IrDA) technology, ultra broadband (UWB) technology, bluetooth (BT) technology and other skillsArt realizes.
In the exemplary embodiment, Set Top Box can be by one or more application specific integrated circuits (ASIC), numeral letterNumber processor (DSP), digital signal processing appts (DSPD), PLD (PLD), field programmable gate array(FPGA), controller, microcontroller, microprocessor or other electronic components realize, be used for performing said method.
Those skilled in the art are considering description and are putting into practice here after disclosure of the invention, will readily occur to its of the present inventionIts embodiment.The application is intended to any modification, purposes or the adaptations of the present invention, these modification, purposes orPerson's adaptations is followed the general principle of the present invention and includes the undocumented common knowledge in the art of the present inventionOr conventional techniques means.Description and embodiments is considered only as exemplary, and true scope and spirit of the invention are by followingClaim is pointed out.
It should be appreciated that the invention is not limited in precision architecture described above and illustrated in the accompanying drawings, andAnd various modifications and changes can carried out without departing from the scope.The scope of the present invention is only limited by appended claim.