• 专利附录
  • 专利说明
  • 权利要求
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    • 专利摘要:
    Method for transmitting over a digital medium from one (1,2) (M), transmitter device re (3), to at least two parallel receivers a video stream with additional material to be (39) published at certain respective specified times, the video stream has an embedded time code. The invention is defined by the steps a) starting the sanding (15) of the video stream from the transmitter device to at least one of the receivers; b) causing the receiver to report (18) the time code in the received video stream; c) calculate (19) the delay (Atvideo) regarding the video stream, and determine (24) a longest delay (Atmax) of the receivers to which the video stream is sent; d) provide (29) a list (30, 33) of the extra material and associated times for publication, the list including all discrete parts to be published at times over a time interval of the length of the identified longest delay and running until the current one; the time code of the transmitting device transmitting the video stream; and e) distributing (34) said list to at least one of the recipients. Application text document 2012-08-22 120040SE
    公开号:SE1250944A1
    申请号:SE1250944
    申请日:2012-08-22
    公开日:2013-10-29
    发明作者:Anders Maarten
    申请人:Ungap Ab；
    IPC主号:
    专利说明:

    1015202530the image material to a time axis. The extra material is transportedtypically on another, separate channel, from the transmitter tothe recipient.
    When broadcasting a video signal via the Internet or otherdigital media, it is inevitable that a delay ofthe video signal is generated in the receiver, so that the video streamis displayed with a certain delay in relation to the transmitter.
    The delay occurs both at the actual distribution, therefactors such as the design of the video encoder, the choice of buffer sizeto even out network interference, and the path of the video signal ina digital network plays a role, but also in each individualell receiver, through, for example, varying performance whatapplies to connected bandwidth and processing power. The delayin the distribution of extras are generally not the sameas the video signal distribution delay. This is i_ syn-truth in the ordinary case that the Internet is used fordistribution.
    In many cases it is important that the video stream and extrasthe material is carefully synchronized, so that the right extrasappears at just the right time during the video streamappears on the recipient page. In order to achieve such a synchronousvideo and extra material in the receiver is neededhowever, due to the delay discussed above,a synchronization mechanism.
    A way to realize. such a synchronization mechanism isto use the embedded time code of the video signal and in the receivermatcha, the. against a list. with. time-bound measures. II thisIn this case, the recipient performs a certain action, such as displaying an imageor a text on the screen, when the time signal of the video signal matchesa timestamp in such a list. For viewing recorded materialrial as the entire action list is known in advance this worksApplication text document 2012-08-22 120040SE1015202530Good. On the other hand, the entire list of actions is often not known inin advance, but occurs or is continuously updated during distributionthe course of action. This is the case, for example, with livear, or when an existing film is distributed in streaming formand at the same time commented on with the help of extra material as thenoccurs during distribution.
    Thus, it would be desirable to provide a means ofbuera. such a 'video stream' and, such extras, whichmethod allows the extra material to be displayed synchronized withseveral different recipients, which recipients have different andhand unknown delay.
    It would further be desirable to provide such a method asis scalable to many receivers. If a video stream shoulddistributed to tens of thousands, hundreds of thousands or toand with even more simultaneous recipients, the distribution ofcontinuously updated extras and associated synchronousinformation from a specific server to all recipientscome to 1it do. a bottleneck. Current. event listcan, for example, during the course of a long live broadcast reachsignificant size.
    Furthermore, problems arise with how different receivers on anbe alerted when a new event occurs. After-as. the individual delay of the recipients is not knownproblems also occur when synchronizing informationto be distributed to newly connected recipients, which are expectedshow the latest extras, even if this is already earlyre, perhaps a long time ago, distributed to already connectedreceiver.
    The present invention solves the problems described above.
    Application text document 2012-08-22 120040SE1015202530Thus, the invention relates to a method of:over a digital medium, from a transmitter device to at leaststone two parallel receivers, distribute a video stream withextra material, where the extra material comprises a numberdiscrete parts to be published at certain respectivecertain times in relation to the video stream, and therethe video stream has an embedded one. time code, and. is characterized by thatthe method comprises the steps of a) starting the transmission of the videothe current from the transmitter device to at least one of the receivingyarn; b) bring receivers to which the video stream is sent toreceive the video stream and report the respective valuethat of the time code in the received video stream; c) calculatethe delay regarding the video stream for receivers towhich video stream is transmitted by comparing it respectivelyreported the value of the time code with the actual value ofthe time code of the video stream transmitted from the transmitting devicebut, as well as determine a longest delay in the nwttagareto which the video stream is sent; d) accomplish and continuouslyupdate a list with. discrete parts of the extra material,or references to such discrete parts, and associatesthe respective dates of publication of the discretethe list, where the list includes all discrete parts such asshall be published at times over a time interval withthe length of the identified longest delay and which runsup to the current time code for it from the transmitter devicedistribute said listtransmitting the video stream; and e)to at least one of the recipients.
    The invention also relates to a transmitter and a transmitter, respectivelyrecipient to perform such a procedure.
    The invention will now be described in detail, with referenceto exemplary embodiments of the invention and thoseattached drawings, where:Application text document 2012-08-22 120040SE1015202530Figure 1 is a flow chart illustrating how a transmitteraccording to the present invention reports its own time toa server according to the invention, how a receiver according tothe finder reports a video stream time code to the server andhow the server can calculate the video delay of an individualreceiver and the longest video delay of any onenumber of recipients;Figure 2 is a flow chart showing how a transmitter according tothe invention based on a longest reported video delaygenerates a list of time-bound actions and how a receivedgare according to the invention reads and interprets the list; andFigure 3 is a flow chart showing a transmitter according tothe finding, which to indicate an event introduces onediscontinuity in the time code, as well as a receiver according to the inventionwhich detects the discontinuity and interprets it as oneevent.
    The figures share reference numerals for the same or equivalentthey share.
    Figure 1 illustrates in principle a system according to the invention.to transfer over a digital medium M, from a transmitter deviceorder 1, 2 to at least two parallel receivers 3,distribute a video stream with extras.
    The term "digital medium" is here to be construed as a digitalcommunication channel, such as wireless or wired Internetnet.
    The term "extra material" is intended to include all typesof multimedia that can be published at certain specified timesin relation to the time of a video stream, such as. pictures,audio clips, text materials, animations, videos, control commandsAnsölmingstextdocx 2012-08-22 120040SE1015202530don to external equipment, and so on. A single extramate-unit, such as a single image or a strip of text, is calledherein "discrete part" extras.
    The extra material comprises a number of discrete parts to bepublished at certain and specified times in relation toembedded time code asto the video stream, son1 has onerelates the video stream to a time axis.
    The system comprises a transmitter device, which in turn includestakes a transmitter 1 and a server 2. The transmitter 1 is arrangedthat, for example through so-called streaming or multicasttechnology, send a video stream to at least two simultaneouslyor parallel receivers 3. The server 2 is arranged tocommunicate with the recipients 3, and to provide and distributean event list to the recipients 3.
    Figure 1 illustrates for clarity only one receiver 3.
    According to a preferred embodiment, the number of simultaneous counter-taker 3 at least 1000, preferably at least 10000, preferablyat least 100,000.
    In addition, there is one for each receiver 3 individuallyvideo delay 6, which in general and by those discussed abovethe reasons are to some extent unpredictable, and asexcept is generally greater than a typical delay for onesignal as. sent over the same digital communication channeland. as. includes * a smaller amount. data. than a video stream,such as many types of extras as well as reports of those typesas described below.
    According to a preferred embodiment, the transmitter 1, ian initial step 10, its current time tsæ fl me to the server2, whereupon server 2 calculates 11 a difference Atß nællan denApplication text document 2012-08-22 120040SE1015202530from the transmitter l reported the time and the server 2 currentserver:Atss I transmitter tserverTo compensate for the signal delay '7 associated withthat the time of the transmitter 1 is reported to the server 2, it isdrawn that the transmitter l measures l2 the time Atsml it takes to sendthe report. Transmitter l reports this time to server 2,and server 2 compensates l3 for the time difference between transmitter land server 2, providedkoms l4:whereby a compensated time difference At $Atss I Atss _ AtsiglThe measurement of Atsml can take place in a conventional manner. Onepreferred way, however, is to measure the response time from theclean l to server 2 and then assume that Atggl is the same asthis response time from the transmitter 1 to the server 2 and backAgain, this gives an overestimationthat is, "roundtrip".of the real delay, which has proven to be goodresults. The present inventors have surprisingly discoveredthat such a relatively rough 'measurement' of 'Atggl at. oneonly initial opportunity gives adequate results. It is namelyso that the signal delay is in many cases relatively stablecar over time.
    Thereafter, the transmitter 1 encodes the pre-recorded by a camera 4.sentation, beds as a time code into its own running time tsæ fl ære, and begins and continues the transmission ofto at leastthe encoded video stream, including the time code,stone one of the recipients 3.
    Application text document 2012-08-22 120040SE1015202530At least one of the connected receivers 3 to which the videothe stream being transmitted receives the video signal from the transmitter 1,wherein the video stream has been delayed by the video delay 6.
    The receiver 3 detects the time code embedded in the video stream.on the 17th, and 18 reports the value of the detected time codetmmtwaæ to the server 2.
    Then the server 2 calculates the delay regardingthe video stream for receiver 3 to which the video stream is sent,through. to compare the respective reported value ofthe time code with the actual value of the time code of the fromtransmitter 1 transmits the video stream.
    Immediately after * the * to the recipient. 3 reported the time codeserver 2 thus calculates the expected simultaneous timetämmæ at the transmitter 1:2 tserver + Atsst transmitterThe difference between the transmitter's 1 time tsæ fi æe and the time code tmmtwaæreported by the receiver 3 is the receiver's calculatedvideo distortion To fi dæzAtvideo = tmottagare _ tsändare-Thus, the server 2 adjusts the respective calculated delayfor the recipients 3 by means of the difference between itfrom the transmitter 1 reported the time and the server 2 currenttime.
    To compensate 21 for the delay 8 in connection withthe receiver's 3 time is reported 18 to the server 2 so measuresthe recipient. 3 the time it takes to send the report.
    This measurement can be made in a similar manner as the one above.Application text document 2012-08-22 120040SE1015202530written the measurement of Atagh and has surprisingly provedcan consist of the same rough approximation as that of Atgghalso with satisfactory results.
    The receiver 3 reports 20 this time Atsmg to the server 2,after which "the server. 2 compensates * 21 for the time difference. betweenreceiver 3 and server 2, so that a final value forthe time difference AtWd fi, achieved 22:Atvideo I Atvideo _ Atsig2Then, the estimated individual video consumption of the receiver 3 is read.delay Atwdæ back of nwttagaren 3 from server 2 forlater use (see below). The result of this subtractionis then also used by the server 2 as the value of the receiveddelay in the subsequent procedure.
    Thereafter, a longest delay of the receivers 3 is determinedto which the video stream is currently being sent, in other wordsthe largest value for Atwdæ calculated for someone connectedreceiver.
    After a broadcast has started, reports 18 come fromdifferent receivers 3 typically to arrive at server 2 atdifferent times. This is because different receivers 3 may havedifferent delays, but also that different receivers 3 canjoin the broadcast at different times, even afterthat the transmission has begun.
    Therefore, it is preferable that the server 2, when a new report 18received from a receiver 3, compare the reportedthe deodorant delay Atwdæ with the previously longest reportedthe video delay Atm fl, and saves 24 if it is longer:Application text document 2012-08-22 120040SE1015202530lOAbout (Atvideo> Atmax) => (Atmax In Atvideo)In this way, the server 2 always pours a value on theuntil the largest reported value for the video delayAt fi d &, at any of the connected receivers 3.
    According to the invention, the transmitter device then provides aevent list, which is then continuously updated. Such an eventselista includes discrete parts of the extra material such asshall be published at the recipients 3, alternatively referencesto such discrete parts, and also associated respectivelytimes, in relation to the time code of the video stream, forpublication 'of the discrete parts. It is preferred thatthe trade list is updated each time a new event occursfar, i.e. when a new discrete part of extra material is attached to onecertain time along the time axis of the video stream.
    The event list can be stored digitally in the server 2 on its ownconventional way, as in the form of a conventional linked onelist or otherwise.
    According to the invention, the trade list is updated so that italways. includes all the discrete. parts extra materialto be published at the times, along with the video streamstime code of the time code, which extends over a time intervalvall son1 has ~ the identified longest delay Atm fllength and which runs until the current time code for itfrom the transmitter device momentarily transmits the video stream. Within other words, the parts of the extra material are included in thethe list to be published most recently in relation tothe current time code of the video stream, and also those to be publishedceras earlier than that, back to Atmm before the current onethe time code.
    Application text document 2012-08-22 120040SE1015202530llIn this way, the system can be made scalable to a large extent.because the connected receivers 3 only need to reada relatively short list of events. from the server. 2, whilethe receivers 3 can still obtain sufficient informationfrom the server 2 in order to be able to correctly publish the intendedregardlessmaterial i. connection. with. the view. of 'video stream,individual delay.
    When new events arise, ie. when the time for the intended publicationnew parts extra material is achieved in the transmitted videocurrent time code or when knowledge of a new such futurepublication arises, according to the invention it is distributedcurrent event list to at least one of the recipients 3,preferably to all recipients 3. Although it is possible totransmitter l or server 2 sends the list with socalled push technique or the like, it is preferred that eachrespective recipient 3 requests an updated event list such asthen sent from server 2 (see below). Analogously distributedthe event list to a new receiver 3 when one is connectedduring transmission of the video stream.illustrates an exemplaryFigure 2 event developmentafter a presenter 9, during a live presentationtion, gives rise to a new part of extra material by showing25 a new image to be published by the recipients 3. Replacedimage 26 is registered at the transmitter 1 as a new time-connected accessfence of the type "show picture".
    Transmitter l responds to this new event by reading 27the longest reported delay Atwx 28 from the server2, which delay Atm fl is determined as above. Then29 transmitter 1 generates an updated event list with timeAnsölmingstextdocx 2012-08-22 120040SE1015202530l2linked measures as follows, preferred, detailedprocedure:First, the new timed action 25 is stored last in a homo-gen list that contains only the same type of action, in thiscase type "show image". For each type of measure which hascome during a period of length Atmm and that ends in itthe current value of the time code for the video stream on the broadcastpure 1, a separate such homogeneous list is preferably used.
    For some or all types of events, this may be the casea certain discrete portion of extras is intended. to remainuntil it is replaced by the next part of the same type, e.g.show some subtitles. For such types of extraspreferably a separate homogeneous list is always used.
    By using individual lists for each type of event,more efficient data processing is achieved, as an eventualsetyp can be processed one at a time in receiver 3. This is notat least the case when several different types of events of different typescan occur at very short or no time intervals, andbecause it can be quickly identified which one is the mostrecently published the event of a certain type. In addition,This allows each receiver 3 to easily assess howmany types of extras that occur and that at onecertain time must be available in published form.
    For each such homogeneous list of time-bound actions of onecertain type stores all events that are not older than orsubstantially older than Atmm. However, if this means thatthe list will be empty for a certain type it is preferred, at leastfor the above type of events to remainpublished until they are replaced, that the most recent measure intan is stored, and it will also be the action to be performedApplication text document 2012-08-22 120040SE1015202530l3initially by a recipient who receives the event list firsttime.
    Then 29 the final event list is created with time link.the measures that. a heterogeneous list genoH1 that they generatedhomogeneous lists are merged into a single list, where eventsare preferably arranged in chronological order.
    It is preferred that the list be finally stored in appropriatedigital format on the server 2.
    A new event list is preferably created in this wayeach new event, possibly in combination with thethe list is updated periodically.
    While the video stream is being sent to at least one receivingre 3, a synchronization marker is then distributed, which3l indicates that the event list has been updated, to itor the receivers 3 to which video stream (s)currently being broadcast.
    The indication 3l can be made in different ways, of which two are preferredexamples are presented below.
    A first example of the indication 31 is that the transmitterl introduces a sync marker embedded in the video signal itself,which. the respective recipients. 3 detects directly in itreceived video signal, In this case, the synchronizedpreferably by a discontinuitysonl is embedded in. the video stream beforeintroduced in. the time codetransmission, and the receivers 3 interpret such a time code discontinuousthe received video stream as the synchronization market.IGÛ.
    Application text document 2012-08-22 120040SE1015202530l4Figure 3 illustrates the development of events in such a distributionwhere a video encoder 40 is used which in turn usesturns a system clock in the transmitter l to create the time code44 in the video stream. It is especially preferred to use thisways to distribute the synchronization cursor when a video encoderre of the so-called "black box" type is used, in other words onevideo encoders that do not give public access to the encodedany data channel or embedded time code of the video stream.
    When the event occurs, which is detected by an eventdetection means 41 in the transmitter. l, is set, with. with the help of atime shift generator 42 in the transmitter 1, the system clock 44 backwardsa few seconds At, 43, and then, after a certain period of time,preferably less than 2 seconds, the system clock 44 is setIn this way, a dis-time code,back forward again just as much.continuity of the otherwise continuous video signalwithout affecting or manipulating the video encoder 40 itselfthe sync cursor.which discontinuity constitutesThe video signals. 45, med. the embedded time code, is distributedto the receivers 3, where the time code of the video signal is lostusing a video decoder 46 and fed to a time shiftdetector 48 in the receiver 3 which is arranged to detect thethe continuity of the time code At,run 49.47 and interpret it as a sync-The sync marker is preferably detected by ateach reading of the real value of the time code compare it with oneexpected value. If the fair value differs sufficiently,preferably at least 1 second from the expected value.that, a sync marker has been detected. Such a procedureprovides good scalability as the event list only needsread by recipient 3 when a new event is actually recordedhits.
    A second example of the indication 31 is that the transmitter 1arranging a state change of a state server,which state change 'is readable by a receiver 3Application text document 2012-08-22 120040SE101520253015to which the video stream is sent. The permission server can besame as, or other than, server 2 or transmitter l.
    A preferred way of effecting such a state change is toring 'is to the transmitter. l writes a control file with. updatedcontent, for example on the server 2. The receiver 3 then readscontrol file from server 2, and detects a sync marker whenit detects that the control file has changed.
    It is preferred that each receiver 3 wait a period of timebetween. two. successive readings * of the stateat the state server, which time period is substantially equallong as the receiver's 3 calculated delay Atw flflfi This givesgood scalability, because relatively sparse readings thencan be used without the recipients 3 risking being reachedof information about new events in time to publish them.
    Thus, 32 the respective receivers 3 detect the sync markerclean. Then 34 they read the current event list 30,33 from the server 2. However, it is preferred that thethe list 30, 33 is only distributed to a certain recipient 3to which the video stream is sent if the latest distributionthe listing took place for at least a certain predeterminedtime ago, which predetermined time is the same or substantiallysame as. the estimated delay of the respective recipientAtwdam That the list of events is only "distributed" should be hereunderstood as the recipient 3 in question only reads the event listwhen this condition is met, alternatively that the server 2only sends a requested event list when the condition isfulfilled.
    More specifically, it is preferred that, when the receiver 3 hasdetected 32 a sync marker, it reads the event list fromserver 2 only if the previous reading from the sameApplication text document 2012-08-22 120040SE1015202530l6recipient 3 took place the same or longer time than the recipientclean 3 in question own video delay Atwdæ. If the readingignored due to this condition shall the event listunconditionally read again within the interval Atwww since itlatest reading. In this way good scalability is achieved, ef-tersom. readings of the event list only need to be maderelatively rarely, without information risking to golost or not reached.
    When reconnecting a certain receiver 3 to the video stream isit is preferred that a method which. similar to the above. ask-written 'is performed, so that the recipient. 3 first receive videostream and reports its video delay, after which itthe current event list is read.
    After the heterogeneous event list 30, 33 is read 34it is again subdivided into several homogeneous lists 36, which wereand one contains time-related events of only one type; asone list with the type "show image" and another list with the type"Show text".
    Then the receiver 3 preferably looks up current eventsby continuously matching 38 each homogeneous event listagainst the video time rolling time code 37, and that in connectionto the video stream publish 39 the timed event inthe list in question which is the most recent event having the same timewhich or which is older than the time code.
    Figure 2 illustrates the publication by displaying an image,but it will be appreciated that different types of extras may be publishedin various appropriate ways in connection with, on or offyarn.
    Application text document 2012-08-22 120040SE1015202530l7Thus, by means of the present invention, a transmission canof a video stream with associated extras in the form of varioustodiscrete multimedia events, various recipients includedpreviously partially unknown properties, achieved on a lotefficiently and scalably, as only events are dis-is distributed containing information necessary for eachrecipients should be able to take initial action and thentake action, andupdated with timedeftersonl each recipient only gets updated. informationwith regard to the extra material when the need for itis for that particular recipient.
    In addition, scalability can be further improved bydeliberately, on the part of the transmitter l, introduce an additionaldelay regarding the distribution of the video stream to somerecipient 3. Such a delay increases the number of possiblerecipients by ensuring that readings from recipients3 to the server. 2 occurs * less frequently, but causes for those affectedreceiver has no effect other than that the video stream with associatedextra material is displayed with a larger delay.
    Preferred embodiments have been described above. However, isit is obvious to the person skilled in the art that many changes can be madeof the described embodiments without departing from the invention.one thought.
    For example, the server 2 and the transmitter 1, in the form of hardwareand / or software, designed to be executed on one and the samecomputer unit. This also applies to the condition described above.the server. The server 2 and the transmitter l can, on the other hand, alsoimplemented to be executed on two different servers aswritten above, which then for load sharing and other reasonscan be arranged in different geographical locations. Transmitter 1may in some embodiments be a central node that collectsApplication text document 2012-08-22 120040SE101520l8and distributes video and extras information fromgeographically disparate sources.
    Furthermore, each or some of the Receivers, as well as the transmitterand / or the recipient, from time to time perform measurements of tsml,tmgh and Atwdæ. For example, each recipient may periodically,alternatively when external information is available on fluctuationdown in. the current maximum available of the internet connectionbandwidth, perform remeasurement of Atwdæ. In particular, it isto carry out a remeasurement of Atwdæ when buffering takes placeof the video stream in the receiver.
    Finally, each receiver can be of different type, such as in shapeof software in a mobile device such as a mobile phone; hardwareor software in a computer; or in the form of software and / orhardware available in distributed form, over several moreinterconnected computers, as part of, for example, a videoconference facility.
    Thus, the invention should not be limited by the methods described herein.na 'embodiments, but can be varied within. framework for thoseattached requirements.
    Application text document 2012-08-22 120040SE
    权利要求:
    Claims (10)
    [1]
    A method for transmitting a video stream over a digital medium from a (1,2) (M) transmitter device to at least two parallel receivers (3). with extra material, where the extra material comprises a number of discrete parts to be published (39) at certain respective fixed times in relation to the video stream, and where the video stream has an embedded time code, characterized in that the method comprises the steps a) start the transmission (15) of the video stream from the transmitter device to at least one of the receivers; b) bring receivers to which the video stream is sent to (16) (18) take. against the video stream. and. to report the respective value of the time code in the received video stream; (19) (htw flflfi regarding the video stream for receivers to which the video stream is transmitted c) calculate the delay by comparing the respective reported value of the time code with the actual value of the time code of the video stream transmitted from the transmitting device, and determine (24) a longest delay (24) Atw fl) of the receivers to which the video stream is sent; d) provide and continuously update (29) a list (30, 33) with discrete parts of the extra material, or references to such discrete parts, and associated respective times for publication of the discrete parts, the list including all discrete parts which is to be published at times over a time interval with the length of the identified longest delay and which runs up to the current time code for the video stream transmitted from the transmitting device; and Application text dococ 2012-08-22 120040EN 10 15 20 25 30 20 e) distribute (34) said list to at least one of the recipients.
    [2]
    Method according to claim 1, characterized in that, in step b), the signal delay of the receiver (3Q) regarding the reporting (l8) of the time code of the video stream is measured and, in step c), subtracted from the calculated delay, the result from subtraction (ATvideo) - for the receiver in question, the tion is then used as the receiver's delay
    [3]
    Method according to claim 1 or 2, characterized in that the transmitter device is caused to comprise a transmitter (1), arranged to transmit the video stream, and a server (2), which server is caused to be arranged to receive reports (18) (3). ), in that the transmitter in respect of the value of the time code from the receivers (30, 33), (10) its current time to (11) and in making said list an initial step reports said server, in that the server then calculates a difference between the the transmitter reported the time and the current time of the server, and that, in step c), the server adjusts (l3) the calculated delays using this difference.
    [4]
    A method according to any one of the preceding claims, wherein - while the video stream is being transmitted (3), (30, 33) is plotted (15) by distributing to at least one receiver a synchronization marker indicating that the list has been updated (3l) to the receiver or receivers to which the video stream or videos are sent.
    [5]
    Method 4, characterized in that the synchronization marker is claimed (31). distributed (43) by introducing in the time code (44) which is embedded (45) discontinuity into the video stream before transmission, and by a receiving (3) interpreting a such time code discontinuity in the received video stream as the synchronization cursor (49).
    [6]
    Method according to claim 4, characterized in that the synchronization marker consists of a state change of a state server which is readable by a receiver (3) to which the video stream is sent, and in that the receiver waits a period of time between two consecutive readings of the state of the state server , which time period is substantially as long as the calculated delay (ATvideo) - as. of the recipient
    [7]
    A method according to any one of the preceding claims, k ä11r1e - t e c k n a t a v that the list (30, 33) only. is distributed (34) to a particular receiver (3), to which the video stream is transmitted, if the last distribution of the list took place a certain predetermined time ago, which predetermined time is substantially the same as the receiver's estimated delay (ATvideo) -
    [8]
    The transmitter device (1,2) for distributing a video stream of extras over a digital medium (M) to at least- (3), takes a number of discrete parts to be published where the extras comprise (39) two parallel receivers at certain respective fixed times in relation to the video stream, and where the video stream has an embedded time code, characterized in that transmitter devices1 are arranged to perform the steps a) start the transmission (15) of the video stream to at least one of the receivers; b) from the receivers to which the video stream is sent receive (18) the respective value of the time code read by the respective receivers in the received video stream; Answerage text document 2012-08-22 120040EN 10 15 20 25 30 22 c) calculate (19) the delay (ATWdæ) regarding the video stream for receivers to which the video stream is sent by comparing the respective reported value of the time code with the actual value of the time code of the transmitting the video stream, reporting to the receivers their respective calculated delays, and determining (24) a longest delay (ATMÜ) of the receivers to which the video stream is transmitted; d) provide and continuously update (29) a list (30, 33) with discrete parts of the extra material, or references to such discrete parts, and associated respective times for publication of the discrete parts, the list including all discrete parts to be published at times over a time interval with the length of the identified longest delay and which runs up to the current time code of the transmitted video stream; and e) distributing (34) said list to at least one of the recipients.
    [9]
    Transmitter device according to claim 8, characterized in that the transmitter device comprises a transmitter device (2), (18) with respect to the value of (1), when transmitting the video stream, and a server which server is arranged to receive reports (3) , in that the transmitter is arranged to report its current time to said servers in an input (10) time code from the receivers and to provide said list (30, 33), in that the server is arranged to calculate thereon (ll ) a difference between the time reported by the transmitter with current. time, and. in that, in the server (13), the server's step c) is arranged to adjust the calculated delays by means of this difference. Application text document 2012-08-22 120040EN 10 15 20 23
    [10]
    A receiver device (3) for receiving a video stream with extras over a digital medium (M) from a transmitter extras comprises a number (39) of arrangements (1,2), in which discrete parts are to be published at certain respective fixed times. in relation to the video stream, and where the video stream has an embedded time code, characterized when the reception (16) that the receiving device is arranged to, from the video stream from the transmitter be initiated, read and report to the transmitting device (18) the value of the time code in the received video stream from the transmitter device obtain (23) a value for the delay of the receiver (ATWÄHJ regarding the received video stream, and to request from the transmitter device (34) a list (30, 33) with discrete parts of the extramaterial, or references to such discrete parts, and associated respective times for publishing the discrete parts, the recipient being arranged to wait a period of time between two on the product draw the following request of the state of the state server, which time period is substantially as long as said delay. Application text document 2012-08-22 120040SE
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    同族专利:
    公开号 | 公开日
    SE536434C2|2013-10-29|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2020-04-28| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    SE1250944A|SE536434C2|2012-08-22|2012-08-22|Method and apparatus for distributing multimedia over digital network|SE1250944A| SE536434C2|2012-08-22|2012-08-22|Method and apparatus for distributing multimedia over digital network|
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