EP2151075A2 - Diffusion simultanée à entrelacement temporel pour une réduction de la syntonisation - Google Patents

Diffusion simultanée à entrelacement temporel pour une réduction de la syntonisation

Info

Publication number
EP2151075A2
EP2151075A2 EP08776420A EP08776420A EP2151075A2 EP 2151075 A2 EP2151075 A2 EP 2151075A2 EP 08776420 A EP08776420 A EP 08776420A EP 08776420 A EP08776420 A EP 08776420A EP 2151075 A2 EP2151075 A2 EP 2151075A2
Authority
EP
European Patent Office
Prior art keywords
time
coded data
data stream
sliced
burst
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08776420A
Other languages
German (de)
English (en)
Inventor
Miska Hannuksela
Vinod Kumar Malamal Vadakital
Imed Bouazizi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Conversant Wireless Licensing SARL
Original Assignee
Nokia Oyj
Nokia Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US11/757,920 external-priority patent/US20080301742A1/en
Priority claimed from US11/758,613 external-priority patent/US8396082B2/en
Application filed by Nokia Oyj, Nokia Inc filed Critical Nokia Oyj
Publication of EP2151075A2 publication Critical patent/EP2151075A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/42—Arrangements for resource management
    • H04H20/426—Receiver side
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/20—Arrangements for broadcast or distribution of identical information via plural systems
    • H04H20/22—Arrangements for broadcast of identical information via plural broadcast systems
    • 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
    • H04N21/238—Interfacing the downstream path of the transmission network, e.g. adapting the transmission rate of a video stream to network bandwidth; Processing of multiplex streams
    • 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]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/41—Structure of client; Structure of client peripherals
    • H04N21/414—Specialised client platforms, e.g. receiver in car or embedded in a mobile appliance
    • H04N21/41407—Specialised client platforms, e.g. receiver in car or embedded in a mobile appliance embedded in a portable device, e.g. video client on a mobile phone, PDA, laptop
    • 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]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
    • H04N21/438—Interfacing the downstream path of the transmission network originating from a server, e.g. retrieving encoded video stream packets from an IP network
    • H04N21/4383—Accessing a communication channel
    • H04N21/4384—Accessing a communication channel involving operations to reduce the access time, e.g. fast-tuning for reducing channel switching latency
    • 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 
    • H04N21/63—Control signaling related to video distribution between client, server and network components; Network processes for video distribution between server and clients or between remote clients, e.g. transmitting basic layer and enhancement layers over different transmission paths, setting up a peer-to-peer communication via Internet between remote STB's; Communication protocols; Addressing
    • H04N21/643—Communication protocols
    • H04N21/64315—DVB-H
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/24—Systems for the transmission of television signals using pulse code modulation

Definitions

  • the present invention relates generally to the transmission of media streams over a Digital Video Broadcasting channel, whereby the media datagrams of an identical source but of different transmission and presentation characteristics are simulcast.
  • DVB-T Digital Video Broadcasting-Terrestrial
  • DVB-T is also referred to as the "Common 2k/8k specification.”
  • the multi- carrier modulation system used by DVB-T provides additional robustness in the presence of noise.
  • Orthogonal Frequency Division Multiplexing is used by DVB-T in two modes: the 2K mode, which uses 1705 carriers, and the 8K mode, which uses 6817 carriers.
  • the size of the SFN depends on the modes used: the 2K mode having a smaller SFN with a single transmitter than an 8K mode.
  • DVB-T mobile services have been launched in various locations. Using diversity antenna receivers, services which targeted fixed antenna reception can now also be received on the move.
  • Handheld mobile terminals require specific features from the transmission system serving them. These features include (1) extended receiver battery life; (2) improved radio frequency (RF) performance for mobile single antenna reception; (3) countering high levels of noise in a hostile transmission environment; and (4) efficient handovers.
  • RF radio frequency
  • the Digital Video Broadcasting Handheld (DVB-H) standard has been developed. DVB-H uses the same basic concepts of DVB-T but adds additional features to improve mobility, power consumption and SFN usability.
  • DVB systems were originally designed to transmit digital multimedia contents to consumers directly to their homes. However, it was also recognized that the same transmission system is useful for broadcasting to consumers other types of data such as firmware updates for set-top boxes, games for set-top boxes, program guides, Internet services, and proprietary data such as stock marker iniormauon. i nis broadcasting of data is referred to as datacasting.
  • datacasting Depending on the different types of applications that can use datacasting and their requirements, six different profiles were defined. These profiles are: (1) data piping; (2) data streaming; (3) multiprotocol encapsulation (MPE); (4) data carousels; (5) object carousels; and (6) other protocols.
  • MPE-Forward Error Correction is an optional multiplexer-layer FEC code based on Reed-Solomon (RS) codes.
  • MPE-FEC is included in the DVB-H specifications to counter high levels of transmission errors.
  • the RS parity data is packed into a special FEC section referred to as MPE-FEC so that an MPE-FEC-ignorant receiver can simply ignore these sections.
  • the computation of MPE-FEC is performed in the link layer, over IP packets before encapsulation into MPE sections.
  • An MPE- FEC frame is arranged as a matrix with 255 columns and a flexible number of rows. Currently, column heights of 256, 512, 768, 1024 bytes are supported.
  • Figure 1 shows the structure of an MPE-FEC frame. Each position in the matrix hosts an information byte. The first 191 columns are dedicated to Open Systems Interconnection (OSI) layer 3 datagrams, such as IP packets, and possible padding. This portion of the MPE-FEC frame is referred to as the application data table (ADT). The next 64 columns of the MPE-FEC frame are reserved for the RS parity information. This portion is referred to as the RS data table (RSDT).
  • ADT application data table
  • RSDT RS data table
  • the ADT can be completely or partially filled with datagrams.
  • the remaining space, when the ADT is partially filled, is padded with zero bytes. Padding is also performed when there is no space left in the MPE-FEC frame to fill the next complete datagram.
  • the RSDT is computed across each row of the ADT using RS (255, 191). It is not necessary to compute the entire 64 columns of parity bytes, and some of the right-most columns of the RS data table can be completely discarded. This procedure is referred to as puncturing. The padded and punctured columns are not sent over the transmission channel.
  • Time slicing of the MPE- FEC frames was used to solve this problem.
  • Time slicing is similar to time division multiplexing (TDM).
  • TDM time division multiplexing
  • An advantage of TDM is its flexibility by allowing dynamic variations in the number of signals sent in the channel and the ability to constantly adjust time intervals to make optimal usage of the channel bandwidth.
  • the data of a time-sliced service is sent into the channel as bursts so that the receiver, using the control signals, remains inactive when no bursts are to be received. This reduces the power consumption in the receiver terminal.
  • the bursts are sent at a significantly higher bit rate, and the inter-time-slice period, also referred to as the off-time, is usually proportional to the average bitrate of the service(s) conveyed in the bursts.
  • Figure 2(a) shows the time-slicing of bursts with the various parameters that characterize it. Each burst typically consists of two parts, the ADT and RSDT.
  • the burst time consists of the burst time for ADT and the burst-time for RSDT.
  • the effective off-time is transmitted for a time duration, referred to herein as the effective off-time.
  • a method referred to as the "delta-t method" is used to indicate the time interval that a receiver can switch off before it can switch back on to receive the next time slice of the service.
  • the delta-t method is used to signal the time from the start of the currently-received MPE (or MPE-FEC) section to the start of the next burst.
  • Delta-t times are indicated in every MPE section header, as illustrated in Figure 2(b), so that the loss of an MPE section or multiple sections does not affect the capability of the receiver to accurately switch on at the beginning of the next time sliced burst.
  • time-slice start and stop times are computed using the delta-t and the maximum_burst_duration fields in the headers of the time-sliced MPE sections.
  • a time-sliced burst cannot start before the delta-t time which is signaled by the MPE section headers of the previous time-sliced burst and cannot end later than the time indicated by delta-t + maximum_burst_duration.
  • the maximum allowed jitter as specified for example in the standard ETSI EN 301 192 Vl.4.1 (2004-11) Digital Video Broadcasting (DVB); DVB specification for data broadcasting can also be taken into account.
  • a burst of data When a burst of data is received by a DVB-H capable receiver, the data is buffered to be processed and presented during the off period between bursts.
  • the burst size S b defined as the amount of network layer bits received in a burst-duration, has to be less than the buffer available at the receiver for the particular service.
  • the maximum burst duration t t is also signaled for every time-sliced elementary stream so that, under poor reception conditions, the receiver can infer when the burst has ended.
  • the layer 3 datagrams are always carried in MPE sections regardless of whether MPE-FEC is used, thus enabling it to be fully backward compatible to MPE- FEC unaware receivers.
  • the last section in an ADT table contains a table_boundary flag that signals the end of layer 3 datagrams within the ADT.
  • an MPE-FEC-aware receiver upon encountering a table_boundary_flag, checks if all ADT sections are received correctly, for example using a Cyclic Redundancy Check (CRC), and discards all remaining sections in the burst if all ADT sections are received correctly. If some of the ADT sections contain errors, then the RSDT sections are received and are used to attempt to correct the errors.
  • An MPE- FEC-ignorant receiver simply ignores the MPE-FEC (the RSDT part of an MPE-FEC matrix) and switches off the receiver until the next burst,
  • Aural and visual information are important components of most multimedia services and applications operating over transmission systems.
  • compression arrangements In order to transmit aural and visual information in the current generation of popular networks, compression arrangements have been standardized. Most of these compression arrangements use known human perceptual qualities along with efficient binary data coding schemes to reduce redundant information and compress the input information. Both audio and video compression arrangements process continuous blocks of uncompressed samples to use the psycho-acoustic and psycho- visual information for redundancy reduction.
  • PTM point-to-multipoint
  • simulcasting is often used to deliver data to receivers with heterogeneous capability.
  • a fair distribution system should deliver the media to the receiver commensurate with the capabilities of the individual receivers. In practice, however, this is a difficult proposition to achieve.
  • the "fairness" issue arises from the fact that PTM transmission involves a trade-off between bandwidth efficiency and granularity of control over the quality of reception to an individual receiver.
  • the media transmission rate is chosen to match the lowest receiver capacity in a particular session.
  • simulcasting approach is used to address this issue of fair distribution, using the transmission of several streams of identical source media at varying transmission and presentation characteristics. For example, two streams of different picture sizes can be transmitted.
  • time-slicing in DVB-H indicates that data of a program is sent to the receiver in high-bit-rate bursts at specific time intervals.
  • a receiver tunes into a program it either tunes into the channel during the time interval when the time-sliced program data is being transmitted or during the off-time.
  • Two different possibilities are possible when a receiver tunes in.
  • the first possibility is that the receiver tunes in during the ADT transmission of the time-sliced burst of the required program.
  • a special case of tuning in during a burst is that that receiver tunes in just at the beginning of the time-sliced burst of the required program.
  • the second possibility is that the receiver tunes in between consecutive time-sliced bursts of the required program.
  • FIGS 3(a)-3(c) show the three different scenarios that can occur when a receiver tunes into a service transmitted in a time-sliced DVB-H channel.
  • the tuning in occurs at the beginning of a burst n.
  • the tuning in occurs in the middle of burst n.
  • the tuning in occurs in between bursts n and n+1.
  • Equation (1) it is assumed that the service is using the full capacity of the channel. It is also possible that a service does not use the full capacity of the channel.
  • a time-sliced set of DVB-H services can be multiplexed with continuous
  • DVB-T services into a single MPEG-2 transport stream.
  • b c is defined to be the total bandwidth available for the set of DVB-H services.
  • Equations (1), (2) and (3) reveal that when b s is much smaller than b c , there is a very high probability that the receiver tunes into the service during the off-time of the service. This indicates that there is a high probability that the receiver has to wait for information when it tunes into a channel to receive a service.
  • Program P is a streamed audio-visual presentation. The audio and the video components are coded separately, multiplexed together, and time-sliced for carnage over the DVB-H radio network. A burst of P contains audio-visual data in an interval [ ⁇ s , ⁇ e ]. The time period during which data of P is transmitted is referred to as the burst-time t b .
  • the burst-time consists of two parts, burst-times for ADT ⁇ t bAD ⁇ ) and RSDT (tb R sor)- After the time interval t b , no data of program P is transmitted for a time duration of ⁇ f, referred to as the off-time. Analogously, after the transmission of the ADT of a burst, no application data of program P is transmitted for time duration of At 3 , referred to as the effective off-time
  • the tune-in initiation time T 1 is defined as that instant on the transmission curve time-line when the user decides to consume P and initiates action to receive data from the channel.
  • the tune-in delay ⁇ y.w) is defined as the amount of time elapsed after ⁇ t to the moment when the rendering of P starts. This is also referred to as channel zapping delay, channel-switch delay, and start-up delay, A ⁇ T-IN ) can be considered as a cumulative sum of the following component delays:
  • Ay.i N is a simplification, as the delay to acquire the required transport-level signaling, such as Program Specific Information/Service Information (PSI/SI) and Entitlement Control Messages (ECM) for conditional access (CA), are not considered. Furthermore, it is assumed that no application-layer content protection is used and hence related delays, e.g., for acquiring the content protection keys, are omitted from the discussion. Finally, the delay jitter of burst intervals (Delta-t Jitter) is not handled as well but is straightforward to use as a guard interval in the activation of the radio reception.
  • PSI/SI Program Specific Information/Service Information
  • ECM Entitlement Control Messages
  • CA conditional access
  • the delay A ( RE FRSH) is usually applicable to video only, whereas in audio, A( REFRSfI) would typically be equal to zero.
  • the values of other delay components are often identical for both audio and video.
  • a ⁇ TSYNQ, A ⁇ CO MP ), and A ⁇ RCP T ) are discussed in more details below.
  • tune-in occurs during a burst carrying P as illustrated in Figure. 3(b).
  • tune-in occurs exactly at the beginning of a burst carrying P ( Figure 3 (a)).
  • tune-in occurs in between two consecutive bursts of P as illustrated in Figure 3(c).
  • the first referred to as the time-slice synchronization delay ⁇ ( T - S YN Q , is defined as the time elapsed from the moment when the user initiates the desire to consume P to the moment when the receiver obtains data of P.
  • the second referred to as the incomplete data compensation delay ⁇ ( CO MP ) , is the delay incurred to compensate for the playback duration of data that was not received before tune-in initiation time ⁇ t in the burst. This delay is applicable only when tune-in occurs in the middle of the burst transmission.
  • the decoding and/or playback has to be delayed by an amount that is equivalent to the playback duration of those coded data units that occurred in the burst prior to the tune-in initiation time in order to guarantee playback without any pause.
  • a ( C O M P ) 0- It is noted that it may not be possible to apply FEC decoding for error correction of an incompletely received time- sliced burst, as the amount of data columns that were not received may outnumber the correction capability of the FEC code.
  • the receiver tunes into the program during the effective off-time period, it has to wait until the next time-sliced burst for the desired program starts. This delay can be anything from zero to the off-time period ⁇ t. If the time instant when receivers tune into the channel is assumed to be uniformly distributed, then the probability P(E 0 ) that a receiver tunes into an off-time is given by
  • the reception duration of the time-sliced burst depends on the size of the first MPE-FEC frame containing the desired program, as well as the transmission bitrate for the MPE-FEC frame.
  • DVB-H allows the service provider to select the size of the MPE-FEC frame in terms of the rows of the frame (256, 512, 768, or 1024), the number of application data columns in the frame, and the number of Reed-Solomon FEC columns in the frame.
  • the transmission bitrate for the MPE-FEC frame depends on the bitrate of the MPEG-2 transport stream multiplex carrying the program which, in turn, depends largely on the modulation system used in the radio transmission. Furthermore, potential non-time-sliced services reduce the transmission bitrate of the time-sliced bursts accordingly.
  • AVC Advanced Video Coding
  • JVT Joint Video Team
  • MPEG Motion Picture Expert Group
  • AVC includes the concepts of a Video Coding Layer (VCL) and a Network Abstraction Layer (NAL).
  • VCL contains the signal processing functionality of the codec- mechanisms such as transform, quantization, motion-compensated prediction, and loop filters.
  • a coded picture consists of one or more slices.
  • the NAL encapsulates each slice generated by the VCL into one or more NAL units.
  • Scalable Video Coding provides scalable video bitstrearns.
  • a scalable video bitstream contains a non-scalable base layer and one or more enhancement layers.
  • An enhancement layer may enhance the temporal resolution (i.e. the frame rate), the spatial resolution, and/or the quality of the video content represented by the lower layer or part thereof.
  • the VCL and NAL concepts were inherited.
  • Multi-view Video Coding is another extension of AVC.
  • An MVC encoder takes input video sequences (called different views) of the same scene captured from multiple cameras and outputs a single bitstream containing all the coded views.
  • MVC also inherited the VCL and NAL concepts.
  • Many video coding schemes utilize inter prediction, which is also referred to as temporal prediction and motion compensation. Inter prediction removes redundancy between subsequent pictures.
  • H.264/AVC as other today's video compression standards, divides a picture to a mesh of rectangles for each of which a similar block in one of the decoded reference pictures is indicated. The location of the prediction block is coded as motion vector that indicates the position of the prediction block compared to the block being coded.
  • Decoded pictures used for predicting subsequent coded pictures and for future output are buffered in the decoded picture buffer (DPB).
  • the DPB management processes including the storage process of decoded pictures into the DPB, the marking process of reference pictures, and the output and removal processes of decoded pictures from the DPB, are specified to enable efficient utilization of the buffer memory.
  • the reference picture management process in H.264/AVC is summarized as follows.
  • the maximum number of reference pictures used for inter prediction, referred to as M, is indicated in the active sequence parameter set.
  • M the maximum number of reference pictures used for inter prediction
  • the decoding of the reference picture caused more than M pictures to be marked as "used for reference,” then at least one picture must be marked as "unused for reference.”
  • the DPB removal process then removes pictures marked as "unused for reference” from the DPB if they are not needed for output as well.
  • Each short-term picture is associated with a variable PicNum that is derived from the syntax element framejnum, and each long- term picture is associated with a variable LongTermPicNum that is derived form the lo ⁇ g_term_frame_idx which is signaled by the memory management control operation (MMCO).
  • MMCO memory management control operation
  • the operation mode for reference picture marking is selected on picture basis.
  • the adaptive memory control requires the presence of MMCO commands in the bitstream.
  • the memory management control operations enable explicit signaling which pictures are marked as "unused for reference,” assigning long-term indices to short-term reference pictures, storage of the current picture as long-term picture, changing a short-term picture to the long-term picture, and assigning the maximum allowed long-term index for long-term pictures.
  • the sliding window operation mode results in first-in-first-out buffering operations among short-term reference pictures.
  • the decoding process generates short-term "non- existing" pictures having the missing framej ⁇ um values. Such "non-existing" pictures are handled in the same way as normal short-term reference pictures in the sliding window reference picture marking process.
  • the hypothetical reference decoder (HRD), specified in Annex C of the H.264/AVC standard, is used to check bitstream and decoder conformances.
  • the HRD contains a coded picture buffer (CPB), an instantaneous decoding process, a decoded picture buffer (DPB), and an output picture cropping block.
  • CPB and the instantaneous decoding process are specified similarly to any other video coding standard, and the output picture cropping block simply crops those samples from the decoded picture that are outside the signaled output picture extents.
  • the DPB was introduced in H.264/AVC in order to control the required memory resources for decoding of conformant bitstreams.
  • the DPB includes a unified decoded picture buffering process for reference pictures and output reordering.
  • a decoded picture is removed from the DPB when it is no longer used as reference and needed for output.
  • the maximum size of the DPB that bitstreams are allowed to use is specified in the Level definitions (Annex A) of H.264/AVC.
  • the syntax element num_reorder_frames indicates the maximum number of frames that precede any frame in the coded video sequence in decoding order and follow it in output order. According to this value, the decoder can start to output pictures as early as possible thus to reduce the end-to-end delay without overflowing the DPB.
  • Various embodiments provide a system and method for providing faster tuning into the chosen program in a time-sliced multicast and/or broadcast transmission environment.
  • Multimedia data of the same source material but of different transmission (bit rate for example) and presentation (display size and sampling rate for example) characteristics are coded and compressed.
  • simulcast programs of a simulcast session are time-sliced, placed maximally apart from each other in terms of transmission time, and sent over the DVB-H channel.
  • the term "simulcast session” refers to representing the same piece of content
  • the term “simulcast program” refers to independent representation of the content containing all media types
  • the term “simulcast stream” refers to an independent stream of one media type.
  • the expected tune-in time i.e. the time from the moment a user switches channels via the user interface to the moment first media is played out
  • ⁇ is the cycle time (i.e., the interval between the transmission start times of two bursts of the same simulcast program)
  • k is the number of the simulcast programs of the same simulcast session. If two replicated programs are used for a simulcast session of a service, the related tune-in delay components are reduced by about half, if three replicated programs are used for the simulcast of a service then the tune-in delay components are reduced by about one-third, etc.
  • Figure 1 is a representation of a structure of an MPE-FEC frame
  • Figure 2(a) is a representation showing time-slicing in a DVB-H channel, where two time-sliced bursts along with parameters that define the bursts
  • Figure 2(b) is a representation showing the signalling of the delta-t in MPE section of a time- sliced burst
  • Figure 3(a) shows a scenario by which a receiver can tune into a service, where the tuning in occurs at the beginning of a burst n
  • Figure 3(b) shows a scenario by which a receiver can tune into a service, where the tuning in occurs in the middle of burst n
  • Figure 3(c) shows a scenario by which a receiver can tune into a service, where the tuning in occurs in between bursts n and n+1
  • Figure 4 is a depiction of a simulcasting occurring over a time-sliced DVB-H channel where program start special handling is used;
  • Figure 5 shows how a single rate service is transmitted over a time-sliced DVB-H channel
  • Figure 6 shows how two simulcasts of the same service can be sent over a time-sliced DVB-H channel according to various embodiments;
  • Figure 7 is a depiction of a simulcasting occurring over a time-sliced DVB-H channel where no program start special handling is used;
  • Figure 8(a) shows time-sliced bursts of a single-rate stream, without simulcasting;
  • Figure 8(b) shows the tune-in and reception of a single rate stream;
  • Figure 8(c) shows time-sliced bursts of an example tune-in time to simulcast streams;
  • Figure 8(d) is an illustration of the reception start time and received bursts of simulcast streams;
  • Figures 9(a) illustrates an arbitrarily selected tune-in point when simulcasting is not utilized
  • Figure 9(b) illustrates an arbitrarily selected reception start point when simulcasting is not utilized
  • Figure 9(c) illustrates a time-line of time- sliced bursts of the streams for different resolutions
  • Figure 9(d) illustrates a situation in which the receiver wishes to process the higher resolution stream, but in which the first time-sliced burst occurring after the tune-in point is of a lower resolution
  • Figure 10 is a representation of a generic multimedia communications system for use with various embodiments of the present invention.
  • Figure 11 is a perspective view of an electronic device that can be used in conjunction with the implementation of various embodiments of the present invention.
  • Figure 12 is a schematic representation of the circuitry which may be included in the electronic device of Figure 11.
  • Various embodiments provide a system and method for providing faster tuning into a chosen program in a time-sliced multicast and/or broadcast transmission environment, such as a DVB-H environment.
  • Multimedia data of the same source material but of different transmission (e.g., bit rate) and presentation (e.g., display size and sampling rate) characteristics are coded and compressed.
  • S ⁇ P,-: 1 ⁇ z ⁇ k ⁇ , where S consists of k independently coded programs P,-, targeted at k different classes of receivers.
  • the programs P,- V i represent the same source, but coded at different qualities.
  • Each program typically comprises more than one stream, such as an audio stream and a video stream.
  • the programs of a simulcast session are time-sliced, placed maximally apart from each other in terms of transmission time, and sent over the DVB-H channel.
  • the related tune-in delay components i.e. the time from the moment a user switches channels (i.e., programs of different origin, i.e., programs of different simulcast sessions) via the user interface to the moment first media is played out, are expected to reduce approximately from about ⁇ /2 to ⁇ /(2k), where ⁇ is the cycle-time (interval between the transmission start times of two bursts of the same simulcast program) and k is the number of the simulcast streams of the same program.
  • the relevant tune-in delay components become approximately ⁇ /4.
  • a 50% saving is expected to be obtained.
  • the operation of the service infrastructure according to the invention is described herein in a simplified form as a simulcast session having two simulcast programs, Pj and P 2 . It is noted, however, that various embodiments can be generalized to any number of simulcast programs.
  • Each program typically comprises more than one stream, such as an audio stream and a video stream.
  • IP packets of both Pi and ? 2 are time-sliced and sent into the channel such that no time-sliced burst containing packets of Pi can have packets of P 2 .
  • the media data in all time-slices (except potentially those that start the program) across the simulcast streams of a program are of the same duration d. Due to temporary variations of media bitrate, the duration d of the media data in time-slices may also be somewhat varying but should be substantially constant on average. Consequently, the cycle- time is in one embodiment also equal to d.
  • a time-sliced burst of P 2 is sent into the channel such that it is placed maximally apart from any time-sliced burst of Pi in time.
  • the interval between (the start of) consecutive time-sliced bursts of the simulcast session is equal to d divided by the number of simulcast programs in the simulcast session.
  • Figures 5 and 6 show the relative transmission times without and with the use of simulcasting, respectively. The height of the bars illustrates the bitrate of the stream, and it is observable that the simulcast programs in Figure 6 are of different bitrates.
  • an ⁇ analog media signal such as audio and video
  • samples include an individual picture (i.e., an array of pixels) of a video sequence or a pulse-code-modulated (PCM) audio sample of a certain sampling frequency.
  • Media playback time refers to the intended rendering (e.g., playout, playback, output) time of a media sample.
  • the media playback position refers to the currently-played media sample on a timeline of all the media samples of a presentation.
  • the transmission start times of each time-sliced burst and the start time of media in the burst are approximately synchronized.
  • a time-sliced burst contains media data in the range of to to t/
  • its transmission start time is To
  • a time-sliced burst of another simulcast program of the same simulcast session contains media data in the range of to+d to tj+d, in which d - (tj-t ⁇ )/2
  • the transmission start time of the second time-sliced burst should be To+d.
  • the presented synchronization of media playback times and transmission start times of bursts is feasible at the start of a simulcast session only if the start of the simulcast programs in terms of media playback position is made such that the set of bursts containing one burst from each simulcast program of a simulcast session is transmitted back-to-back.
  • the first burst of Pi (denoted as S a in the figure) contains coded media samples for the range of 0 to d in playback time.
  • the transmission of the first burst OfS 0 is started in wall-clock time of T 0 .
  • the transmission duration (i.e., the burst-time) of the first burst of S a is equal to d x .
  • the first burst of P? (denoted as Sb in the figure) is transmitted right after the first burst of S 0 and contains coded media samples for the range of d x to d/2 in media playback time.
  • the second burst of S a contains coded media samples for the range of d to 2d in playback time.
  • the transmission of the second burst ofS a is started in wall-clock time o ⁇ To+d.
  • the second burst of S b contains coded media samples for the range of d/2 to 2d-d/2 in playback time.
  • the transmission of the second burst of Sb is started in wall-clock time of To+d/2.
  • the order of the first bursts of simulcast programs should be in ascending order of receiver capability. In other words, the simulcast program requiring the least capabilities from receivers should be sent first, followed by the simulcast program requiring the second least of receiver capabilities, etc. This order ensures that all receivers can receive and play the program right from its beginning.
  • Another method for arranging the media data of simulcast programs to bursts at the start of the simulcast session is as follows.
  • the first MPE-FEC matrices for every simulcast program are transmitted back-to-back as one burst. It is assumed that the cycle-time ⁇ for each simulcast program is identical after the second time-sliced burst for each stream.
  • the first burst of each simulcast program contains media samples approximately of the range of 0 to ⁇ 5; ; i.
  • the cycle-time of all simulcast programs of a simulcast session is arranged to be constant (after the first cycle).
  • achieving a constant cycle-time ⁇ may require, e.g., the use of "parallel elementary streams" and/or a small number of rows in MPE-FEC matrices when the bitrate of the simulcast program is relatively low.
  • the cycle-time of program P 1 - is arranged to be an integer multiple of the cycle-time of program P j , assuming that i > j and programs are ordered in ascending order in terms of required receiver capability.
  • the bursts of the simulcast programs maximally apart, only ( ⁇ 5; / ⁇ j )-th bursts of program P j can be considered. Consequently, some of the bursts of P,- and P j may be sent back-to-back.
  • Other algorithms for placing bursts of simulcast programs apart are also possible.
  • the second time-sliced bursts of a simulcast session are transmitted such that P ⁇ is sent first followed by P ⁇ - i), etc. until P ⁇ .
  • P ⁇ is sent first followed by P ⁇ - i), etc. until P ⁇ .
  • the ascending order of packets according to sampling instants is not particularly helpful for reducing the tune-in delay.
  • Coded data units such as Real-time Transport Protocol (RTP) packets, are ordered in ascending order of sampling instants, i.e., RTP timestamps in case of RTP packets.
  • RTP Real-time Transport Protocol
  • the delay component to compensate potentially incomplete reception of the first time-sliced burst A( COMP ) is proportional to the tune-in initiation time relative to first sampling instant of the burst.
  • the descending order of packets according sampling instants enables receivers to obtain the first media packet of the burst, in decoding order, but is likely to result into a pause between the playback of the first and second received bursts.
  • coded data units of burst D/ for i > 1 are split to two groups according to their sampling instants, the first and second groups consisting of data within [ ⁇ S (i-i) > ⁇ e t] and [ ⁇ S i, V/-/;], respectively, and the packets of the first group are sent earlier than the packet of the second group.
  • coded dataunis of burst D / are transmitted as two groups containing data within [T ff o r e i] and [ ⁇ s j, T ⁇ ], and packet of the first of these groups is sent prior to the packets of the second group.
  • a receiver that desires to consume program P m receives the first time-sliced burst of any simulcast program in S that carries data either commensurate with or inferior to its capabilities.
  • a receiver may also tune in to D 1 -, i > m, and decode the contents of D,- in those parts that it is capable of, such as the audio track or intra pictures only.
  • any receiver is able to tune in to any burst D,- with potentially reduced audio-video reproduction quality compared to the best achievable quality decodable from D f .
  • the expected probability to tune-in during any burst D,- becomes
  • the next received burst will contain the immediately subsequent period of data, hence enabling pauseless playback,
  • This tune-in time range is referred to as the second playback portion of the burst and with subscript bs in the delay components.
  • subscript bf is used to denote that the reception started during the first playback portion of the burst, i.e., the period of [ ⁇ si , ⁇ S fi-i ) ], i > 1, or
  • the expected reception duration of the first burst and the expected probability of tuning in during the first playback portion are as follows:
  • MBMS Multimedia Broadcast/Multicast System
  • D. Tian V.K. Malamal Vadakital
  • M.M. Hannuksela S. Wenger
  • M. Gabbouj "Improved H.264/AVC video broadcast/multicast," Proc. of Visual Communications and Image Processing (VCIP), July 2005.
  • MBMS essentially uses continuous transmission, as observed by the application layer, rather than time-sliced transmission. It is expected that the impact of priority- wise grouping on tune-in delay reduction in time-sliced transmission is moderate.
  • the number of peer MPE-FEC matrices in a time-sliced burst is equal to the number of unique priority labels assigned to the datagrams.
  • the FEC code rates of the peer MPE-FEC matrices of a burst is selected such that the most important MPE-FEC matrix gets the strongest protection.
  • the peer MPE-FEC matrices of a burst are transmitted in ascending order of priority, i.e., the most important MPE-FEC matrix as the last one, to reduce the expected tune-in delay and increase the number of decodable audio and video frames from the first burst.
  • Priority-wise grouping of data units takes advantage of the fact that different portions of the coded bit stream have different levels of importance to the overall subjective quality of the presentation.
  • Priority partitioning is performed across all media streams of the same program. For example, the audio stream can be ranked as high priority.
  • the priority partitioning methods for video can be roughly categorized into data partitioning, region-of-interest prioritization, spatial, quality and temporal layering.
  • Priority- wise and time-wise grouping of data units can be combined to achieve the benefits of both grouping methods - unequal error protection provided by the priority- wise grouping and reduced tune-in delay provided by the time-wise grouping.
  • time-wise grouping is performed first as an outer grouping mechanism, the expected tune-in delay is the same or slightly better compared to the use of the time- wise grouping only.
  • unequal error protection would require the use of double the amount of peer MPE-FEC matrices compared to the use of priority-wise grouping only and the virtual interleaving depth of the peer MPE-FEC matrices is likely to be shallower, which may affect negatively to the overall error robustness.
  • the receiver receives the first time-slice of any simulcast program of the desired simulcast session, regardless of the capability of the receiver. If the first received time-slice of the simulcast session is intended for receivers with capabilities lower than the receiver could process, then the receiver continues to decode and play the lower quality program until such, point when a time slice of a simulcast program commensurate with is capability arrives. If the first time- slice of the simulcast session is intended for receivers with higher capabilities than the receiver could process, then the receiver nevertheless starts reception. In such a scenario, however, the receiver is not able to decode all of the received data and may have to perform post processing after decoding in order to properly present the media data based on the receiver's capabilities.
  • multiple simulcast streams are only provided for a subset of the media components of a simulcast session, whereas only one stream is provided for the remaining media components.
  • two independent video streams originating from the same source video signal can be provided as simulcast streams, whereas only one audio stream is provided.
  • the various embodiments are equally applicable to simulcast streams of one media type rather than simulcast programs containing a composition of media types.
  • Media types having one stream in a simulcast session can be multiplexed to the same bursts with any of the simulcast stream of another media type, or can be transmitted in separate bursts.
  • S 0 and S ⁇ are coded at picture size of Quarter Video Graphics Array (QVGA) (320x240 pixels), and Sb is coded at picture size of Video Graphics Array (VGA) (640x480 pixels).
  • IP packets of both S a and Si are time-sliced and sent into the channel such that no time-sliced burst containing packets of S a can have packets of St 1 .
  • a time-sliced burst of S a contains compressed video data of 1 sec duration. In this case, it is desirable that a time-sliced burst of S t also have a compressed video data of 1 second duration.
  • a time-sliced burst of S b is then sent into the channel such that it is placed maximally apart from any time-sliced burst of S 0 in time. It should be noted that the arrangement for the start of the program is not considered in order to simplify the example.
  • Figures S(a)-8(d) are representations depicting when a receiver tunes in and actual reception start times with and without simulcasting according to various embodiments.
  • Figure 8(a) shows time-sliced bursts of a single-rate stream, without simulcasting.
  • Figure 8(b) shows the tune-in and reception of a single rate stream.
  • Figure 8(c) shows time-sliced bursts of an example tune-in time to simulcast streams.
  • Figure 8(d) is an illustration of the reception start time and received bursts of simulcast streams.
  • time-sliced bursts of S 0 are sent at relative time instants 0 sec and 1 sec
  • time-sliced bursts of S h are sent at relative time instants 0.5 sec (as depicted in Figure 8(c)).
  • the time-sliced bursts of S a correspond to the ranges from 0 to 1 second and from 1 to 2 seconds, respectively, in a relative media playback timeline
  • the time-sliced burst of Sj corresponds to the range from 0.5 to 1.5 seconds in a relative media playback timeline.
  • a receiver capable of receiving S a but not S b , tunes into the channel at time instant 0.3, then the next time-sliced burst it can receive is that of S f1 .
  • S b is not commensurate with its capabilities, it nevertheless receives at least the first half the time-sliced burst of S b as depicted in Figure 8(d) (corresponding to the range from 0.5 seconds to 1 second in the media playback timeline), decodes the subset of pictures of which it is capable within the computational constraints of the receiver (which typically is at least the present intra- coded pictures), post processes (which, in this case, may require sub-sampling of the resulting VGA pictures to QVGA display), and plays out the data before it receives the next time-sliced burst suitable for its capabilities.
  • all simulcast streams of a program can be time-sliced identically in terms of media playback ranges per bursts.
  • the time-sliced burst of S b would correspond to the range from 0 to 1 second in the relative media playback timeline. Bursts are still placed maximally apart as described previously, but no special handling of the start of the program is needed. This arrangement is illustrated in Figure 7, with no special handling involved.
  • the expected tune-in time becomes approximately d/4 or 3cf/8 when the stream of S 0 or S b , respectively, provides the desired picture size.
  • These expected tune-in times are 50% or 25% smaller, respectively, compared to the expected tune-in time of a single-stream broadcast.
  • a receiver can receive a simulcast program of a simulcast session. If there are transmission errors that are unrecoverable in a time-sliced burst (referred to herein as burst A), then the receiver should receive the next time-slice burst (referred to herein as burst B) of any simulcast program of the same session. If burst B is intended for receivers with capabilities lower than the receiver could process, then the receiver can use all samples in burst B to conceal unrecoverable samples in burst A.
  • burst B is intended for receivers with capabilities higher than the receiver could process, then the receiver may only be able to use some of the samples in burst B given the limited computational and memory resources. If there are more than two simulcast programs for the same simulcast session, the receiver can use any subsequent time-sliced burst of the session, provided that it would be better suited for the receiver for concealment of burst A. It should be noted that it may not be possible to conceal the first samples of burst A with samples of burst B, as the playback time of some burst A samples may have already passed at the time burst B is received.
  • the decoding of samples in burst B may require the presence of a random access point, such as an Instantaneous Decoding Refresh (IDR) frame, in burst B.
  • IDR Instantaneous Decoding Refresh
  • immediate decoding of samples regardless of the absence or presence of earlier samples is possible.
  • the multicast streams cause the identical management of samples for prediction references, and consequently no random access point is necessary.
  • identical management of samples is obtained when the same original pictures are encoded with two H.264/AVC encoders, the choice of reference and non-reference pictures is identical, and sliding window and adaptive reference picture marking processes are applied identically.
  • an IDR picture may be present in one stream, whereas another stream may contain a corresponding non-IDR picture with a memory management control operation equal to 5 (according to H.264/AVC), causing all the reference pictures to be marked as "unused for reference” and the values of frame_num and picture order count to be considered as 0 after the decoding of the picture.
  • a non-IDR picture with a memory management control operation equal to 5 is identical.
  • the receivers can tune into a program carried by the channel by joining a broadcast/multicast (PTM) session.
  • a program can be advertised using an electronic service guide (ESG).
  • ESG electronic service guide
  • a user tunes into a particular program at an arbitrary moment relative to the time-sliced transmission of the program.
  • tuning in can occur either during the transmission of a time- sliced burst of the program or in the off-time between the transmissions of two time- sliced bursts.
  • a receiver (with the help of information from the ESG) is aware that a program in the ESG is available as more than one simulcast programs of a simulcast session and also has access to any of those simulcast programs.
  • a simulcast session contains simulcast programs, each having replicated media streams of different transmission and presentation characteristics, but a representation of the same media source.
  • a simulcast session S has n simulcast programs.
  • the bandwidth allocated to a simulcast session referred to as session bandwidth and restricts the total cumulative bit rate of the simulcast programs.
  • the total number of programs n in the session S is greater than or equal to 2.
  • the index k runs from 1 to n, with both k and n being positive integers.
  • a receiver chooses to tune in to simulcast session S.
  • the choice of the simulcast program within the session is made by matching the receiver's capability to the simulcast program characteristics.
  • the receiver chooses the simulcast program that is best commensurate with its terminal capability.
  • the receiver then becomes a part of the multicast groups for the streams in the simulcast program with m co-receivers tuned to the same simulcast program.
  • the simulcast program with all its simulcast streams and the receivers can be represented as S ⁇ .
  • Every simulcast stream of a session is sent in a separate time-sliced burst of a DVB-H channel. If a' denotes the i ih time-slice burst of the simulcast session S 1 then the time-sliced bursts ⁇ , s must contain all media datagrams of one simulcast stream A: per a particular media type, and the time sliced burst _£, and ⁇ * +1 contains datagrams of a simulcast stream other than k of the same media type.
  • no time-sliced burst carrying the simulcast session S can have datagrams of stream S 1 and S 2 in the same time-slice.
  • the start time for a time sliced burst carrying datagrams of simulcast stream k of simulcast session £ is selected such that it is maximally apart from the start times of the time sliced bursts carrying datagrams of all other simulcast streams (of the same media type) other than k.
  • a simulcast session S has two simulcast streams Sj and Sz (of a particular media type) and the start times for two adjacent time-sliced bursts carrying datagrams of Si are ⁇ , and /,+/, then the start time of the time sliced burst carrying the datagrams of the simulcast stream & is chosen such that it is maximally apart from /, and /, +/ , i.e., (t, +t, + i)/2.
  • a receiver tuning into a simulcast session receives the first time sliced burst of any simulcast program in the simulcast session S irrespective of whether the simulcast stream was aimed for its capabilities.
  • the receiver tunes into a simulcast program that is superior to its capabilities, then it decodes a subset of received data and may have to perform post-processing so that it can start consumption of the media data. For example, if a receiver is capable of decoding and presenting a video stream at Quarter Common Intermediate Format (QCIF) (176x144 pixels) resolution but has tuned into a simulcast stream carrying datagrams with Common Intermediate Format (CIF) (352x288 pixels) resolution, then it decodes a subset of the coded pictures and down-samples the video frame resolution.
  • QCIF Quarter Common Intermediate Format
  • CIF Common Intermediate Format
  • the receiver tunes into a simulcast program that is inferior to its capabilities, it continues to consume this inferior media until such time when a time-slice burst carrying the simulcast stream commensurate with its capability arrives. It can then switch to the simulcast program which carries datagrams tuned to its capabilities. Switching can occur at the earliest random access point, such as an IDR access unit of H.264/AVC video, in the simulcast program commensurate with the receiver capabilities.
  • the content encoder and the server may reside in the same physical device, or they may be included in separate devices.
  • the content encoder and the server may operate with live real-time content, in which case the coded media bitstream is typically not stored permanently, but rather buffered for small periods of time in the content encoder and/or in the server to smooth out variations in processing delay, transfer delay, and coded media bitrate.
  • the content encoder may also operate for a considerable amount of time before the bitstream is transmitted from the server.
  • the system may include a content database, which may reside in a separate device or in the same device as the content encoder or the server,
  • the traditional task of IP encapsulator is to compute MPE-FEC for a certain duration of media IP packets, encapsulate it into MPE-FEC sections, and segment the MPE and MPE-FEC sections into smaller transport stream packets.
  • the IP encapsulator has an additional task of ensuring that no time-sliced burst containing datagrams of a simulcast stream of a simulcast session contains data from another simulcast stream of the same media type of the same simulcast session. Differentiation between the simulcast streams of the same media type of a single simulcast session may be performed based on the multicast address in the IP header.
  • Time-slice bursts for any simulcast program of the simulcast session are, in one embodiment, all approximately of the same duration. This is done to facilitate constant time-slice intervals maximally apart from each other, which consequently minimizes the expected tune-in delay. Transmission times of the time-sliced burst between programs of a simulcast session are appropriately set so that any time-sliced burst start time of a program in a simulcast session is maximally apart from other time-sliced burst start times of any other programs in the same simulcast session.
  • Figures 9(a) and 9(b) illustrate an arbitrarily selected tune-in point and a reception start point, respectively, when simulcasting is not utilized.
  • the decoding of a lower or higher spatial resolution is desired in Figures 9(a) and 9(b), respectively, and consequently reception can start from the subsequent time-sliced burst for that resolution.
  • Figure 9(c) illustrates a time-line of time-sliced bursts of the streams for both resolutions.
  • Figure 9(d) illustrates the situation in which the receiver wishes to process the higher resolution stream, but in which the first time-sliced burst occurring after the tune-in point is of the lower resolution. In this scenario, the receiver receives the time-sliced burst of the lower resolution, and additionally decodes and renders data from the time-sliced burst of the lower resolution until the first time-sliced burst of the higher resolution is received.
  • a server comprises a normal IP Multicast server using real-time media transport over Real-time Transport Protocol (RTP) as specified in Internet Engineering Task Force (IETF) Request for Comments (RFC) 3550 and 3551.
  • RTP Real-time Transport Protocol
  • IETF RFC 3550 can be found at www.ietf.org/rfc/rfc3550.txt
  • IETF RFC can be found at www.ietf.org/rfc/rfc3551.txt.
  • the server encapsulates the coded media bitstream into RTP packets according to an RTP payload format. Typically, each media type has a dedicated RTP payload format. It should be noted that a system may contain more than one server.
  • the server typically announces the availability media streams to the IP encapsulators using Session Description Protocol (SDP) over Real Time Streaming Protocol (RTSP).
  • SDP Session Description Protocol
  • RTSP Real Time Streaming Protocol
  • RFC 2326 which can be found at www.ietf.org/rfc/rfc2326.txt
  • SDP Session Description Protocol
  • RTSP Real Time Streaming Protocol
  • the characteristics of the RTP streams are announced using SDP as specified in RFC 2327, which can be found at www.ietf.org/rfc/rfc2327.txt.
  • the server can use the SDP extension called the "grouping of media lines" discussed in RFC 3388 (which can be found at -www.ietf.org/rfc/rfc3388.txt) to associate two RTP streams together.
  • a new group attribute value similar to lip synchronization (LS) and flow identification (FID) described in section 4 of RFC 3388, is also specified. This new attribute is referred to as alternate streams (AS).
  • AS alternate streams
  • the source IP address has to differ (as the source IP address is used to differentiate an IP stream from another IP stream in Program Specific Information (PSiyService Information (SI) of DVB-H). Therefore, the c attribute in SDP is used in the media-level to specify the destination IP address.
  • PSiyService Information SI
  • V6 defines a backwards-compatible method for signaling media alternatives in a single SDP file using the "alt” and "alt-default-id” attributes and the optional "al .-group” attribute. An old PSS client will simply ignore these attributes and will identify only one alternative per media.
  • the "alt” and “alt- default-id” attributes may be used to signal the alternative simulcasts as discussed herein.
  • the "a]t” attribute is used to define the different fields and attributes for each of the existing simulcast streams.
  • the "alt-default-id” is used to indicate the default media configuration.
  • the "alt-group” attribute may also be used to group media streams into several alternatives based on grouping criteria such as bandwidth or language. Grouping based on the bandwidth is especially suitable for signalling the existence of the different simulcasts.
  • the existence of alternate simulcast programs and streams can also be signalled in the ESG in a backward compatible manner.
  • the ESG provides the service guide for all services available over a given DVB-H network.
  • the ESG specification document [IP Datacast over DVB-H: Electronic Service Guide, ETSI TS 102471; downloadable at webapp.etsi.org/exchangefolder/ts_l 0247IvOl 0201p.pdf] defines the data model for providing the service guide.
  • An ESG is defined also in the Service Guide of Open Mobile Alliance Mobile Broadcast Services (OMA BCAST Service Guide for Mobile Broadcast Services; Draft Version 1.0 - 04 Jan 2007). Based on the displayed ESG information, the user can select a specific service.
  • the ESG provides the necessary information for the terminal to connect to the related IP streams carrying the media streams of the selected service.
  • the data model is represented through an XML schema definition that applies to all ESG instances.
  • An ESG instance comprises a set of ESG fragments and their relationships in conformance with the ESG data model.
  • ESG defines several fragments such as the service fragment, schedule fragment, purchase fragment, and acquisition fragment.
  • the acquisition fragment provides the necessary information to locate and access the service.
  • the acquisition fragment also provides a description of the contents of the service in the component characteristic field.
  • the complete syntax for this feature is specified in section 5.10.7.1 of the ESG specification document Sample syntax of the component characteristic element is as follows:
  • the ESG there are two different ways to specify alternative simulcasts of the same content: in the Service fragment or in the ScheduleEvent fragment.
  • the Service fragment several AcquisitionRef elements may be defined in order to refer to different alternatives for acquiring the same program.
  • the existence of several references to different acquisition fragments should indicate alternative simulcasts of the same content and the description of each of the alternatives can be taken from the ComponentDescription metadata.
  • the terminal is then able to deploy the herein specified mechanism for fast access to any of the alternative streams that come first in the DVB-H multiplex.
  • the ScheduleEvent Fragment may also be used to link a content instance with the corresponding Service and several Acquisition fragments.
  • the ScheduleEvent allows the definition of several AcquisitionRef elements for each content element. This should indicate alternative simulcasts of the same content. The terminal therefore knows how the different simulcasts are accessed and can then implement the various embodiments discussed herein. It should be noted that these mechanisms are backwards-compatible to the current ESG specification.
  • an extension of the AcquisitionFragment can be realized to indicate that the components of this service that are described through ComponentDescription elements are alternatives. This can be achieved by adding an attribute that gives the alternative group name to the ComponentDescription element as follows:
  • the terminal is then able to identify alternative simulcasts based on the
  • FIG. 10 is a graphical representation of a generic multimedia communication system within which various embodiments of the present invention maybe implemented.
  • a data source 100 provides a source signal in an analog, uncompressed digital, or compressed digital format, or any combination of these formats.
  • An encoder 110 encodes the source signal into a coded media bitstream. It should be noted that a bitstream to be decoded can be received directly or indirectly from a remote device located within virtually any type of network. Additionally, the bitstream can be received from local hardware or software.
  • the encoder 110 may be capable of encoding more than one media type, such as audio and video, or more than one encoder 110 may be required to code different media types of the source signal.
  • the encoder 110 may also get synthetically produced input, such as graphics and text, or it may be capable of producing coded bitstreams of synthetic media.
  • only processing of one coded media bitstream of one media type is considered to simplify the description.
  • typically real-time broadcast services comprise several streams (typically at least one audio, video and text sub-titling stream).
  • the system may include many encoders, but in Figure 10 only one encoder 110 is represented to simplify the description without a lack of generality. It should be further understood that, although text and examples contained herein may specifically describe an encoding process, one skilled in the art would understand that the same concepts and principles also apply to the corresponding decoding process and vice versa.
  • the coded media bitstream is transferred to a storage 120.
  • the storage 120 may comprise any type of mass memory to store the coded media bitstream.
  • the format of the coded media bitstream in the storage 120 may be an elementary self- contained bitstream format, or one or more coded media bitstreams may be encapsulated into a container file. Some systems operate "live", i.e. omit storage and transfer coded media bitstream from the encoder 110 directly to the sender 130.
  • the coded media bitstream is then transferred to the sender 130, also referred to as the server, on a need basis.
  • the format used in the transmission may be an elementary self-contained bitstream format, a packet stream format, or one or more coded media bitstreams maybe encapsulated into a container file.
  • the encoder 1 10, the storage 120, and the server 130 may reside in the same physical device or they may be included in separate devices.
  • the encoder 110 and server 130 may operate with live real-time content, in which case the coded media bitstream is typically not stored permanently, but rather buffered for small periods of time in the content encoder 110 and/or in the server 130 to smooth out variations in processing delay, transfer delay, and coded media bitrate.
  • the server 130 sends the coded media bitstream using a communication protocol stack.
  • the stack may include but is not limited to Real-Time Transport Protocol (RTP), User Datagram Protocol (UDP), and Internet Protocol (IP).
  • RTP Real-Time Transport Protocol
  • UDP User Datagram Protocol
  • IP Internet Protocol
  • the server 130 encapsulates the coded media bitstream into packets.
  • RTP Real-Time Transport Protocol
  • UDP User Datagram Protocol
  • IP Internet Protocol
  • the server 130 encapsulates the coded media bitstream into packets.
  • RTP Real-Time Transport Protocol
  • UDP User Datagram Protocol
  • IP Internet Protocol
  • the gateway 140 may perform different types of functions, such as translation of a packet stream according to one communication protocol stack to another communication protocol stack, merging and forking of data streams, and manipulation of data stream according to the downlink and/or receiver capabilities, such as controlling the bit rate of the forwarded stream according to prevailing downlink network conditions.
  • gateways 140 include multipoint conference control units (MCUs), gateways between circuit-switched and packet- switched video telephony, Push-to-talk over Cellular (PoC) servers, IP encapsulators in digital video broadcasting-handheld (DVB-H) systems, or set-top boxes that forward broadcast transmissions locally to home wireless networks.
  • MCUs multipoint conference control units
  • PoC Push-to-talk over Cellular
  • DVD-H digital video broadcasting-handheld
  • set-top boxes that forward broadcast transmissions locally to home wireless networks.
  • RTP the gateway 140 is called an RTP mixer or an RTP translator and typically acts as an endpoint of an RTP connection.
  • the system includes one or more receivers 150, typically capable of receiving, de-modulating, and de-capsulating the transmitted signal into a coded media bitstream.
  • the coded media bitstream is transferred to a recording storage 155.
  • the recording storage 155 may comprise any type of mass memory to store the coded media bitstream.
  • the recording storage 155 may alternatively or additively comprise computation memory, such as random access memory.
  • the format of the coded media bitstream in the recording storage 155 may be an elementary self-contained bitstream format, or one or more coded media bitstreams may be encapsulated into a container file.
  • a container file is typically used and the receiver 150 comprises or is attached to a container file generator producing a container file from input streams.
  • Some systems operate "live,” i.e., omit the recording storage 155 and transfer coded media bitstream from the receiver 150 directly to the decoder 160.
  • the most recent part of the recorded stream e.g., the most recent 10-minute excerption of the recorded stream, is maintained in the recording storage 155, while any earlier recorded data is discarded from the recording storage 155.
  • the coded media bitstream is transferred from the recording storage 155 to the decoder 160. If there are many coded media bitstreams, such as an audio stream and a video stream, associated with each other and encapsulated into a container file, a file parser (not shown in the figure) is used to decapsulate each coded media bitstream from the container file.
  • the recording storage 155 or a decoder 160 may comprise the file parser, or the file parser is attached to either recording storage 155 or the decoder 160.
  • the coded media bitstream is typically processed further by a decoder 160, whose output is one or more uncompressed media streams.
  • a Tenderer 170 may reproduce the uncompressed media streams with a loudspeaker or a display, for example.
  • the receiver 150, recording storage 155, decoder 160, and renderer 170 may reside in the same physical device or they may be included in separate devices.
  • Figures 11 and 12 show one representative electronic device 12 within which various embodiments may be implemented. It should be understood, however, that the various embodiments are not intended to be limited to one particular type of device.
  • the electronic device 12 of Figures 11 and 12 includes a housing 30, a display 32 in the form of a liquid crystal display, a keypad 34, a microphone 36, an ear-piece 38, a battery 40, an infrared port 42, an antenna 44, a smart card 46 in the form of a UICC according to one embodiment, a card reader 48, radio interface circuitry 52, codec circuitry 54, a controller 56 and a memory 58.
  • Individual circuits and elements are all of a type well known in the art, for example in the Nokia range of mobile telephones.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • General Engineering & Computer Science (AREA)
  • Business, Economics & Management (AREA)
  • General Business, Economics & Management (AREA)
  • Television Systems (AREA)
  • Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)

Abstract

L'invention concerne un système et un procédé pour permettre une syntonisation plus rapide dans un programme choisi dans un environnement de transmission en multidiffusion et/ou diffusion par tranches de temps. Des données multimédias de la même source originale mais de différentes caractéristiques de transmission et de présentation sont codées et compressées. Selon divers modes de réalisation, des flux de diffusion simultanée d'un programme sont découpés dans le temps, placés à une distance maximale l'un de l'autre en termes de temps de transmission, et envoyés sur le canal.
EP08776420A 2007-06-04 2008-05-30 Diffusion simultanée à entrelacement temporel pour une réduction de la syntonisation Withdrawn EP2151075A2 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US11/757,920 US20080301742A1 (en) 2007-06-04 2007-06-04 Time-interleaved simulcast for tune-in reduction
US11/758,613 US8396082B2 (en) 2007-06-05 2007-06-05 Time-interleaved simulcast for tune-in reduction
PCT/IB2008/052130 WO2008149271A2 (fr) 2007-06-04 2008-05-30 Diffusion simultanée à entrelacement temporel pour une réduction de la syntonisation

Publications (1)

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EP2151075A2 true EP2151075A2 (fr) 2010-02-10

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EP08776420A Withdrawn EP2151075A2 (fr) 2007-06-04 2008-05-30 Diffusion simultanée à entrelacement temporel pour une réduction de la syntonisation

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EP (1) EP2151075A2 (fr)
WO (1) WO2008149271A2 (fr)

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EP1928111A2 (fr) * 2006-11-29 2008-06-04 Samsung Electronics Co., Ltd. Procédé et système pour régler un canal dans un service DVB-H

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WO2006114830A1 (fr) * 2005-04-06 2006-11-02 Matsushita Electric Industrial Co., Ltd. Procede d’insertion de flux d’effacement dans une trame mpe-fec et recepteur
EP1949676A4 (fr) * 2005-10-31 2010-07-07 Mediaphy Corp Commutation de canal sans retard

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Also Published As

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WO2008149271A3 (fr) 2009-10-29
WO2008149271A2 (fr) 2008-12-11

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