Method for managing the time-shifted playback of multimedia content that has been broadcast in real time

Abstract

The invention relates to a method for managing the transmission of data relating to a description file describing a set of addresses of content segments that have been broadcast, characterized in that it comprises, during playback, a step of receiving an item of time data (tj) representing a point in time of the time-shifted playback; a step of transmitting a description file (Ad-MNF(j)) describing a subset of segment addresses linked to the item of time data.

Description

method for managing the delayed playback of multimedia content that has been broadcast in real time.

[0001] The field of the invention is that of managing the playback of multimedia content that has been broadcast in real time. The invention relates more specifically to managing the delayed playback of content that has been broadcast in real time.

[0002] The invention is particularly relevant to segmented content, where the segments are accessible in several formats associated with respective sizes in bytes, which have varying degrees of impact on the bandwidth of the network from which the content is downloaded. The invention is particularly relevant to content downloaded using a technique known as adaptive progressive download (APD), or any other downloading technique employing the same principle.

[0003] Note that segment addresses are included in a description file. In the context of adaptive progressive download, a description file contains, among other things, the network addresses (IP address or URL) of the segments to be downloaded and read by a playback device. In other words, a description file describes segments as network addresses, and it is up to the playback device to access these segments via a network, such as the internet.

[0004] The reading device refers to all data processing devices equipped with processors and capable of accessing content segments through a network, receiving segments from a network, decoding the received segments and requesting a rendering of the decoded segments for example on a screen integrated into the reading device or external to the reading device. State of the art

[0005] When accessing multimedia content, a playback device sends a request to a content server specifying the selected multimedia content (video and / or audio). The playback device then receives a digital data stream related to this content. Within a local communication network, such a request may pass through a network access gateway, such as a residential gateway.

[0006] The received data is then decoded by the reading device, and then displayed as the corresponding video.

[0007] The distribution of digital content over the internet is often based on client-server protocols from the HTTP (Hyper Text Transport Protocol) family. In particular, adaptive streaming (HTTP Adaptive Streaming, abbreviated HAS) of digital content allows for the real-time transmission and playback of data. This means that digital data is transmitted over the network and delivered to the playback device as it arrives. Upon receiving the stream, the playback device stores the received data in a buffer before delivering it. This distribution method is particularly useful when the user's available bandwidth is insufficient for real-time video transmission.

[0008] Adaptive progressive downloading also allows data to be sent and received at different qualities, corresponding, for example, to different respective encoding bitrates. These different qualities are described in a description file, also called a "Manifest" by those skilled in the art.

[0009] When a user accesses the Live stream broadcast in HTTP Adaptive Streaming (HAS), the playback device receives at regular intervals, generally every two seconds, successive description files, hereafter called real-time description files, which each generally describe the last sixty seconds of the stream (30 segments of 2 seconds) by providing IP addresses (Anglo-Saxon acronym for "Internet Protocol") of segments corresponding to these last sixty seconds.

[0010] In general, the video segments are chosen to be short in duration because we want to be as close as possible to the stream broadcast in real time, which those in the know also call a Live stream.

[0011] Note that an encoding bitrate is selected from the available bitrates based on the available bandwidth or the storage and decoding capabilities of the playback device. This type of technique allows for consideration of bandwidth variations on the link between the client playback device and the content server.

[0012] In addition to content playback, some playback devices offer a feature known as "Start Over" (also called "rewind" or "return to beginning") which allows a user watching live content to replay all or part of the broadcast. This feature allows users to restart content from the beginning. For example, if a live movie starts at 9:00 PM and the user accesses the live stream by switching to the channel at 9:40 PM, the user can select a command related to the rewind function to restart playback from the beginning of the movie. In this case, the user switches from real-time playback to delayed playback or rewind mode.

[0013] In this catch-up mode, a command interface allows users to select one or more commands that modify the current playback of the content being streamed in real time. These commands allow users, for example, to pause playback or to rewind to a previous viewing point, thus enabling delayed viewing.

[0014] When content is played and the catch-up function is not available, the description files received sequentially, referred to below as "real-time description files," are those described above. However, when the catch-up function is available, the playback device receives specific description files sequentially from the start of content playback, referred to below as "catch-up description files." These files describe not just the last sixty seconds, but a much larger time period, often several hours, for example, the last four hours, so that the content can be replayed from a point within that four-hour window.

[0015] In summary, a real-time description file targets segments to be read in real time; a catch-up description file targets segments that have been created but are older, their reading transforming real-time reading into delayed reading.

[0016] Such a catch-up description file, describing, for example, the last four hours, is two hundred and forty (240) times larger than a standard description file because it includes all the network addresses of all segments created in the last four hours. Specifically, a real-time description file is approximately 12 KB (describing 30 two-second segments), while a catch-up description file is approximately 2.8 MB (describing 7200 two-second segments).

[0017] Just like the real-time description file, the catch-up description file is downloaded periodically, for example, every two seconds. Due to its enormous size, the periodic transmission of the catch-up description file requires significant network bandwidth, which can degrade the quality of service during content playback, especially for households with slow internet connections such as ADSL. Furthermore, such catch-up description files require excessive processing time (what experts call parsing time), which can disrupt normal content playback if the playback device has limited processing power. This can result in unbearable image freezes for the user.

[0018] These problems impair the user experience even though the user has not selected a command resulting in delayed playback and does not intend to replay the broadcast content.

[0019] The invention improves the situation. The invention

[0020] To this end, according to a first functional aspect, the invention relates to a method for managing the transmission of data relating to a description file describing a set of content segments that have been broadcast, characterized in that it comprises, during a review,

[0021] a stage of receiving temporal data (tj) representative of a delayed reading moment;

[0022] a step of transmitting a description file (Ad-MNF(j)) describing a subset of segments linked to said temporal data.

[0023] According to the invention, when the time range associated with the replay time is identified, a description file, referred to as the index file in the following description, is transmitted; this file being limited to the description of segments related to the time range in question. Again, just as with the root file, the transmission of such an index file over the network has very little impact on the available bandwidth.

[0024] Ultimately, thanks to the invention, catch-up mode is accessible without generating excessive bandwidth consumption and without causing processor overload.

[0025] According to a particular embodiment of the invention, the method comprises a preliminary step of obtaining a plurality of subsets of description files, called index files, describing the addresses of segments that were broadcast over different respective broadcast time periods; and a description file, called the root file, associated with said plurality of index files; the reception step described above including the reception of data representing the root file (Ad-MNF-rac) and the time data (tj). In this method, following a request to access the content in catch-up mode, the reading device receives a description file that does not describe the addresses of the segments that were broadcast but instead describes a root description file referencing several associated index description files for the time periods, the index files describing the segments that were broadcast.

[0026] In other words, this mode allows the playback device to request delayed playback using the root file while avoiding the transmission of a description file describing previously broadcast segments, which is unnecessary if delayed playback is not requested. Under this mode, an index file is only transmitted when delayed playback is requested; the index file is chosen from a set of index files based on the desired delayed playback time. The index file is not a complete file covering the entire time range of stored segments accessible via delayed playback, but rather a "sub-time range" included within the complete time range.

[0027] The initially received root description file does not include segment addresses; the size of such a root file is significantly smaller than a typical description file describing several hours of broadcast. Receiving this root file enables access to the delayed playback mode as soon as a description file containing this root file is received. Furthermore, transmitting such a root file over the network has very little impact on available bandwidth, especially since such a file is transmitted very frequently, for example, every two seconds. Also, due to its small size, the root file is read very quickly by the playback device's processor; the processor load related to reading is reduced, freeing up additional capacity for processing other computing tasks.

[0028] According to yet another particular embodiment of the invention, which may be implemented alternatively or cumulatively with the preceding one, access addresses to segments are transmitted with the root file. The segment addresses cover, for example, a depth of a few minutes, such as the latest network addresses (URLs) of audio / video segments. In this way, real-time playback can be performed using the latest segment addresses included in the received description file; or delayed playback can be performed using the root file.

[0029] According to yet another particular embodiment of the invention, which may be implemented alternatively or cumulatively with the previous one, the time slots are associated with different broadcast content. For example, one time slot is associated with a film, another with a sporting event such as a football match.

[0030] According to yet another particular embodiment of the invention, which can be implemented alternatively or cumulatively with the preceding ones, the time slots are discontinuous. The advantage of this embodiment is that it allows for the removal of slots relating to unwanted content such as advertising.

[0031] According to yet another particular embodiment of the invention, which may be implemented alternatively or cumulatively with the preceding ones, the time ranges are continuous. In other words, the set of said "sub-ranges" covers the entire storage time range of the segments accessible on a delayed basis on the broadcast channel in question. This method offers the distinct advantage of being able to access, on a delayed basis, any segment that was broadcast before the current broadcast time.

[0032] According to a first material aspect, the invention relates to a data transmission management entity for a description file describing segments of content that have been broadcast, characterized in that it comprises,

[0033] A module for receiving temporal data (tj) representative of a delayed reading moment;

[0034] A module for transmitting a description file (Ad-MNF(j)) describing a subset of segments linked to said temporal data

[0035] We will see that, in one embodiment, the preceding entity includes

[0036] a module for obtaining in advance a plurality of description files, called index files, describing segments that have been broadcast over different broadcast time periods; and a description file, called root file, associated with said plurality of index files;

[0037] a module for transmitting data representative of the root file;

[0038] a receiving module capable of receiving in return data representing the root file and temporal data representing a delayed reading moment;

[0039] a module for transmitting the index file associated with the root file and said temporal data.

[0040] In another material aspect, the invention relates to a server comprising a management entity as defined above. The server includes a processor capable of executing the following steps of the process defined above.

[0041] According to another material aspect, the invention relates to a computer program suitable for implementation on a management entity as defined above, the program comprising code instructions which, when executed by a processor, carries out the steps of the management process defined above.

[0042] According to another material aspect, the invention relates to a data carrier on which at least one series of program code instructions has been stored for the execution of a management process as defined above.

[0043] According to a second functional aspect, the invention relates to a method for managing access to delayed content via a description file describing a set of content segments that have been broadcast, characterized in that it comprises,

[0044] a step of transmitting temporal data (tj) representative of a delayed reading moment;

[0045] a step of receiving a description file (Ad-MNF(j)) describing a subset of segments linked to said temporal data.

[0046] We will see that, in one embodiment, the process will include:

[0047] a step involving receiving data representative of a description file, called the root file,

[0048] a transmission step capable of transmitting back the data representing the root file and a temporal data representing a delayed reading moment;

[0049] a step of receiving a description file, called an index file associated with the temporal data and describing segments corresponding to a time range associated with the temporal data.

[0050] According to a material aspect linked to the second functional aspect, the invention relates to an entity for managing access to content via a description file describing segments of content that have been disseminated, characterized in that it comprises,

[0051] A module for receiving temporal data (tj) representative of a delayed reading moment;

[0052] A module for transmitting a description file (Ad-MNF(j)) describing a subset of segments linked to said temporal data

[0053] We will see later, according to one embodiment, that the preceding entity comprises:

[0054] a module for receiving data representative of a description file, called the root file,

[0055] a transmission module capable of transmitting back the data representing the root file and a time data representing a delayed reading moment;

[0056] a module for receiving a description file, called an index file associated with the temporal data and describing segments corresponding to a temporal range associated with the temporal data.

[0057] According to another material aspect related to the second functional aspect, the invention relates to a reading device comprising a management entity as defined above in connection with the second functional aspect. The STB reading device includes a processor capable of executing the following steps of the process defined above with reference to the second functional aspect.

[0058] According to another material aspect linked to the second functional aspect, the invention relates to a computer program suitable for implementation on a management entity as defined above, the program comprising code instructions which, when executed by a processor, carries out the steps of the process defined in connection with the second functional aspect.

[0059] According to another material aspect linked to the second functional aspect, the invention relates to a data carrier on which at least one series of program code instructions has been stored for the execution of a process defined above in connection with the second functional aspect.

[0060] The media referred to above can be any entity or device capable of storing the program. For example, a medium can include a storage means, such as a ROM, for example a CD-ROM or a microelectronic circuit ROM, or a magnetic recording means, for example a hard drive. On the other hand, an information medium can be a transmissible medium such as an electrical or optical signal, which can be transmitted via an electrical or optical cable, by radio, or by other means. The program according to the invention can, in particular, be uploaded to a network such as the Internet. Alternatively, the information medium can be an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in the execution of the method in question.

[0061] The invention will be better understood upon reading the following description, given by way of example and with reference to the accompanying drawings in which:

[0062] represents a progressive download architecture on the Internet based on the use of adaptive streaming according to an embodiment of the process of the invention;

[0063] illustrates schematically the hardware structure of a server capable of transmitting description files;

[0064] schematically illustrates the physical structure of a reading device capable of reading multimedia streams in real time;

[0065] illustrates content and the segments available for multimedia content.

[0066] illustrates a root description file associated with index description files.

[0067] illustrates an embodiment of the process of the invention; this figure illustrates the communication between the reading device and the content server; this shows a transmission of root description file in order to reduce the size of the data transmitted from the server to the reading device while giving access to a delayed reading of the content.

[0068] Detailed description of embodiments of the invention

[0069] Larepresents an SYS computer system in which a content distribution network called CDN (Content Distribution Network) is implemented by the person skilled in the art, from which content is transmitted to client devices or content reading devices and description files associated with multimedia content.

[0070] In our example, the SYS system comprises a single STB reading device. However, the invention applies to any number of reading devices.

[0071] The STB reading device is, for example, a digital reading device such as a decoder.

[0072] The multimedia content referred to here is video content corresponding, for example, to a television channel on which so-called live television programs are broadcast, that is to say, broadcast in real time.

[0073] In our example, the STB playback device is connected to a TV output terminal such as a television. The STB playback device could also be integrated into a TV output device.

[0074] In our example, the STB playback device is connected to a port on the TV playback device.

[0075] In our example, the STB reading device is located in a local area network (LAN) managed by a GTW home gateway. We will see later that the STB reading device includes a first management entity, ENT1.

[0076] The GTW gateway is capable of communicating via an LI1 communication link which can be a telecommunications network such as a WAN known to a person skilled in the art.

[0077] The SYS computer system implements a content distribution network called CDN (Content Distribution Network) by those skilled in the art, from which content is transmitted to client devices or STB content playback devices.

[0078] The CDN consists of networked servers within the wide area network; these servers cooperate to make multimedia content available to users in unicast mode. To simplify the description of the invention, a single SRV content server will be represented to depict the CDN. In our example, the SRV content server is located within the wide area network.

[0079] The SRV content server, for example, receives digital television content channels from a broadcast television network (not shown), and makes them available in real time to client terminals, here the STB playback device.

[0080] C1 multimedia content is, for example, content downloaded using adaptive streaming. The MPEG-DASH standard (for "Dynamic Adaptive Streaming over HTTP") is a standard for audiovisual streaming formats over the Internet. This standard is based on preparing content in different representations of varying quality and bitrate, divided into short segments (on the order of a few seconds), also called "chunks" by those skilled in the art. Each of these segments is made available individually via an exchange protocol between the playback device and the multimedia content provider's server. The primary protocol is HTTP, but other protocols (e.g., FTP) can also be used. The organization of the segments and their associated parameters are published in a description file in XML format.We will not go into further detail about this download method as it is irrelevant to the presentation of the invention.

[0081] An example of a description file or "manifest" (MPD) conforming to the MPEG-DASH standard and containing a description of content available in three different qualities (N1 = 512 kb / s, N2 = 1024 kb / s, N3 = 2048 kb / s) of fragmented content is presented in Appendix 1. This simplified description file describes digital content in an XML (Extended Markup Language) syntax, comprising a list of content in the form of segments classically described between an opening tag ( <segmentlist>) and a closing tag (< / segmentlist>Segmentation allows for fine-tuning to bandwidth fluctuations. Each segment corresponds to a specific duration (the "duration" field) with several quality levels and allows for the generation of its addresses (URLs – Uniform Resource Locators). In this example, this generation is done using the "BaseURL" element ("HTTP: / server.com"), which indicates the content server address, and the "SegmentURL," which lists the additional parts of the addresses for the different segments.

[0082] - “C1_512kb_1.mp4” for the first fragment of the “C1” content at 512 kilobits per second (“kb”) in MPEG-4 (“mp4”) format,

[0083] - "C1_512kb_2.mp4" for the second fragment,

[0084] - etc.

[0085] The SRV server is also equipped with at least one CPU2 processor and MEM2 memory for data processing. The server also includes a management entity, ENT2, also known as the second management entity, capable of handling the transmission of content and its associated description file from the SRV server to one or more reading devices, in this case, the STB reading device. The SRV server communicates with the GTW gateway via a WAN. The server includes a communication module, labeled COM2, for WAN communication. In the following discussion, we will focus primarily on the transmission of the description file rather than the transmission of the segments.

[0086] This represents the architecture of an STB reading device. This STB device typically includes MEM1 memories associated with a CPU1 processor. The memories can be of the ROM (Read Only Memory) or RAM (Random Access Memory) type, or even Flash.

[0087] The STB playback device can transmit content to be displayed to the TV playback device via a COM12 communication module. This COM12 module is, for example, an HDMI connection.

[0088] The STB reading device communicates with the gateway via an Ethernet module for wired local communication or via a WiFi radio module for wireless local communication with the GTW residential gateway. This module is referenced as COM11 on the diagram.

[0089] The STB reading device includes a streaming-mode download module HAS (not shown) capable of handling the download of description files and the download of content segments described in the received description files. The STB reading device also includes a management entity ENT1, referred to as the first management entity hereafter, capable of reading a description file specifically constructed during a catch-up reading, as explained below. The download module HAS and the first entity ENT1 can be a single entity, in which case the HAS module is integrated into the first entity ENT1, or they can be separate entities.

[0090] We now present, in relation to this, a schematic view of a main content C1 divided into segments and stored in the SRV content server. More precisely, the HAS content server exposes a video C1 in the form of C1i@Nj segments encoded at different encoding rates Nj, where the index i designates a temporal identifier of the C1i@Nj segment.

[0091] The HAS download module, referred to as the classic download mode below, of the STB playback device is responsible for retrieving segments from the HAS content server, selecting the video quality Nj based on available network resources. We will not describe in detail here how the HAS download module chooses the encoding bitrate for the next video segment to be downloaded. It is worth noting that, most often, the general principle of such algorithms relies on downloading an initial segment at the lowest encoding bitrate offered in the description file, and then evaluating the retrieval time of this first segment. Based on this, the HAS download module assesses whether, considering the size of the segment and the time taken to retrieve it, the network conditions allow the subsequent segment to be downloaded at a higher encoding bitrate.Some algorithms rely on a gradual increase in the quality level of downloaded content segments; others propose riskier approaches, with jumps in the encoding bitrate levels of successive segments.

[0092] In a typical scenario, if a video segment lasts three seconds, the HAS download module must not retrieve the segment in more than three seconds to allow for uninterrupted playback of the content by the STB playback device. Therefore, the HAS download module must strike the best possible balance between playback quality, and thus the highest possible encoding bitrate, and the segment download time, which must be short enough to allow continuous playback on the TV.

[0093] Initially, the HAS module retrieves the description file corresponding to the C1 video content in order to discover the available segments of the C1 video content, and the different associated video qualities Nj. In the example shown, the C1 content is offered as 3-second segments, with a first encoding bitrate N1 = 400 kb / s, a second encoding bitrate N2 = 800 kb / s, a third encoding bitrate N3 = 1200 kb / s, etc.

[0094] In a normal operating mode, not illustrated on the, the HAS module operates the download for example, of successive segments C11@N1 (i.e. the first time segment at an encoding rate of 400 kb / s), then C12@N3 (i.e. the second time segment at an encoding rate of 1200 kb / s), then C13@N3 (i.e. the third time segment at an encoding rate of 1200 kb / s), etc.

[0095] The various segments downloaded by the HAS download module are then transmitted to a display module capable of requesting a display on the TV.

[0096] The algorithm implemented by the HAS download module to determine which segment at which encoding rate should be downloaded in normal operating mode may be one of the existing prior art algorithms. Therefore, this algorithm will not be described in further detail here.

[0097] Sometimes, you might miss the beginning of a live television program (movie, series, etc.). A feature called "start over" or "restart" (also known as "Start Over" or "Restart" by those in the know) allows you to resume the program at any time from a point earlier than the current one; for example, you can restart playback from the beginning. For instance, if a movie starts at 9:00 PM and the user changes the channel at 9:40 PM, they can request that playback resume from the beginning of the movie. In this case, you switch from watching the content in real time to watching it on demand.

[0098] When a user accesses a live stream broadcast in real time (live content) using HTTP Adaptive Streaming (HAS), the playback device, meaning the HAS component installed on that device, typically retrieves a description file every two seconds. This file, referred to as the real-time description file, usually describes the last sixty seconds of the stream (30 two-second segments). A portion of the stream (up to a maximum of 60 seconds) can then be stored in memory (buffered). The video segments are short because the goal is to be as close as possible to the actual live event, such as a football match. This is also why the description file is retrieved every two seconds and the buffer depth is generally limited to around fifteen seconds to avoid a significant lag between the football match and its display on a screen.

[0099] A control interface (the symbols most often found on a remote control are "<<" for rewind, ">>" for fast forward, and "II" for pause) allows you to control the current playback of live content. Specific controls allow you to activate catch-up (or start over) mode.

[0100] To ensure the execution of a command from the command interface, such as the rewind command, the retrieved description file no longer describes the last sixty seconds but a time window larger than sixty seconds. This time window can encompass several hours, for example, the last four hours of broadcast; in this case, the content can be replayed from any point within the four-hour time window. In our example, the server automatically records the live streamed content over a rolling four-hour time window. During this time window, the content is recorded; due to the rolling time window, in our example, segments recorded at a given point in time that are no longer within the rolling time window at a later point in time are deleted.

[0101] In the following, the description file, which describes the latest segments produced on the server in connection with the real-time reading of the content, will be referred to as the "Real-Time File" (MNFtr). This file corresponds to a network address referenced as Ad-MNFtr.

[0102] We will also call "catch-up files" the description files describing segments that have already been broadcast and allowing to replay segments on delay.

[0103] The catch-up file is a description file that describes a set of segments that have been broadcast and are accessible on delay; generally, access to the segments over a fixed time range is made possible by the broadcaster, for example over a four-hour period preceding the current broadcast time.

[0104] According to the invention, with reference to the, two types of catch-up files are created: An MNF-rac description file, referred to as the root file below, containing MNFk description files (k is an integer), referred to as index files described below,

[0105] According to the invention, the ENT2 management entity associated with the broadcast server performs the following steps:

[0106] a stage of receiving temporal data (tj) representative of a delayed reading moment;

[0107] a step of transmitting a description file (Ad-MNF(j)) describing a subset of segment addresses linked to said temporal data.

[0108] According to a first embodiment, when the STB playback device wishes to replay previously broadcast content, the STB playback device transmits a time-based data point (tj) representing a delayed playback moment to the server, which receives the time-based data point. The server then transmits a description file (Ad-MNF(j)) describing a subset of segment addresses linked to said time-based data point. The STB playback device can then access segments based on the file describing the subset of segments.

[0109] According to a second particular embodiment, which will be described below with reference to the, a description file, called the root file, is created by dividing the latter into several description files describing subsets of segments over several respective time ranges.

[0110] In our example, the entity will perform the following steps:

[0111] a. A preliminary step of obtaining a plurality of description files, called index files, describing segments that have been broadcast over different broadcast time periods; and a description file, called root file, associated with said plurality of index files;

[0112] b. following a request for access to content, a step of transmitting data representative of the root file associated with that content;

[0113] c. A step of receiving back temporal data representing a moment of delayed reading;

[0114] d. A step of transmitting the index file associated with the relevant root file and the said received temporal data.

[0115] The invention is not limited to this example, given that a root directory is only useful if there are multiple root files on the server. Therefore, if there are multiple root files, their network addresses can be loaded into the STB reading device without having to be transmitted over the RES1 network to the STB reading device; in this case, the transmission step (b) above is not necessary.

[0116] In our example, the representative data of the root description file is an identifier; this identifier of the root file is transmitted during the transmission step described above.

[0117] Laillustre an embodiment of the process of the invention.

[0118] This diagram represents two vertical axes, each corresponding to a different entity: the first entity, ENT1, located on the STB reading device, and the second entity, ENT2, located on the SRV server. This illustrates the data exchange that takes place between the STB reading device and the SRV content server.

[0119] Note that only some of the messages relevant to understanding the invention are illustrated here. For example, after receiving a description file, the STB reading device typically requires access to the segments described in that file; we have chosen not to show these access messages as they are irrelevant to the explanation of the invention.

[0120] Commands whose execution involves a delayed replay of the content from a chosen reading time, prior to the current time, require a description of segments that have been broadcast in the past; a real-time description file that only describes the latest produced segments related to real-time broadcasting is therefore not sufficient; the first entity ENT1 will therefore be responsible for retrieving the root description file MNF-rac in order to be able to execute a command correctly.

[0121] With reference to the, the steps of an implementation method are as follows;

[0122] Laillustre illustrates a first phase of segment production and storage of broadcast segments and a second phase of access to segments.

[0123] The first phase includes the production of description files (not shown) and the generation, over time, of respective network addresses Ad-MNF1, Ad-MNF2, ..., Ad-MNF(i), Ad-MNF(i+1), ..., Ad-MNF(tr), where these description files are stored and from which segments can be downloaded by the STB reading device. For example, a description file MNF(i) is created at time t(i) and a network address Ad-MNF(i) is associated with this file.

[0124] At any given time tc, the description files corresponding to the addresses Ad-MNF1, Ad-MNF2, ..., Ad-MNF(i), Ad-MNF(i+1), ..., up to the MNFtr file, are catch-up files allowing for delayed playback of the content. The address Ad-MNFtr corresponds to the last "real-time file" created and therefore to the most recently created segments corresponding to the live broadcast currently being streamed. Note that the "tr" subscript in Ad-MNFtr refers to a real-time description file.

[0125] According to the invention, a root description file is created in order to group index catch-up files associated with respective time ranges.

[0126] It should be noted here that, in order to reduce the number of backup description files, only the most recent files created within a given time period T are stored. However, nothing prevents all created files from being stored if memory space allows.

[0127] In our example, the SRV server creates a description file every 2 seconds, namely

[0128] - MNF(i) at time ti

[0129] - MNF(i+1) at time ti + 2 sec.

[0130] - Etc.

[0131] In our example, the second phase includes the following steps:

[0132] During the first step of this second phase, at time tc, the first entity ENT1 requests ACC access to multimedia content.

[0133] In a second step, the SRV server and therefore the second entity ENT2 receives the ACC access request.

[0134] In a third step, according to one embodiment, the second entity ENT2 requires the transmission of a description file including data representative of a root description file, for example an identifier or address of a root description file Ad-MNF-rac.

[0135] In our example, the transmitted description file also includes a description of the latest MNFtr segments, known as real-time segments, produced by the server to enable access to the real-time stream. For the implementation of the invention, the description of the latest MNFtr segments is not necessary; only files accessible in catch-up mode could be offered to the user.

[0136] The received description file therefore allows access in our example to either the stream broadcast in real time, or to the delayed content.

[0137] At this stage, we understand that receiving the Ad-MNF-rac address allows for delayed reading of the content at any time.

[0138] In a fourth step, a delayed playback time is selected on the STB playback device. This selection can be made, for example, via a graphical interface displayed on the TV playback device, for example by executing the return command "<<".

[0139] According to a first variant, the delayed reading time is transmitted by the STB reading device in association with the data representing the root file.

[0140] According to a second variant, during the third step described above, the second entity ENT2 requests the transmission of an identifier for the root file Ad-MNF-rac and time ranges associated with description files stored on the content server. In this variant, the first entity ENT1 identifies the time range corresponding to the desired delayed playback time and requests the transmission of the root file identifier and the identified time range.

[0141] In a subsequent fifth step, the SRV content server receives the access request and transmits back the index description file corresponding to the identified time range or corresponding to the received delayed reading time depending on the variant used.

[0142] At this stage, the STB reading device receives an index file and accesses the segments by downloading them from the addresses described in the relevant index file.

[0143] The embodiment may be subject to variants which can be implemented in isolation or in combination.

[0144] In one possible variation, the time slots mentioned above are associated with different broadcast content. For example, one time slot is associated with a film, another with a sporting event such as a football match.

[0145] In a sub-variant, a time range can be divided into "temporal sub-ranges". Using the example of a match, the sub-ranges are associated with different phases of the match.

[0146] According to another possible variant, the time slots are discontinuous. The advantage of this variant is that slots relating to unwanted content, such as advertising, can be removed. Furthermore, using the sub-variant described above, in the match example, the sub-slots would be associated with important moments or scenes in the match, for example, when a goal was scored by a team.

[0147] According to another possible variant, the time slots are continuous. This variant offers the distinct advantage of being able to access any segment that was broadcast before the current broadcast time.

[0148] Finally, it should be noted here that the term "entity" or "module" can refer to a software component, a hardware component, or a set of hardware and software components. A software component itself corresponds to one or more computer programs or subprograms, or more generally, to any element of a program capable of implementing a function or set of functions as described for the modules in question. Similarly, a hardware component corresponds to any element of a hardware assembly capable of implementing a function or set of functions for the module in question (integrated circuit, smart card, memory card, etc.).

Claims

Method for managing the transmission of data relating to a description file describing a set of content segments that have been broadcast, characterized in that it includes, during a replay, a step of receiving a temporal data (tj) representative of a delayed reading moment; a step of transmitting a description file (Ad-MNF(j)) describing a subset of segments linked to said temporal data (tj). A management method according to claim 1, characterized in that it comprises a step of prior obtaining a plurality of subsets of description files, called index files, describing addresses of segments that have been broadcast over different respective broadcast time ranges; and of a description file, called root file, associated with said plurality of index files; and in that the reception step includes receiving data representative of the root file (Ad-MNF-rac) and of the time data (tj), Management method according to claim 1, characterized in that access addresses to segments are transmitted with the root file. Management method according to claim 1, characterized in that the time slots are associated with different content that has been broadcast. Management method according to claim 1, characterized in that the time ranges are discontinuous. Management method according to claim 1, characterized in that the time ranges are continuous. Entity for managing data transmission relating to a description file describing segments of content that have been broadcast, characterized in that it comprises, A module for receiving temporal data (tj) representing a delayed reading moment; A module for transmitting a description file (Ad-MNF(j)) describing a subset of segment addresses linked to said temporal data. Content server (SRV) characterized in that it comprises an entity (ENT2) as defined in claim 7. Computer program capable of being implemented on a management entity (ENT2) as defined in claim 6, the program comprising code instructions which, when executed by a processor, carries out the steps of the process defined in claim 1. Data carrier on which at least one series of program code instructions for the execution of a method according to claim 1 has been stored. Method for managing access to delayed content via a description file describing a set of content segments that have been broadcast, characterized in that it comprises, a step of transmitting a temporal data (tj) representative of a delayed reading moment; a step of receiving a description file (Ad-MNF(j)) describing a subset of segment addresses linked to said temporal data. Entity for managing access to content via a description file describing segments of content that have been broadcast, characterized in that it comprises: A module for transmitting temporal data (tj) representing a delayed reading moment; A module for receiving a description file (Ad-MNF(j)) describing a subset of segments linked to said temporal data. Reading device (STB) comprising a management entity (ENT1) as defined in claim 12. Computer program capable of being implemented on a management entity (ENT1) as defined in claim 12, the program comprising code instructions which, when executed by a processor, carries out the steps of the process defined in claim 11. Data carrier on which at least one series of program code instructions for the execution of a method according to claim 11 has been stored.

Images