method for managing the reading of multimedia content.

Abstract

TITLE: Method for managing the playback of multimedia content. The invention relates to a method for managing the playback of content segments by a device accessible from content sources capable of transmitting segments of the same content with a time delay, characterized in that during the playback of content from a first source (n-CDN) at a reading speed, called the reference speed, the reception of a return command to the content is followed by the playback of segments from a second source (SU) at a speed different from the reference speed, the playback of the content continuing by reading segments from the first source (n-CDN) when the segments to be read are available from the first source (n-CDN). Figure 1

Description

Title of the invention: Method for managing the reading of multimedia content. technical field

[0001] The field of the invention is that of digital multimedia content, namely digital audio and / or video content, also called audiovisual content.

[0002] The invention relates particularly to a method for managing the reading of multimedia content.

[0003] In the example which will serve to illustrate the invention, the contents are content cut into segments associated with several respective encoding rates selectable on requests issued from a multimedia stream reading device.

[0004] The content referred to here is accessible from several data sources (servers for example); the sources have the particularity of transmitting content with a time delay; for example one source makes available to STB reading devices content in real time (or in Live); another source for example broadcasts in unicast and can on request transmit the same content later in delayed mode, for example when a rewind is required.

[0005] A reading device refers to any device capable of receiving multimedia streams, for example a decoder, a mobile phone, a tablet, etc. State of the art

[0006] It sometimes happens that one misses the beginning of a television program (movie, series, etc.). A function called "play from the beginning" or "catch-up" (also called "Start Over" or "Restart" by those skilled in the art) allows one to resume the program currently being broadcast from the beginning or from a specific moment, for example, to watch a particular scene. For example, if a movie starts at 8:50 p.m. on a broadcast channel (a television channel) and a user switches to that television channel at 9:07 p.m., they can activate the "start over" function to be able to watch the content from the beginning.

[0007] Generally, real-time content streaming (also called "Live" or "direct") relies on multicast technology (also called "multipoint" or "group" streaming, or simply "Multicast" by those skilled in the art). This technology saves considerable bandwidth in the network of an operator managing the streaming because the content is replicated as close as possible to the playback devices. However, when a playback device requests the "play from beginning" function, accessing the requested content triggers an automatic switchover to multicast technology. towards a point-to-point (unicast) content delivery technology which is much more bandwidth-intensive in a telecommunications operator's network.

[0008] Once the user activates the "play from the beginning" function and a rewind has been performed, the playback device remains on a unicast stream and consumes only that unicast stream until the next channel change (zapping) or return to live TV action. However, using a unicast stream will result in bandwidth consumption that can be enormous if multiple rewinds from several playback devices are performed simultaneously, for example, when the content relates to a major event.

[0009] The invention offers a solution that does not present the disadvantages of the prior art.

[0010] The invention

[0011] To this end, according to a first functional aspect, the invention relates to a method for managing the reading; by means of a reading device, of segments of content accessible from content sources capable of transmitting segments of the same content with a time offset, characterized in that during a reading of the content from a first source with a reading speed, called the reference speed, a reception of a command to return to the content is followed by a reading of segments from a second source with a speed different from the reference speed, and a continuation of the reading of segments from the first source when the segments to be read are available from the first source.

[0012] According to the invention, the reading of segments from the second source is modified relative to a reference speed; this modification of the speed, which can be an acceleration of segment reading, makes it possible to catch up with the flow from the first source and to continue reading from the base of the segments from the first source. The invention limits the use of the second source for reading the content.

[0013] Note that in the case where the different speed referred to above relates to an acceleration of reading, ideally the speed will be chosen in such a way that the accelerated rendering is almost imperceptible to the human eye.

[0014] According to a first embodiment, playback at a different speed is performed only if the rewind time is less than a given duration, referred to as the first duration. The execution of playback at a different speed is conditional in this case; the condition being that the rewind time in the content does not exceed a given duration, so as to avoid a catch-up that would not be possible. For example, if the user rewinds 45 minutes on content with a duration of 60 minutes, it is pointless to try to catch up with the stream from the first server because this would imply a much too high accelerated playback speed. This is similar to fast-forwarding (symbolized by "Fast Forward" on most media players) rather than accelerating playback. In other words, playback of segments from the second source (SU) occurs at a different speed if resuming playback from the second source is possible. If the rewind is too significant, it's clear that catching up to the stream from the first source at a reasonable speed is virtually impossible. For example, if the user rewinds 45 minutes of a 60-minute video, speeding up playback and trying to catch up to the stream from the first source (such as a live stream) is pointless because it would require playing the content far too quickly; the goal is to provide playback at a slightly faster speed so that the content is understandable to the user.

[0015] Note that an accelerated reading speed is to be distinguished from a fast forward; an accelerated reading speed allowing an understanding of the content rendered.

[0016] According to a second embodiment, which may be implemented alternatively or cumulatively with the previous embodiment, the reading of segments from the second source is initially performed at the so-called reference speed, and a different speed is used after a given duration, referred to as the second duration. According to this embodiment, reading at a different speed, for example, a speed higher than the reference speed, is performed after the expiration of the second duration, which can be considered a delay time. For example, if the user requests a 30-second rewind to view a sequence in the past, the reading from the requested playback point is initially performed at the normal reference speed and continues at a speed other than the reference speed as soon as the requested sequence is finished.It can indeed be considered that if the user is interested in a specific sequence, they will appreciate a reading at a normal speed of the requested sequence.

[0017] According to a variant of the second embodiment, the second duration is equal to the duration of the return to the content. For example, if a 120-second return is requested, a reading at the reference speed takes place for 120 seconds, and then at a higher speed.

[0018] Other variations are of course conceivable; for example, the given duration can be chosen as a function of the backtracking duration. The longer the backtracking duration, the longer the given duration; conversely, the shorter the backtracking duration, the shorter the given duration.

[0019] According to a third embodiment, which may be implemented alternatively or cumulatively with the preceding embodiments, the first source transmits the content in real time and the second source is capable of transmitting the content with a delay. This fourth embodiment relates to a system configuration in which the invention is found a definite interest in having a first source that is preferred for reading because of the advantages of multicast but is not able to rewind the content; and a second source that allows rewinding the content and therefore delayed reading of the same content broadcast in multicast; such a second source is typically a unicast source.

[0020] According to a fourth embodiment, which can be implemented alternatively or cumulatively with the preceding embodiments, the first source is a transformation entity that transforms a multicast stream received from a multicast server into a unicast stream. This embodiment aims for an optimal configuration of the method of the invention in which the second source offers advantages in terms of bandwidth and image quality; recording segments from a multicast server provides image quality during playback that is far superior to unicast mode.

[0021] According to a material aspect, the invention relates to a reading management entity by a device for reading segments of content accessible from content sources capable of transmitting segments of the same content with a time offset, the entity comprising a processor configured to, during a reading of the content from a first source with a reading speed, called the reference speed, following the receipt of a return command in the content, read the segments from a second source with a speed different from the reference speed, the reading of the content continuing by reading segments from the first source when the segments to be read are available from the first source.

[0022] According to another material aspect, the invention relates to a reading device including a management entity as defined above.

[0023] According to another material aspect, the invention relates to a computer program suitable for implementation on an entity as defined above, the program comprising code instructions which, when executed by a processor, performs the steps of the management process defined above.

[0024] According to another material aspect, the invention relates to a data carrier on which at least one series of program code instructions for the execution of a process as defined above has been stored.

[0025] Such a recording medium can be any entity or device capable of storing the program. For example, the 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 USB flash drive or a hard drive.

[0026] On the other hand, such a recording 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, so that the computer program The program it contains is executable remotely. In particular, the program according to the invention can be downloaded onto a network, for example, the Internet.

[0027] Alternatively, the recording medium may 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 aforementioned management process.

[0028] 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:

[0029] [Fig-1] Fig. 1 represents a computer system on which is illustrated a example of an implementation of the invention.

[0030] [Fig.2] The [Fig.2] is a simplified synoptic diagram of the material structure of the reading device;

[0031] [Fig.3] Fig.3 illustrates an embodiment of the method of the invention showing the execution of a return command in the content by means of the startover mode and the triggering of an accelerated reading of the content from the second source.

[0032] Detailed description of an example embodiment illustrating the invention:

[0033] Fig. 1 represents a computer system SYS in which a content distribution network called a CDN (Content Distribution Network) is implemented, from which content is transmitted to client devices or content reading devices.

[0034] In our example, the SYS system comprises a single STB reading device. However, the invention applies to any number of reading devices.

[0035] The reading device STB is for example a digital television decoder.

[0036] In our example, the STB reading device is connected to a port of the TV playback device; the STB reading device and the TV playback device could also form a single device.

[0037] In our example, the STB reading device is located in a local area network (LAN) managed by a GTW home gateway.

[0038] The GTW gateway is capable of communicating via a LU telecommunications network such as a WAN known to a person skilled in the art.

[0039] The CDN consists of servers connected in a network within the wide area network.

[0040] The multimedia content referred to here is multimedia content corresponding to a television channel on which television programs are broadcast.

[0041] Content may initially be available on a DIF source.

[0042] This source is connected to the content delivery network, CDN (for "Content Delivery Network"), which forms, in a way, an overlay on the telecommunications network, such as the Internet. The delivery network The CDN content server comprises several separate SU / SM content servers capable of transmitting the same content to the STB reading device with a time delay.

[0043] In our example, a first server is capable of transmitting content in unicast mode, called a unicast server SU, and a second server SM is capable of transmitting the content in real time, for example in multicast.

[0044] The invention is not limited to this configuration but extends to any server capable of transmitting the same segments with a time offset.

[0045] The configuration described above allows, for example, receiving a multicast stream of segments, requesting a rewind in the content, and continuing playback of segments from the unicast server from the desired segment. It is clear that there is a time lag between the segments broadcast by the multicast source and the segments received from the unicast server.

[0046] Typically, the segments from the DIF source are transmitted to the first unicast server and to a second multicast server. The multicast server SM, or "multicaster," can receive the segments from the unicast server SU when a decision is made to enable multicast transmission. This decision can, for example, be made by the first content source, SU, or by a monitoring device (not shown) that is aware of the number of playback devices wishing to receive given content.

[0047] CNT content is made available in a given format. Such CNT content is, for example, content downloaded in adaptive streaming mode. 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 by means of an exchange protocol between the playback terminal and the multimedia content provider server. The primary protocol targeted is HTTP, but other protocols (for example, FTP) can also be used.The organization of the segments and the 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 not relevant to the description of the invention.

[0048] Figure 2 represents an architecture of an STB reading device. This STB device typically comprises 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.

[0049] The STB decoder 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 referred to as COM1 in [Fig. 2]. This connection is referred to as LI2 in [Fig. 1].

[0050] The STB decoder can transmit content to be displayed to the TV display device via a COM2 communication module. This COM2 module is, for example, an HDMI connection. This connection is referred to as LI3 in [Fig. 1].

[0051] The STB decoder includes a streaming-mode download entity (not shown) capable of managing the downloading of segments. The STB decoder also includes an ENT management entity whose function will be described below.

[0052] In addition, the STB reading device is equipped with a STRT "replay content" function (also called "startover" by those skilled in the art) which is intended to replay content that is being broadcast.

[0053] The servers have an equivalent hardware structure. A server equipped with at least one processor and memory for performing computer processing. An SRV server communicates with the GTW gateway via a WAN network.

[0054] The SU unicast server provides description files to the STB reading device through the GTW gateway. From these description files, the STB reading device can transmit requests to download a segment of the resolution chosen from those available in the last received description file.

[0055] The SM multicast server broadcasts a continuous stream of the IPTV or equivalent type. The multicast server broadcasts the content in a broadcast tree, independently of the STB playback devices registered to obtain it. The nodes of the broadcast tree handle transmission up to the leaves constituted by the management entities, in particular the transformation entity present in the GTW gateway.

[0056] The system includes a transformation entity referenced as n-CDN that receives the real-time (or Live) multicast stream and segments it; after segment production, the transformation entity makes the segments available to the STB playback device in Unicast mode. The n-CDN transformation entity creates description files accordingly. The STB playback device can thus access the description files and the content segments described in these files through the stream transformation entity referenced as n-CDN in the figures.

[0057] The location of the n-CDN transformation entity in the system is arbitrary. In our example, this transformation entity is located in the GTW gateway.

[0058] From the perspective of the STB reading device, a transformation entity thus forms the input of the content delivery network, CDN. Such a transformation entity can therefore correspond to the terminology "nano CDN" or "n-CDN", known to those skilled in the art.

[0059] In conclusion, to simplify the explanation, the STB reading device has two content sources, a first n-CDN source based on a multicast stream and a second source which is the SU unicast server; the first n-CDN source being connected to the multicast server and providing real-time segments at the basis of a real-time data stream from the multicast server; the second SU source providing delayed segments.

[0060] It is assumed that the reception of the segment stream takes place at a given time from the n-CDN source. This transmission mode is often preferred when such a stream is available due to the performance of multicast mode compared to unicast mode in terms of network bandwidth and image quality.

[0061] It is assumed that, upon receiving content segments from the n-CDN source, a user requests to rewind the content. In this case, the ENT management entity triggers a request to receive the segments from the unicast server. The STB reading device then receives the segments from the SU unicast server from the desired replay point.

[0062] Ultimately, the n-CDN source is a first source of content, and the SU unicast server is a second source of content; both of these sources are capable of transmitting segments with a time offset.

[0063] Also, in general, the segments are read with a given reading speed, called the reference speed.

[0064] According to the invention, when reading the content from the n-CDN source, a reception of a return command in the content is followed by a reading of segments from the SU source with a speed modified with respect to the reference speed; then as soon as the segments to be read are available from the n-CDN source, the reading resumes at the base of the segments from the n-CDN source.

[0065] The modified speed, which can vary over time, is chosen so as to catch up with the stream from the second source as quickly as possible without disturbing the user viewing the screen, the goal being to resume reading the content from the base of the segments from the first n-CDN source as quickly as possible.

[0066] Preferably, the higher speed is chosen such that the difference between playback at a reference speed and playback at a higher speed is almost imperceptible to the human eye. Accelerated reading should not be confused with fast-forwarding through the content.

[0067] An embodiment will now be described with reference to [Fig.3].

[0068] This [Fig.3] illustrates a timing diagram for an example of implementing a process between an STB reading device, an SU source capable of transmitting the content in unicast mode and an n-CDN source receiving multicast streams from the SM multicast server; the n-CDN source will produce segments of the content in real time and make them available.

[0069] In this embodiment, to simplify the explanation, neither the transmission of description files nor the transmission of segment access requests will be described. It will be understood that each segment reception is preceded by a segment access request. It will also be understood that description files are transmitted by both sources so that the STB reading devices can access the segments.

[0070] Initially, the STB reading device transmits successive access requests to S1-S9 segments to the n-CDN transformation entity and receives back the requested S1-S9 segments successively.

[0071] Upon receiving a request, the n-CDN transformation entity subscribes to the desired multicast stream from the SM multicast server and receives a multicast data stream in return. The n-CDN transformation entity then transforms the continuous stream into encoded segments and makes these segments available.

[0072] It is assumed that, when receiving content segments from the n-CDN transformation entity, a user requests at some point a step back (") in the content.

[0073] The STB reading device receives the return command ("), the command including a specific segment identifier from which reading should resume. In our example, a replay from the beginning, namely the first SI segment, is requested.

[0074] In our example, only the SU unicast server is capable of reading delayed content. The STB playback device executes the command and requests the reception of segments from segment S1 from the SU unicast server.

[0075] According to the invention, when passing from a reception of the content of the multicast server MC to the SU server, the STB reading device modifies the reading speed of the segments from the unicast server SU.

[0076] It will be understood later that accelerating playback requires downloading segments at a higher frequency and that reading a segment will be faster. Since a video is a succession of images, accelerating playback will consist, for example, of displaying images of a segment for a shorter time than normal; or of extracting judiciously chosen images from the segment so as to read only a subset of images from a segment and therefore accelerate the reading of the relevant segment while ensuring comprehension of the content.

[0077] In our example, the STB reading device continues to receive segments from the n-CDN source during accelerated reading of content from the SU unicast server.

[0078] During accelerated reading of the content, phase referenced (xl,l) on [Fig.3], access requests are made at a higher frequency because the segments are read faster.

[0079] At a given moment, the S15 segment is received from both the SU unicast server and the n-CDN source. The STB reading device, understood to be the ENT management entity, prioritizes the S15 segment from the n-CDN source for the reasons explained above. Upon reception, the STB reading device decodes the S15 segment received from the n-CDN source and requests the rendering of the S15 segment images; the STB reading device then continues reading based on S16 / S17 / etc. segments from the n-CDN source.

[0080] Note that the preceding example is based on a replay from the beginning. However, the invention also applies to a replay from another point in time; for example, the reading of segments from the unicast server could have started at the third segment S3.

[0081] It is therefore understood from the above that following the execution of the return command (symbol used on most devices “ “), the STB playback device subscribes to the Unicast stream and will attempt, throughout the accelerated playback of the segments received from the unicast server, to reconnect to the stream transmitted by the n-CDN source, i.e., the SM multicast server with which the n-CDN source communicates. Thus, as seen above, when the playback of the delayed Live stream (consumed in Unicast) results in segments of content originating from the n-CDN source, the STB playback device then stops receiving the Unicast stream and uses the segments coming from the n-CDN source.

[0082] Let's take a concrete example:

[0083] A program starts at 9:00 PM and lasts 1 hour 45 minutes.

[0084] Suppose that the user accesses a live television program at 9:05 PM. The stream is transmitted via multicast from the SM multicast server and forwarded to the gateway where the n-CDN source transforms the multicast stream into a unicast stream.

[0085] Suppose the user activates the "StartOver" function and accesses the Live stream with a 5-minute delay. Upon receiving a 5-minute return command, the STB playback device subscribes to the unicast stream from the SU unicast server to access the delayed content. At this point, according to one embodiment, the STB playback device accelerates the playback of the segments from the SU unicast server.

[0086] After viewing a few minutes of unicast content, while the playback catches up with the segments from the n-CDN source, it reaches a unicast segment that corresponds to the segment to be played from the n-CDN source. The STB playback device will then unsubscribe from the unicast stream with the SU unicast server and continue playing the segments from the n-CDN source, the latter subscribing to the relevant multicast stream.

[0087] Ultimately, out of 1 hour and 45 minutes of programming, only a few minutes were received via unicast. The remaining time, the received segments were those created at the base of the multicast stream. This optimizes bandwidth consumption in the operator's LU network.

[0088] The embodiment described above may be subject to variations.

[0089] According to a first variant, the ENT management entity obtains data representing a possible catch-up of the multicast stream. In this configuration, the ENT management entity decides whether or not to accelerate the reading of segments received in unicast from the SU unicast server. It is clear here that acceleration is only useful if catch-up is possible and that failing to take into account an impossibility results in inappropriate processing that consumes processor resources.

[0090] According to another variant, the reading speed from the SU unicast source with an accelerated speed is timed by a duration which is a function of the desired delayed reading time included in the return command.

[0091] According to another embodiment, the delay time is equal to the duration of the rewind in the content. For example, if a 5-minute rewind is desired, playback occurs at the reference speed for 5 minutes, and then the playback speed is accelerated to catch up with the stream from the SM multicast server and resume playback of the segments from the n-CDN source. Ultimately, the aim of this invention is to limit the use of the SU unicast server; when a relatively shallow rewind is required, a slightly accelerated playback allows the stream to return to the Live stream as quickly as possible. Thanks to the invention, the bandwidth saved on the LU operator's network is significant.

[0092] Finally, let us clarify here that the term entity 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 a set of functions as described for the modules concerned. 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

Demands

1. Method of managing the reading by a reading device of segments of content accessible from content sources capable of transmitting segments of the same content with a time offset, characterized in that during a reading of the content from a first source (n-CDN) with a reading speed, called the reference speed, a reception of a command to return to the content is followed by a reading of segments from a second source (SU) with a speed different from the reference speed, and a continuation of the reading of segments from the first source (n-CDN) when the segments to be read are available from the first source (n-CDN).

2. Management method according to claim 1, characterized in that a reading with a different speed is performed only if the backtracking time is less than a given time, called the first time.

3. Management method according to claim 1, characterized in that the reading of segments from the second source (SU) is initially carried out with the reference speed and in that a different speed is used after a given duration, called the second duration.

4. Management method according to claim 3, characterized in that the second duration is equal to the duration of the return in the content.

5. Management method according to claim 1, characterized in that the first source transmits the content in real time and the second source is capable of transmitting the content in delayed time.

6. Management method according to claim 1, characterized in that the first source is a transformation entity transforming a multicast stream received from a multicast server into a unicast stream.

7. Entity for managing the reading by a device of content segments accessible from content sources capable of transmitting segments of the same content with a time offset, the entity comprising a processor configured to, during a reading of the content from a first source (n-CDN) at a reading speed, called the reference speed, following the receipt of a return command in the content, read the segments from a second source (SU) at a speed different from the reference speed, the reading of the content continuing by reading segments from the first source (n-CDN) when the segments to be read are available from the first source (n-CDN).

8. Reading device reading device (STB) comprising an entity as defined in claim 7.

9. A computer program capable of being implemented on a management entity (MTE) as defined in claim 7, the program comprising code instructions which, when executed by a processor, performs the steps of the process defined in claim 1.

10. Data carrier on which at least one series of program code instructions for executing a method according to claim 1 has been stored

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