FR3081647A1 - MANAGEMENT OF ADAPTIVE PROGRESSIVE DOWNLOAD (HAS) OF DIGITAL CONTENT WITHIN A REAL-TIME MULTIMEDIA STREAM READER TERMINAL. - Google Patents

Abstract

The invention relates to a method for managing the adaptive progressive download (HAS) of a digital content (C1) within a real-time multimedia streaming player terminal (30), in a local communication network, said reader terminal real-time multimedia stream being associated with a rendering terminal (5) of said digital content. According to the invention, after a first period of determined duration of absence of interaction of a user of said digital content with said media streaming player terminal in real time and / or with said terminal for rendering said content numerically, it implements a progressive reduction (311) of a rendering quality of said downloaded digital content, on said rendering terminal.

Description

Management of the adaptive progressive download (HAS) of digital content within a real-time multimedia stream reader terminal.

1. Field of the invention

The field of the invention is that of digital multimedia content, namely digital audio and / or video content. More specifically, the invention relates to the optimization of the network resources of a communication operator, within the framework of the routing of digital contents according to a technique called adaptive progressive downloading within a local communication network, such as 'a home network.

2. Prior art and its drawbacks

Access to multimedia content, such as television or video on demand, from an Internet-type network is possible today, for most playback terminals, in particular when they belong to a communication network. local, such as a home network.

The terminal generally sends a request to a server, indicating the content selected and it receives in return a stream of digital data relating to this content. In the context of a local communication network, such a request passes through the network access gateway, for example the residential gateway.

The terminal is suitable for receiving this digital content in the form of multimedia data and for rendering it. This rendering consists in supplying the digital content at the terminal in a form accessible to the user. For example, data received corresponding to a video is generally decoded, then restored at the terminal in the form of a display of the corresponding video with its associated soundtrack. In the following, for the sake of simplification, digital content will be assimilated to a video and the restitution by the terminal, or consumption by the user of the terminal, to a display on the screen of the terminal.

The distribution of digital content on the Internet is often based on client-server protocols of the HTTP family (“Hyper Text Transport Protocol”). In particular, the download in progressive mode of digital content, also called streaming, makes it possible to transport and consume data in real time, that is to say that digital data is transmitted over the network and restored by the terminal as and as they arrive. The terminal receives and stores part of the digital data in a buffer memory before restoring it. This distribution mode is particularly useful when the bit rate available to the user is not guaranteed for real-time transfer of video.

Adaptive progressive download, in English HTTP Adaptive Streaming, abbreviation HAS, also makes it possible to broadcast and receive data according to different qualities corresponding for example to different bit rates. These different qualities are described in a parameter file available for download on a data server, for example a content server. When the client terminal wishes to access content, this description file makes it possible to select the correct format for the content to be consumed as a function of the available bandwidth or of the storage and decoding capacities of the client terminal. This type of technique makes it possible in particular to take account of variations in bandwidth on the link between the client terminal and the content server.

There are several technical solutions to facilitate the distribution of such streaming content, such as the proprietary Microsoft® Smooth Streaming, Apple® HLS, Adobe® HTTP Dynamic Streaming solutions or the MPEG-DASH standard of the ISO / IEC which will be described below. These methods propose to send the client one or more intermediate description files, also called documents or manifests, containing the addresses of the different segments with the different qualities of the multimedia content.

Thus, the MPEG-DASH standard (for English Dynamic Adaptive Streaming over HTTP, in French "diffusion in dynamic adaptive stream over HTTP") is a standard format for audiovisual broadcasting on the Internet. It is based on the preparation of content in different presentations of variable quality and throughput, cut into short-lived segments (of the order of a few seconds), also called "chunks". Each of these segments is made available individually by means of an exchange protocol. The mainly targeted protocol is the HTTP protocol, but other protocols (for example FTP) can also be used. The organization of the segments and the associated parameters are published in a manifesto in XML format.

The principle underlying this standard is that the MPEG-DASH client makes an estimate of the bandwidth available for reception of the segments, and, depending on the filling of its reception buffer, chooses, for the next segment to be loaded, a representation whose flow:

ensures the best possible quality, and allows a reception time compatible with the uninterrupted rendering of the content.

To adapt to varying network conditions, in particular in terms of bandwidth, existing adaptive downloading solutions allow the client terminal to switch from one version of content encoded at a certain bit rate, to another encoded one. other speed, during download. Indeed, each version of the content is divided into segments of the same duration. To allow continuous playback of content on the terminal, each segment must reach the terminal before its scheduled playback time. The perceived quality associated with a segment increases with the size of the segment, expressed in bits, but at the same time, larger segments require a longer transmission time, and therefore present an increased risk of not being received in time for continuous playback of content.

The rendering terminal must therefore find a compromise between the overall quality of the content and its uninterrupted rendering, by carefully selecting the next segment to be downloaded, from the different encoding bit rates offered. To do this, there are different algorithms for selecting the quality of the content as a function of the available bandwidth, which may present more or less aggressive, or more or less secure strategies.

The consumption of digital content in adaptive progressive download (HAS) is tending to become more widespread. It is used in particular by many streaming services (in French, streaming, or streaming), but also by certain TV set-top boxes, or set-top-boxes, which use it to access delinearized content, such as video on demand (VOD), deferred broadcasting of television programs (Replay), or even offers of the Network PVR type (for "Personal Network Video Recorder", ie a digital content recording service, carried out by the content provider itself rather than at the home of the end user).

In addition, other devices such as real-time media stream playback devices also access digital content in progressive adaptive download mode for real-time (or Live) television content. This is the case, for example, with the Chromecast® device developed by Google®, or the Orange® CléTV®.

Such devices are typically connected to the HDMI port of a television and communicate, via Wi-Fi® connection, with another device on the home communication network connected to a wide area Internet communication network (residential gateway, computer, telephone smartphone, tablet, etc.), in order to restore multimedia content received by a compatible software application on the television. These devices will subsequently be designated under the generic designation of HDMI key.

Such devices can also be used to access video-on-demand content, or to play personal content stored on the home network on the TV, such as a video from the last vacation or from the last family event.

Most often, their power supply is via a micro-USB port (for "Universal Serial Bus"), located for example at the back of the HDMI key, which connects to a corresponding USB port on the TV or an external power source. In the latter case, the operation of such devices is therefore uninterrupted, since they are generally not equipped with on / off switches. Indeed, the user will naturally turn off or put on standby his television but will not disconnect his HDMI key from the sector so that, when the television is again switched on, access the content without delay related to the restart of the key HDMI.

However, so-called “live” digital content, ie which corresponds to television programs in real time, has, by its nature, no predefined duration or end date. As a result, if the end user does not explicitly stop the distribution of this content, for example by explicitly stopping the distribution of the content on the HDMI key (for example by returning to the home page) or by interrupting its supply electric, they can be played indefinitely by the HDMI key, which receives them from a device connected to the home network, and provides them to the television so that it reproduces them, even if the latter is turned off and therefore displays no content on his screen. This therefore results in permanent and unnecessary consumption of bandwidth resources, both within the local communication network and the extended communication network of the Internet service provider.

This can be problematic from several points of view.

First of all, the end user is generally not aware of this problem. Indeed, more often than not, when he stops watching the television program, he turns off or puts his television on standby, which leaves him to think that he has thus effectively stopped broadcasting the content he was viewing. He is generally unaware that the HDMI Key continues to acquire digital content in progressive adaptive download mode. He may therefore be surprised that the speed or bandwidth in the home network is low, for the other uses he wishes to make of it, which is a source of dissatisfaction.

In addition, unlike multicast content (for example for conventional IP television), content broadcast in HAS adaptive progressive download mode consumes a lot more network resources for the operator of the wide area network. Indeed, the flow is not duplicated as close as possible to the customer, but multiplied by the number of customers who consume it. When a multitude of clients use such an HDMI key, which they allow to run continuously without necessity, this unnecessary consumption of network resources can take problematic proportions for the network operator.

For these two reasons, it is important for the provider of access to the extended communication network to ensure that the digital content broadcast in real time in adaptive progressive download mode is properly used, and in particular ceases to consume unnecessary network resources, when the end user no longer wishes to view them, for example if he is no longer present in front of his television.

To solve this problem, we considered implementing the following method: on detection that a user has not interacted with his HDMI key for a certain time (for example four hours), a pop-up window (in French , intruder window or "pop-up" window) is displayed on the TV screen for a predetermined period (for example sixty seconds). The message displayed in this window prompts the user to confirm their presence in front of the screen, for example by pressing a button on the TV's remote control. If the user responds to this invitation, the content will continue to be broadcast by the HDMI key. Otherwise, at the end of the predetermined duration of display of the popup window, the stream associated with the live digital content is suddenly cut off, in order to free up network resources.

This interesting solution turns out, however, to be radical and quite brutal. In addition, the consumption of network resources continues long after the user has ceased to be interested in the content broadcast, which is not optimal. One could consider reducing the duration of broadcasting of the content before the pop-up window is displayed, for example to two hours, but to the possible detriment of a dissatisfaction of the user, which could be hampered by the untimely display of this. window, right in the middle of his television program.

There is therefore a need for a technique for interrupting the broadcasting in adaptive progressive download mode of digital content on detection of absence of the user, which does not have these various drawbacks of the prior art. In particular, there is a need for such a technique which allows better optimization of the consumption of network resources, by taking advantage in particular of the technical specifications of HAS progressive adaptive downloading.

3. Statement of the invention

The invention responds to this need by proposing a method for managing the adaptive progressive download (HAS) of digital content within a real-time multimedia stream reader terminal, in a local communication network, said reader terminal multimedia stream in real time being associated with a terminal for rendering said digital content.

At the end of a first period of fixed duration of absence of interaction of a user of the digital content with the terminal reader of multimedia flow in real time and / or with the terminal of restitution of the digital content, such a method implements a progressive reduction in the quality of restitution of the digital content downloaded, on the restitution terminal.

Thus, the invention is based on a completely new and inventive approach to the management of progressive adaptive downloading in a local communication network, and in particular in a real-time multimedia stream reader terminal, of the HDMI key type. In fact, unlike the solutions of the prior art, which propose a sudden interruption in the downloading of content, at the end of a period during which no interaction of the user of the content with the television or the HDMI key. has been detected, the solution of the invention aims to operate a smoother cut in the stream, which is based on a progressive decrease in the video quality consumed. This has the effect of reducing the consumption of network resources by as much, for the operator of the wide area network, as for the client of the local communication network.

This first period of predetermined duration is preferably of duration shorter than the period of absence of interaction provided for in the solutions of the prior art before total interruption of the download stream.

According to a first aspect, the digital content being associated with a description file of the digital content, comprising a list of time segments (Cl, @ Nj) of the content each associated with several bit rates for encoding the content, the progressive reduction of a quality of restitution of the downloaded digital content is based on a download of time segments of the content associated with decreasing encoding rates over time.

Thus, the solution of the invention relies on the capabilities of HAS technology. Indeed, content broadcast in HAS is offered to the client at different encoding rates. Depending on the network conditions, the HAS client embedded in the HDMI key constantly adapts the quality of the downloaded stream, in order to be able to benefit from the best possible quality of playback, while ensuring the smooth delivery of content on the playback terminal ( eg the television). To do this, it downloads the proposed time segment at the optimal encoding rate, depending on bandwidth and network resource constraints.

According to the invention on the contrary, as soon as it is detected that the user of the content has not interacted with the HDMI key or the television for a certain time (for example three hours), the HDMI key no longer downloads the time segments of the content at the optimal encoding rate, but downloads time segments at increasingly reduced encoding rates, until the lowest rendering quality of the content is reached. This progressive decrease in the encoding bit rates of the downloaded time segments can take place, for example, over a period of one hour, from the optimal bit rate relative to the network resource constraints, to the lowest bit rate proposed in the associated manifest. to the content.

According to another aspect, said progressive reduction is accompanied by a display, on the restitution terminal, of an alert message intended for the user and relating to the progressive reduction in quality of restitution.

This alert message can take the form of a pop-up window, which is displayed on the television (or on the control terminal of the HDMI key, for example the user's tablet), and which informs that the quality of content reproduction will gradually decrease. The user can then, with a simple press of a button on the TV remote control or the HDMI key, signal its presence, and thus return to the initial management mode of the HAS adaptive progressive download algorithm, which aims to optimize the quality of content reproduction.

Thus, upon detection of an interaction of the user with the terminal for streaming multimedia streams in real time and / or with the terminal for rendering digital content, the progressive reduction in quality of playback is interrupted and the method implements a downloading of time segments of the content associated with optimized encoding rates as a function of a resource constraint estimated by the terminal for streaming media streams in real time.

According to another aspect, at the end of a second period of fixed duration of absence of interaction of the user with the terminal reader of multimedia flow in real time and / or with the terminal of restitution of the digital content, it implements a display, on the rendering terminal, of an information message of the next interruption in the downloading of digital content and, in the absence of user interaction with the terminal for streaming multimedia time real and / or with the restitution terminal resulting from said display, an interruption in the download.

This second period of fixed duration begins, for example, at the initiation of the progressive reduction in the quality of restitution of the content, and lasts for example one hour. During this second period, if no user interaction is detected, the quality of content reproduction is gradually reduced from the optimal quality corresponding to the nominal operating mode of the HAS download algorithm to the highest quality. low expected in the manifesto associated with the content.

At the end of this second period, a new pop-up window is displayed on the television, which warns the user that in the absence of action on his part, for example during the next sixty seconds, the stream content download via the HDMI key will be cut to avoid unnecessary consumption of network resources.

Of course, if the user shows up, this flow cut does not take place.

This interaction of the user with the multimedia player terminal in real time and / or with the terminal for rendering said digital content can implement a terminal control terminal, for example a remote control for the television set or the HDMI key (by example, pressing the volume or channel change key), or a user's smartphone or tablet, on which the software application is installed to control the operation of the HDMI key.

The invention also relates to a device for managing the adaptive progressive download (HAS) of digital content within a real-time multimedia stream reader terminal, in a local communication network, the real-time multimedia stream reader terminal real being associated with a digital content rendering terminal. Such a device comprises a module for progressive reduction of a quality of restitution of the digital content downloaded, on the restitution terminal, activated at the end of a first period of determined duration of absence of interaction by a user of the digital content with the real-time multimedia stream reader terminal and / or with the digital content rendering terminal.

According to one aspect, such a module for progressive reduction of a quality of restitution of the downloaded digital content comprises means for transmitting commands for downloading time segments of the content associated with encoding rates decreasing in time.

The invention also relates to a real-time multimedia stream reader terminal, such as an HDMI key, which includes such a device for managing the adaptive progressive download (HAS) of digital content.

The invention also relates to a computer program product comprising program code instructions for implementing a method as described above, when executed by a processor.

The invention also relates to a recording medium readable by a computer on which a computer program is recorded comprising program code instructions for the execution of the steps of the adaptive progressive download management method according to the invention such as described above.

Such a recording medium can be any entity or device capable of storing the program. For example, the support may include a storage means, such as a ROM, for example a CD ROM or a microelectronic circuit ROM, or else a magnetic recording means, for example a USB key or a hard disk.

On the other hand, such a recording medium can be a transmissible medium such as an electrical or optical signal, which can be routed via an electrical or optical cable, by radio or by other means, so that the program of computer it contains is executable remotely. The program according to the invention can in particular be downloaded from a network, for example the Internet.

Alternatively, the recording 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 aforementioned display control method.

The device for managing the adaptive progressive download (HAS) of digital content, the terminal for real-time multimedia stream streaming and the corresponding computer program mentioned above have at least the same advantages as those conferred by the download management method. adaptive progressive (HAS) of digital content according to the present invention.

4. List of figures

Other objects, characteristics and advantages of the invention will appear more clearly on reading the following description, given by way of simple illustrative example, and not limiting, in relation to the figures, among which:

FIG. 1 represents a progressive download architecture on the Internet based on the use of adaptive streaming according to the invention;

FIG. 2 schematically illustrates the hardware structure of a real-time multimedia stream reader terminal integrating an adaptive progressive download management device according to an embodiment of the invention;

FIG. 3 illustrates an example of optimized and gradual cutoff of a real-time multimedia stream obtained in adaptive progressive download mode by an HDMI key of FIGS. 1 and 2.

5. Detailed description of embodiments of the invention

The general principle of the invention is based on the gradual reduction of the quality of digital content downloaded in adaptive progressive download mode (HAS) by a terminal streaming media player in real time, when it is detected that a user of the content has not interacted, for a fixed period of time, with the multimedia stream player terminal, or a content rendering terminal, which is associated with it. This gradual reduction makes it possible to optimize the consumption of network resources, both for the operator of the extended communication network and for the local communication network.

We now present, in relation to FIG. 1, a progressive download architecture based on the use of adaptive streaming according to the invention.

Terminal 3, for example a “smartphone” type smart phone, terminal 4, for example a laptop, and terminal 8, for example an HDMI key connected to a television set 5, are in this example located in a network. local (LAN, 10) controlled by a home gateway 6. The context of the local network is given by way of example and could be easily transposed to an Internet network of the “best effort” type, a corporate network, etc.

According to this example, a digital content server 2 is located in the wide area network (WAN, 1) but it could equally be located in the local network (LAN, 10), for example in the home gateway 6 or any other equipment capable of host such a content server. The content server 2 receives, for example, digital television content channels from a broadcast television network, not shown, and / or videos on demand, and makes them available to client terminals.

The client terminals 3, 4 and 8 can communicate with the content server 2 to receive one or more content (films, documentaries, advertising sequences, etc.).

It is frequent, in this client-server context, to use, to exchange data between client terminals 3, 4 and 8 and server 2, an adaptive progressive download technique, in English "adaptive streaming", abbreviated as HAS based on the HTTP protocol. This type of technique makes it possible in particular to offer a good quality of content to the user by taking account of the variations in bandwidth which may occur on the link between the client terminal 3, 4 and 8 and the service gateway 6, or between the latter and the content server 2.

Conventionally, different qualities can be encoded for the same content of a string, corresponding for example to different bit rates. More generally, we will speak of quality to refer to a certain resolution of the digital content (spatial, temporal resolution, level of quality associated with video and / or audio compression) with a certain bit rate. Each quality level is itself divided on the content server into time segments (or "fragments" of content, in English "chunks", these three words being used interchangeably throughout this document).

The description of these different qualities and the associated time segmentation, as well as the content fragments, are described for the client terminal and made available to them via their Internet addresses (URI: Universal Resource Identifier). All of these parameters (qualities, addresses of fragments, etc.) are generally grouped together in a parameter file, known as a description file. Note that this parameter file can be a computer file or a set of information describing the content, accessible at a certain address.

Terminals 3, 4 and 8 have their own characteristics in terms of decoding capacity, display, etc. In a context of progressive adaptive downloading, they can adapt their requests to receive and decode the content requested by the user to the quality that best suits them. In our example, if the content is available at bit rates 512 kb / s (kilobits per second) (Resolution 1, or level 1, noted NI), 1024 kb / s (N2), 2048 kb / s (N3) and the client terminal has a bandwidth of 3000 kb / s, it can request content at any bit rate below this limit, for example 2048 kb / s. In general, we denote “Ci @ Nj” the content number i with the quality j (for example the j-th level Nj of quality described in the description file).

The service gateway 6 is in this example a domestic gateway which ensures the routing of the data between the wide area network 1 and the local area network 10, manages the digital contents by ensuring in particular their reception coming from the network and their decoding thanks to the decoders that l 'We assume here integrated into the gateway 6 or the client terminals 3, 4 and 8. As a variant, the decoders can be located elsewhere in the wide area network 1 or local 10, in particular at the level of an element of STB type (of the 'English Set-Top-Box) (not shown) associated with a television.

In this example, to view content, the terminal 3, 4 or 8 first of all interrogates the service gateway 6 to obtain an address of the description document 7 of the content (for example, Cl) desired. The service gateway 6 responds by supplying the terminal with the address of the description file 7. In the following, it will be assumed that this file is a manifest type file according to the MPEG-DASH standard (denoted “C.mpd”) and on will refer indifferently, depending on the context, to the expression "description file" or "manifest".

Alternatively, this file can be retrieved directly from a local Internet server or external to the local network, or can already be found on the service gateway or on the terminal at the time of the request.

An example of a manifest file (MPD) conforming to the MPEG-DASH standard and comprising the description of content available in three different qualities (NI = 512 kb / s, N2 = 1024 kb / s, N3 = 2048 kb / s) of the content fragmented is presented in appendix 1. This simplified manifest file describes digital contents in an XML syntax (from the English "extended Markup Language"), including a list of contents in the form of fragments classically described between an opening tag (<SegmentList> ) and a closing tag (</SegmentList>). Cutting into fragments makes it possible in particular to finely adapt to fluctuations in bandwidth. Each fragment corresponds to a certain duration (“duration” field) with several quality levels and makes it possible to generate their addresses (URL - Uniform Resource Locator). This generation is done in this example using the elements "BaseURL" ("HTTP://server.com") which indicates the address of the content server and "SegmentURL" which lists the complementary parts of the addresses of the different fragments :

- "Cl_512kb_l.mp4" for the first fragment of the content "Cl" at 512 kilobits per second ("kb") in MPEG-4 format ("mp4"),

- "Cl_512kb_2.mp4" for the second fragment,

- etc.

Once it has the fragment addresses corresponding to the desired content, the service gateway 6 obtains the fragments via a download to these addresses. It should be noted that this download takes place here, traditionally, through an HTTP URL, but could also take place through a universal address (URI) describing another protocol (dvb: // monsegmentdecontenu for example).

It is assumed here that the HDMI key 8 is connected to the television 5 by connection to the latter's HDMI port, and is used to restore, on the television screen 5, a television program broadcast live, which therefore does not have, by nature, no predetermined duration or end date. Subsequently, this television program is designated by the name of content C1. Such content C1 is described in a manifest file 7.

As a variant, it will be noted that the content C1 can also be a television program broadcast on deferred time, or a video on demand, or a personal video of the user, or any other multimedia content of fixed duration, for which the invention s also applies.

In this example, the HDMI 8 key is connected by WiFi® directly to the residential gateway 6. As a variant, the HDMI 8 key could also be connected by WiFi® to another mobile device on the home network, for example to the laptop 4 or the smart phone 3, through which it could access the extended communications network 1.

The HDMI 8 key can also be controlled by the user using the smart phone 3, on which a software application for controlling the HDMI 8 key is installed.

The fragments of content obtained by the residential gateway 6 are for example transmitted via WiFi® to the HDMI key 8, which controls their display on the screen of the television set 5, for restitution to the user.

FIG. 2 represents an architecture of a real-time multimedia stream reader terminal according to an embodiment of the invention, for example the HDMI key 8 of FIG. 1.

It conventionally includes memories M associated with a processor CPU. The memories can be of the ROM (from the English "Read Only Memory") or RAM (from the English "Random Access Memory") or even Flash. The HDMI key 8 communicates with the local network 10 and the extended Internet network 1 via the WIFI module for local wireless communication with the residential gateway 6 or another communication terminal of the local network 10, for example the smart phone 3. The HDMI 8 key further includes an adaptive HAS progressive download module capable of requesting a progressive download of one of the contents to one of the qualities offered in a description file 7. This description file 7 can be saved for example in the memories M of the HDMI 8 key or be outside.

The HDMI 8 key also includes a progressive reduction module for the quality of RED_Q content, which controls the HAS adaptive progressive download module, in order to force the latter to request a progressive download of the content at a quality, offered in the file description 7, lower than the optimal quality to which it could claim, in the case where no user interaction has been detected for a predetermined period of time, for example three hours.

The HDMI 8 key according to the invention can also contain other modules such as a hard drive not shown for storing video fragments, a module for controlling access to content, a module for processing orders received from a tablet or a smartphone on which the application for controlling the HDMI key is installed, thanks to which the user can control its operation, etc. Indeed, such an HDMI 8 key generally does not contain an I / O interface module, and it is the I / O interface module of the user's smart phone or tablet that is used by the user. to choose for example its content.

The HDMI key 8 also includes an INT module for managing the interface with the television 5, by which it obtains, for example, information on the possible interactions of the user with the television 5 (action on the remote control of the television, for example by press the volume key or a channel change key), and by which it can control the display on the TV screen 5 of pop-up windows, allowing it to deliver messages or alerts to the user.

It will be noted that the term module can correspond as well to a software component as to a hardware component or a set of hardware and software components, a software component corresponding itself to one or more computer or computer programs or subroutines. 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 (or hardware) capable of implementing a function or a set of functions for the module concerned (integrated circuit, smart card, memory card, etc. .).

More generally, such an HDMI 8 key comprises a random access memory (for example a RAM memory), a processing unit equipped for example with a CPU processor, and controlled by a computer program, representative of the progressive download management module. adaptive HAS, stored in a read only memory (for example a ROM memory or a hard disk). On initialization, the code instructions of the computer program are for example loaded into the RAM before being executed by the processor CPU of the processing unit. The RAM contains in particular the manifest description file 7. The processor of the processing unit controls the evaluation of the presence or absence of user interactions with the HDMI key 8 or the television 5, l display of pop-up windows on the television screen 5, and the gradual reduction in the quality of the downloaded content, through the choice of the time segments and associated encoding bit rates to download, and the issuance of corresponding commands to the HAS client module.

FIG. 2 illustrates only one particular way, among several possible, of producing the HDMI key 8, so that it performs the steps of the method detailed below, in relation to FIG. 3 (in any of the different modes of embodiment, or in a combination of these embodiments). Indeed, these steps can be carried out indifferently on a reprogrammable calculation machine (a PC computer, a DSP processor or a microcontroller) executing a program comprising a sequence of instructions, or on a dedicated calculation machine (for example a set of logic gates like an FPGA or an ASIC, or any other hardware module).

We now present, in relation to FIG. 3, an example of optimized and gradual cut-off of a multimedia stream obtained in adaptive progressive download mode by a real-time multimedia stream reader terminal 30, for example the HDMI key 8 of FIGS. 1 and 2.

The real-time multimedia stream reader terminal 30 is connected to a television set TV 5, via an HDMI link. It includes an INT module for interfacing with the television 301, a RED_Q module 302 for gradually reducing the quality of downloaded content, and a HAS client module 303.

A HAS 2 content server exposes a video Cl in the form of “chunks” Cli @ Nj encoded at different encoding rates Nj, where the index i denotes a temporal identifier of the “chunk” Cl, ®Nj.

According to the prior art, a HAS client module is responsible for retrieving its “chunks” from the HAS 2 content server by choosing the video quality Nj as a function of the available network resource. We do not describe here in more detail how the HAS client module chooses the encoding bit rate of the next video fragment to download: there are indeed many algorithms allowing this choice to be made, whose strategies are more or less secure or aggressive. It is recalled, however, that, more often than not, the general principle of such algorithms is based on the downloading of a first fragment at the lowest encoding bit rate proposed in the manifest, and on the evaluation of the recovery time of this first fragment . On this basis, the HAS client module assesses whether, depending on the size of the fragment and the time taken to recover it, the network conditions allow the next fragment to be downloaded at a higher encoding speed. Some algorithms are based on a gradual increase in the quality level of the fragments of content downloaded; others propose riskier approaches, with jumps in the levels of the encoding rates of successive fragments.

In the classic case, if a video “chunk” lasts 3 seconds, the recovery of the “chunk” by the HAS client module must not exceed 3 seconds, in order to allow an uninterrupted restitution of the content by the terminal 30. It is therefore appropriate for the HAS client module to operate the best compromise between a quality of restitution, and therefore an encoding bit rate, as high as possible, and the download time of the fragment, which must be sufficiently low to allow a continuous restitution on the TV 5.

In the embodiment illustrated in FIG. 3, on the other hand, the HAS 303 client module may not command the downloading of the fragment at the optimal encoding rate, in order to optimize the consumption of network resources, in the case where one suspects that the user is not present in front of the television screen 5, as described in more detail below.

During a step referenced 310, the HAS module 303 recovers the manifest file 7 in order to discover the available fragments of the video content C1, and the various video qualities Nj associated. In the example of FIG. 3, the content C1 is for example proposed in the form of fragments of duration 3 s, with a first encoding bit rate NI = 500 kb / s, a second encoding bit rate N2 = 1000 kb / s , a third encoding bit rate N3 = 2000 kb / s, etc.

In a normal operating mode, not illustrated in FIG. 3, the HAS 303 module downloads, for example, successive Cli @ Nl fragments (ie the first time fragment at an encoding rate of 500 kb / s), then C1 ₂ @ N3 (i.e. the second time fragment at an encoding speed of 2000 kb / s), then C1 ₃ @ N3 (i.e. the third time fragment at an encoding speed of 2000 kb / s), ...

The different fragments downloaded by the HAS client module 303 are transmitted to the INT interface module 301 for their restitution to the user on the screen of the television set TV 5.

The algorithm implemented by the HAS 303 client module to determine which fragment at which encoding rate must be downloaded in normal operating mode (that is to say outside of the periods when it is controlled by the RED_Q module 302 progressive reduction in quality) may be one of the already existing algorithms of the prior art. This algorithm will therefore not be described here in more detail.

In parallel, in accordance with FIG. 3, the INT module 301 monitors the interactions of the user with the television 5, and receives for example, via the HDMI port, information relating to the actions carried out by the user on the remote control of the television. 5 and on the television 5 itself. It transmits this information to the RED_Q module 302, which also receives information relating to the possible interactions of the user with the terminal 30 itself, via its remote control or a smartphone or tablet type control terminal.

With each interaction information received, the RED_Q 302 module initiates a counter, or "timer", for example of a duration of two or three hours. Meanwhile, the download of successive time fragments of the content by the HAS module 303 continues, according to a conventional adaptive progressive download algorithm. If, at the expiration of this “timer”, no new interaction information has been received, it can be assumed that the user is no longer present in front of the television screen 5, and that the downloading of the content Cl unnecessarily consumes network resources.

The RED_Q 302 module then sends a command to the INT 301 interface module, to control the display on the television screen 5 of a pop-up window, in which a message is displayed, intended for the user, informing him that without action on his part, for example within sixty seconds, the quality of restitution of the content C1 on the screen of the television set 5 will gradually decrease.

If the user reacts, for example by pressing a button on the remote control of the television set 5, the interface module INT 301 receives the corresponding information, and transmits it to the module RED_Q 302: the client module HAS 303 then continues to download the time fragments of the content in a conventional manner.

If, on the other hand, the user does not appear within sixty seconds following the display of the pop-up window on the television screen 5, the RED_Q 302 module sends a command to the HAS 303 client module, in order to force this the latter to gradually reduce the quality of the temporal fragments of downloaded content, in order to reduce the consumption of network resources.

Thus, as illustrated in FIG. 3, the HAS 303 client module will successively download (312) the fragments C1 ₂ @ N4, C1 ₃ @ N3, C1 ₄ @ N2 and C1 ₅ @ N1, to reduce the quality of content reproduction Cl, as illustrated by the arrow referenced 311, up to the lowest quality proposed in the manifest 7, corresponding to a speed of 500 kb / s.

In practice, the reduction 311 of the encoding rates of the temporal fragments is not as rapid, but is spread over time, for example over a period of one hour. Figure 3 therefore corresponds to a simplified illustration of this principle, allowing it to be understood visually. For example, the HAS 303 client module controls the downloading of successive time fragments at quality level N4 for a period of fifteen minutes, then lowers this level by downloading time fragments at quality level N3 during the following quarter of an hour, and so on, until reaching the lowest NI quality level provided for in manifest 7, after about an hour.

If, at the end of this second time period of one hour, for which the RED_Q 302 module has initiated a second “timer”, no new user interaction has been detected, it sends a command to the module d INT 301 interface, for display on the screen of the television 5 of a pop-up window informing the user that the cut of the flow is imminent and that, without interaction on his part within sixty seconds for example, the download of the Cl content will be interrupted. At the end of these sixty seconds, the RED_Q module 302 sends the HAS client module 303 a command to interrupt the downloading of the content C1, which is executed: the unnecessary consumption of network resources then stops.

If, on the other hand, at any time during this second time period, or following the display of this pop-up window, the user manifests his presence by operating the remote control of the television 5, or by action on the smartphone 3 controlling the terminal 30, the RED_Q module 302 sends the HAS client module 303 a return to normal command. The 5 HAS 303 client module then determines, according to the network conditions, the optimal bit rate bit rate it can claim, and starts downloading the next fragment at this optimal bit rate: in the example of figure 3, the client module HAS 303 then downloads the time fragment C1 ₆ @ N5.

APPENDIX 1: example of manifest file <? Xml version = 1.0?>

<MPD xmlns: xsi = http: //www.w3.org/2001/XMLSchema-instance xmlns = urn: mpeg: DASH: schema: MPD: 2011 xsi: schemaLocation = urn: mpeg: DASH: schema: MPD: 2011 DASH -MPD.xsd type = dynamic profiles = urn: mpeg: dash: profile: isoff-live: 2011> Representation id = 0 codecs = avc1 mimeType = video / mp4 width = 1024 height = 768 startWithSAP = 1 bandwidth = 46986>

<BaseURL> HTTP://server.com / </ BaseURL>

<! - Content C1 to N1 = 512kb ->

<SegmentBase>

initialization sourceURL = Cl_l5sec_512kb / Cl_5l2kbit_dash.mp4 />

</ SegmentBase>

<SegmentList duration = 10>

<Media segmentURL = C1_512kb_1 .mp47>

<Media segmentURL = C1_512kb _2.mp47> ....

</ SegmentList>

<! - Content C1 to N2 = 1024kb ->

<SegmentBase>

initialization sourceURL = Cl_15sec_500kbit / Cl_1024kbit_dash.mp4 />

</ SegmentBase>

<SegmentList duration = 10>

<Media segment = C1_512kb_1 .mp47> ....

</ SegmentList>

<! - Content C1 to N3 = 2048kb ->

<SegmentBase>

<Initialization sourceURL = Cl_l5sec_512kb /Cl_2048kbit_dash.mp4/> </SegmentBase>

<SegmentList duration = 10>

<Media SegmentURL = C1 _2048kb_1 .mp47> ...

</ SegmentList>

<! - Content C2 to N1 = 512kb ->

<SegmentBase>

<Initialization sourceURL = C2_15sec_500kbit / C2_512kbit_dash.mp4 /> </SegmentBase>

<SegmentList duration = 10>

<Media segment = C2_512kb_1 .mp47> ....

</ SegmentList>

<! - Content C2 to N2 = 1024kb ->

<SegmentBase>

<Initialization sourceURL = C2_15sec_500kbit / Cl_1024kbit_dash.mp4 /> </SegmentBase>

<SegmentList duration = 10>

<Media segment = C2_1024kb_1 .mp47> ....

</ SegmentList>

<! - Content C2 to N3 = 2048kb ->

<SegmentBase>

<Initialization sourceURL = C2_15sec_500kbit / Cl_2048kbit_dash.mp4 /> </SegmentBase>

<SegmentList duration = 10>

<Media segmentURL = C1_2048kbit_1 .mp47> ...

</ SegmentList>

</ SegmentList>

</ MPD>

Claims (10)

1. Method for managing the adaptive progressive download (HAS) of digital content (Cl) within a real-time multimedia stream reader terminal (8; 30), in a local communication network (2), said real-time multimedia stream reader terminal being associated with a terminal for rendering (5) said digital content, characterized in that at the end of a first period of determined duration of absence of interaction by a user of said digital content with said real-time multimedia stream reader terminal and / or with said terminal for rendering said digital content, it implements a progressive reduction (311) in the quality of reproduction of said downloaded digital content, on said reproduction terminal . 2. Management method according to claim 1, characterized in that, said digital content being associated with a description file (7) of said digital content, comprising a list of time segments (Cli @ Nj) of said content each associated with several bit rates encoding said content, said progressive reduction (311) of a quality of restitution of said downloaded digital content is based on a download of time segments of said content associated with decreasing encoding rates over time. 3. Management method according to any one of claims 1 and 2, characterized in that said progressive reduction is accompanied by the display, on said rendering terminal, of an alert message intended for said user and relating to said progressive reduction in quality of restitution. 4. Management method according to any one of claims 2 and 3, characterized in that, upon detection of an interaction of said user with said terminal reader of multimedia stream in real time and / or with said terminal for rendering said digital content , said progressive reduction in quality of restitution is interrupted and said method implements a downloading of time segments of said content associated with encoding bit rates optimized as a function of a resource constraint estimated by said terminal for streaming media streams in real time . 5. Management method according to any one of claims 1 to 4, characterized in that at the end of a second period of determined duration of absence of interaction of said user with said terminal multimedia player time stream real and / or with said rendering terminal of said digital content, it implements a display, on said rendering terminal, of an information message of the next interruption in downloading of said digital content and, in the absence of said user interacts with said real-time multimedia stream reader terminal and / or with said playback terminal resulting from said display, an interruption of said download. 6. Management method according to any one of claims 1 to 5, characterized in that said interaction of said user with said multimedia player terminal in real time and / or with said terminal for rendering said digital content implements a terminal for control of said terminal. 7. A computer program product comprising program code instructions for implementing an adaptive progressive download management (HAS) method of digital content according to any one of claims 1 to 6, when it is executed by a processor. 8. Device for managing the adaptive progressive download (HAS) of digital content within a real-time multimedia stream reader terminal, in a local communication network, said real-time multimedia stream reader terminal being associated with a terminal for restoring said digital content, characterized in that it comprises a module for progressive reduction (302) of a quality for restitution of said digital content downloaded, to said restitution terminal, activated at the end of a first period for a fixed period of time when a user of said digital content does not interact with said real-time multimedia stream reader terminal and / or with said terminal for rendering said digital content. 9. Management device according to claim 8, characterized in that, said digital content being associated with a description file of said digital content, comprising a list of time segments (Cl, @ Nj) of said content each associated with several bit rates encoding of said content, said module for progressive reduction of a quality of restitution of said downloaded digital content comprises means for transmitting commands for downloading time segments of said content associated with encoding rates decreasing over time. 10. Real-time multimedia stream reader terminal, characterized in that it includes a device for managing the adaptive progressive download (HAS) of digital content according to claim 8 or 9.