WO2021105585A1

WO2021105585A1 - Method for managing a list of contents accessible for zapping, the digital contents being downloadable in an http adaptive streaming (has) mode, and corresponding management device, multimedia stream reader and computer program

Info

Publication number: WO2021105585A1
Application number: PCT/FR2020/052109
Authority: WO
Inventors: Hervé Marchand; Mathieu Rivoalen
Original assignee: Orange
Priority date: 2019-11-29
Filing date: 2020-11-18
Publication date: 2021-06-03
Also published as: EP4066512A1; FR3103988A1

Abstract

The invention relates to a method for managing a list of contents accessible for zapping, the digital contents being downloadable in an HTTP adaptive streaming (HAS) mode by a multimedia stream reader terminal. Said digital contents are each associated with a description file comprising a list of time segments of the contents, each time segment being associated with multiple encoding rates of the contents. Said zapping management method involves: - receiving a request to access a list of the digital contents; - obtaining description files associated with the digital contents in the list; - determining a maximum rate for encoding the time segments of the digital contents accessible for downloading, on the basis of a resource constraint obtained by the multimedia stream reading terminal; - creating an enhanced list of contents in which at least one of the digital contents is associated with a playback quality indicator assigned to the content on the basis of the determined maximum encoding rate.

Description

DESCRIPTION

TITLE: Method for managing a list of content accessible by zapping, the digital content being downloadable in adaptive progressive download mode (HAS), management device, multimedia stream player and corresponding computer program

Technical field of the invention.

The field of the invention is that of digital multimedia content, namely digital audio and / or video content, and more particularly digital multimedia content obtained according to a technique known as adaptive progressive downloading (HAS) within a network of local communication, such as a home network.

More precisely, the invention relates to the optimization of the zapping from one digital multimedia content to another, that is to say the abandonment of the consumption of a first digital multimedia content to switch to a new multimedia content. digital, within a multimedia stream reader terminal.

Prior art.

Access to digital multimedia content, such as television or video on demand, from an Internet-type network, is possible today for most client 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 chosen, and in return it receives 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 back. This restitution consists in providing the digital content at the level of the terminal in a form accessible to the user. For example, data received corresponding to a video is generally decoded, then restored at the level of the terminal in the form of a display of the corresponding video with its associated soundtrack. In the following, for the sake of simplification, we will assimilate the digital content to a video and the restitution by the terminal, or consumption by the user of the terminal, when viewed or read on the terminal screen.

The distribution of digital content on the Internet is often based on client-server protocols of the HTTP family (from the English "Hyper Text Transfer Protocol", for "hypertext transfer protocol"). In particular, the progressive downloading of digital content, also called streaming, makes it possible to transport and consume the data in real time, that is to say that the digital data is transmitted over the network and returned by the terminal as it goes. and as they arrive. The terminal receives and stores part of the digital data in a buffer memory before returning them. This mode of distribution is particularly useful when the speed available to the user is not guaranteed for real-time transfer of video.

Adaptive progressive downloading, in English HTTP Adaptive Streaming, abbreviated HAS, also makes it possible to broadcast and receive data in 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 right format for the content to be consumed according to the available bandwidth or the storage and decoding capacities of the client terminal. This type of technique makes it possible in particular to take account of the 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 solutions Microsoft® Smooth Streaming, Apple® HLS, Adobe® HTTP Dynamic Streaming or even the MPEG-DASH standard of the ISO / IEC which will be described below. These methods propose to send the customer one or more intermediate description files, also called documents or manifests, containing the addresses of the different segments with different qualities of the multimedia content.

Thus, the MPEG-DASH standard (for English “Dynamic Adaptive Streaming over HTTP”, in French “dynamic adaptive streaming over HTTP”) is a standard of audiovisual broadcast format on the Internet. It is based on the preparation of the content in different presentations of varying quality and speed, cut into short 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 predominantly targeted protocol is HTTP, but other protocols (eg FTP) can also be used. The organization of the segments and the associated parameters are published in a manifest in XML format.

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

- ensures the best possible quality,

- and allows a reception delay compatible with the uninterrupted rendering of the content.

Thus, to adapt to variations in network conditions, particularly in terms of bandwidth, existing adaptive downloading solutions allow the client terminal to switch from one version of the content encoded at a certain speed, to another encoded at a certain speed. other speed, during the download. This is because each version of the content is divided into segments of the same duration. To allow continuous playback of the 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 longer transmission time, and therefore present an increased risk of not being received on time. continuous restitution of content.

The client terminal must therefore find a compromise between the overall quality of the content, and its uninterrupted reproduction, by carefully selecting the next segment to download, among the various encoding 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 have more or less aggressive, or more or less secure, strategies. In other words, in order to ensure a certain fluidity during reading, if the available bandwidth does not allow access to the best broadcast quality, the client terminal will use data streams of poorer quality. This technique thus makes it possible to offer the best possible video quality while guaranteeing smooth reading or viewing of digital content.

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

In addition, other devices such as real-time media streaming 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® TV Stick®. Such devices are conventionally connected to the HDMI port of a television set and communicate, by Wi-Fi® connection, with another device of the home communication network connected to an extended communication network such as the Internet (residential gateway, computer, telephone smart device (smartphone, tablet, etc.), in order to reproduce, on the television, the multimedia content received by a compatible software application. These devices will be referred to below under the generic designation of HDMI Key.

In the following, for the sake of simplification, the term “client terminal” will be assimilated to the association of a multimedia stream reader terminal (for example HDMI key) and of a playback terminal (for example a television set) making it possible to view the content. It will be noted that the rendering terminal can be the multimedia stream reader terminal itself (for example an intelligent mobile telephone, a tablet), or be distinct from this one (for example a television connected to an HDMI key, or to a set-top box (STB)).

When a user uses the services of such digital content servers, he may wish to quickly switch from one digital content to another: this is called "zapping".

Indeed, by "zapping" (in French "channel jump") is meant the fact that the user abandons the consumption of digital multimedia content (for example a first program, or a first television channel) to switch to a other digital media content (for example another program or another channel) in a fast way.

In the present application, the term “zapping” is extended to any change of digital multimedia content obtained in HAS to another. In a first example, this can be from digital multimedia content broadcast LIVE (in French in "real time") to another, such as for example from one television channel to another. In a second example, it could be from one VOD-type digital media content to another, such as from one episode of a series to another episode of the same series. It can also be the switch from real-time content to delayed content, for example from a LIVE television program to a delayed replay type program, or to video on demand.

In this context of HAS adaptive progressive downloading, and in particular in the context of OTT type services (or over-the-top service, for "Over-The-Top service" in English), the user is not informed of the quality. restitution, that is to say of the display quality or resolution, of a digital content when it wishes, while viewing a first content, to zap for new digital content. In fact, in the context of OTT type services, the availability of bandwidth for downloading and restoring digital content is not guaranteed. In addition, in the context of downloading using HAS, the characteristics of the digital content consumed are not known in advance. These will in fact depend on the qualities available (set out in the manifest file specific to each of the contents), as well as on the bandwidth available between the content server and the client terminal. Thus, when the user wishes to switch to new digital content, he does not know with what quality of reproduction he will be able to obtain and view it. In particular when he selects the content he wishes to view from a list of accessible content, presented on the screen of his playback terminal, (also called virtual zapping list or VZL (in English "Virtual Zapping List" )), no information on the quality of restitution of the content accessible by zapping is provided to it. Thus, when the user uses a VZL to select new digital content to be viewed, he cannot distinguish, for example, between digital content broadcast in high definition, or in standard definition.

Consequently, the user does not know the qualities of restitution to which he can claim. He cannot anticipate how well new content will be rendered and may be disappointed with its quality. However, this quality can condition his choice of zapping.

This lack of information on the quality of content reproduction is all the more detrimental to the user's experience since it is information to which he may have been used to accessing, in as part of a subscription with an internet service provider, in which the availability of bandwidth for downloading and playing back digital content depends only on the user's subscription contract with his internet service provider. Internet. Thus, a user subscribed to low-speed ADSL ("Asymmetric Digital Subscriber Line") can only view digital content at a so-called standard definition (SD) reproduction quality. On the contrary, a user having a broadband ADSL type subscription can view digital content in high definition (HD).

In this context of historical service offers such as IP TV (standing for Internet Protocol Television) or TNT (Digital Terrestrial Television), the quality of reproduction is thus displayed to the user during zapping. of real-time content to which it will access. This information tells the user whether the content to be accessed is SD (“Standard Definition”), HD (“High Definition”) or UltraHD (“Ultra High Definition” or 4K) content. The display of this information is possible because the characteristics of the consumed content are known. Indeed, the network resources are managed according to the user's line and his subscription with his Internet service provider. It is therefore possible to predict the quality of reproduction of different digital content and to inform the user thereof, since this is guaranteed by the internet service provider. Thus, when the user selects new content to be viewed in a VZL type list, he is informed of the quality of reproduction to which he can claim for all or part of the contents of the list, ideally each of the contents. This information may for example take the form of a logo associated with digital content and representing a quality of reproduction. He can therefore choose new content to view with full knowledge of the facts.

There is therefore a need for a technique for managing zapping of digital content obtained by adaptive progressive downloading (HAS) during zapping, which does not have these various drawbacks. In particular, there is a need for such a technique which makes it possible to inform the user in real time about the quality of reproduction of digital content accessible for download, and thus to improve his quality of experience, in particular by taking advantage of the technical specificities. Adaptive Progressive Download (HAS).

Presentation of the invention

The invention responds to this need by providing a method for managing a list of content accessible by zapping, the digital content being downloadable in adaptive progressive download (HAS) mode by a multimedia stream reader terminal. These digital contents are respectively associated with a description file, comprising a list of time segments of the contents each associated with several content encoding rates.

This zapping management process includes:

- receipt of a request for access to a list of digital content,

- obtaining the description files associated with the digital contents of the list,

a determination of a maximum encoding rate of the time segments of the digital content accessible for download as a function of a resource constraint obtained by the multimedia stream reader terminal, a construction of an enriched list of contents, in which at least one of the digital contents is associated with a reproduction quality indicator assigned to the content as a function of the determined maximum encoding rate.

Thus, the invention is based on a completely new and inventive approach to the management of zapping between several digital contents exposed in a virtual zapping list or VZL (in English "Virtual Zapping List"), in an adaptive progressive download context. . More particularly, the invention proposes to enrich the list of accessible contents provided to the user, by adding an indicator of quality of restitution to at least one of the contents: this indicator is determined according to a joint analysis of the files of description of the contents on the one hand, and of the resource constraints obtained by the multimedia stream reader terminal on the other hand. Indeed, the quality of restitution of the contents to which the user can claim depends on a maximum encoding rate of the time segments determined for each of the contents as a function of a resource constraint obtained by a multimedia stream reader terminal, such as, for example, a bandwidth constraint.

Thus, when the user issues, during the restitution of a first digital content, a command to access the list of content accessible for zapping, the digital media stream reader terminal receives it and requests it from the server. contents, the manifest description files of the various contents available for download. It then compares the encoding rates of the time segments exposed in the description file of each of these contents, with the encoding rates allowing uninterrupted restitution of the content, as a function of the bandwidth available at the present time and of the availability of the content server. Indeed, the multimedia stream reader terminal knows the current bandwidth constraints, according to the conventional HAS technique. At the end of this comparison, a maximum encoding rate of the time segments of the contents exposed in the VZL, accessible for download for a smooth reproduction, is then determined for each of these contents.

It is then possible to build an enriched list of content, in which each content is recorded in association with a quality indicator. restitution, which is chosen according to the maximum encoding rate which has been determined for the content.

It will be noted that, by reproduction quality, we mean the display quality, or resolution, of the digital content on a reproduction terminal, such as for example a television set. In one example, the so-called standard definition or SD (“Standard Definition”) quality represents a resolution of 720 × 576 pixels. In another example, the so-called high definition or HD resolution represents a resolution of 1280 x 720 pixels, the so-called "Full HD" definition represents a resolution of 1920 x 1080 pixels, and the so-called "definition". Ultra HD ”represents a resolution of 3840 x 2160 pixels, and the definition known as“ Ultra HD 4 K ”represents a resolution of 4096 x 2160 pixels.

Thus, in our example, for each of the digital content exposed in the VZL virtual zapping list, a reproduction quality indicator is associated with it, in order to be returned to the user. The user then knows in real time the quality of playback of several content exposed in the VZL at the time of issuing the zapping command and can therefore choose the new content to view based on its accessible quality of playback.

In other words, the invention proposes, during the zapping phase, to provide information on the quality of reproduction (SD, HD or UHD) to the user, in the form of a label associated with each one. of the contents of the VZL, in order to indicate to him the quality of restitution of the contents to which he can claim. For this, when zapping in the VZL, as for example on the HDMI Key, the terminal knows the bandwidth to which it has access and retrieves the manifest files of each digital content exposed in the VZL. We therefore retrieve the manifest file of all the content of the VZL, even if the user ultimately does not zap this content.

Thus, it is possible to know the characteristics of the different encoding qualities of the content exposed by the content server. The terminal, for example the HDMI key, will then compare chain by chain the quality of encoding of the digital contents exposed in the manifest file and the available bandwidth, in order to determine for each of the contents the encoding rate. maximum content that will be accessible for download for a smooth and uninterrupted return of the content to the user.

According to a particular aspect, the method according to the invention further comprises a display of said enriched list of content on a playback terminal.

It will be noted that, as indicated above, this rendering terminal can be the multimedia stream reader terminal itself, or be distinct from the latter. In the latter case, the multimedia stream reader terminal transmits the enriched list of contents to the rendering terminal, for display on a screen of the latter.

The method according to one embodiment of the invention therefore makes it possible to optimize the quality of experience of the user, by informing him in real time of the quality of restitution of several digital contents exposed in a VZL and on which he can zap, thanks to the association of these contents with an indicator of quality of reproduction.

In a first example, in the context of digital content broadcast in real time (or "LIVE" in English) in HAS, the method according to the invention allows the user, at the time of the transmission of his command to zapping, to differentiate the contents displayed in the VZL by their quality of reproduction thanks to the display of a quality indicator for each content. The user can then choose a digital content on which he will zap, knowing the quality of reproduction to which he can claim.

In a second example, in the context of digital content of the VOD type, the enriched list of content may present two occurrences of the same content, but associated with two different rendering quality indicators, and accessible for example at two different prices. The user can then decide, for example, to access the more expensive version of the content, knowing that this price difference is justified by a better quality of accessible reproduction.

In another example, the user can also decide to subscribe to a cinema package if he knows that he has access to digital content in high definition (HD), or even in ultra high definition (UHD or 4K). .

Thus, the method according to the invention allows the user to know in real time the quality of reproduction to which he can claim for several contents exposed in a VZL according to the bandwidth at the time of the emission of a zapping command and thus to be able to make an informed choice among a set of digital contents offered.

According to another aspect of the invention, the rendering quality indicator is displayed in the form of an information label belonging to the group comprising: a graphic; a string of alphanumeric characters; a display mode of a thumbnail representative of the associated content.

Thus, on the screen of the rendering terminal, the user sees for example displayed, for each content accessible to zapping, a thumbnail representative of the content and an associated information label.

This information label may for example be in the form of a graphic associated with the content, such as for example a logo representing a resolution. In one example, an SD logo represents standard resolution, an HD logo represents high definition resolution.

In another example, this information tag may be an alphanumeric character string associated with the content, such as a resolution value such as 720p for high definition resolution, 1080p for Full HD resolution.

It can still take the form of a particular display mode of the content thumbnail. For example, one can imagine that the thumbnails of content accessible in HD are displayed larger on the screen than the thumbnails of content accessible in SD. It is also possible to envisage a particular coloring of the images representative of the contents, each shade of coloring being associated with a quality of reproduction.

According to another aspect of the invention, such a method implements an update of the enriched list of contents at determined time intervals and / or in the event of modification of the resource constraint.

A dynamic real-time display of the information label associated with various digital contents displayed in the VZL is thus enabled, which makes it possible to optimize the quality of the user's experience. Thus, if the resource constraints change before the user has made his choice of zapping, updating the displayed list allows him to make an informed choice of the content to which he will switch.

The invention also relates to a computer program product comprising program code instructions for implementing a method for managing a list of contents accessible for zapping, as described above, when it is executed by a processor.

The invention also relates to a recording medium readable by a computer on which is recorded a computer program comprising program code instructions for the execution of the steps of the method of managing a list of contents accessible for zapping according to the invention as described above.

Such a recording medium can be any entity or device capable of storing the program. For example, the medium may comprise 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 conveyed via an electrical or optical cable, by radio or by other means, so that the program computer it contains can be executed remotely. The program according to the invention can in particular be downloaded over a network, for example the Internet network.

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 invention also relates to a device for managing a list of contents accessible for zapping, the digital contents being downloadable in adaptive progressive download mode (HAS) by a multimedia stream reader terminal. These digital contents are respectively associated with a description file, comprising a list of time segments of the contents each associated with several encoding bit rates of the contents. This device for managing a list of content accessible to zapping comprises:

- a module for receiving a request for access to a list of digital content,

- a module for obtaining description files associated with the digital contents of the list,

- a module for determining a maximum encoding rate of the time segments of digital content accessible for download according to a resource constraint obtained by the multimedia stream reader terminal,

- a module for building an enriched list of content, in which at least one of the digital content is associated with a reproduction quality indicator assigned to the content according to the determined maximum encoding rate.

According to a particular aspect of the invention, the device for managing a list of contents accessible by zapping comprises a module for generating a command for displaying the enriched list of contents on a rendering terminal.

Finally, the invention also relates to a multimedia stream reader terminal, comprising a device for managing a list of content accessible by zapping as described above.

The management device, the multimedia stream reader terminal and the corresponding computer program mentioned above have at least the same advantages as those conferred by the method for managing a list of contents accessible for zapping according to the different embodiments of the present invention.

Brief description of the figures

Other aims, characteristics and advantages of the invention will emerge 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]: shows a progressive download architecture over a home network based on the use of adaptive streaming according to one embodiment of the invention;

[Fig 2]: schematically illustrates the hardware structure of a multimedia stream reader terminal incorporating a device for managing a list of content accessible by zapping; [Fig 3]: illustrates an example in the form of a timing diagram of the implementation of a method for managing a list of content accessible by zapping, the digital content being downloadable in progressive adaptive download mode (HAS) by a terminal multimedia stream player according to FIG. 2, associated with a playback terminal;

[Fig 4a]: illustrates a first example of display in a virtual zapping list (VZL) of an information label on a quality of reproduction for each of the digital content exposed;

[Fig 4b]: illustrates a second example of display in a virtual zapping list (VZL) of an information label on a quality of reproduction for each of the digital content exposed.

Detailed description of the invention

The general principle of the invention is based on the enrichment of a virtual zapping list or VZL (in English "Virtual Zapping List"), exposing the contents obtained by adaptive progressive downloading (HAS), with quality indicators of reproduction. digital content.

The quality of restitution of the contents to which the user can claim depends on a maximum encoding rate of the time segments determined for each of the contents as a function of a resource constraint obtained by a multimedia stream reader terminal, such as for example a bandwidth constraint.

Thus, the user then knows in real time the quality of reproduction of several content exposed in the VZL at the time of the issuance of the zapping command and can therefore choose the new content to view according to its quality of reproduction.

In relation to FIG. 1, a progressive download architecture is now presented in a home network based on the use of adaptive streaming according to the invention.

Terminal 3, for example an intelligent telephone of the “smartphone” type, terminal 4, for example a tablet, and terminal 8, for example an HDMI key connected to a television 5, are, in this example, located in a local network (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 company network, etc.

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

The client terminals 3, 4 and the HDMI key 8 in association with the television 5, can enter into communication with the content server 2 to receive one or more content (films, documentaries, advertising sequences, etc.).

It is common, in this client-server context, to use, in order to exchange data between the terminals 3, 4 and 8 and the content server 2, an adaptive progressive download technique, in English "adaptive streaming", abbreviated as HAS based on HTTP protocol. This type of technique makes it possible in particular to offer a good quality of content to the user, taking into account the variations in bandwidth which may occur on the link between the client terminals 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 digital content, 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 split 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 temporal segmentation, as well as the content fragments, are described for the client terminal and made available to it via their Internet addresses (URI: Universal Resource Identifier). The set of these parameters (qualities, addresses of fragments, etc.) is generally grouped together in a parameter file, called a description or manifest file. It will be noted that this parameter file can be a computer file or a set of descriptive information about the content, accessible at a certain address.

Terminals 3, 4 and 8 have their own characteristics in terms of decoding capability, display, etc. In a progressive adaptive download context, they can adapt their requests to receive and decode the content requested by the user at the quality that best suits them. In our example, if the contents are available at 1000 kb / s (kilobits per second) (Quality 1, or level 1, denoted D1), 2,500 kb / s (D2), 5,000 kb / s (D3), 7,500 kb / s (D4) and the client terminal has a bandwidth of 10,000 kb / s, it can request the content at any rate below this limit, for example 5000 kb / s. In general, we denote “C _/ , i @ Dj” the segment number i with the quality j (for example the j-th quality level Dj described in the description file) of the content number n.

The service gateway 6 is in this example a home gateway which ensures the routing of data between the wide area network 1 and the local network 10 and manages the digital content, in particular ensuring their reception from the wide area network 1.

The terminals 3, 4 and 8 receive the data coming from the extended network 1, via the domestic gateway 6, and ensure their decoding, and possibly their reproduction on their screen, or in the example of the HDMI key 8 on the television 5 associate. In one variant, the terminals 3 and 4 transmit these data to the HDMI key 8 for reproduction on the screen of the television 5. In another variant, the decoder can be located elsewhere in the extended 1 or local 10 network, in particular at the level an STB type element (standing for Set-Top-Box) (not shown) associated with a television 5.

In this example, to view a content, the terminals 3, 4 or 8 first of all interrogate the service gateway 6 to obtain an address of the description document 7 of a first desired digital content C1. The service gateway 6 responds by providing 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- standard. DASH (denoted "C.mpd") and one will refer indifferently, according to 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 be already 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 (N1 = 512 kb / s, N2 = 1024 kb / s, N3 = 2048 kb / s) of the contents fragmented is presented in Annex 1. This simplified manifest file describes digital content in XML syntax (from the English “eXtended Markup Language”), comprising a list of content in the form of fragments conventionally described between an opening tag (<SegmentList> ) and a closing tag (</SegmentList>). Cutting into fragments makes it possible in particular to adapt finely to fluctuations in bandwidth. Each fragment corresponds to a certain duration (“duration” field) with several quality levels and allows 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. :

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

"C1_512kb_2.mp4" for the second fragment, and so on.

Once it has the fragment addresses corresponding to the desired content, Service Gateway 6 proceeds to obtain the fragments by downloading to these addresses. Note 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: // my content segment for example).

It is assumed here that the HDMI 8 key is connected to the television 5 by connection to the latter's HDMI port, and is used to reproduce, on the screen of the television 5, a content Cn (n being an integer representing the n-th content viewed), described in a manifest file 7. It will be noted that the content Cn can be a television program broadcast live or on a delayed basis (such as for example a film, a series , a television program, an advertising sequence, etc.), or a video on demand, or any other digital multimedia content.

In one example, a user wishes to view multimedia digital content, such as a film, on his television 5 connected to an HDMI key 8. The HDMI key 8 is connected via WiFi® directly to the residential gateway 6. As a variant, the HDMI key 8 could also be connected via WiFi® to another mobile device in the home network, for example to the tablet 4 or to the smart phone 3, through which it could access the extended communication network 1.

The HDMI 8 key can also be controlled by the user by means of the smartphone 3, on which a software application for controlling the HDMI 8 key is installed.

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

FIG. 2 represents an architecture of a multimedia stream reader terminal 9, or stream reader 9, according to one embodiment of the invention. This stream reader terminal 9 can be for example the HDMI key 8, or the smart phone 3 of FIG. 1. As a variant, this stream reader 9 is integrated at the level of an STB type element associated with a television set (not represented). The example of the HDMI 8 key is described more specifically below.

The stream reader terminal 9 conventionally comprises memories MEM associated with a processor CPU. The memories can be of the ROM type (standing for “Read Only Memory”) or RAM (standing for “Random Access Memory”) or else Flash. The multimedia stream player 9 comprises an adaptive HAS progressive download module, or HAS client module, capable of requesting a progressive download of one of the contents with one of the qualities offered in one of the description files Mn (n being an integer representing the n-th file manifest associated with the n-th content denoted Cn). This description file Mn can be recorded for example in the memories MEM of the multimedia stream player 9 or be located outside. The HAS download module is also able to obtain several manifest files of several different digital contents, when the latter is controlled by the ZAP zapping module of the multimedia stream player 9. More particularly, the pilot ZAP zapping module, via the HAS download module, obtaining manifest files of digital content exposed in a virtual zapping list or VZL.

The ZAP zapping module allows a user to zap, that is, to abandon the consumption of one digital content and switch to another quickly. Such a ZAP zapping module is able to receive a zapping request, and more particularly a request to display a virtual zapping list or VZL for zapping, when the user issues a zapping command, for example by means of a remote control associated with the television 5, or by action on an interface of the smart phone 3 or of the tablet 4. This VZL list exposes several digital contents to the user, thus allowing him to choose among several different contents and to switch to either of these contents.

The multimedia stream player 9 also comprises a module for determining a maximum encoding rate of the time segments of the digital contents exposed in the VZL as a function of a resource constraint and a module for building an enriched list (CONST ), or CONST construction module. When implementing a zapping by the ZAP zapping module, and more particularly when a request to display the VZL for zapping, the ZAP zapping module controls the HAS download module, in order to force the latter to request the obtaining of the manifest files denoted Mn, respectively associated with the digital contents Cn exposed in the VZL. The determination module DET evaluates the encoding rates of the time segments of the digital contents of the VZL proposed in these various manifest files as a function of the bandwidth available at the time of zapping and then determines, as a function of the bandwidth measured continuously by the HAS download module, the maximum encoding rate of the time segments exposed in the manifest files of the contents of the VZL that it is possible to download for a smooth and uninterrupted reproduction of the contents. The CONST construction module then builds an enriched list of contents, in which all or part of the contents of the VZL is associated with an indicator of quality of restitution. The quality of reproduction depends on the maximum encoding rate of the time segments of the contents of the VZL determined by the determination module DET.

The multimedia stream player 9 also comprises a module for generating a display command TRANS, or module TRANS, to a display terminal, such as for example the television set 5, of the enriched list of contents, containing the quality indicators. restitution. The TRANS module transmits the enriched list of contents to the rendering terminal, for display on a screen of the latter. In the case where the multimedia stream player 9 is merged with the rendering terminal (example of the smart phone 3), this TRANS module manages the display of the enriched list of contents for its rendering to the user.

The multimedia stream player 9 according to one embodiment of the invention can also contain other modules (not shown) such as a hard disk for storing video fragments, a module for controlling access to content, a module for processing of commands received from a remote control, or from a tablet, from a smartphone on which the application for controlling the stream reader 9 is installed, thanks to which the user can control its operation, etc.

In the example where the stream reader terminal 9 is the HDMI key 8, this one generally does not contain an I / O interface module, and it is the I / O interface module of the smartphone 3 of the user or his tablet 4, or the television 5, which is used by the latter to choose for example its content.

It will be noted that the term module can correspond just as well to a software component as to a hardware component or a set of hardware and software components, a software component itself corresponding to one or more computer programs or subroutines 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. In the same way, a hardware component corresponds to any element of a hardware set (or hardware) capable of implement a function or a set of functions for the module concerned (integrated circuit, chip card, memory card, etc.).

More generally, such a stream reader 9 comprises a random access memory MEM (for example a RAM memory), a processing unit equipped for example with a processor CPU, and controlled by a computer program, and comprising code instructions representative of the ZAP zapping, DET determination, CONST construction, generation of a TRANS display command, and the HAS adaptive progressive download management module, 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 random access memory before being executed by the processor CPU of the processing unit.

The random access memory contains in particular the manifest description files Mi to M _n . The processor of the processing unit controls the determination of the maximum encoding rates of the time segments of the contents exposed in the VZL, as a function of a resource constraint obtained by the multimedia stream reader terminal 9, and the identification of the resolution quality of the contents of the VZL according to their maximum encoding rate.

FIG. 2 illustrates only one particular way, among several possibilities, of producing the stream reader terminal 9, so that it performs the steps of the method detailed below, in relation with FIG. 3 (in any one of the different embodiments, or in a combination of these embodiments). Indeed, these steps can be performed either on a reprogrammable computing machine (a PC computer, a DSP processor or a microcontroller) executing a program comprising a sequence of instructions, or on a dedicated computing machine (for example a set of logic gates such as an FPGA or ASIC, or any other hardware module).

In relation to FIG. 3, in the form of a timing diagram, an example of the implementation of a method for managing a list of content accessible to zapping is now presented, the digital content being downloadable in adaptive progressive download mode ( HAS) by a multimedia stream reader terminal, according to one embodiment of the invention. In this example, the stream reader terminal 9 according to FIG. 2 is the HDMI key 8, which controls the reproduction of the digital multimedia content on the associated television 5. The HDMI key 8 therefore comprises a DET determination module, a CONST construction module, a HAS download module, a ZAP zapping module and a module for generating a display command TRANS. The HDMI key 8 can be controlled via a remote control for the television 5 or via a software application for controlling a smart phone 3 or tablet 4.

According to the conventional HAS downloading method, prior to the reproduction of a first digital content C1, the user, via the association of the television 5 and the HDMI key 8, sends a request, which passes through the domestic gateway 6 (not shown), indicating the chosen content to the “HAS” content server 2.

The “HAS” content server 2 then sends in response to this request a data stream representative of the content chosen via the domestic gateway 6 (not shown). The content server “HAS” 2 exposes a digital content C1 in the form of fragments, or “chunks” C1i @ Dj encoded at different encoding rates Dj, where the index i designates a temporal identifier, or position, of the “chunk »C1i @ Dj.

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

In a classic case, if a video “chunk” lasts 4 seconds, the recovery of the “chunk” by the HAS module must not exceed 4 seconds, in order to allow restitution without interruption of the content. It is therefore necessary for the HAS module to operate the best compromise between a reproduction quality, and therefore an encoding rate, as high as possible, and the download time of the fragment, which must be sufficiently low to allow reproduction in continuous on TV 5 for example.

During a step E1, the HAS client module retrieves the manifest file M1 in order to discover the available fragments of the digital content C1, and the various associated video qualities Dj. In this example, the digital content C1 is for example offered in the form of fragments of duration 4s, with a first encoding rate D1 = 1,000 kb / s, a second encoding rate D2 = 2,500 kb / s, a third encoding rate D3 = 5,000 kb / s, a fourth encoding rate D4 = 7,500 kb / s and a fifth encoding rate D5 = 10,000 kb / s.

In a conventional operating mode, the HAS client module downloads, for example, successive C1i @ D1 fragments (i.e. the first temporal fragment at an encoding rate of 1000 kb / s), then C1 ₂ @ D5 (i.e. the second time fragment at an encoding rate of 10 000 kb / s), up to normal mode playback in high quality of a C1i @ D5 video (i.e. the i-th time fragment at an encoding rate of 10,000kb / s).

The algorithm implemented by the HAS client module to determine which fragment at which encoding rate should be downloaded in conventional mode of operation may be one of the already existing algorithms of the prior art. This algorithm will therefore not be described in more detail here.

The various fragments downloaded by the HAS client module are then transmitted in a step E2 to the television 5 via the HDMI key 8, for example for their return to the user.

During the viewing of the first digital content C1, such as for example a film broadcast LIVE on a television channel, on its television 5 associated with the HDMI 8 key, the user can decide at any time to stop viewing to switch to new digital content.

This is the case, for example, when the user is watching a movie and a commercial break interrupts their movie. He can then decide to skip the ad and watch other digital content, for example on another television channel, while waiting to resume his film.

Thus, in a step E3, the user issues a zapping command from a first digital content C1 to new digital content. In this example, the zapping command is a request to display a virtual zapping list, or VZL. The VZL exhibits several digital content, for example different digital LIVE content broadcast on different television channels or video on demand VODs, which are offered to the user in order to allow him to make a choice of new content among all those displayed in the VZL.

The digital contents exposed in the VZL are for example displayed on the reproduction terminal 5 in the form of a thumbnail extracted from the digital contents. In another example, the digital content is represented by a poster representative of this content (such as for example the movie poster in the case of VOD type content). Additional information is also accessible to the user in the VZL, such as for example the title of the content, the television channel broadcasting it (for example TF1, France 2, France 3, Canal + etc.) and its nature ( for example action film, adventure film, documentary, etc.), or, in the case of VOD-type content, the price of this content. Examples of display of a VZL according to the invention are illustrated below in connection with Figures 4a and 4b.

In another example, the VZL exhibits several television channels in the form of a mosaic of channels represented, for example, by their logo.

The transmission of the request to display the VZL can be carried out for example by pressing the "ok" key on the remote control of the playback terminal 5, or by a long press on the left or right arrow of the latter. here, or by swiping the touch screen of tablet 4 or smartphone 3.

At the end of this step E3, the ZAP zapping module receives a zapping request REQ_ZAP_VZL, corresponding to a display request of the VZL for zapping between a first digital content C1 to a new content chosen by the user from among several content offered in the VZL.

The VZL is stored in the multimedia stream player 9 which controls its display on a graphical interface of the restitution terminal 5 on receipt of a zapping request REQ_ZAP_VZL.

In a step E4, the ZAP zapping module controls the HAS client module so that the latter sends a REQ_Manifest_ (C1 ... Cn) request, containing a request to retrieve the manifest files M1 to Mn to the “HAS” content server 2 of the digital contents C1 to Cn exposed in the VZL and accessible to the user.

In a step E5, in response to this request, the “HAS” content server 2 sends a data stream representative of the digital contents C1 to Cn of the VZL to the HAS client module, which then retrieves the associated manifest files M1 to Mn. The “HAS” content server 2 exposes the various manifest files in the form of fragments, Cri @, U \ encoded at different encoding rates Dj, where the index i designates a temporal identifier, or position, of the “chunk” C / 7i @ Dj.

During a step E6, the HAS client module identifies the fragments available for all of the digital content C1 to Cn of the VZL, and the various associated video qualities Dj. In this example, the digital contents C1 to Cn are for example all offered in the form of fragments of duration 4s, with a first encoding rate D1 = 1000 kb / s, a second encoding rate D2 = 2500 kb / s, a third encoding rate D3 = 5,000 kb / s, a fourth encoding rate D4 = 7,500 kb / s and a fifth encoding rate D5 = 10,000 kb / s.

It should be noted that the different digital contents C1 to Cn exposed in the VZL can have different associated video qualities Dj.

In a step E7, the determination module DET of the multimedia stream player 9 compares for each digital content C1 to Cn of the VZL the different video qualities Dj associated with the fragments available for each content to the resource constraint, that is to say - tell the bandwidth available at the time of reception of the zapping request REQ_ZAP_VZL. Indeed, the HAS client module knows the current bandwidth constraints, according to the conventional HAS technique. At the end of this comparison, the determination module DET determines the encoding rate maximum of the time segments of the contents of the VZL at which it is possible to view each of these contents without interruption, depending on the availability of bandwidth.

In one example, the user's bandwidth, continuously measured by the HAS client module, is 15Mbs / s. In the manifest files M1 to Mn, there are 5 different qualities (D1 to D5) and the time segments are 4 seconds long. The DET determination module then determines that the maximum encoding rate for each of the contents C1 to Cn exposed in the VZL is 10 Mbs / s (D5).

In another example, the user's bandwidth is measured at 3Mbps.

The DET determination module then determines that the maximum encoding rate for each of the contents C1 to Cn exposed in the VZL is 2.5 Mbs / s (D2).

In a step E8, the construction module CONST selects a reproduction quality for each of the digital contents C1 to Cn of the VZL, as a function of the maximum encoding rate determined in the preceding step E7.

In a first example, the user's bandwidth is measured at 3 Mbs / s, and the maximum encoding rate of C1 to Cn content exposed in the VZL is 2.5 Mbs / s (D2). The CONST construction module then selects for each of the content offered in the VZL a standard type resolution, or SD (720 x 576 pixels).

The CONST construction module then updates an ETQ information label, intended for the user, on the quality of reproduction of the contents of the VZL which is accessible to him. The enriched list of contents is updated at determined time intervals and / or in the event of modification of the resource constraint. Each digital content of the VZL is thus associated with an ETQ information label on the quality of reproduction. This information label enriches the information already available in the VZL, and then allows the user to differentiate the content offered by it.

In connection with FIG. 4a, a first example of display in a virtual zapping list (VZL) of an information label on a reproduction quality for each of the digital contents exposed is illustrated. The various contents offered to the user are illustrated, for example, by a thumbnail I extracted from the contents. Information regarding the content is also available like TRT title (eg "Mad Max: Furry Road", "Hunger Game: Revolt" ... etc), NAT nature (eg Action movie, Movie of adventure ...), and the channel on which the content is broadcast CHN (for example France 2, FRANC 3, Canal + ...).

In the example in connection with FIG. 4a, the multimedia stream player 9, via the construction module CONST, selects a so-called standard (SD) reproduction quality for the contents C1 to Cn, since the bandwidth is measured at 3Mbs / s and that the maximum encoding rate is determined at 2.5 Mbs / s (D2). An ETQ information label on an SD type rendering quality is then associated with each (or only some) of the content, for example in the form of an SD logo, displayed in association with the thumbnail I of the content in the VZL.

In a variant, the ETQ information label can be composed of alphanumeric characters, such as for example a text associated with the quality of rendering.

In a second example, the user's bandwidth is measured at 15 Mbs / s. The DET determination module then determines that the maximum encoding rate for each of the contents C1 to Cn exposed in the VZL is 10 Mbs / s (D5).

The CONST construction module then selects a high definition type resolution, or HD (720 x 1280 pixels), provided that the content is offered for broadcasting in HD by the television channel for LIVE content or by the access provider. Internet for VOD.

Indeed, the contents C1 to Cn can have different encoding rates, for example, a C4 content can be offered in the form of fragments of duration 4s, with a first encoding rate D1 = 400 kb / s, a second encoding rate D2 = 800 kb / s, a third encoding rate D3 = 2100 kb / s, a fourth encoding rate D4 = 2500 kb / s and a fifth encoding rate D5 = 3000 kb / s. In the case where the bandwidth is measured at 10Mbs / s, the C4 content can only be broadcast at a maximum encoding rate of 3000 kb / s, which corresponds to a quality of restitution of standard or SD type. The CONST construction module then updates the ETQ information label intended for the user on the quality of restitution accessible to the user of the contents of the VZL.

In connection with FIG. 4b, a second example of display in a virtual zapping list (VZL) of an information label on a quality of reproduction for each (or only some) of the digital contents exposed is illustrated.

The media stream player 9, via the CONST build module, selects a high definition HD quality when the maximum encoding rate is determined at 10 Mbs / s, and a standard SD quality when the maximum encoding rate is determined at 3 Mbs / s (for example when the maximum encoding rate offered by the manifest file of a content does not allow HD quality to be achieved), when the bandwidth is measured at 15Mbs / s.

An ETQ information label is then displayed in the VZL in association with the thumbnail I of each (or some) of the contents of the VZL in the form of an HD or SD logo.

The preceding examples are not limiting. Thus, a customer having fiber and being able to access digital content at maximum encoding rates such that he can claim a quality of reproduction of the UHD or 4k type, is informed about the quality of reproduction by the display. in the VZL, in association with the image I of each of the contents of the VZL, an ETQ information label in the form of a UHD or 4k logo for example.

In a step E9, the CONST construction module, via the TRANS module, transmits the enriched list of contents LIST_ENR to the rendering terminal, for display on a screen of the latter.

More particularly, the information label on the quality of rendering is displayed at the level of the rendering terminal, via a graphical interface, in the VZL, for example in the form of graphic information, such as for example a logo representing a resolution. In one example, an SD logo represents a standard resolution, an HD logo represents a high definition resolution, an FHD logo represents a “Full HD” resolution, a UHD or 4K logo represents an “Ultra HD” resolution. In another example, this information label can be a text, such as for example a resolution value such as 720p for high definition resolution, 1080p for Full HD resolution ... etc.

Alternatively, the resolution quality information label can represent intermediate rendering qualities and can then be displayed for example in the form of intermediate logos such as SD +, HD +, etc.

In a step E10, the user can then select a content in an informed manner and send to the stream reader terminal 9 a SELECT_CONT selection request for a particular content that he wishes to view.

APPENDIX 1: example of manifest file

Claims

1. Method for managing a list of contents accessible for zapping, said digital contents (C1, C2, Cn) being downloadable in adaptive progressive download mode (HAS) by a multimedia stream reader terminal (3, 4, 8, 9), said digital contents (C1, C2, Cn) being respectively associated with a description file (7, M1, M2, Mn), comprising a list of time segments (Cni @ Dj) of said contents each associated with several bit rates d 'encoding of said contents, characterized in that it comprises:

- receipt (E3) of a request for access to a list (VZL) of said digital content,

- obtaining (E4) of said description files (7, M1, M2, Mn) associated with said digital contents (C1, C2, Cn) of said list (VZL),

a determination of a maximum encoding rate of said time segments (Cni @ Dj) of said digital contents (C1, C2, Cn) accessible for download, as a function of a resource constraint obtained by said multimedia stream reader terminal ( 3, 4, 8, 9),

- a construction of an enriched list of contents, in which at least one of said digital contents (C1, C2, Cn) is associated with a reproduction quality indicator assigned to said content according to said determined maximum encoding rate.

2. A method of managing a list of content accessible to zapping according to claim 1, characterized in that it further comprises a display of said enriched list of content on a playback terminal.

3. A method of managing a list of content accessible to zapping according to claim 2, characterized in that said quality indicator of restitution is displayed in the form of an information label belonging to the group comprising:

- graphics;

- a string of alphanumeric characters;

- a display mode of a thumbnail representative of said associated content.

4. A method of managing a list of contents accessible to zapping according to any one of claims 1 to 3, characterized in that it implements a updating of said list enriched with contents at determined time intervals and / or in the event of modification of said resource constraint.

5. Computer program product comprising program code instructions for the implementation of a method for managing a list of contents accessible to zapping according to any one of claims 1 to 4, when it is executed. by a processor.

A computer readable recording medium on which a computer program according to claim 5 is recorded.

7. Device for managing a list of content accessible for zapping, said digital content (C1, C2, Cn) being downloadable in adaptive progressive download mode (HAS) by a multimedia stream reader terminal (3, 4, 8, 9), said digital contents (C1, C2, Cn) being respectively associated with a description file (7, M1, M2, Mn), comprising a list of time segments (Cni @ Dj) of said contents each associated with several bit rates d 'encoding of said contents, characterized in that it comprises:

- a reception module (ZAP) of a request for access to a list (VZL) of said digital content,

- a module for obtaining (HAS) said description files (7, M1, M2, Mn) associated with said digital content (C1, C2, Cn) from said list (VZL),

- a determination module (DET) of a maximum encoding rate of said time segments (Cni @ Dj) of said digital contents (C1, C2, Cn) accessible for download, as a function of a resource constraint obtained by said terminal media stream player (3, 4, 8, 9),

- a construction module (CONST) of an enriched list of contents, in which at least one of said digital contents (C1, C2, Cn) is associated with a reproduction quality indicator assigned to said content as a function of said encoding rate maximum determined.

8. Device for managing a list of contents accessible to zapping according to claim 7, characterized in that it comprises a module for generating a command (TRANS) for displaying said enriched list of contents on a terminal. restitution.

9. Multimedia stream reader terminal, characterized in that it comprises a device for managing a list of content accessible by zapping according to claims 7 to 8.