FR3005386A1 - METHOD AND DEVICE FOR PROVIDING A PART ALREADY DIFFUSED FROM A MULTIMEDIA STREAM, USER TERMINAL, CORRESPONDING COMPUTER PROGRAM AND MEDIUM STORAGE MEDIUM - Google Patents

Abstract

The invention relates to a method for providing, to a user terminal, an already broadcast part of a multimedia stream currently being broadcast in a digital broadcasting network, comprising a step of providing said part, by a remote server of said user terminal, from a predetermined time position in said multimedia stream, via a communication network separate from said digital broadcast network, comprising: a sub-step of receiving said multimedia stream and, for each received portion of said multimedia stream: encoding said received portion delivering at least one fragment of independent content; o storing said fragment in a circular buffer zone of predetermined size; A sub-step of concatenating said fragments, starting from the fragment corresponding to said predetermined temporal position.

Description

Method and device for providing an already broadcast portion of a corresponding media stream, user terminal, computer program and storage medium. FIELD OF THE INVENTION The field of the invention is that of the transmission and digital broadcasting of multimedia contents, in particular television contents. More specifically, the invention relates to the display, on a user terminal, of an already broadcast portion of a multimedia stream, from a predetermined time position in the stream, the latter being being broadcast in a network of digital broadcasting. The invention applies in particular, but not exclusively, to a multimedia stream that complies with the DVB-T or DVB-T2 ("Digital Video Broadcasting - Terrestrial") broadcast standards for "digital terrestrial video broadcasting" and terminals users compatible with connected television type HbbTV ("Hybrid Broadcast Broadband TV" in English) for example. 2. Prior Art There are now several solutions for (re) viewing, from a predetermined time (for example from its beginning), a video being broadcast or already broadcast. For example, there are so-called back-shifting solutions. A disadvantage of these solutions lies in the need to have active local equipment, already registering the chain on which we want to go back. There are also other solutions offering catchup television services, or "catchup". According to these solutions, the video programs are made available to users but only at the end of the broadcast of the current program, or only the day after its broadcast.

There is therefore a need for a new visualization technique, from a predetermined time position in the stream being broadcast, of a previously broadcast portion of this stream, which is simple to implement and inexpensive, and does not require local equipment. 3. DISCLOSURE OF THE INVENTION The invention relates to a method of providing, to at least one user terminal, an already broadcast portion of a multimedia stream being broadcast in a digital broadcast network. According to a particular characteristic of the invention, the method comprises a step of providing the part of the multimedia stream, by a remote server of the user terminal, from a predetermined time position in the multimedia stream, via a communication network. distinct from the digital broadcasting network, the supplying step comprising: - a substep of reception u multimedia stream and, for each received portion of the multimedia stream and for at least a predetermined delivery rate of the portion of the multimedia stream to the terminal user, the following substeps, implemented in the remote server: o encoding of the received portion delivering at least one fragment of independent content; storing the independent content fragment in a circular buffer zone of predetermined size, called circular buffer; a substep of concatenation of the independent fragments stored in the circular buffer, from the stored independent fragment corresponding to the predetermined temporal position. The invention, according to its various embodiments, thus proposes an original solution for the provision of an already broadcast part of a multimedia stream being broadcast on a network, but not necessarily being displayed on the user terminal. Indeed, unlike the solutions of the prior art proposing either to use a local storage device connected to the user terminal to record content and replay at the request of the user (time shifting solutions), or to allow access to content on a server, once the live broadcast is over, and sometimes only the next day (catch-up television solutions), the solution according to the invention allows a user to view, from a moment chosen, a previously broadcast part of a multimedia stream, without requiring local storage equipment, and as it would have visualized live. In addition, according to a particular embodiment of the invention, the already broadcast portion of the multimedia stream is accessible by the user's terminal via an IP communication network, the multimedia stream being for example broadcast via a digital television network. earthly. Moreover, according to this embodiment of the invention, the method also allows a user to "navigate" in the already broadcast portion of the multimedia stream, that is to say to go back, to go further. or to pause the playback of the already broadcast part of the multimedia stream, within the limit of the size of the circular buffer.

Thus, according to this embodiment of the invention, the remote server receives the multimedia stream broadcast on the network, the cut and the encode as and when it is received in a plurality of independent fragments, also called "chunks" , and stores these fragments in a circular buffer of predefined size, for transmission at a predetermined rate.

If several transmission rates are desired, several encodings are implemented, so as to have "chunks" for the different desired rates. These "chunks" each constitute a multimedia content that is self-sufficient, that is to say that can be read independently. For example, a video chunk includes video data and bit rate information and allows a video to start at the beginning of its playback. The remote server then concatenates these stored fragments, as and when the transmission to the user terminal, the desired rate. In this way, the flow resulting from the concatenation of independent fragments, implemented progressively, can be transmitted / made available to the user terminal during the real-time broadcast of the stream on the network, within the limit of the size of the circular buffer . Thus, a content of the multimedia stream already broadcast, having a duration less than the size of the buffer can be viewed by the user even after the end of its broadcast in real time, the "chunks" corresponding to the content are still available in the buffer circular. In this case, the concatenation of "chunks" corresponding to the content starts from a "chunk" stored at a certain place in the circular buffer, according to the time elapsed since the beginning of the recording of "chunks" in this buffer . On the other hand, a step back in the multimedia flow can be done only until a "chunk" video still stored in the buffer memory, and the fast advance will be limited to the moment when one will have caught up with the diffusion in real time of the multimedia stream. In addition, in the case of the pausing feature, a user may find it impossible to resume viewing a previously played part, if the pause time has been too long and the "chunks" video corresponding to the part of which it wishes to resume viewing are no longer stored in the buffer, because replaced by "chunks" video more recent. In this case, the user terminal might display an error message or a message indicating that the service is no longer available.

According to a particular aspect of the invention, the predetermined size of the circular buffer corresponds to a maximum number of stored independent content fragments, and, for a current independent content fragment to be stored, the method comprises, prior to the substep of storage, a sub-step of deleting the oldest stored independent content fragment, when the number of stored independent content fragments corresponds to the predetermined size of the circular buffer. Thus, the circular buffer is intended to store a maximum number of "chunks", and, according to the conventional operation of a circular buffer, when the buffer is filled, the storage of a new "chunk" requires the removal of the oldest "Chunk".

For example, the encoding step includes a substep of associating an identifier with said independent content fragment. Thus, according to this embodiment of the invention, an identifier is associated with each video "chunk", so as to be able to locate the video "chunk" (corresponding to the time position chosen by the user) from which to concatenate the "Chunks" and provide them to the user. Indeed, a "chunk" video is independent, the provision of the concatenation of "chunks" can start from any "chunk" video. According to a particular characteristic of the invention, the method comprises a step of providing, by the remote server to the user terminal, the part of the multimedia stream, on request of the user terminal. Thus, according to this embodiment, the provision of the multimedia stream part, already broadcast, required by the user follows a request from this user for navigation in the multimedia stream, from a time chosen in the flow, corresponding for example to the beginning of a content, or to a specific location of a content. For example, the user validates with his remote control access to the service of providing a part of the multimedia stream already broadcast, from a chosen moment in the stream, and the user terminal "recovers" this part of the multimedia stream already broadcast, on the remote server. For example, the request of the user terminal comprises at least one piece of information representative of the predetermined time position.

Thus, according to this embodiment of the invention, the user indicates, when he wants to access an already broadcast portion of a multimedia stream, which time position in the stream he wants to start reading. For example, the user may wish to view a content from a specific moment in the stream, or the user may also go back, so choose a moment "earlier" in the stream, or advance and so choose a moment "later" in the stream, or pause the visualization, so as to resume the temporal position of the pause, all this within the limit of the size of the circular buffer, as already described ci -above. Whatever the situation, information representative of the temporal position chosen by the user is transmitted at the same time as the request.

On the other hand, in the case where the user resumes the display after a pause, the method has stored in the user terminal, the pause time position and the resume playback request of the content, after pausing therefore understands this position. For example, this information representative of the temporal position chosen by the user may correspond to an image in the multimedia stream, or to a temporal information indicating the moment in the content ... In particular, the information representative of the predetermined time position corresponds to an identifier of one of the independent content fragments and the sub-step of providing the part of the multimedia stream concatenates the independent fragments stored from the stored independent fragment identified by the identifier. Thus, according to this embodiment of the invention, the information representative of the instant chosen in the content by the user corresponds precisely to a "chunk" video identifier, so as to be able to directly supply the already broadcast portion of the Multimedia stream from the identified video chunk. In this way, the step of providing the already broadcast portion of the multimedia stream concatenates the "chunk" from that identified in the user's request, corresponding to the time position chosen by the user. According to one particular aspect of the invention, the request from the user terminal comprises at least one piece of information representative of the desired bit rate for the provision of the part of the multimedia stream. Thus, the user terminal can choose the rate at which it wants to view the already broadcast portion of the multimedia stream, for example depending on the bandwidth available between the supply module on the remote server, and the user terminal. According to this particular embodiment of the invention, the desired bit rate can be indicated in the request for viewing the content. According to a particular embodiment of the invention, the method further comprises a step of providing, by the remote server, to the user terminal, at least one piece of information representative of the part of the multimedia stream.

Thus, information for accessing an already broadcast portion of the multimedia stream is made available by the remote server for the user terminal, such as the stream access URL, etc. In this way, when the user terminal requires the service, it obtains this information which allows it to access the part of multimedia stream already broadcast to read it and return it to the user. According to one particular aspect of the invention, when a plurality of user terminals issue requests, the method comprises a step of managing the requests of the user terminals delivering, to the user terminals, rights of access to the part of the multimedia stream.

Thus, when several user terminals transmit a request for viewing an already broadcast part of the same multimedia stream, the method according to the invention manages these requests so as to avoid saturation of the modules providing the multimedia contents, and therefore of to ensure the quality of service.

For example, query management can set up tokens delivered during access requests. According to a particular embodiment of the invention, the method also comprises a step of encrypting the part of the multimedia stream. Thus, the multimedia content corresponding to the concatenation of the multimedia fragments of the already broadcast part of the multimedia stream to be provided can be encrypted so as to protect it from illegal copies. For example, a Digital Rights Management (DRM) type digital rights management technique is applied to the multimedia content, which is then encoded according to a technique that complies with the HbbTV 1.5 standard, for example Dynamic Adaptive Streaming over HTTP (DASH).

According to a particular characteristic of the invention, the method comprises the following steps: displaying, on the user terminal, a temporal representation of the part of the multimedia stream; selecting from the representation displayed by the user of the predetermined time position, delivering a time position information in the part of the multimedia stream; conversion of the time position information delivering the information representative of the predetermined time position. Thus, according to this embodiment of the invention, the user has a graphical interface allowing him to navigate in the multimedia stream, and therefore to choose a moment in the stream from which he wants to start a visualization. For example, a temporal representation of the flow flow is provided to the user, on which he can move a cursor to choose the start time of viewing.

For more ergonomics, some images of the stream, for example "keyframes" of a movie, can also be displayed on the terminal of the user, so that the latter is temporally identified in the stream and choose the moment from which he wants to start his visualization. According to another variant, the graphical interface represents the various programs, or contents, forming the multimedia stream, and the user can then choose a viewing start time corresponding for example to the beginning of a program, or content . Once the selection is made by the user, that is to say once chosen the moment from which it wishes to start its viewing, this selection is converted into information that can be used by the content delivery server, for example information corresponding to an image in the stream, or temporal information, or a program number, or directly a "chunk" video identifier. The invention also relates to a device for providing, to at least one user terminal, an already broadcast part of a multimedia stream being broadcast in a digital broadcasting network, the device, remote from the user terminal, comprising means for providing the part of the multimedia stream, from a predetermined time position in the multimedia stream, via a communication network separate from the digital broadcasting network, the supply means comprising: means for receiving the multimedia stream and, for each portion received from the multimedia stream and for at least one predetermined delivery rate of the portion of the multimedia stream to the user terminal, the following means: encoding means of the received portion delivering at least one independent content fragment; storage means of the independent content fragment in a circular buffer zone of predetermined size, called circular buffer; means for concatenating the independent fragments stored in the circular buffer, from the stored independent fragment corresponding to the predetermined time position. The invention also relates to a user terminal of an already broadcast part of a multimedia stream being broadcast in a digital broadcast network, comprising the following means: means for displaying a temporal representation of the multimedia stream; selection means from the representation displayed by the user of the predetermined time position, delivering a time position information in the multimedia stream; means for converting the time position information delivering the information representative of the predetermined time position; means for transmitting a request for supplying the part of the multimedia stream comprising at least the information representative of the predetermined instant. The invention also relates to a computer program comprising instructions for the implementation of a supply method as described above, when this program is executed by a processor. The invention also relates to a computer-readable and non-transitory storage medium, storing a computer program comprising instructions executable by a processor to implement a supply method as described above. 4. List of Figures Other features and advantages of the invention will appear more clearly on reading the following description of a particular embodiment, given as a simple illustrative and non-limiting example, and the accompanying drawings, among which: Figure 1 shows the main steps of a method of providing an already broadcast portion of a multimedia stream, according to a particular embodiment of the invention; Figure 2 shows a sequence diagram illustrating the implementation of the invention, according to this particular embodiment of the invention; FIG. 3 illustrates an exemplary system embodying the invention, according to a particular embodiment of the invention; FIG. 4 illustrates an example of temporal representation of a multimedia stream on a user terminal, according to a particular embodiment of the invention. 5. DESCRIPTION OF AN EMBODIMENT OF THE INVENTION 5.1 GENERAL PRINCIPLE The general principle of the invention is based on the progressive encoding and cutting (into independent fragments) of a multimedia stream as it is broadcast. in real time in a first digital broadcast network, so as to store, as and when this real-time broadcast, successive independent fragments in a circular buffer area.

This circular buffer zone then makes it possible to concatenate the various independent fragments stored to provide at least one user terminal an already broadcast portion of a multimedia stream, during the real-time broadcast of this stream, from a predetermined time position. in the stream (for example the beginning of a program) and via a second communication network.

Thus, a terminal having requested such a service for viewing an already broadcast part of a multimedia stream, also called a navigation service in a streaming multimedia stream, enables a user to view the multimedia content corresponding to this part. already broadcast the multimedia stream without requiring local equipment to the user terminal, the multimedia content being provided to the user terminal by a remote server, also called "service delivery platform". In addition, the provision of this already broadcast portion of the multimedia stream is implemented via a communication network separate from the real-time broadcast network of the stream. For example, the real-time broadcast network corresponds to digital terrestrial television (DTT) and the communication network of the multimedia content file corresponds to an IP network. Moreover, the invention, according to its various embodiments, is also based on the transmission, from the user terminal to the remote server, of information representative of the temporal position in the stream chosen by the user to start the visualization. , this information being transmitted with the request sent by the user terminal to the remote server. The main steps of the method according to a particular embodiment of the invention are now presented with reference to FIG. A multimedia stream 10, for example a video, is considered to be broadcast 100 in a broadcast network, for example DTT. According to this embodiment of the invention, a delivery step 110 delivers, from a predetermined time position in the multimedia stream 10, also called the predetermined instant t, a part 11 of the multimedia stream, already broadcast, to a terminal during broadcast 100 of the corresponding multimedia stream. This provisioning step 110 comprises a sub-step of receiving the multimedia stream 10, portion by portion, and the following substeps, implemented for each portion received from the multimedia stream 10: encoding 112 of the received portion delivering the minus an independent content fragment; storage 113 of the independent content fragment in a circular buffer zone of predetermined size, called circular buffer. Then, at the request of a user, a step 114 of concatenation of the independent fragments stored in the circular buffer, from the stored independent fragment corresponding to the predetermined time position, is implemented, to deliver to the user the part 11 of the multimedia stream, already broadcast.

If we take an example of the broadcasting of a video 10 in a digital terrestrial television network, the encoding step 112 of the video takes as input the real-time stream of the chain supporting the service and delivers data. video fragments of a few seconds, independent of each other, still called "chunks". These video fragments are then stored, during the storage step 113, in a circular buffer. These two steps 112 and 113 are implemented as the real-time streaming of the multimedia stream and thus allow to gradually store, in a circular buffer, independent video fragments from the encoding of the video stream. broadcast course. Next, the concatenation step 114 takes as input the video fragments stored to provide the user terminal with the part 11 (already broadcast) of the multimedia stream, via an IP network for example. Part 11 of the multimedia stream required by the user is therefore accessible at any time, during the streaming of the stream in real time, within the limit of the size of the circular buffer used to store the independent fragments. Indeed, as the real time streaming of the multimedia stream, the oldest stored fragments are deleted to make room for the most recent fragments to store. Moreover, according to another characteristic of this embodiment of the invention, several parts of multimedia stream 11 may be available, depending on several desired bit rates by different user terminals. Indeed, the service of viewing a previously broadcast part of a multimedia stream being broadcast, from a predetermined time t, allows different user terminals, which may have different technical characteristics, to view the part of flow required at the proper flow. The location of the user terminal with respect to the server providing the service, as well as the quality of the transmission network between this terminal and this server, can also be taken into consideration for the choice of the delivery rate of the multimedia content. Thus, the solution according to this particular embodiment of the invention makes it possible to provide, from a multimedia stream being broadcast, the same part, already broadcast, of the multimedia stream at several different rates. 5.2 Description of an embodiment With reference to FIG. 2, an example of operation of such a navigation service in a multimedia stream currently being broadcast is presented, when at least one user terminal, denoted M4, wish to benefit from the service. In this sequence diagram presented in FIG. 2, different modules of the server, or of the service delivery platform are involved, according to a particular embodiment of the invention. It is understood that this example is not restrictive and that certain tasks can be implemented by other modules of the server, according to other particular embodiments of the invention. It is considered that the opening of the service is carried out at the initiative of the multimedia stream supply operator, which transmits service opening information to the service delivery platform. It is also the operator who transmits to the service delivery platform information indicating the closure of the service (for example when the real-time broadcast of the multimedia stream is completed). According to a variant of this particular embodiment of the invention, a module M '(not shown) of the service delivery platform can be implemented to process the information received from the operator (opening / closing of the service) and transmit them to a main service management module on the service delivery platform. In particular, in this example, we consider the following main modules M1 to M3 of the service delivery platform: M1: this module, also called coder, provides the encoding of the multimedia stream broadcast in real time, as and when measurement of its diffusion, according to the steps 111 of reception and 112 of encoding already described above. This module M1 thus takes as input the multimedia stream and outputs a plurality of multimedia content fragments, called "chunks". These fragments of content are therefore delivered to the module M2 described below, as and when the streaming of the stream in real time. M2: this module takes as input the multimedia stream cut into "chunks" by the module M1 and stores each of these content fragments in a circular buffer of predetermined size, as already described above in relation to the step 113. Fragments of content are stored as and when they are supplied by module M1 and are therefore available as and when for module M3 described below. M3: this module, also called video server, takes as input the content fragments stored by the module M2 and the concatenes (step 114 described above) so as to provide the user terminal M4 a part 11, already broadcast, of the multimedia stream. For the user terminal, this part of the multimedia stream is seen as a file to download, at any moment of the real-time broadcast of the multimedia stream, when the service is open and within the buffer size limit circular. Moreover, this module M3 can be duplicated in as many instances as necessary, in order to respond to a large number of requests from user terminals wishing to benefit from the service. Thus, a plurality of instances of the module M3 is able to provide an already broadcast portion of a multimedia stream to a plurality of user terminals.

A module M "(not shown), also called" front office "for front end server or front area, provides the user terminal M4 information necessary for the use of the service, such as the access address (" URL When the multimedia content (corresponding to the already broadcast part of the multimedia stream) is supplied to the user terminal via an IP communication network, this module M "obtains this information on the service via the main module for managing the service. from which he can previously register. As for the module M3, this module M "can be duplicated in as many instances as necessary, in order to respond to a large number of requests from user terminals wishing to benefit from the service, thus a plurality of instances of the module is able to to provide information necessary for the use of the service to a plurality of user terminals This module M "can also manage the different requests of the user terminals by the implementation of access tokens, provided to the user terminals, for example before to deliver service information to them, thus enabling the M3 video servers to "regulate" the load and to ensure quality of service. Moreover, this module M "may also be in charge of collecting, at the user terminals, information necessary for calculating statistics of the service As already indicated, it should be noted that the sequences described previously can be implemented. for several delivery rates of an already broadcast portion of a multimedia stream, an advantage of the invention, according to its different embodiments, is that it can provide, at different rates, the same part already broadcasted of a multimedia stream. multimedia stream, while this stream is being broadcast, because of the disparity of the user terminals, from a technical point of view and a location point of view with respect to the service delivery platform, it is advantageous to be able to provide multimedia contents with different transmission rates Concretely, each instance of the module M3 makes available the same multimedia content at speeds This allows each user terminal M4 to choose the bit rate best suited to the bandwidth between it and the module M3 of the service delivery platform. For example, to choose this rate, the user terminal M4 can download a file of predefined size, preferably small (for example 300 K bytes), on the module M3 and estimate the flow available between him and M3 from the time download. Furthermore, it should be noted that, according to a particular embodiment of the invention, the exchanges between the different modules of the service delivery platform are implemented via IP networks. In addition, charge controllers (not shown) can be added in the front office part of the service delivery platform to support a large load within this service delivery platform. FIG. 3 shows an exemplary implementation system of the invention, according to this embodiment of the invention, in which is illustrated an example of a device for providing an already broadcast part of a multimedia stream, under the form of a service providing platform, and an example of an M4 user terminal. According to this embodiment of the invention, such a device comprises means / module (s) for providing, to at least one user terminal, an already broadcast part of a multimedia stream currently being broadcast in a network of digital broadcasting, from a predetermined time position in the multimedia stream, via a communication network separate from said digital broadcast network. According to this embodiment, the means for supplying the device comprise means for receiving the multimedia stream and, for each portion received from the multimedia stream and for at least one predetermined delivery rate, the following means: means / module (s) M1 encoding the received portion, delivering at least one fragment of independent content; means / module (s) M2 for storing the independent content fragments in a circular buffer zone of predetermined size, called circular buffer. In addition, the means for providing the device also comprise means / module (s) M3 for concatenating the independent fragments stored in the circular buffer, from the stored independent fragment corresponding to the predetermined time position chosen by the user.

The modules M1 to M3 have already been described above, as well as the relations between these different modules, and with the user terminal M4. The user terminal M4 may comprise the following modules M4a and M4b (not shown): M4a: this module is an IP video decoding module, taking a "URL" as input and decoding the multimedia stream portion 11 transmitted by the module M3 of the service delivery platform. In addition, this module M4a receives, from the module M4b (control module), a command C1 including information representative of the predetermined time t in the stream chosen by the user to start viewing. This information representative of the time t chosen by the user may be temporal information, information indicating an image corresponding to the instant t or directly an identifier of the independent video fragment ("chunk" video) corresponding to this instant t. The module M4a sends to the module M3 of the service delivery platform a command C comprising in particular this information representative of the time t chosen by the user. - M4b: this module allows the user to choose from what time position he wants to view the multimedia stream. The user can thus "navigate" in the stream being broadcast, that is to say, view a portion of stream from any time position in this stream, including go back or make an advance fast (and within the time limit corresponding to the size of the circular buffer memory, that is to say that the backtracking can be done until a video "chunk" still stored in the buffer memory, and the fast forward will be limited to the moment when one will have caught up with the diffusion in real time), or to pause the visualization of the contents. When the user has chosen this temporal position, also noted instant t, this module M4b transmits to the module M4a a command C1, including in particular information on the stream to be displayed and information representative of the time position chosen by the user. Furthermore, the user terminal M4 also comprises means / module (s) for displaying a temporal representation of the multimedia stream, for example in the form of a "timeline" having a time scale and / or images of the flow at certain time positions and / or indications corresponding to names or numbers of programs, or a horizontal or vertical bar graduated temporally ... This temporal representation of the flow thus allows the user to navigate in the current stream broadcast, and to choose the temporal position in the stream, from which it wishes to view part of the stream already broadcast. Once this temporal position has been chosen by the user, the module M4b transmits to the module M4a the command C1 including information representation of this time position chosen by the user. In the particular case where the user pauses the playback of the content, the time position corresponding to this pause is stored, for example within the user terminal, and when the user requests resume playback of the content, after pausing, the user terminal issues a request including this stored time position to the remote server (the service delivery platform). 5.3 Application example Consider a user wishing to display, on his connected television type HbbTV, a program Pj, already broadcast on a channel i, offering the navigation service in a video stream being broadcast. On its television, the user can interact with an interface displaying, for example in the form of a timeline as illustrated in Figure 4, the x (eg four) last hours of program, already broadcast on the channel i. For example, time markers represent slices of 15 minutes, below the frieze, while numbers and / or program names are indicated in the frieze. The user can navigate a cursor (bold line in Figure 4, at the beginning of the program Pj) and then validate the position of the cursor, for example via a key "validation" on his remote control, when he has selected the moment from which it wishes to view an already broadcast part of the multimedia stream being broadcast. It should be noted that this temporal representation of the multimedia stream takes into account the size of the circular buffer zone used to store the "chunks", so as not to offer the user an already broadcast portion of the stream that is not more stored in this buffer area.

When the user validates this choice, a request is sent, as already described above, to the service delivery platform, which in turn provides the multimedia content from the time position chosen by the user. Thus, the user can view a part, already broadcast, of a multimedia stream being broadcast, from a chosen time position. In the example, the user will be able to view the program Pj, then the advertising (Pub) that follows and the following programs, unless he chooses to stop viewing, or to navigate again in the stream to view content, or part of the stream, already broadcast. Thus, unlike the prior art catch-up television techniques, which allow a user to view a program, as such and not as a "part of a stream", that is, without intermediates, advertising cuts, advertisements, etc ..., the solution according to the various particular embodiments of the invention allows a user to view an already broadcast part of a multimedia stream being broadcast, this part may correspond to a program, a portion of a program, a suite of programs, ... as it would have been displayed live. It should be noted that if the service is not available, the user terminal may display a message informing the user of the unavailability of the service.

Claims (13)

REVENDICATIONS1. A method of providing, to at least one user terminal, an already broadcast portion of a multimedia stream being broadcast in a digital broadcast network, characterized in that said method comprises a step of providing said portion of said multimedia stream by a server remote from said at least one user terminal, from a predetermined time position in said multimedia stream, via a communication network separate from said digital broadcasting network, said provisioning step comprising: - a substep of reception said multimedia stream and, for each portion received from said multimedia stream and for at least one predetermined delivery rate of said portion of said multimedia stream to said at least one user terminal, the following substeps, implemented in said remote server: o encoding said received portion delivering at least one independent content fragment; storing said at least one fragment of independent content in a circular buffer zone of predetermined size, called circular buffer; a substep of concatenation of said independent fragments stored in said circular buffer, from the stored independent fragment corresponding to said predetermined time position. 2. A method of supply according to claim 1, characterized in that said predetermined size of said circular buffer corresponds to a maximum number of stored independent content fragments, and in that, for a current independent content fragment to be stored, said method comprises prior to said storage sub-step, a sub-step of deleting the oldest stored independent content fragment, when the number of stored independent content fragments corresponds to said predetermined size of said circular buffer. 3. The method of provision of claim 1, characterized in that said encoding step comprises a substep of association of an identifier to said independent content fragment. 4. The method of supply according to claim 1, characterized in that said method comprises a step of providing, by said remote server to said at least one user terminal, said portion of said multimedia stream, on request of said user terminal. 5. Method of supply according to claim 4, characterized in that said request of said user terminal comprises at least one piece of information representative of said predetermined time position. 6. A method of supply according to claim 5, characterized in that said informationrepresentative of said predetermined time position corresponds to an identifier of one of said independent content fragments, and in that said sub-step of providing said part of said multimedia stream concatenates said independent fragments stored from the stored independent fragment identified by said identifier. 7. A method of supply according to claim 4, characterized in that said request of said user terminal comprises at least one information representative of the desired bit rate for said provision of said part of said multimedia stream. 8. A method of supply according to claim 1, characterized in that said method further comprises a step of providing, by said remote server, said user terminal, at least one piece of information representative of said portion of said multimedia stream. 9. The method of provision of claim 5, characterized in that said method comprises the steps of: displaying, on said at least one user terminal, a temporal representation of said portion of said multimedia stream; selecting from said representation displayed by said user, said predetermined time position, delivering a time position information in said portion of said multimedia stream; converting said time position information delivering said information representative of said predetermined time position. Device for providing, to at least one user terminal, an already broadcast portion of a multimedia stream being broadcast in a digital broadcast network, characterized in that said device, remote from said at least one user terminal, comprises means for supplying said part of said multimedia stream, from a predetermined time position in said multimedia stream, via a communication network distinct from said digital broadcasting network, said provisioning means comprising: means for receiving said stream and for each portion received from said multimedia stream and for at least one predetermined rate of supply of said portion of said multimedia stream to said at least one user terminal, the following means: encoding means of said received portion delivering at least one independent content fragment; storage means for storing said at least one independent content fragment in a circular buffer zone of predetermined size, called circular buffer; means for concatenating said independent fragments stored in said circumferential buffer from the stored independent fragment corresponding to said predetermined time position. 11. User terminal of an already broadcast part of a multimedia stream being broadcast in a digital broadcasting network, characterized in that it comprises the following means: means for displaying a temporal representation of said multimedia stream ; selection means from said representation displayed by said user of said predetermined time position, delivering time position information in said multimedia stream; means for converting said time position information delivering said information representative of said predetermined time position; means for transmitting a request for supplying said part of said multimedia stream comprising at least said information representative of said predetermined instant. 12. A computer program comprising instructions for implementing a method of supply according to any one of claims 1 to 9 when the program is executed by a processor. A computer-readable and non-transitory storage medium storing a computer program comprising processor-executable instructions for implementing a delivery method according to any one of claims 1 to 9.20