FR2976149A1 - Device for obtaining e.g. TV program available in different versions corresponding to different transmission bit rates for transmission to content receiver, has sensor, where content version is adapted to instruct content receiver - Google Patents

Abstract

The device (D) has a sensor (CD), where the device is arranged to determine display resolution on a basis of one dimension, maximum resolution of a display screen (EC) and estimated distance separating the screen from a viewer in front of the screen. A content version is adapted to the specific display resolution, and to instruct a content receiver (RC) e.g. set-top box, to retrieve part of the determined content version. An independent claim is also included for a method for obtaining multimedia content available in different versions.

Description

The invention relates to the transmission of multimedia content in a so-called streaming mode (or "streaming mode"). The invention relates to the transmission of multimedia contents in a so-called streaming mode (or "streaming mode"). Or reading on the fly). 1 o It is recalled that streaming consists of transmitting successively to at least one content receiver, via a communication network (wired or non-wired), parts (or "chunks" - micro-files) of a content so that they can be used in real time in reading on the fly. This type of transmission can be done by means of different streaming protocols, such as for example RTP or MPEG-TS over UDP, HTTP streaming, or more recently HTTP adaptive streaming. Here, "multimedia content" is understood to mean a set of audio and video data prepared in a manner adapted to its consumption so as to optimize its transmission. It may therefore be, for example, a television or video program or a game containing, for example, animations and / or textures and / or 3D models whose complexity may be reduced to decrease. the amount of information to be transmitted. It will be noted that the content may be of a stereoscopic type. State of the art The available bandwidth of a communication network is a parameter that fluctuates over time, sometimes significantly and / or durably, even when this network is of the domestic or residential type. This available bandwidth can be simultaneously used by different applications or different services, possibly different users, the operation of an application or service can be disrupted or altered when it becomes (very) low. This is particularly the case for applications or services relating to obtaining multimedia content. Indeed, if the bandwidth offered at a given instant by a communication network is momentarily incompatible with the data transmission bit rate of a required multimedia content, part of the data of this multimedia content can not be received by the client. content receiver requiring, and therefore the latter may at best restore images and / or sounds degraded quality and at worst not return anything at all. In order to limit the consequences of the aforementioned fluctuations, it has been proposed to generate from the same content several different versions that correspond to different transmission bit rates. Thus, when a content receiver, connected to a communication network, wants to retrieve content via the latter, it requires at any given time chosen version of this content that is best suited to the conditions offered by this communication network to this chosen moment, which avoids frozen or degraded images. This continuous selection of versions of content based on the available bandwidth allows some adaptation to the fluctuations of the network. However, it does not take into account the position of a user (or observer) with respect to the screen that is used to display the images of the received multimedia content. It may therefore happen that during certain time slots a part of the available bandwidth of a communication network is used to recover a version of content which corresponds to an image resolution much greater than the real temporary needs of the user ( or observer). It will be understood that when a user moves away from his display screen, he temporarily no longer needs images having as good a resolution as he needed when he was closer to this screen. display. Whenever the aforementioned situation occurs, a small portion of the available bandwidth of a communication network is unnecessarily used, even though it could possibly be used for another application or service.

SUMMARY OF THE INVENTION The object of the invention is therefore notably to improve the situation, and more precisely to prevent a part of the bandwidth of a communication network from being unnecessarily used to recover, in a broadcasting mode. continuously, a version of multimedia content that is temporarily unsuited to the needs of a user. For this purpose, the invention proposes in particular a device intended to obtain, in a streaming mode, multimedia contents which are available in different versions corresponding to different bit rates of transmission and suitable for transmission to a radio receiver. content via a communication network for display by a screen. This device is characterized in that it is arranged, on the one hand, to determine a display resolution as a function of at least one dimension and a maximum definition of the screen and a distance estimate separating this screen. an observer screen placed in front of him, then a version of content adapted to this determined display resolution, and, secondly, to order the content receiver to recover at least part of this determined content version.

The device according to the invention may comprise other characteristics that may be taken separately or in combination, and in particular: it may comprise at least one sensor arranged (or designed) to estimate the distance that separates the screen from an observer who is placed before him; it can be arranged to determine a normalized distance as a function of the distance estimate, of a selected dimension of the screen and of a value representative of the ratio between a theoretical screen / observer distance, adapted to the screen for the maximum definition of this screen, and the chosen size of the screen, and to determine the display resolution according to this determined normalized distance; the chosen dimension of the screen may be its width, and the maximum definition of the screen may be that which it has along this width; it can be arranged i) to determine the display resolution by calculating the inverse of the determined normalized distance, ii) to determine an intermediate value equal to the product of the display resolution by a maximum definition offered by the versions of the content to be recovered, and iii) for determining among the different versions of the content to be retrieved which one offers a definition close to this determined intermediate value; it can be arranged to choose a display resolution equal to 1 when the determined normalized distance is less than or equal to 1; it can be arranged to determine among the different versions of the content to be retrieved which one offers the definition closest to the determined intermediate value, by higher value; it can be arranged to recover at least one description file which is stored in correspondence of the versions of a content that it wishes to obtain and which describes their respective transmission bit rates and maximum offered definitions; it can be arranged, in the presence of several observers placed in front of the screen at different distances, to use in the determination of the display resolution the smallest distance among these different distances; - it can be arranged to take into consideration only observers watching the screen; it can be arranged to require exclusively the audio data of a content version in the absence of an observer in front of the screen; it can be arranged to choose the content version which corresponds to the highest transmission bit rate when the current value of the available bandwidth of the communication network is adapted to this highest transmission bit rate and there is no competing application (or service) that can simultaneously use this available bandwidth.

The invention also proposes a content receiver comprising a device for obtaining multimedia contents of the type presented above. Such a content receiver may, for example, be in the form of a set-top box, a decoder, a home or residential gateway, a game console, a computer fixed or portable, a mobile phone, a personal digital assistant, or an electronic tablet.

The invention also proposes a method for obtaining, in a streaming mode, multimedia contents which are available in different versions, corresponding to different bit rates of transmission and able to be transmitted to a content receiver via a network. communication network, for display by a screen. This method is characterized by the fact that it comprises: a step (i) of determining a display resolution as a function of at least one dimension and a maximum definition of the screen and an estimate of the distance separating this screen of an observer placed in front of the latter, then a content version adapted to this determined display resolution, and a step (ii) of ordering the content receiver to recover at least part of this version of content determined. BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the invention will become apparent upon examination of the following detailed description, and the accompanying drawings, in which: FIG. 1 schematically and functionally illustrates a communication network to which is connected a multimedia content server and a content receiver, equipped with a content obtaining device according to the invention and coupled to a television set; - FIG. 2 schematically illustrates six different versions of the same content corresponding respectively to six different bit rates of transmission, - Figure 3 schematically illustrates in a diagram an example of time evolution (t) of the normalized distance (dn) of an observer with respect to a screen on which are displayed images obtained by a device for obtaining multimedia content according to the invention, Figure 4 schematically illustrates within a diagram an example of time evolution (t) of the normalized display resolution (rn) of the images displayed by a screen in the presence of the time evolution of the normalized distance (dn) illustrated in FIG. 3, - FIG. schematically illustrates in a diagram an example of time evolution (t) of the data transmission rate (BR) of a content in the presence of the temporal evolution of the normalized display resolution (rn) illustrated in FIG. FIG. 4, and FIG. 6 schematically illustrates, in a diagram, an example of a law of evolution of the normalized display resolution (rn) as a function of the normalized distance (dn). The attached drawings may not only serve to complete the invention, but also contribute to its definition, if any.

DETAILED DESCRIPTION The object of the invention is notably to propose a device for obtaining multimedia content D intended to obtain multimedia contents, in a streaming mode, for at least one content receiver RC coupled to a R. communication network

In what follows, it is considered by way of non-limiting example that the communication network R is a network consisting of the Internet network connected in particular to a content receiver RC by an access network xDSL. But the invention is not limited to this type of communication network. Indeed, the communication network R may be wired or non-wired. Thus, it could also be a wired network of cable or fiber type, or a mobile or cellular network or WLAN ("Wireless Local Area Network" - possibly type 802.11 (or WiFi) or WiMAX), or a very short wireless LAN bluetooth type. The communication network R may also consist of disjoint subnetworks with, for example, a unidirectional broadcast network, for example of the television type, and a bidirectional network, for example broadband Internet access (xDSL). Furthermore, it is considered in the following, by way of non-limiting example, that the content receiver RC is a set-top box (or STB). But the invention is not limited to this type of content receiver. It concerns indeed any type of content receiver that can be connected to at least one communication network to receive multimedia content, and capable of rendering a multimedia content. Consequently, it may also be, for example, a decoder, a residential gateway (or "residential gateway"), a home gateway (or "home gateway"), a fixed computer or portable, a mobile phone (possibly of "smartphone" type), a personal digital assistant (or PDA (for "Personal Digital Assistant")), an electronic tablet, or a game console. In addition, it is considered in the following, by way of non-limiting example, that the multimedia content is video. But the invention is not limited to this type of multimedia content. It concerns any type of multimedia content available in the form of data files or file chunks, and in particular television programs, games, cinematographic programs, sports event images, content educational, and computer-generated images (or CGIs (for Computer Generated Imagery).

FIG. 1 schematically illustrates a communication network R connected to a content server SC, capable of storing contents (multimedia), and an content receiver RC, intended to decode contents (multimedia) transmitted by the server. SC (at the request of a content obtaining device D according to the invention).

For example, and as illustrated without limitation, the set-top box RC is coupled to at least one television set TS responsible for rendering on an EC screen the contents that it has decoded and which are for example from an SC server via the communication network R. The (content) server SC is for example responsible for storing different Vj versions of contents in storage means MS. These storage means MS may be in any form known to those skilled in the art, including software. Therefore, it could be a memory.

By "different versions of a content" is meant here versions that correspond to different transmission bit rates BRj. FIG. 2 schematically illustrates six different versions V1 to V6 (j = 1 to 6) of the same content respectively corresponding to six different transmission bit rates BRj, for example 1 Mbps (megabits per second) for the first time. version V1, 2 Mbps for the second version V2, 3 Mbps for the third version V3, 4 Mbps for the fourth version V4, 5 Mbps for the fifth version V5 and 6 Mbps for the sixth version V6. Each version Vj of a content consists of a multiplicity of parts (or "chunks" - micro files) of identical durations. In the example of FIG. 2, each part of a version Vj is represented by a rectangle whose height is representative of the corresponding transmission bit rate BRj. The number of versions of the same content can be equal to any value at least equal to two (2). It is important to note that the versions Vj of the same content correspond to resolutions rj which are preferably all different. It is recalled that the resolution r is equal to the product of the horizontal definition dh (per line) of an image by the vertical definition dv (by column) of this same image (ie r = dh * dv). It should be noted, however, that at least two versions of the same content may correspond to the same resolution but to different compression rates. By way of nonlimiting example, one can have: a first version V1 corresponding to a first transmission bit rate BR1 equal to 1 Mbps, a first horizontal definition dhl equal to 784 pixels and a first vertical definition dv1 equal to 441 pixels a second version V2 corresponding to a second transmission bit rate BR2 equal to 2 Mbps, a second horizontal definition dh2 equal to 1109 pixels and a second vertical definition dv2 equal to 624 pixels; a third version V3 corresponding to a third bit rate; a transmission bit BR3 equal to 3 Mbps, a third horizontal definition dh3 equal to 1358 pixels and a third vertical definition dv3 equal to 764 pixels; a fourth version V4 corresponding to a fourth transmission bit rate BR4 equal to 4 Mbps; horizontal definition dh4 equal to 1568 pixels and a fourth vertical definition dv4 equal to 882 ft xels, - a fifth version V5 corresponding to a fifth transmission bit rate BR5 equal to 5 Mbps, a fifth horizontal definition dh5 equal to 1753 pixels and a fifth vertical definition dv5 equal to 986 pixels, and - a sixth version V6 corresponding to a sixth transmission bit rate BR6 equal to 6 Mbps, a sixth horizontal definition dh6 equal to 1920 pixels and a sixth vertical definition dv6 equal to 1080 pixels. It will be noted that in the nonlimiting example which precedes the six different transmission bit rates BRj all correspond to the same number of bits per pixel (namely 2.96) and to the same ratio dhj / dvj (namely 1.78 ). This makes it possible to vary the resolution of a version Vj to another Vj '(with j' # j) while maintaining constant aspect ratio. But this is not obligatory. It will also be noted that the versions Vj of the same content may, for example, have been generated by encoding by means of a video compression technique, such as MVC ("Multiview Video Coding"), AVC ("Advanced Video Coding"). »), SVC (" Scalable Video Coding "), MPEG2, H264, and more generally any type of video compression allowing encapsulation in a format dedicated to transport in streaming mode, including for audio data. It will also be noted, as illustrated in FIG. 2, that the versions Vj of the same content preferably comprise reference frames TR whose temporal positions are identical from one version to another. It is recalled that reference frames TR are those that allow random access to a part (or chunk) of a content that is transmitted in streaming mode. In the illustrated example, each reference frame TR is placed at the beginning of a chunk of a version Vj of content. This allows a decoder installed in an RC content receiver to go from one version Vj to another Vj ', on request, at specific times (which are the transmission instants of the reference frames TR) without this being the case. induces visual artefact (typically every video chunk starts and eventually ends with a keyframe for a transition from one chunk to another invisible to the user). It will also be noted that the Vj versions of each content are preferably stored in correspondence of at least one description file which describes their respective bit rates BRj and their respective horizontal definitions dhj and / or their respective vertical definitions dvj. Each description file is for example in the format M3U8 (possibly one per resolution) or MPD ("MPEG DASH" (MPEG Dynamic Adaptive Streaming over HTTP)). We will return later on the interest of this file (s) of description. The Vj versions, which are stored in the SC server, are intended to be transmitted on request to at least one RC content receiver, at the request of a device for obtaining multimedia content D according to the invention.

It will be noted that a device for obtaining multimedia content D may be associated with at least one content receiver RC. The term "associate" here means both the fact of being an integral part of the RC content receiver (as illustrated without limitation), that the fact of being directly coupled to the RC content receiver. Therefore, a device for obtaining multimedia content D can be realized in the form of software (or computer) modules, or a combination of electronic circuits and software modules. But a device D can be implanted in a different equipment RC content receiver. Thus, the sensor that is positioned near the EC screen can inform a device D which is located in a residential gateway, which is then responsible for making the adjustments for the RC content receiver (here the STB). It is also possible to have several EC screens and / or several sensors, and possibly a central D device (for example in a residential gateway) which decides on the allocation of the bandwidth between the different receivers of RC contents associated with the various screens EC. This device (for obtaining multimedia contents) D is firstly arranged to determine a display resolution according to at least one dimension and a maximum definition of the screen EC (on which the images of the screen must be displayed. 'desired content') and an estimate of the distance d between this EC screen and an observer placed in front of it (EC). The screen / observer distance d is estimated by at least one distance (or movement) sensor CD which is, for example and as illustrated, coupled to the content receiver RC, and placed substantially at the level of the screen EC. Note that this CD sensor may be part of the EC screen (or the electronic equipment of which it is part), or it may be additional equipment that is connected to the RC content receiver (or, as here, to the TV set TS, or to a game console coupled to the television set TS). In another variant embodiment, the sensor (s) CD may be part of the device D. As non-limiting examples, the sensor may be additional equipment of the Kinect® type (manufactured by Microsoft) or a simple distance detector. Any technology known to those skilled in the art and making it possible to estimate a distance may be considered here, and in particular technologies based on the emission of waves in the infrared spectrum or in the ultrasound spectrum (as in certain devices parking assistance for motor vehicles).

It will be noted that it is possible for the device D to determine a normalized distance dn from each screen / observer distance d. For example, this normalized distance dn can be determined as a function of the distance estimate d, of a selected dimension (for example the width w) of the screen EC and of a value v representative of the ratio between a screen distance / theoretical observer dt, adapted to the EC screen for the maximum definition considered of the EC screen, and the selected dimension (for example the width w) of the screen E. Thus, it is possible for example to use the formula dn = d / (w * v).

The theoretical screen / observer distance dt is an optimal distance to separate an observer from an EC screen to take full advantage of the maximum definition of this EC screen. For example, in the case of a maximum horizontal resolution of 1920 pixels (HD 1080p format), the ratio v generally recommended by the TV manufacturers (when the selected dimension considered is the width w) is equal to 1.4, which means that the observer is placed optimally with respect to the screen EC when the distance d which separates it from the screen EC is equal to 1.4 times the width w of this screen EC. It is verified that when d = 1.4 * w and v = 1.4, we get a normalized distance of 1 dn equal to 1. Note that when the chosen dimension is the height h of the screen EC (and therefore that the maximum definition of the screen EC is the one that it possesses according to this width w), one must multiply the value v aforesaid by the report w / h. The device D can, for example, obtain the chosen dimension of the screen EC (for example its width w) from its content receiver RC, because it is coupled to this screen EC (and more precisely here to the ET television set, for example via an HDMI type socket). This parameter that is the chosen dimension is part of the data that is exchanged between the EC screen and the RC content receiver and which are designated by the English acronym EDID ("Extended Display Identification Data"). Alternatively, the selected dimension can be provided manually. FIG. 3 schematically illustrates an example of the evolution of the normalized distance dn of an observer as a function of time t. The device D is also arranged, once it has determined a normalized distance dn, to determine a normalized display resolution rn as a function of this normalized distance dn. For example, the normalized display resolution rn may be equal to the inverse of the normalized distance determined dn (ie rn = 1 / dn). Note that the device D may optionally be arranged to choose a normalized display resolution rn equal to 1 when the normalized distance dn determined is less than or equal to 1 (the value dn = 1 is here a threshold). In this case, the law of evolution of the normalized display resolution rn as a function of the normalized distance determined dn may be of typel / dn when dn is strictly greater than 1, as shown in non-limiting manner in FIG. schematically illustrated in Figure 4 an example of evolution of the normalized resolution rn images displayed by an EC screen (at the request of a device D) in the presence of the example of time evolution of the normalized distance dn of the Figure 3 and six content versions Vj (of the type shown in Figure 2). The device D is also arranged, once it has determined for a required content a display resolution (possibly normalized), to determine a version Vj of this content which is adapted to this determined display resolution, and to order to its RC content receiver to retrieve at least part of this determined content version Vj. Note that this recovery is done in a streaming mode (or streaming). To do this, one can for example use the http / TCP or RTP / UDP transport protocol. When the device D has determined for a required content a normalized display resolution rn, it can determine an intermediate value vi equal to the product of this display resolution rn by the maximum definition dm which is offered by the versions Vj of this content that is vi = rn * dm. Note that this maximum definition dm must correspond to the direction (horizontal or vertical) that was used to perform the calculation of rn. For example, this is the maximum horizontal definition. In the nonlimiting example described above with reference to FIG. 2, the maximum horizontal definition is that of the sixth version V6, which is equal to 1920 pixels. Once the device D has determined an intermediate value vi for a content, it must then determine among the different versions Vj of this content that which offers a definition which is close to this determined intermediate value vi. For example, it is possible to determine among the different versions of the content to be retrieved which offers the definition closest to the determined intermediate value vi, by higher value. For example, if the screen / observer distance d is equal to 3 meters, the width of the screen EC is equal to 94 cm and the ratio v is equal to 1.4, we obtain a normalized distance dn equal to 2 , 28 (3 / (0.94 * 1.4)) and a normalized display resolution of 0.44 (1 / 2.28). If the maximum definition dm offered by the Vj versions of the required content is equal to 1920 pixels, then the intermediate value vi is equal to 845 (1920 * 0.44). The horizontal definition that is offered by the six versions V1 to V6 of the above example and which is the nearest by higher value of the determined intermediate value vi (here equal to 845) is therefore 1109. This horizontal definition equal to 1109 pixels is here associated with the second version V2. Consequently, the device D will choose as the content version to request this second version V2 (which here corresponds to a second data transmission bit rate BR2 equal to 2 Mbps). It will be understood that to know the different versions Vj of a required content and the associated parameters (data transmission bit rate BRj and horizontal definition dhj and / or vertical dvj), the device D is preferably arranged to order its RC content receiver to retrieve from the SC server concerned the description file (s) it stores in correspondence of these Vj versions. In this case, once the RC content receiver has recovered from the SC server concerned the required description file (s), it communicates it to the device D, which makes its version selection Vj, in particular according to the estimated distance d of the observer from the EC screen. Then, the device D can start a content playback session by controlling in a substantially continuous manner the selected version Vj (or selected) of the desired content, in particular according to the estimated distance screen / observer d. The device D will then provide its content receiver RC with the designation of each version Vj that it has selected (and which is mentioned in the file (s) of description) so that it claims it from the server SC concerned. Note that when several observers are placed in front of the screen EC at different distances and that the device D is informed by the sensor CD (or the equipment of which it is part) of each of these (estimated) distance, it can be arranged to use in its determination of the display resolution (possibly normalized) the smallest distance among these different distances. This will not penalize the observer who is closest to the EC screen, because it must have the best display resolution possible. If the device D is also informed by the sensor CD (or the equipment of which it forms part) of the orientation of the head of each observer with respect to the screen EC, it can be also, although possibly, arranged to take into consideration only the observers watching this EC screen. It is considered here that the display resolution should be determined only according to the positions of the observers who look at the screen EC, and not others, even if they are placed closer to the screen 1 o EC. It will also be noted that the device D can also and possibly be arranged to require exclusively the audio data of a content version in the absence of an observer in front of the screen EC. In this case, no image is temporarily displayed on the screen EC, or a still image is displayed, since no one is looking at this screen EC. However, one continues to broadcast the soundtrack (or audio) because the observer may want to continue to listen to it even if it is temporarily hogged by another task. It will also be noted that the device D may also be and optionally arranged to automatically choose the version Vj of a required content which corresponds to the highest transmission bit rate when the current value of the available bandwidth of the communication network R is adapted to this highest transmission bit rate and at the same time there is no other application or service capable of simultaneously using this available bandwidth. This makes it possible to automatically offer an observer the best resolution possible in the absence of bandwidth need for an application or service different from the one he uses to retrieve content. It is also important to note that the invention can also be considered from the angle of a content obtaining method, which can be implemented in particular by means of a device D of the type described above. . The functionalities offered by the implementation of the method according to the invention being identical to those offered by the device D presented above, only the combination of main functionalities offered by the method is presented below. This method of obtaining contents comprises: - a step (i) of determining a display resolution according to at least one dimension and a maximum definition of the screen EC and a distance estimate separating this screen EC of an observer placed in front of the latter, then a content version adapted to this determined display resolution, and - a step (ii) of ordering the RC content receiver to recover at least part of this version of content determined. The invention is not limited to embodiments of content obtaining device, content receiver and content obtaining method described above, only by way of example, but encompasses all variants that may consider those skilled in the art within the scope of the claims below.

Claims (14)

REVENDICATIONS1. Device (D) for obtaining, in a streaming mode, multimedia contents, available in different versions corresponding to different bit rates of transmission and adapted to be transmitted to a content receiver (RC) via a network of communication (R) for display by a screen (EC), characterized in that it is arranged to determine a display resolution according to at least one dimension and a maximum definition of said screen (EC) and an estimated distance separating said screen (EC) from an observer placed in front of the latter (EC), then a content version adapted to this determined display resolution, and ordering said content receiver (RC) to recover at least part of this determined content version. 2. Device according to claim 1, characterized in that it comprises at least one sensor (CD) arranged to estimate the distance separating said screen (EC) from an observer placed in front of the latter (EC). 3. Device according to one of claims 1 and 2, characterized in that it is arranged to determine a normalized distance according to said distance estimate, a selected dimension of said screen (EC) and a representative value the ratio between a theoretical screen / observer distance, adapted to said screen (EC) for said maximum screen definition (EC), and said selected screen dimension (EC), and for determining said display resolution according to of this determined normalized distance. 4. Device according to claim 3, characterized in that said selected dimension of the screen (EC) is the width of this screen (EC) and said maximum definition of the screen (EC) is the one that it has following this width. 5. Device according to one of claims 3 and 4, characterized in that it is arranged i) to determine said display resolution by calculating the inverse of said determined normalized distance, ii) to determine an intermediate value equal to product of said display resolution by a maximum definition offered by the versions of the content to be recovered, and iii) to determine among the different versions of the content to be retrieved that which provides a definition close to said determined intermediate value. 6. Device according to one of claims 3 to 5, characterized in that it is arranged to choose a display resolution equal to 1 when said determined normalized distance is less than or equal to 1. 7. Device according to one of claims 3 to 6, characterized in that it is arranged to determine among the different versions of the content to recover the one that offers the closest definition of said determined intermediate value by higher value. 8. Device according to one of claims 1 to 7, characterized in that it is arranged to recover at least one description file stored in correspondence of the versions of a content he wishes to obtain and describing their transmission bit rates. and the respective maximum definitions offered. 9. Device according to one of claims 1 to 8, characterized in that it is arranged, in the presence of several observers placed in front of said screen (EC) at different distances, to use in the determination of said display resolution the smaller distance among said different distances. 10. Device according to claim 9, characterized in that it is arranged to take into consideration only observers looking at said screen (EC). 11. Device according to one of claims 1 to 10, characterized in that it is arranged to require exclusively the audio data of a content version in the absence of an observer in front of said screen (EC). 12. Device according to one of claims 1 to 11, characterized in that it is arranged to select the content version corresponding to the highest transmission bit rate when a current value of the available bandwidth of said network of communication (R) is adapted to this highest transmission bit rate and that there is no concurrent application capable of simultaneously using this available bandwidth. 13. Content receiver (RC), characterized in that it comprises a device for obtaining multimedia contents (D) according to one of the preceding claims. 14. Method for obtaining, in a streaming mode, multimedia contents, available in different versions corresponding to different transmission bit rates and adapted to be transmitted to a content receiver (RC) via a communication network (R) for a display by a screen (EC), characterized in that it comprises a step (i) of determining a display resolution according to at least one dimension and a maximum definition of said screen (EC) and a distance estimate separating said screen (EC) from an observer placed in front of the latter (EC), then a content version adapted to this determined display resolution, and a step (ii) of instructing said content receiver (RC) to recover at least a portion of that determined content version.