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    • 专利摘要:
    The description relates in particular to a device (DEV) for controlling Bluetooth multimedia devices, the control device comprising a Bluetooth chip (BC) arranged to implement a modified A2DP profile (A2DP ') so as to create a link (LNK ) point-to-multipoint from said Bluetooth chip to several Bluetooth multimedia devices (SPK1, SPK2, SPKN), the Bluetooth chip of the control device being arranged to broadcast a plurality of multimedia streams linked to each other to each of a respective Bluetooth multimedia device among said multiple Bluetooth multimedia devices, relying on a non-blocking use of Bluetooth. The description also relates to a method for controlling Bluetooth multimedia devices, to a computer program arranged to implement such a method and to a storage medium storing such a computer program.
    公开号:FR3054399A1
    申请号:FR1657050
    申请日:2016-07-22
    公开日:2018-01-26
    发明作者:Julien GOUPY；Thomas GIRARDIER
    申请人:Tap Sound System SAS；
    IPC主号:
    专利说明:

    Holder (s): TAP SOUND SYSTEM Simplified joint-stock company.
    Extension request (s)
    Agent (s): CABINET PLASSERAUD.
    FR 3 054 399 - A1 (54) DRIVING BLUETOOTH MULTIMEDIA DEVICES
    The description relates in particular to a device (DEV) for controlling Bluetooth multimedia devices, the control device comprising a Bluetooth chip (BC) arranged to implement a modified A2DP profile (A2DP ') so as to create a link (LNK ) point to multipoint from said Bluetooth chip to several Bluetooth multimedia devices (SPK ^ SPK 2 , SPK N ), the Bluetooth chip of the control device being arranged to broadcast several multimedia streams linked to each other to each multimedia device Respective Bluetooth among said several Bluetooth multimedia devices, based on a non-blocking use of Bluetooth. The description also relates to a method for controlling Bluetooth multimedia devices, to a computer program arranged to implement such a method as well as to a storage medium storing such a computer program.
    SEPsî

    DRIVING MULTIMEDIA BLUETOOTH DEVICES
    The description relates in particular to a device for controlling Bluetooth multimedia devices, in particular Bluetooth speakers (Bluetooth is a registered trademark of Bluetooth SIG, Inc).
    Bluetooth is a communication standard well known to those skilled in the art, defined since 1994 and managed by a group of manufacturers (Bluetooth SIG) which publishes successive versions. The current version is version 4.2 and version 5 has just been announced. Bluetooth allows a bidirectional exchange of data at short distance (we speak of a piconet network, which means a network covering a personal area). The range of a Bluetooth device is thus limited to a few tens of meters. Bluetooth uses radio waves which are in the UHF band (between 300 MHz and 3 GHz). Bluetooth aims to simplify connections between electronic devices by removing wired links. Bluetooth thus makes it possible to replace by wireless communications the cables between a master multimedia device (Hi-fi system, car radio, computer, tablet, mobile phone, etc.) and target multimedia devices such as speakers arranged to reproduce a received multimedia stream. .
    Bluetooth speakers have met with some success due to their high portability.
    However, the Bluetooth standard does not allow a Bluetooth chip to transmit several audio streams in parallel to several multimedia devices which it is desired to synchronize, if an audio data exchange profile called the A2DP profile is used. This A2DP profile does not allow point-to-multipoint synchronized transmission. The Bluetooth standard indicates in fact: The following restrictions are applied to this profile: 1. The profile does not support a synchronized point-to-multipoint distribution. (ie in French: the following restrictions apply to this profile: 1. this profile does not support point-to-multipoint synchronized distribution). Thus, it is not possible in theory to design a synchronized control device for Bluetooth multimedia devices, the synchronized control device comprising a single Bluetooth chip for controlling several multimedia devices, because Bluetooth does not allow this.
    It has already been proposed to create a point-to-multipoint Bluetooth device for several speakers. For example, application FR2920930, filed on September 6, 2007 and now definitively expired, proposed such a device. But this request did not describe how to make such a device, which seems impossible with regard to the Bluetooth standard if one uses only a Bluetooth chip. The inadequacy of the description of this request makes it impossible to draw relevant lessons from it as to how to make a point-to-multipoint link, and a fortiori a synchronized point-to-multipoint link.
    Although Bluetooth does not provide for it, it would be possible to create in a Bluetooth chip for a control device several SEPs Source in order to control several Bluetooth devices (instead of providing in a control circuit as many Bluetooth chips as there are Bluetooth devices to control). A SEP is a Stream End Point. Bluetooth communications are point-to-point between two
    SEPs. A SEP represents the resources and capacities of a device. For example, a device such as a mobile phone may have three SEPs, one representing its capabilities as a video receiver, another representing its capabilities as an audio receiver with SBC coding and one representing its capabilities. audio receiver with coded aptX. Each codec must be associated with a SEP different from that or those to which one (s) is (are) associated (s) another (s) codec (s), but the same codec can be associated with several SEPs.
    However, in the case where the Bluetooth devices are Bluetooth multimedia devices, the problem arises of synchronizing the signals transmitted to each of these Bluetooth multimedia devices in A2DP.
    The acronym A2DP stands for Advanced Audio Distribution Profile, or in French advanced audio distribution profile. The conventional A2DP profile defines a set of protocols and procedures for the exchange of audio data through the Bluetooth protocol between a master device (said Source) and a slave device (said Sink, term meaning sink in French and designating the ultimate destination of 'a stream, for example a Bluetooth speaker). This A2DP profile is built from several bricks defined by the Bluetooth standard.
    The profile is based in particular on low level bricks well known to those skilled in the art. These bricks include:
    a Baseband brick (English word meaning baseband in French, the Baseband brick being identified by the reference BB in FIG. 1), an LMP brick (acronym of English Link Manager Protocol meaning link management protocol), a L2CAP brick (acronym of the expression Logical Link Control and Adaptation Protocol meaning protocol for controlling and adapting a logical link), an SDP brick (Service Discovery Protocol, or in French: service discovery protocol). These bricks are protocols defined in the Bluetooth standard.
    The A2DP profile is also based on a high level layer called the application layer (references AASo and AASi in FIG. 1, respectively for Application Audio Source and Application Audio Sink, respectively meaning application audio source and application audio destination). It is the layer in which the device determines the transport parameters and the different services available. It is also at this level that the choice of coding used to transmit the audio data is made (which may involve decoding followed by re-encoding, when the audio stream to be transmitted is already encoded, which is usually the case).
    The A2DP profile is finally based on an AVDTP brick (acronym meaning
    Audio / Video Distribution Transport Protocol (audio / video distribution transport protocol) which defines binary transactions between Bluetooth devices for the implementation of a stream and for the broadcasting of an audio and / or video stream using L2CAP . This therefore covers procedures for establishing the audio stream, negotiating the audio stream parameters and transmitting the audio stream data. AVDTP includes a signaling entity for negotiating broadcast parameters and a transport entity to manage the flow itself. The AVDTP defines a protocol for transporting audio and / or video data. More specifically, AVDTP is interested in transporting audio and / or video data between two SEPs.
    io A limitation imposed by the AVDTP according to the Bluetooth standard is that when a connection has been negotiated between two SEPs, these two must be locked to each other for the broadcast of the stream. By default, a connected SEP refuses any new connection. On recent Bluetooth products, a so-called social mode function (social mode in French) can sometimes change this behavior by default. But this social mode function which allows a new connection interrupts the current connection. We can therefore be in the presence, for example, of two telephones connected to the same Bluetooth speaker. But you cannot set up several simultaneous transports. Switching to a new connection is typically done by terminating the previous connection while keeping the previously connected phone in memory. Consequently, if there is only one single source audio SEP on a Source device, then only one AVDTP transport can be established to a given Sink device at a given time, according to the Bluetooth standard.
    The L2CAP layer defines the minimum data exchange protocol of the Bluetooth specification. The L2CAP layer notably allows the segmentation and reassembly of packets, multiplexing and quality of service. It is from this L2CAP layer that the various transport protocols (such as AVDTP) are based on the various Bluetooth profiles (such as A2DP). An L2CAP channel is created between a CID (Channel Identifier, meaning channel identifier in French) of a master device and a CID of a slave device, allowing the exchange of data between these two devices. The L2CAP channels are each the subject of a configuration allowing in particular to manage the control of the data flows passing through the channels that L2CAP defines (L2CAP channels). For this, different parameters can be taken into account independently for each L2CAP channel, in particular:
    • An FTO or Flush Timeout parameter defines the expiration time of a data packet in a buffer of a master device. This delay is infinite by default (blocking mode), which means that a transmitted packet which does not reach its destination is returned until no packet (the initial packet or the returned packets) has reached its destination. However, the delay can also be such that there is never any retransmission (if the Flush Timeout parameter is set to an appropriate value defined by the Bluetooth standard), which amounts in a way to zero delay. The delay can also take a finite value. There is also a Boolean variable called in English flag nonautomatically flushable (meaning in French: flag no automatic deletion) present in Bluetooth packets, allowing to indicate that the packet concerned cannot be deleted automatically.
    • A QoS parameter (acronym of the English expression Quality of service meaning quality of service) allowing to define in particular the maximum latency between the taking into account of a packet to be transmitted in an L2CAP channel and its effective transmission.
    • Parameters called Extended Flow features (replacing extended flow characteristics in English), replacing and completing the combination of the Flush Timeout and QOS parameters mentioned above.
    These parameters are negotiated between the Bluetooth stack of a master Bluetooth device and the Bluetooth stack of a slave Bluetooth device and, apart from the default values, are not always supported.
    L2CAP allows the implementation of different modes. These modes are also parameters of the L2CAP channels, in the same way as the Extended Flow features parameters or the Flush Timeout parameter.
    All of these parameters (including modes) allow you to modify the flow control. Each mode defines different procedures for managing data flows. Within the framework of conventional Bluetooth (known as BR / EDR) five operating modes are possible for an L2CAP channel. These modes are:
    • Basic Mode (meaning basic L2CAP mode in French), • Flow Control Mode (meaning flow control mode in French), • Retransmission Mode (meaning retransmission mode in French), • Enhanced Retransmission Mode (known as ERTM, and meaning io retransmission mode increased in French) and • Streaming Mode (known as SM, and meaning mode of distribution in French).
    Basic Mode is the default mode and is supported by all Bluetooth batteries. It does not require any configuration. Flow Control Mode sends packets but never retransmits lost packets. However, these packets (called PDUs) are detected when they are lost, and the Flow Control Mode allows the communication of a report listing the lost packets. Flow Control Mode and Retransmission Mode can only be used if the ERTM and SM are not usable. These two modes (Flow Control Mode and Retransmission Mode) are practically no longer used. The ERTM allows in particular to take into account a given maximum number of retransmissions, a maximum given duration during which a retransmission can take place and makes it possible to identify packets which are not or badly transmitted. The SM is suitable for asynchronous data flows. It takes into account a finite Flush Timeout parameter. On the side of the Bluetooth receiver, if the buffer memory is full, then the previous data is overwritten.
    In the Bluetooth standard, a parameter called Retransmission and flow control option, which means retransmission and flow control option, allows you to choose a mode. The Bluetooth standard recommends establishing reliable connections (reliable in English) limiting data loss, using a Basic Mode with an infinite Flush Timeout, or on more recent Bluetooth batteries the ERTM with any Flush Timeout.
    In practice, no product on the market offers a A2DP point to multipoint synchronized control function for any Bluetooth multimedia devices.
    io The invention aims to improve the situation.
    The invention relates in particular to a device for controlling Bluetooth multimedia devices, the control device comprising a Bluetooth chip arranged to implement an A2DP profile modified so as to create a point-to-multipoint link from said Bluetooth chip to several multimedia devices. Bluetooth, the Bluetooth chip of the control device being arranged to broadcast several multimedia streams linked to each other each intended for a respective Bluetooth multimedia device among said several Bluetooth multimedia devices, based on a non-blocking use of Bluetooth.
    This device is advantageous in that it makes it possible to use a single Bluetooth chip to control several Bluetooth multimedia devices, even though the Bluetooth standard does not provide for such a possibility. It is thus possible to modify the A2DP profile without violating the Bluetooth standard, by allowing a point-to-multipoint link not provided for in the standard. This preserves interoperability (Bluetooth functions are supported normally). There is no violation of the Bluetooth standard insofar as the device only adds a function not initially planned without calling into question the existing functions. In addition, the non-blocking use of Bluetooth makes it possible to prevent desynchronization of the broadcast multimedia streams.
    The device according to the invention may include one or more of the following characteristics taken alone or in combination.
    The invention relates in particular to a device for controlling Bluetooth multimedia devices in which the Bluetooth chip is arranged, when a multimedia stream packet which it has transmitted destined for a Bluetooth multimedia device is lost, to return said packet multimedia stream to said Bluetooth multimedia device, the Bluetooth chip being arranged to determine a filling rate of a buffer memory of at least one Bluetooth multimedia device, and to determine a maximum duration during which it can resend the multimedia stream packet lost to the Bluetooth multimedia device as a function of the filling rate of the buffer memory of the at least one Bluetooth multimedia device.
    The invention relates in particular to a device for controlling Bluetooth multimedia devices in which the Bluetooth chip is arranged to generate several SEPs for controlling Bluetooth multimedia devices.
    The invention relates in particular to a device for controlling Bluetooth multimedia devices in which the Bluetooth chip is arranged to control up to five Bluetooth multimedia devices, using an SBC code.
    The invention relates in particular to a method for controlling Bluetooth multimedia devices in which the Bluetooth chip implements an A2DP profile modified so as to create a point-to-multipoint link from said Bluetooth chip to several Bluetooth multimedia devices, the Bluetooth chip broadcasting several multimedia streams linked to each other each intended for a respective Bluetooth multimedia device among said several Bluetooth multimedia devices, based on a non-blocking use of Bluetooth.
    The invention relates in particular to a method for controlling Bluetooth multimedia devices in which, when a multimedia stream packet that the Bluetooth chip transmitted to a Bluetooth multimedia device is lost, the Bluetooth chip returns said stream packet multimedia to said Bluetooth multimedia device, and determines a filling rate of a buffer memory of at least one Bluetooth multimedia device, to deduce therefrom a maximum duration during which it can send back the lost multimedia stream packet to the multimedia device
    Bluetooth according to the filling rate of the buffer memory of the at least one Bluetooth multimedia device.
    The invention relates in particular to a method for controlling Bluetooth multimedia devices in which the Bluetooth chip generates several SEPs for controlling Bluetooth multimedia devices.
    The invention relates in particular to a method for controlling Bluetooth multimedia devices in which the Bluetooth chip controls five Bluetooth multimedia devices using an SBC code.
    The invention relates in particular to a computer program comprising a series of instructions which, when executed by a processor, implement a method according to one aspect of the invention.
    The invention relates in particular to a non-transient storage medium readable by computer, storing a computer program according to one aspect of the invention.
    Other characteristics and advantages of the invention will appear on reading the description which follows. This is purely illustrative and should be read in conjunction with the accompanying drawings in which:
    - Figure 1 illustrates a conventional A2DP profile as well as an A2DP 'profile according to an embodiment of the invention arranged to communicate with the conventional A2DP profile;
    - Figure 2 illustrates a system comprising a device according to an embodiment of the invention as well as a set of Bluetooth speakers;
    - Figure 3 illustrates a variant of the system of Figure 2.
    The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each element mentioned within the framework of an embodiment relates only to this same embodiment, or only to characteristics of this embodiment. only apply to this embodiment.
    FIG. 1 illustrates a communication between an A2DP 'profile according to an embodiment of the invention used by a so-called Source master device (which corresponds to a device emitting an audio stream) and a conventional A2DP profile used by a Sink device. The Sink device corresponds for example to a Bluetooth speaker, it being understood that a Bluetooth speaker can comprise several Sink SEPs (several Sink SEPs can therefore correspond to the same Bluetooth speaker, each Sink SEP can then correspond in particular to a respective coded among all the supported by this Bluetooth speaker).
    In practice, Bluetooth batteries from Bluetooth chip manufacturers introduce only one SEP Source per codec and per Bluetooth chip. It is therefore impossible to connect several audio devices (speakers for example) to a mobile phone, for a given codec.
    The A2DP profile 'is precisely distinguished from the A2DP profile by an AVDTP brick' used in place of the AVDTP brick. The AVDTP brick provides all the functions of the AVDTP brick, but also allows a synchronized point-to-multipoint connection.
    FIG. 2 illustrates a system comprising at least three enclosures
    Bluetooth SPKi, SPK 2 and SPKn each associated with a respective SEP Sink
    SPEsi, SEPs2, SEPsn (as mentioned above, each enclosure
    SPKi could be associated with several Sink SEPs rather than a single SEP
    Sink SEPsî, but to simplify only the SEP Sink actually used is shown). The system also includes a device DEV 'for controlling Bluetooth speakers according to a possible implementation of the invention. The device DEV 'includes a Bluetooth BC chip'. This Bluetooth BC 'chip stores a unique SEP USEP identifying it. This Bluetooth BC chip 'establishes a point-to-multipoint link LNK' with the three Bluetooth speakers SPKi, SPK 2 and SPK N , via respective SEPs SEP S i, SEP S2 and SPE sn .
    FIG. 3 illustrates a system comprising at least three io Bluetooth speakers SPKi, SPK 2 and SPKn each associated with a respective SEP Sink SPE S i, SEP S 2, SEPsn (as mentioned above, each SPKi speaker could be associated with several SEPs Sink rather than a single SEP Sink SEPsî, but to simplify only the SEP Sink actually used is shown). The system also includes a device DEV for controlling Bluetooth speakers according to a possible implementation of the invention. The DEV device includes a Bluetooth BC chip. This Bluetooth BC chip stores at least three SEPs SEPi, SEP 2 and SEPn which simulate three separate Bluetooth chips (but these are virtual Bluetooth chips because in reality there is only one). The Bluetooth BC chip establishes a point-to-multipoint LNK connection with the at least three SPK 1 Bluetooth speakers ; SPK 2 and SPK N , but from the Bluetooth standard point of view, this LNK link seems to be a set of three (at least) point-to-point links. Indeed, the SEP SEPi is connected to a SEP SEPsî of the SPKi enclosure, the SEP SEP 2 is connected to a SEP SEP S2 of the SPK 2 enclosure and the SEP SEP N is connected to a SEP SEP sn of the SPK N enclosure.
    A first embodiment relates to a device (for example DEV or DEV ') for controlling Bluetooth multimedia devices, the control device comprising a Bluetooth chip (for example BC or BC').
    Bluetooth multimedia devices are for example Bluetooth speakers. By Bluetooth speaker, we mean any Bluetooth device containing at least one speaker arranged to broadcast a sound perceptible simultaneously by several human beings. It can for example be an acoustic speaker for a hi-fi system, or even a portable telephone provided with a loudspeaker intended to be audible by several people, insofar as it is this loudspeaker which is piloted by the piloting device. More precisely, by its perceptible sound is meant simultaneously by several human beings a perceptible sound (in the sense that its content can be distinguished) by any human being endowed with normal hearing placed at a distance of at least one meter from the speaker, in the presence of an ambient noise corresponding to that of a conversation, that is to say approximately 40 dB SPL. An audio headset, an in-ear earpiece or even a telephone earpiece are therefore not speakers within the meaning of the present application, since they must be applied in or against the ear to perceive the sounds emitted.
    According to one possible implementation, the Bluetooth multimedia devices are Bluetooth headphones. Such headphones are for example connected to a television and need to be synchronized with each other in addition to being synchronized with a video stream broadcast on the television.
    Each of the Bluetooth multimedia devices can be, more generally, a Bluetooth television, a Bluetooth screen, a Bluetooth mobile phone, a Bluetooth laptop or desktop computer, a Bluetooth tablet, a Bluetooth hi-fi system, a Bluetooth car radio, or even a Bluetooth digital music player.
    The DEV or DEV 'control device is for example a Bluetooth television, a Bluetooth screen, a Bluetooth mobile phone, a Bluetooth laptop or desktop computer, a Bluetooth tablet, a Bluetooth hi-fi system, a Bluetooth car radio, or even a Bluetooth digital music player.
    The Bluetooth chip (for example BC or BC 'in the figures) is arranged to implement a modified A2DP profile (denoted A2DP' in Figure 1) so as to create a point to multipoint link (for example LNK or LNK ') from said Bluetooth chip to several Bluetooth multimedia devices
    SPKi, SPK 2 , SPKn. The Bluetooth chip of the control device is arranged to broadcast several multimedia streams linked to each other each intended for a respective Bluetooth multimedia device among said several Bluetooth multimedia devices by relying on a non-blocking use of Bluetooth. By multimedia streams linked to each other, it is meant that the multimedia streams relate to the same situation (for example the same scene, or the same music), but can nevertheless be different. For example, the multimedia streams can be six audio streams each corresponding to one of the 5.1 channels of an audio recording, or else can be several videos of the same scene, filmed at the same time but from different points of view. The control device is for example arranged to emit an audio stream (or more generally multimedia) via a wireless link of Bluetooth type. For example, it stores or relays a multimedia stream comprising at least one audio channel. For example, it stores MP3 files, or connects to a server (such as a Youtube® server) from which it downloads a stream which it transmits progressively, simultaneously, via Bluetooth, to several multimedia devices Bluetooth.
    By relying on a non-blocking use of Bluetooth instead of a blocking use used by default in A2DP, the control device avoids loss of synchronization. By non-blocking use of Bluetooth, we mean any configuration of Bluetooth (by a Bluetooth mode and / or by other Bluetooth parameters) which avoids blocking the Bluetooth chip of the device for controlling Bluetooth multimedia devices. A non-blocking use of Bluetooth is therefore a use of Bluetooth which avoids forcing the Bluetooth chip to retransmit a packet which has not been received until it has been received, and which also avoids forcing it to re-transmit such a packet to beyond a time when at least one Bluetooth multimedia device has no more data in the buffer memory, for example because of the unsuccessful attempts to retransmit the packet, which monopolize Bluetooth communications. Non-blocking use corresponds to a set of parameters (FTO, QoS, Mode, Extended Flow features) and not only to a mode (such as SM mode) within the meaning of the Bluetooth standard. This is for example the Flow Control mode or any mode for which the Flush Timeout parameter is fixed according to the Bluetooth standard to prevent any retransmission. A blocking use is a contrario a use which leads for example to re-emit data as long as they are not received, or which leads to re-emit data whereas a multimedia multimedia device with higher priority also waited for data and did not not received because of said use (it is then blocked). Blocking usage is used in the prior art because it avoids occasional loss of data (in the event of prolonged outage for a duration greater than a given threshold io blocking does not make it possible to avoid data loss). In the event that Bluetooth is adapted to allow point-to-multipoint broadcasting, using non-blocking use avoids the risk that a Bluetooth multimedia device becomes inaccessible and prevents any data transmission to all Bluetooth multimedia devices. A multimedia device
    Bluetooth may become inaccessible for example because it has been moved out of range of the DEV driver's Bluetooth chip, or because it contains a discharged battery, or for any other reason.
    The default Bluetooth L2CAP settings recalled in the introduction are not suitable for setting up an A2DP synchronized link from a master Bluetooth device to several slave Bluetooth devices. Indeed if one of the links established between the master and a slave (for example a speaker) is configured with an infinite Flush Timeout, and if the speaker leaves the Bluetooth field or if it is powered by a battery which has emptied, then the data will be continuously sent back to it which, never receiving it, will block any other data transmission to the other slave devices (the data being sent sequentially). In addition, if the Flush Timeout parameter is set by default, the return of data to one speaker could cause a time difference between this and the others. In fact, when a speaker leaving the Bluetooth field of the master Bluetooth device returns to this field, it would continue to broadcast the stream from the moment it stopped by leaving this field.
    According to a possible implementation, the device for controlling Bluetooth multimedia devices is arranged to automatically determine, from the different configurations supported by the Bluetooth batteries of the Bluetooth multimedia devices, the configuration to be adopted for each L2CAP channel (corresponding to a logical link between the Bluetooth chip of the Bluetooth speaker control device and a Bluetooth multimedia device) so as to keep a synchronized link between the Bluetooth multimedia device control device and the various slave multimedia devices. The L2CAP parameters of each of the multimedia devices can be different (they can depend on the characteristics of these multimedia devices, on their ability to support certain protocols, etc.).
    According to a possible implementation, the device for controlling Bluetooth multimedia devices is designed to configure all of the Flushes
    Timeout for the various L2CAP channels at the value defined by the Bluetooth standard (i.e. 1, but this could vary depending on the implementation) so that no retransmission is carried out. The link thus obtained is unreliable in the sense that transmission errors or losses are not caught, but ensures synchronization after possible loss of packets.
    According to a possible implementation, the modification of the A2DP profile consists in modifying the AVDTP brick used by the A2DP profile, for example in one of the ways indicated below. In order to produce an AVDTP brick corresponding to a modified AVDTP brick, it is possible in particular to use a free implementation such as the implementation called BlueZ (well known to those skilled in the art), designed to implement Bluetooth technology on Linux operating systems, and available under the GNU GPL license. The BlueZ implementation has become a benchmark Bluetooth implementation for Linux and has been integrated into the Linux kernel.
    According to a second embodiment, the Bluetooth chip of a device for controlling Bluetooth multimedia devices according to the first embodiment is arranged, when a multimedia stream packet which it has transmitted intended for a Bluetooth multimedia device is lost, to return said multimedia stream packet to said multimedia device
    Bluetooth. The Bluetooth chip being arranged to determine a filling rate of a buffer memory of at least one Bluetooth multimedia device SPK 1; SPK 2 , SPK N and to determine a maximum duration during which it can send back the lost multimedia stream packet to the Bluetooth multimedia device as a function of the filling rate of the buffer memory of the at least one Bluetooth multimedia device.
    According to one possible implementation, this maximum duration corresponds to the least full buffer memory among the buffer memories of all the other Bluetooth multimedia devices, from which the time necessary to transmit a sufficient portion of multimedia stream must be deducted. The content of the buffer of the Bluetooth multimedia device which lost a packet is therefore not taken into account.
    According to another implementation, this maximum duration corresponds to the least full buffer memory among the buffers of all Bluetooth multimedia devices (including the one which lost the packet), from which the time necessary to transmit a portion must be deducted. sufficient multimedia stream. Indeed, if the Bluetooth multimedia device which lost the packet runs the risk of running out of multimedia stream data to play, it may be considered more appropriate to abandon the attempt to retransmit the lost packet which would in any case be delayed and therefore out of sync with other Bluetooth multimedia devices.
    According to another implementation, the Bluetooth chip is arranged to identify Bluetooth multimedia devices for which it is not useful to check the filling rate of the buffer memory. For example, the Bluetooth chip can exclude a number n of Bluetooth multimedia devices whose buffers it last supplied, if it can deduce that there are necessarily other multimedia devices
    Bluetooth whose buffer memory is less full and which will determine the aforementioned maximum duration.
    According to another implementation, the Bluetooth chip is arranged to store an identifier of the Bluetooth multimedia device for which it has supplied the buffer memory for the longest time. When a packet is lost, the Bluetooth chip then checks only the buffer memory of this Bluetooth multimedia device for which it has supplied the buffer memory for the longest time.
    According to a possible implementation, the control device is arranged io to transmit portions of audio stream of approximately 14 ms (which corresponds to the duration of a block of audio stream encoded by the coded SBC). According to one possible implementation, the piloting device controls four Bluetooth multimedia devices, and the transmission of a portion of approximately 14 ms takes approximately 1.3 ms. It therefore takes approximately 4 * 1.3 ms or approximately 5.2 ms to transmit approximately 14 ms of flow to the four Bluetooth multimedia devices, which leaves approximately 14 ms-5.2 ms or approximately 8.8 ms during which the control device can identify the packets badly or not transmitted and re-issue them.
    According to one possible implementation, the device for controlling Bluetooth multimedia devices is arranged to configure the Flush Timeout of each L2CAP channel as a function of the filling status of the buffers of the Bluetooth multimedia devices, which it must first estimate by example by one of the above methods.
    According to one possible implementation, the Bluetooth chip of a device for controlling Bluetooth multimedia devices according to the first embodiment is arranged to generate a single SEP for controlling all the Bluetooth multimedia devices. More specifically, the A2DP profile of the SEP Source (the Bluetooth chip) is modified, for example by replacing a conventional AVDTP brick with a modified AVDTP 'brick. The modification consists in removing the restrictions preventing a SEP
    Source to connect to more than one SEP Sink. However, the Bluetooth standard does not involve checking, at the level of a SEP Sink, that the Source SEP with which it dialogues does not also dialogue with another SEP Sink. It turns out that we can technically, from the same
    SEP Source, broadcast multimedia streams (in particular audio) to several Sink SEPs from the same Bluetooth chip.
    Since the Bluetooth standard does not allow communication from a Source SEP to several Sinks SEPs, this implementation constitutes a kind of extension to the Bluetooth standard, an extension which does not generate any difficulties insofar as the Bluetooth standard does is not intended to detect such an extension.
    Of course, it is possible to provide in the device for controlling Bluetooth multimedia devices several Bluetooth chips each arranged to generate a single SEP for controlling the multimedia devices
    Bluetooth respectively managed by each of them. For example, a Bluetooth number 1 chip could manage multimedia devices number 1 to 5, a Bluetooth number 2 chip could manage multimedia device numbers 6 to 10 and a Bluetooth number 3 chip could manage multimedia device numbers 11 to 15. Indeed , the maximum speed of a Bluetooth chip limits the number of multimedia devices it can control, and if the number of multimedia devices exceeds a given threshold, adding a Bluetooth chip allows you to control additional multimedia devices simultaneously.
    According to a third embodiment, the Bluetooth chip of a device for controlling Bluetooth multimedia devices according to the first or second embodiment is arranged to generate several SEPs for controlling Bluetooth multimedia devices.
    According to an advantageous implementation, the Bluetooth chip generates a
    SEP Separate source for each SEP Sink (corresponding to each Bluetooth multimedia device that it must control). This is an alternative to the above implementation, in which the Bluetooth chip conforms more to the Bluetooth standard. Indeed, we have point-to-point links, and not a point-to-multipoint link. But it is of course a device, which consists in generating a multiplicity of virtual Source SEPs in the same Bluetooth chip to simulate a multiplicity of Source devices where there is actually only one Bluetooth chip.
    Of course, it is possible to provide in the device for controlling Bluetooth multimedia devices several Bluetooth chips each arranged to generate as many Source SEPs as there are Bluetooth multimedia devices managed respectively by each of them. For example, a Bluetooth number 1 chip could manage Bluetooth multimedia devices number 1 to 5 using respective SEPs Source SEPi to SEP 5 , a Bluetooth number 2 chip could manage Bluetooth multimedia devices number 6 to 10 using from respective SEPs Source SEP 6 to SEP 10 and a Bluetooth number 3 chip could manage Bluetooth multimedia devices numbers 11 to 15 using respective SEPs Source SEPu to SEP15. In fact, the maximum speed of a Bluetooth chip limits the number of multimedia devices that it can control, and if the number of multimedia devices exceeds a given threshold, adding a Bluetooth chip makes it possible to control additional multimedia devices simultaneously. The number of Source SEPs generated by a Bluetooth chip does not influence the bandwidth available in this Bluetooth chip, which remains the same but is shared between these different Source SEPs. According to a possible implementation, the Bluetooth chip creates a maximum of 7 source SEPs in order to manage the Bluetooth multimedia devices that it controls using a piconet. A piconet is a network comprising from 1 to 8 Bluetooth devices, including a single master Bluetooth device (i.e. Source) and up to 7 slave Bluetooth devices (i.e. Sink), such as this is specified by the Bluetooth standard. The limitation to 7 Sink devices per Source device comes from Bluetooth addressing which identifies each slave Bluetooth device using three bits, the combination 000 being reserved for a specific mode called "Connectionless Broadcast". ).
    According to a fourth embodiment, the Bluetooth chip of a device for controlling Bluetooth multimedia devices according to one of the first to third embodiments is arranged to control up to five Bluetooth multimedia devices, using an SBC coded. By controlling up to five Bluetooth multimedia devices, it is understood that whatever the SBC audio stream broadcast, it is possible to broadcast this stream on five speakers. If there are less than five speakers, it is a fortiori possible.
    A CD-quality stereo audio stream is sampled at 44.1 kHz and samples the 16-bit audio signal. Every second, 44,100 16-bit samples are provided for the left channel and 44,100 other 16-bit samples are provided for the right channel. The gross speed of such a flow is therefore 44 100 * 2 * 16 bit / s, which is a little more than
    1.4 Mbit / s. Such a speed is very important, and it is therefore useful to compress it in order to reduce the bandwidth required during a transmission, in particular a Bluetooth transmission whose speed is not very high. To perform this compression, codecs are used. The SBC codec is a very simple and very effective codec. By effective is meant that the SBC coded requires very little memory and processor resources to operate. This is very useful for Bluetooth chips, which are often limited in memory in computing power. The SBC code is also free. It is also advantageous because it is very widespread, and thus ensures great interoperability. However, it is not very efficient from the point of view of the compression rate obtained and the audio quality. The bit rate of an audio stream encoded by an SBC coded is a maximum of 372 kbit / s (in some cases, SBC generates a lower bit rate, in particular to adapt to the available bandwidth, and thus makes it possible to control if necessary more than five Bluetooth multimedia devices). But more efficient codecs exist. For example, an AAC codec generates a compressed audio stream of approximately 192 kbit / s of quality roughly equivalent to that of an SBC stream at 372 kbit / s. The coded apt-X also allow improved performance (lower bit rate at equivalent quality), but are not free.
    The Bluetooth bandwidth for EDR compatible devices (acronym of English origin meaning Enhanced Data Rate or increased data rate) like conventional Bluetooth speakers is 2.1 Mbit / s. It is thus possible to pass at least five streams encoded by an SBC codec (at 372 kbit / s maximum) in the available bandwidth.
    According to one possible implementation, the Bluetooth chip uses an AAC coded, which in theory makes it possible to transmit ten (almost eleven) io streams encoded in AAC at 192 kbit / s. It is nevertheless advantageous, according to a possible implementation, to limit the number of AAC streams to seven in order to be able to set up a piconet according to the Bluetooth standard (which limits the number of slave devices to 7). According to other alternatives, other coded ones are used, and make it possible to transmit up to seven encoded streams, or less if the bit rate of the encoded stream is greater than 300 kbit / s (in this case the number of possible encoded streams is equal to the ratio of 2,100,000 by the bit rate of an encoded stream expressed in bit / s).
    A fifth embodiment relates to a method for controlling Bluetooth multimedia devices by a Bluetooth chip. The Bluetooth chip implements a modified A2DP profile (denoted A2DP ') so as to create a point-to-multipoint link from said Bluetooth chip to several Bluetooth multimedia devices, the Bluetooth chip broadcasting several multimedia streams linked to each other at each destination. a respective Bluetooth multimedia device among said several Bluetooth multimedia devices, based on a non-blocking use of Bluetooth.
    According to one possible implementation, the Bluetooth chip comprises a processor and executes a computer program adapted to implement an A2DP 'profile so as to create a point-to-multipoint link from said Bluetooth chip to several Bluetooth multimedia devices, the chip Bluetooth broadcasting several multimedia streams linked to each other each destined for a respective Bluetooth multimedia device among said several Bluetooth multimedia devices, based on a non-blocking use of Bluetooth.
    According to an alternative implementation, it is a device for controlling Bluetooth multimedia devices comprising said Bluetooth chip which also includes a processor and executes a computer program suitable for implementing an A2DP 'profile so as to create a point link. to multipoint from said Bluetooth chip to several Bluetooth multimedia devices, the Bluetooth chip broadcasting several multimedia streams linked to each other, each intended for a respective Bluetooth multimedia device among said several Bluetooth multimedia devices, based on non-use Bluetooth blocker.
    In the two above-mentioned implementations, the computer program is stored in a memory (for example of the EEPROM, Flash or ROM type). This memory can be installed in the Bluetooth chip or in the device for controlling Bluetooth multimedia devices, outside the Bluetooth chip. According to a variant, the computer program is stored partly in the Bluetooth chip, and partly in the device for controlling Bluetooth multimedia devices. According to a variant, the device for controlling Bluetooth multimedia devices and the Bluetooth chip each comprise at least one separate processor, and each execute a part of the computer program, which is stored either in a single place (single memory chip) or distributed way on several memory chips (for example a memory chip of the Bluetooth chip and a memory chip of the device for controlling Bluetooth multimedia devices).
    According to another implementation, the method is implemented not by a computer program but by a dedicated electronic chip, which is for example an FPGA or any other suitable circuit, including an ad hoc circuit. According to a variant, the method is implemented partially by a dedicated electronic chip such as the aforementioned dedicated chip, and partially by a processor executing an appropriate computer program.
    According to a sixth embodiment, the Bluetooth chip of a method for controlling Bluetooth multimedia devices according to the fifth embodiment, when a packet of multimedia streams that the Bluetooth chip transmitted to a Bluetooth multimedia device is lost , returns said multimedia stream packet to said Bluetooth multimedia device, and determines a filling rate of a buffer memory of each Bluetooth multimedia device SPKi, SPK 2 , SPKn, to deduce therefrom a maximum duration during which it can resend the packet of multimedia stream lost to the Bluetooth multimedia device as a function of the filling rate of the buffer memory of the Bluetooth multimedia devices.
    According to a seventh embodiment, the Bluetooth chip of a method for controlling Bluetooth multimedia devices according to the fifth or sixth embodiment generates several SEPs 1 SEP ; SEP 2 , ... SEP N to control the Bluetooth multimedia devices SPKi, SPK 2 , ... SPKn.
    According to an eighth embodiment, the Bluetooth chip of a method for controlling Bluetooth multimedia devices according to one of the fifth to seventh embodiments controls five Bluetooth multimedia devices using an SBC code.
    A ninth embodiment relates to a computer program comprising a series of instructions which, when executed by a processor, implement a method according to one of the fifth to eighth embodiments. This computer program is for example written in a low level language such as an assembly language, or in a higher level and more portable language, such as the C language. According to a possible implementation, the program computer is divided into several modules. According to a possible implementation, the different modules are all written in the same language, for example C language or the assembler. According to an alternative, certain modules are written in different languages, for example certain modules are written in C language, others in assembly language. According to a possible implementation, all the modules are stored in the same memory. According to an alternative, certain modules are stored in separate memories.
    A tenth embodiment relates to a non-transient computer-readable storage medium storing a computer program according to the ninth embodiment. Depending on a possible implementation, the storage medium is a USB key, an SD card or a micro SD card. According to a variant, the storage medium is any memory card. According to another variant, the storage medium is a memory chip which is intended to be mounted on an electronic circuit. This is for example an EEPROM, ROM, or even Flash memory. According to a possible variant, the storage medium is a magnetic medium (for example of the hard disk type) or even an optical medium (for example of the CD type or
    DVD).
    The invention is not limited to the embodiments described above by way of examples. The memories that can be used cover any type of memory.
    The embodiments described in relation to the device for controlling Bluetooth multimedia devices can be transposed to the methods for driving Bluetooth multimedia devices, as well as to computer programs and program storage media according to embodiments of the invention, and vice versa.
    权利要求:
    Claims (10)
    [1" id="c-fr-0001]
    1. Device (DEV, DEV ') for piloting Bluetooth multimedia devices 5, the piloting device comprising a Bluetooth chip (BC, BC') arranged to implement a profile A
    [2" id="c-fr-0002]
    2DP modified (A2DP ') so as to create a point-to-multipoint link (LNK, LNK') from said Bluetooth chip to several Bluetooth multimedia devices (SPK-ι, SPK 2 , SPK N ), the Bluetooth chip of the control device being arranged to io broadcast several multimedia streams linked to each other each intended for a respective Bluetooth multimedia device among said several Bluetooth multimedia devices, based on a non-blocking use of Bluetooth.
    2. A device for controlling Bluetooth multimedia devices according to claim 1, in which the Bluetooth chip is arranged, when a multimedia stream packet which it has transmitted destined for a Bluetooth multimedia device is lost, to return said packet multimedia stream to said Bluetooth multimedia device, the Bluetooth chip being
    20 arranged to determine a filling rate of a buffer memory of at least one Bluetooth multimedia device (SPK-ι, SPK 2 , SPK N ), and to determine a maximum duration during which it can send back the lost multimedia stream packet to the Bluetooth multimedia device according to the filling rate of the buffer memory of the at least one
    25 Bluetooth multimedia device.
    [3" id="c-fr-0003]
    3. Device (DEV) for controlling Bluetooth multimedia devices according to claim 1 or 2, in which the Bluetooth chip (BC) is arranged to generate several SEPs for controlling Bluetooth multimedia devices.
    [4" id="c-fr-0004]
    4. Device for controlling Bluetooth multimedia devices according to one of the preceding claims, in which the Bluetooth chip is arranged to control up to five Bluetooth multimedia devices, using an SBC code.
    [5" id="c-fr-0005]
    5. Method for controlling Bluetooth multimedia devices by a Bluetooth chip, in which the Bluetooth chip implements a modified A2DP profile (A2DP ') so as to create a point-to-multipoint link from said Bluetooth chip to several Bluetooth multimedia devices, the puce io Bluetooth broadcasting several multimedia streams linked to each other each intended for a respective Bluetooth multimedia device among said several Bluetooth multimedia devices, based on a non-blocking use of Bluetooth.
    15
    [6" id="c-fr-0006]
    6. Method for controlling Bluetooth multimedia devices according to claim 5, in which, when a multimedia stream packet that the Bluetooth chip transmitted to a Bluetooth multimedia device is lost, the Bluetooth chip returns said multimedia stream packet said Bluetooth multimedia device, and determines a filling rate of a
    20 buffer memory of at least one Bluetooth multimedia device (SPK-i, SPK 2 , SPK N ), in order to deduce therefrom a maximum duration during which it can send back the lost multimedia stream packet to the Bluetooth multimedia device according to the filling rate the buffer memory of the at least one Bluetooth multimedia device.
    [7" id="c-fr-0007]
    7. Method for controlling Bluetooth multimedia devices according to claim 5 or 6, in which the Bluetooth chip generates several SEPs (SEP-i, SEP 2 , SEP n ) for controlling the Bluetooth multimedia devices (SPK-i, SPK 2 , SPK N ).
    [8" id="c-fr-0008]
    8. Method for controlling Bluetooth multimedia devices according to one of claims 5 to 7, in which the Bluetooth chip controls five Bluetooth multimedia devices using an SBC code.
    5
    [9" id="c-fr-0009]
    9. Computer program comprising a series of instructions which, when executed by a processor, implement a method according to one of claims 5 to 8.
    [10" id="c-fr-0010]
    10. A non-transient computer-readable storage medium storing a computer program according to claim 9.
    1/2
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    同族专利:
    公开号 | 公开日
    US10244018B2|2019-03-26|
    CN109661828A|2019-04-19|
    EP3273705A1|2018-01-24|
    EP3273705B1|2018-10-17|
    JP2019531669A|2019-10-31|
    FR3054399B1|2018-08-03|
    WO2018015439A1|2018-01-25|
    KR20190033525A|2019-03-29|
    US20180027034A1|2018-01-25|
    JP6949956B2|2021-10-13|
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    法律状态:
    2017-07-26| PLFP| Fee payment|Year of fee payment: 2 |
    2018-01-26| PLSC| Search report ready|Effective date: 20180126 |
    2018-05-29| PLFP| Fee payment|Year of fee payment: 3 |
    2019-05-24| PLFP| Fee payment|Year of fee payment: 4 |
    2021-04-09| ST| Notification of lapse|Effective date: 20210305 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1657050|2016-07-22|
    FR1657050A|FR3054399B1|2016-07-22|2016-07-22|CONTROL OF BLUETOOTH MULTIMEDIA DEVICES|FR1657050A| FR3054399B1|2016-07-22|2016-07-22|CONTROL OF BLUETOOTH MULTIMEDIA DEVICES|
    KR1020197001645A| KR20190033525A|2016-07-22|2017-07-19|Bluetooth Multimedia Device Control|
    EP17182123.4A| EP3273705B1|2016-07-22|2017-07-19|Controlling bluetooth multimedia devices|
    PCT/EP2017/068234| WO2018015439A1|2016-07-22|2017-07-19|Controlling bluetooth multimedia devices|
    JP2019524515A| JP6949956B2|2016-07-22|2017-07-19|Control of bluetooth multimedia devices|
    CN201780045417.1A| CN109661828A|2016-07-22|2017-07-19|Control bluetooth multimedia device|
    US15/655,585| US10244018B2|2016-07-22|2017-07-20|Controlling bluetooth multimedia devices|
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