Method for determining an audio data spatial encoding mode

1. A method of determining a spatial coding mode for audio data, the audio data being coded and sent by a sender entity ( 20 ) to a receiver terminal ( 10 ) adapted to receive audio data in one or more available reproduction formats, the sender entity being adapted to code data according to at least one spatial coding mode, wherein said method comprises the steps of:

the receiver terminal ( 10 ) indicating ( 1 ) to the sender entity ( 20 ) the one or more available reproduction formats of the receiver terminal in a given order of preference;

the sender entity ( 20 ) determining a mode for spatial coding of the audio data compatible with one of the reproduction formats indicated by the receiver terminal, taking into account the given order of preference; and

the sender entity ( 20 ) indicating ( 2 ) to the receiver terminal ( 10 ) the reproduction format of the receiver terminal which is compatible with the determined mode for spatial coding in order for the receiver terminal to spatially decode received audio data by using a spatial decoding adapted to the compatible reproduction format.

2. The method according to claim 1 , wherein said sender entity is a bridge in a centralized multipoint connection.

3. The method according to claim 1 , wherein said sender entity is a terminal in a point-to-point or distributed multipoint connection.

4. The method according to claim 1 , wherein the receiver terminal indicates said reproduction format(s) and said order of preference in a message sent to the sender entity and said sender entity indicates the reproduction format to be used in a response message sent to the receiver terminal.

5. The method according to claim 3 , wherein the receiver terminal indicates said reproduction format(s) and said order of preference in a message sent to the sender entity and said sender entity indicates the reproduction format to be used in a response message sent to the receiver terminal, and wherein the sender entity also indicates one or more reproduction formats in a given order of preference in said response message and said receiver terminal indicates the reproduction format to be used in a response message sent to the sender entity.

6. The method according to claim 4 , wherein said messages are signaling messages.

7. The method according to claim 6 , wherein said signaling messages are SIP signaling messages.

8. A receiver terminal adapted to receive in one or more available reproduction formats spatial audio data sent by a sender entity, the sender entity being adapted to code data according to at least one spatial coding mode, wherein said receiver terminal is adapted to indicate to the sender entity the one or more available reproduction formats of the receiver terminal in a given order of preference and said sender entity is adapted to determine a spatial coding mode compatible with one of the reproduction formats indicated by the receiver terminal, taking into account the order of preference, the receiver terminal being adapted to receive an indication from the sender entity of the reproduction format of the receiver terminal which is compatible with the determined spatial coding mode in order for the receiver terminal to spatially decode received audio data by using a spatial decoding adapted to the compatible reproduction format.

9. A sender entity adapted to code data according to at least one spatial coding mode and send the spatial audio data to a receiver terminal adapted to receive spatial audio data in one or more available reproduction formats in a given order of preference, wherein said sender entity is adapted to receive from the receiver terminal an indication of the one or more available reproduction formats of the receiver terminal and to determine a spatial coding mode compatible with one of the reproduction formats indicated by the receiver terminal, taking into account the order of preference, the sender entity being further adapted to indicate to the receiver terminal the reproduction format of the receiver terminal which is compatible with the determined spatial coding mode in order for the receiver terminal to spatially decode received audio data by using a spatial decoding adapted to the compatible reproduction format.