expanded layout support in IAMF

[yilun-zhangs]

Hi @trsonic

In IAMF spec, some expanded layout are defined,
But in obr, AudioElementType doesn't contain that.
Do you have plan to support expanded layout inputing in obr ?

[trsonic]

Hello @yilun-zhangs

Thanks for the question. obr doesn't differentiate loudspeaker layouts according to IAMF's loudspeaker_layout and expanded_loudspeaker_layout.

All available layouts are listed here as AudioElementType enum. The coordinates of virtual loudspeakers for each layout can be found here.

The above list can be easily extended to support more layouts (including the extended ones), we just need to agree on the coordinates of virtual loudspeakers. Where possible we will follow BS.2051-3 recommendation. Do you have any specific layouts in mind that are missing from the current implementation? Or you'd like to see all expanded layouts implemented? I'm happy to discuss this further.

[yilun-zhangs]

Hello @trsonic

Thanks for your explanation,
Yes, you are right, some sub layouts could be easily to extend to original layout.
But 10.2.9.3 and 7.1.5.4 are new added in IAMF v2, it will be great if these two layouts could be supported in obr