[vlc-devel] [RFC 0/8] Ambisonics channels support

[Francois Cartegnie]

Le 25/02/2017 à 15:39, Jean-Baptiste Kempf a écrit :
> Hello,
> 
> On Fri, 24 Feb 2017, at 16:40, Francois Cartegnie wrote:
>> The ambisonic channels will never be reordered, and you have no aout 
>> which will support that high number of ambisonic channels, or will just 
> 
> That is incorrect. There are different ordering, and while the ACN is
> now the default, it wasn't always the case.
> 
> Indeed a lot of amb files will need a reordering to get in the ACN
> order.

They won't, at least not through aout_reorder(), as reorder is done
against a bitmask addressing of known channels positions.
Mapping channels above AOUT_MAX would be arbitrary, and introduce new
channels names which likely will never have mapping to existing aout
channels.

In real use, it will be 'remuxed' to something < AOUT_MAX and so fall
back into the bitmask addressing.

> Of course, we could do it on the demuxer, but don't believe that
> reordering ambisonic is an heresy.

Reordering would only happen in the 'remuxer' or dedicated ambisonic
routine (and I don't fully understand the point of reordering in that
case if there is spatial information).

Francois