[pulseaudio-discuss] 7.1 surround problem

Colin Guthrie gmane at colin.guthr.ie
Thu Jun 24 00:55:12 PDT 2010

'Twas brillig, and Brendon Costa at 24/06/10 07:38 did gyre and gimble:
> Thanks for the info. It seems the channel mapping init is the problem.
> pa_channel_map_init_auto()
> From the docs it seems like it does not have a default mapping for 7
> or more channels.

>From a quick look at the code: for the case of PA_CHANNEL_MAP_AIFF (aka
PA_CHANNEL_MAP_DEFAULT), there is no support for 8 channels (7.1) (note
that exactly 7 channels is generally not supported anywhere - only
mention it due to your "7 or more) comment :)).

Using PA_CHANNEL_MAP_ALSA has support for 8 channels.

Due to compatibility with RFC3551, I'm not sure if the default channel
map should support 8 channels or not. I've only glanced at the spec but
it only seems to mention up to 6 channels. I'm not sure if there is a
generic extension case to >6 channels or not (I didn't read that deeply).



(oh and don't be afraid to look at the PA source. It's good to ask
questions, about bits of it (like 8 channel support with the default
channel map) but it wouldn't have taken you long to know as much as me
about the above!)


Colin Guthrie

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