[alsa-devel] [PATCH 1/2] Remove definition for surround sound devices on ICE1712.
gineera at aspect135.co.uk
Wed Jan 21 17:45:29 CET 2009
On Wednesday 21 January 2009 10:00, Takashi Iwai wrote:
> At Tue, 20 Jan 2009 17:33:24 +0100,
> Diego E. 'Flameeyes' Pettenò wrote:
> > Jaroslav Kysela <perex at perex.cz> writes:
> > > Note that front and surround devices does not support automatic sample
> > > conversion. Use plug:front, plug:surround40 etc. devices.
> > Using the correct format, front:IDX should work with two channels sound
> > files, and it doesn't, nor surround40:IDX works with four channels or
> > surround71:IDX with eight channels.
> > [I'm using IDX because I have it on :1 rather than :0]
> I thought plug:front:IDX works, at least on 1.0.19, too...
It does work here on older Alsa.
I think Diego's point though is that 'surround40:IDX' might be expected to be
a 4-channel stream, whereas it is as dependant on the hardware as 'hw:IDX'
is. In the later case it is clear that the user must provide audio in
whatever format/channels the hardware uses. However it is unexpected that eg
on ice1712 'surround40:IDX' requires a 10-channel playback stream and ignores
6 of them, and will not play a 4-channel stream.
It is also not symetrical, so if you capture it has to be a 12-channel stream,
which it is then not possible to play without using the plug: devices.
Unless I am mistaken...
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