Re: [Alsa-devel] Question regarding substreams or voices

[Takashi Iwai]

At Sat, 29 May 2004 16:05:05 +0100,
James Courtier-Dutton wrote:
 
 Hi,
 
 I am trying to do work on the Audigy LS driver.
 
 I have now discovered that I can send sound to the Front, Rear and 
 Center/LFE.
 I have not found out how to set the amount of interleaved channels that 
 the sound card can do, so it is fixed at 2 channels per stream.
 
 The sound card has 4 voices for 4 separate stereo streams.
 Each voice has it's own DMA and HW pointer.
 voice 0 sends sound to the Front speakers.
 voice 1 sends sound to the Center/LFE speakers.
 voice 2 sends sound to unknown, (no sound comes out yet)
 voice 3 sends sound to the Rear speakers.
 There does not appear to be any hardware mixing, so each voice can only 
 be opened once.
 
 Should this be set up as: -
 1)
 /proc/asound/card0/pcm0p
 info sub0 sub1 sub2 sub3
 
 or instead ?
 2)
 /proc/asound/card0/pcm0p
 /proc/asound/card0/pcm1p
 /proc/asound/card0/pcm2p
 /proc/asound/card0/pcm3p
 
 I think (2) is the correct way, so I will make a start using that method.

both are ok for ALSA native apps.  you can specify the substream index
in the configuration.
the latter would be easier for OSS compatible layer, though.


Takashi


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Re: [Alsa-devel] Question regarding substreams or voices

[Takashi Iwai]

At Tue, 1 Jun 2004 13:18:26 GMT,
[EMAIL PROTECTED] wrote:
 
 
  both are ok for ALSA native apps.  you can specify the substream index
  in the configuration.
  the latter would be easier for OSS compatible layer, though.
 
 Do you have a preference? I can change the emu10k1x driver to do (2)
 as well. I've done some tests (analog only) and the first two
 channels/voices get mixed together on headphones and analog output, so
 I am not sure if (2) is the right way or not. 

i prposed the latter because each substream corresponds to a different
purpose (front, rear, center/lfe) without mixing.  in the case of
emu10kx, all three substreams are mixed, hence the first case would be
suitable.


Takashi


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