Subject: Re: [ecasound] ecasound with alsa
From: Kai Vehmanen (k_AT_eca.cx)
Date: Wed Sep 26 2001 - 13:52:47 EEST
On Wed, 26 Sep 2001, martijn wrote:
> it is weird indeed, but i think i might have to look into alsa more then
> ecasound for this one. i'm using the cvs version of alsa too now, it still
> doesn't work. when i use "alsa,hw:0,0,0" however, i get different errors:
> maybe it's because i don't fully understand how to setup my new Midiman
> Audiophile 24/96, it only acceps s32_le and i tried all kinds of channel
This probably explains it. The ALSA design philosophy is that absolutely
no audio format conversions are done in kernel-space (ie. in alsa-driver).
As the alsa,hw:x,y directly accesses to hw-layer, you can only open the
device with audio params supported by the specific soundcard.
The consumer cards typically support cd-quality audio directly
(-f:s16_le,2,44100,i), while many highend soundcards don't.
> so i tried to specify it -f:s32_le,2,96600, but then:
> ERROR: [ECA-CHAINSETUP] : "Enabling chainsetup: AUDIOIO-ALSA3: Channel count
> 2 is out of range!"
How about "ecasound -i some.wav -f:s32_le,10,96000,i -o alsa,hw:0"?
The 'i' stands for interleaved. So all params have to match. Here's
the appropriate hw-capability struct for playback from
static snd_pcm_hardware_t snd_ice1712_playback_pro =
info: (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_SYNC_START),
rates: SNDRV_PCM_RATE_KNOT | SNDRV_PCM_RATE_8000_96000,
period_bytes_min: 10 * 4 * 2,
I think this is the right one for Audiophile 24/96. So noninterleaved is
not supported (this is common), s32_le the only sample format, no less or
more than 10 channels and rates from 4000-96000Hz. So based on this info,
-f:s32_le,10,96000,i should work.
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