Re: usb-audio

[Niklas Werner <bergtroll@gmx.li>]

Am Dienstag, 28. Oktober 2003 11:11 schrieb Takashi Iwai:
> At Mon, 27 Oct 2003 20:53:08 +0100,
>
> Antonio Willy Malara wrote:
> > On 2003.10.27 19:16, Takashi Iwai wrote:
> > > > 	/* FIXME: correct endianess and sign? */
> > >
> > > could you give more information:
> > > which program, which device and what format doesn't it work?
> >
> > the system is a powermac, the device is a Griffin iMic, the app is
> > jack version 0.80, the output is:
> >
> > Sorry. The audio interface "hw:1"doesn't support either of the two
> > hardware sample formats that jack can use.
>
> then it's a problem of JACK, not ALSA.
> the hardware doesn't support 32bit integer but only 24bit packed in 3
> bytes.
No, I don't think it is.
I get similar problems with my emi 2|6 and alsaplayer, mplayer, xmms, ...

My impression is that ALSA assumes that the connected interfaces _always_ 
allow for the same Endianess as the system. This, of course, isn't always 
so.
Mplayer:

Checking audio filter chain for 44100Hz/2ch/16bit -> 44100Hz/2ch/16bit...
AF_pre: af format: 2 bps, 2 ch, 44100 hz, big endian signed int 
AF_pre: 44100Hz 2ch Signed 16-bit (Big-Endian)
alsa-init: requested format: 44100 Hz, 2 channels, Signed 16-bit 
(Big-Endian)
alsa-init: soundcard set to emi
alsa-init: format Signed 16-bit (Big-Endian) are not supported by 
hardware, trying default
alsa9: 44100 Hz/2 channels/4 bpf/65536 bytes buffer/Signed 16 bit Little 
Endian
AO: [alsa9] 44100Hz 2ch Signed 16-bit (Little-Endian) (2 bps)

alsaplayer either dies with "FIXME: f_unsynchronization is set.Please 
contact alsaplayer team." or produces static noise.

aplay does get this right, so it seems to use a different method of 
querying the device.

Have fun*

Niklas



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