Re: Alsa plays only wav files
On Mon, 2002-09-16 at 15:57, Ondrej Certik wrote:
>
> > > when starting xmms, it stops with an error:
> > > snd_mixer_attach: No such file or directory.
> >
> > Remove alsa-xmms, it prevents xmms from starting
> > without ALSA.
>
> Which solves the problem. Thanks. But I have no idea
> how you could dicover it.
'snd' reminded me of ALSA, so I suspected alsa-xmms and verified the
suspicion by removing it. This is probably an alsa-xmms bug BTW.
> > > Does it mean, that the bug is in the alsa drivers?
> >
> > Yes. Amongst other things, they try to be too clever
> > about endianness, causing problems of their own.
>
> I thought that ALSA is Advanced Linux Sound
> Architecture. And in the source file for snd-powermac
> there is that it is based on dmasound_pmac. So why do
> they introduce new bugs I don't know. Maybe it is not
> as easy as I think to write a driver.
It's hardly easy, and as I said they aim for the good and try to be
clever, unfortunately that doesn't always work out well.
> So you think that ASLA on PPC is still not mature enough?
It's not in my experience, but everybody has to judge for themselves.
> And I still don't understand how it was possible, that
> wav files were ok and mp3/ogg weren't. I thought that
> mp3/ogg is decoded in the player and to ALSA it is
> send as wav (or PCM)....?
That's correct. The problem is probably a mismatch between what xmms (or
its plugins) _thinks_ the endianness of the PCM data they send to the
device is (and thus tells the device) and what it _actually_ is. E.g.,
this works with dmasound if the app thinks its data is little endian but
it's native endian in fact (a common mistake), because dmasound never
swaps bytes. In contrast, ALSA will swap bytes, and you'll hear noise;
an effort in vain.
--
Earthling Michel Dänzer (MrCooper)/ Debian GNU/Linux (powerpc) developer
XFree86 and DRI project member / CS student, Free Software enthusiast
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