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List:       kde-core-devel
Subject:    Re: patch for arts on ppc
From:       Thomas <zander () xs4all ! nl>
Date:       2000-10-07 16:35:10
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Hmm, sorry I can not really think along with this, but your proposed patch
has the following effect:

 [zander@imac zander]$ artsd
Error while initializing the sound driver:
Can't set 16bit (AFMT_S16_LE) playback

Further I played 3 .mp3 files concurrently without problems (well, it has
severe performance problems, but..).

Next I played a cd (kscd), which also mixes nicely with the rest.

Even adjusting volumes etc works.

Next I wanted to play a wav, but that completely locked up artsd, even after a 
restart playing a wav had the effect that artsd takes 100% processor time and
stops playing anything.

As to what is correct: all applications need 2 ways to output sound
currently (big and little). I think it would be really nice if artsd would take away
that problem from the client side.

So, if you can think of a solution to the error message above I am willing to
test more for you. Otherwise lets use this, at least until the release.

> What we can see from the patch is:
> The mp3 decoder (splay) puts the pcm data out in big endian,
> but we need to swap it, because the audiosubsys.cc configures
> /dev/dsp as little endian.
> 
> line 253: kdelibs/arts/flow/audiosubsys.cc
> 
> int format = AFMT_S16_LE;  
> if (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &format)==-1)
> 
> What is correct depends on the "things" which happens after
> the mp3 decode and before we send it to /dev/dsp.
> Im mean: the mixing and the int->float->int conversion.
> I really think, that the int->float->int conversion goes
> wrong, because it depends on that the int values are in big endian
> (but with this patch its in little endian.)
> 
> I think that the outout of the mp3 decoder is ok
> when it is big endian and that the patch (although it works)
> is at the "wrong place"

-- 
Thomas Zander                                            zander@earthling.net
The only thing worse than failure is the fear of trying something new

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