From alsa-devel-owner@alsa.jcu.cz  Wed Mar 25 19:45:08 1998
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Date: Wed, 25 Mar 1998 19:45:00 +0100 (MET)
From: Jaroslav Kysela <perex@jcu.cz>
To: Ian Main <imain@gimp.org>
cc: alsa-devel@alsa.jcu.cz
Subject: Re: alsa of course.
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On Tue, 24 Mar 1998, Ian Main wrote:

> Hello :)
> 
> 
> I've been anctiously lurking on your list waiting for a few emails so I
> figured I'd take a plunge and send one :)
> 
> I've been busy working on an audio mixer/sound editor for linux called
> Audiotechque (or atech for short) for the past few weeks, and have been
> having a heck of a time trying to get full duplex working.. so, I happened
> across this.
> 
> alsa looks like it could really rock :-)  From reading the source code, I
> managed to figure out most of the new API, and it looks quite good.  I even
> wrote a rather crappy native driver for atech.  However, I haven't expanded
> on it much since I wrote it a few days ago - busy fixing other bugs.  The
> OSS emulation seems, for my purposes at least, to work better than the
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
OK. This is important for alsa project. I'm preffering native API of
course. Do you have any comments for native API & ideas what could be done
better for your use?

> native alsa for this app.
> 
> I got full duplex (mostly) working via the OSS api on both my SB16, and my
> GUS MAX.  I've got a few bug reports for you if you're interested.  I'd also

You can send errors to this list.. I found some bugs, too.. It's mainly
caused by driver testing. I'm working mainly with OSS/Lite applications
due to absence of native application.

I looked to your code and here are my comments:

1) For applications are very recomended use ALSA C library rather than
   direct calls (open/close/read/write/ioctl). Include files are (after
   install) in
     /usr/include/linux/sound.h
     /usr/include/sys/soundlib.h
   Maybe we can now talk if this place is best... 
2) I found this bug (after quick look):

--- atech_play_alsa.c.old       Wed Mar 25 19:36:35 1998
+++ atech_play_alsa.c   Wed Mar 25 19:36:54 1998
@@ -220,7 +220,7 @@
        pcm_fmt.format = SND_PCM_SFMT_S16_LE;
        /* pcm_fmt.format = SND_PCM_SFMT_U16_LE; */
     } else {
-       pcm_fmt.format = SND_PCM_SFMT_S8;
+       pcm_fmt.format = SND_PCM_SFMT_U8;
     }
     pcm_fmt.rate = rate;
     pcm_fmt.channels = channels;

Note that 8-bit samples are by default UNSIGNED....

						Jaroslav

-----
Jaroslav Kysela <perex@jcu.cz>
Academic Computer Centre, University of South Bohemia
Branisovska 31, C. Budejovice, CZ-370 05 Czech Republic



