[gst-devel] GStreamer, libaudiofile and ALSA

Erik Walthinsen omega at temple-baptist.com
Mon Feb 26 22:08:01 CET 2001

> GStreamer seems to be very nice, and it looks as if you guys now what
> you are doing. However, I am sure that you are aware of that there
> exists a  library called libaudiofile - just for decoding and encoding
> of audiofiles. Since, there already exists such a library, why do you
> not use it instead of writing everything yourself? Ofcourse, as of
> today, libaudiofile doesn't support mpeg-streams, avi-stuff and
> video-streams - but it could nevertheless be used just for the
> audio-handling.
I haven't had a chance to look at audiofile, but if it has a usable enough
interface, I definitely would use it.  The problem I've found, though, is
that most libraries don't have enough of a complete API to do everything
GStreamer is capable of.  Some of this has to do with optimization, but
others are more fundamental, like the ability to seek fast and accurately.
I'll give it a look when I have a chance and see if it can be used.

> By moving the mpg-stuff out from GStream and perhaps commiting it into
> libaudiofile other people can benefit more directly from this. Sine
> GStreamer is supposed to handle video as well - libaudiofile might not
> be suited for that job. But, since I always repeat myself, some code
> could to added to it.
Again, that depends on whether audiofile has a useable API.

> Anyhow, for reading and writing of wav, au and those files libaudiofile
> should be very nice.
Hopefully ;-)

> Another thing I noticed, there seems to be a lack of ALSA-support -
> since I am a big fan of ALSA, I was wondering if anyone of you are
> working on this or if it is on some TODO-list? One setback by using ALSA
> is that it is not as portable as OSS is - but it handles multiple
> soundcards very nicely :)
Yes, I have to get an ALSA plugin worked out.  I have to have it for my
RME Hammerfall card (16in, 16out), so...  The main problem until now has
(and maybe still) is the lack of a stable API...

> I am doing some stuff with ALSA right now, and since there doesn't seem
> to be any work or code for this in the 0.1.1 release - I will have do
> create it anyhow...
Would be willing to help out with the alsasrc and alsasink elements?

> Another thing, I haven't found any way to write the audiostream _back_
> to disk? Is this me, or...?
em, heheh.  We haven't bothered.  I will make sure a filesink is in CVS
soon, since I'll need it too.

> Ooops, a lot of feature-requests here :)
> Most of this stuff I will probably have to implement myself anyway, so I
> look forward to your reply.
Cool.  I hope to hear back soon ;-)

> I don't know if I was supposed to send this to the devel-list but I
> thought "better safe than sorry", and spammed it away to you instead.
This is development stuff, so yeah, go ahead and send it to the list.

      Erik Walthinsen <omega at temple-baptist.com> - System Administrator
       /  \                GStreamer - The only way to stream!
      |    | M E G A        ***** http://gstreamer.net/ *****
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