[alsa-devel] PCM parameters in file plugin
perex at perex.cz
Tue Jan 6 11:31:02 CET 2009
On Tue, 6 Jan 2009, Pavel Hofman wrote:
> Pavel Hofman napsal(a):
> > Hello,
> > I am working on a file plugin patch to allow adding PCM parameters
> > (rate, format) to the name of the file created (plus the ability to run
> > an external command via popen, such as upsampling with sox). I got stuck
> > in trying to obtain these parameters in pcm_file.c:_snd_pcm_file_open().
> > Is it actually possible or the information is not available at the time
> > of opening the file (and the whole patch is thus nonsense)?
> > Thanks a lot for help.
> I am now opening the output file in pcm_file.c:snd_pcm_file_write_bytes.
> Surprisingly it seems to work fine. Could such hack be accepted as a
> patch to the plugin (if coded properly)? Is there a better place to open
> the file?
The file should be opened in the hw_params callback (all PCM parameters
are known in this time). Also, extending filename with PCM parameters
should be optional (configurable). But the idea looks nice.
Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.
More information about the Alsa-devel