[alsa-devel] [PATCH] PCM parameters in file plugin

Pavel Hofman pavel.hofman at insite.cz
Mon Jan 26 15:28:51 CET 2009

Pavel Hofman wrote:
> Pavel Hofman wrote:
>> Jaroslav Kysela wrote:
>>> 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
> Hello,
> please find enclosed a patch for the file plugin. The
> checkpatch.pl script throws 5 bogus errors in doxygen comments.
> Signed-off-by: Pavel Hofman <pavel.hofman at insite.cz>
> * added support for including pcm stream params in the output filename
> * added support for piping the stream to a shell command if the filename
> string starts with a pipe char
> Thanks a lot,
> Pavel.


Please let me know if there some areas to work on before the patch can
be accepted for merge.

Thanks a lot,


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