[alsa-devel] [Q] playing / recording mono on a stereo-only hardware

[Michael Trimarchi]

Guennadi Liakhovetski wrote:
> (re-adding the list)
>
> On Tue, 2 Feb 2010, Michael Trimarchi wrote:
>
>   
>> Hi,
>>
>> Guennadi Liakhovetski wrote:
>>     
>>> On Sat, 30 Jan 2010, Michael Trimarchi wrote:
>>>
>>>   
>>>       
>>>> Guennadi Liakhovetski wrote:
>>>>     
>>>>         
>>>>> Hi
>>>>>
>>>>> I know this question belongs rather to alsa-users, and I did ask it
>>>>> there,
>>>>> but got no solution so far. Maybe someone here can help.
>>>>>
>>>>> The recently posted SuperH SIU driver only supports stereo playback and
>>>>> capture (channels_min = channels_max = 2). Is there a way to tell
>>>>> alsa-lib
>>>>> to duplicate the mono-channel during playback and to mix recorded
>>>>> channels
>>>>> (or use one of them), if mono recording is requested?
>>>>>         
>>>>>           
>>>> I'm not an expert but I think that you can use plughw support of alsa-lib
>>>>
>>>> pcm.record {
>>>>       type plug
>>>>       slave {
>>>>               pcm record_hw
>>>>       }
>>>>       route_policy average
>>>>       rate_converter "linear"
>>>> }
>>>>
>>>> I think that automatically change rate and channel for supporting mono
>>>> channel
>>>> too
>>>>     
>>>>         
>>> Thanks for the snippet, but, I'm afraid, it didn't help either.
>>>   
>>>       
>> Sorry can you explain a little bit more why it doesn't help you?
>>     
>
> I certainly gladly would explain this, if only I knew... It just doesn't 
> change anything. Are you using it anywhere? If yes, with which hardware 
> configuration and software (alsa-lib) versions?
>   
alsa-lib 1.0.16

#define BUILD_PCM_PLUGIN_RATE "1"
#define BUILD_PCM_PLUGIN_ROUTE "1"

Hardware android openmoko gta02. Test it with arecord 1 month ago

Android

Michael
> Thanks
> Guennadi
> ---
> Guennadi Liakhovetski, Ph.D.
> Freelance Open-Source Software Developer
> http://www.open-technology.de/
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