[alsa-devel] Playback and capture synchronization

Patrick Lai plai at codeaurora.org
Wed Nov 9 19:38:05 CET 2011

On 11/9/2011 3:55 AM, Clemens Ladisch wrote:
> Patrick Lai wrote:
>> I have a use case requiring playback and capture starting at the same
>> time. Latency between starting of playback and capture streams need to
>> be less than few PCM samples. Base on my understanding on ALSA which
>> does not have the concept of grouping multiple streams,
> snd_pcm_link()
Awesome! I will look into this API

> If the driver doesn't actually implement starting of linked streams
> (which would be pointless if the hardware doesn't support it), ALSA
> calls the second trigger callback after the first one.
> It might be possible to implement simultaneous starting of two streams.
> What hardware (driver) are you using?
It's Qualcomm hardware. As far as I know, HW has this synchronization 
support but I would have to build driver to make use of this functionality

Thanks very much for the feedback

> Regards,
> Clemens
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