[alsa-devel] Noise in begnning of alsa application

[Pavel Hofman]

Dne 21. 01. 19 v 18:46 Chakravarthi Pradeep napsal(a):
> On Wed, Jan 16, 2019 at 5:07 PM Chakravarthi Pradeep <doubleq7 at gmail.com> wrote:
>>
>> I have ALSA driver for capture device which works fine with VLC. when
>> I try to capture and render using own application having some issues.
>> When I start play, it has some noise in beginning and audio is
>> discontinuous in between. Discontinuous means, some audio frame are
>> getting dropped in between. cut cut sound for sine wave. I have tried
>> snd_pcm_drop and snd_pcm_drain but no use. Kindly suggest how to
>> remove the starting noise in ALSA.

I have experienced the same issue, with ice172 driver. IMO part of the 
first period when opening the stream contains samples from the previous 
run. In one of my my projects I have to drop initial samples in order to 
get correct and stable results from FFT analysis.

I do not know if the problem is in the driver, alsa-lib or if the 
application (in my case the SDL library) uses alsa-lib API incorrectly. 
To tell the truth I did not investigate details and "fixed" it by 
dropping the initial samples.

Best regards,

Pavel.