[pulseaudio-discuss] unable to play very small beep (.wav) sounds

[David Henningsson]

On 08/20/2011 06:12 PM, Tanu Kaskinen wrote:
> On Fri, 2011-08-19 at 14:08 +0530, Himanshu Chug wrote:
>> Hi All
>>
>> I am able to get the small beep files working consistently using gst-launch
>> now by modifying tsched_buffer_size param of module-alsa-sink like:
>>
>> load-module module-alsa-sink tsched_buffer_size=1024,
>> (buffer size is default to 2s)
>>
>> I am using timer based tsched audio scheduling , on OMAP4 platform.
>>
>> I have few questions:
>>
>> Q1. how does this change affect my system, if I always make
>> tsched_buffer_size=1024? I suspect it may increase the power
>> consumption and increase the ALSA
>> wakeup's , if I reduce the buffer size and period like like this?
>
> Yes.
>
>> Q2. When the beep file is not played on speakers , I can see a lot of rewind
>> prints from PA
>> protocol-native.c: Requesting rewind due to rewrite. and it continues and
>> finally I got EOS from my gst pipeline
>>
>> I need to know what is rewind ? and what triggers PA to make these rewinds?
>
> As the log message says, the rewrites cause the rewinds.
>
>> and what is "rewrite" here in terms of pulseaudio?
>
> It means rewriting part of the sink (hw) buffer. If that log message
> appears, it means that the client has written data to a position that
> requires a part of the sink's buffer to be overwritten, and thus a
> rewind is needed.
>
>> (Just to remind you I can play the beep wav with paplay and  pacmd
>> play-file,  without any issues and without modifying the buffersize param.
>> so I am just confused whats going here ? )
>
> So did you find out whether your system has David's patches that I
> referred to in my previous reply? If you did, and the patches are
> applied, then there's still something to fix in Pulseaudio's and
> Gstreamer's interaction.

Btw, I posted an improved version of the patch a few days ago to the 
gstreamer mailinglist, and it has been committed. See 
http://cgit.freedesktop.org/gstreamer/gst-plugins-good/commit/ext/pulse/pulsesink.c?id=e70020b45630d99132a99892ecc6e1dcd1ce6f8a

Hopefully that can help.

-- 
David Henningsson, Canonical Ltd.
http://launchpad.net/~diwic