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

Tanu Kaskinen tanuk at iki.fi
Sat Aug 20 09:12:53 PDT 2011

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?


> 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.


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