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Subject: Re: 20050729 audio buffering

Re: 20050729 audio buffering

From: Magnus Holmgren <>
Date: 2005-07-29

Pedro Vasconcelos wrote:

> I've compiled todays cvs and noticed a much worse use of buffering in
> decoding vorbis files: the buffer keeps being refilled even when it's
> about 70-80% full. The previous build (before replaygain) 20050729 would
> run the buffer down to about 30% (still wasteful but not quite so much).
> This means cpu_boost is on >50% of the time even with files avg 192kb
> versus 33% with last weeks build..

You can also note that the pcm buffer is much smaller (especially with
no crossfade), and the so called watermark limit has not been reduced
(when amount of buffered pcm data is below this, the cpu is boosted). It
may be that this is a bit tight for Vorbis.

I have a build with somewhat lower watermark, and also a bit larger
buffer. With that, I get a boost ratio of about 31-32% on a file around
180 kbps (-q6, with replaygain on). Perhaps I should commit those
changes soon (I do want to test a bit more though).

Received on Fri Jul 29 15:30:53 2005

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