[MPlayer-dev-eng] [PATCH] fix for -srate bug

[D Richard Felker III]

On Tue, Oct 19, 2004 at 11:19:37PM +0100, Ed Wildgoose wrote:
> Hmm, interesting.  I think I may have done my earlier benchmarks 
> incorrectly.  mplayer with "-vo null" uses about 45-50% on my machine, 
> but with the video playing then it runs more like 6-10% normally (alsa 
> output), and 13-15% with any of the above resampling options (except 
> linint which is basically free) and jack output at 44100Khz.  This is 
> playing a film with a 6 channel audio track at 48Khz (ie a non integer 
> resample)

hmm, mplayer with -vo null is very weird. what ao were you using?

> Certainly 5% CPU to do resampling is very good!  However, I suspect that 
> it's just too low to be doing it "properly" (where properly means burn 
> CPU like crazy...).  I will investigate the code a little more, but 
> libsamplerate (for a benchmark) will be chewing 20%+ CPU in order to do 
> this resampling (unless I messed up those benchmarks as well...).  
> Brutefir is chewing more CPU than mplayer and it's only doing 
> crossovers... (And brutefir uses FFTW which is one of the fastest fir 
> implementations out there)
> 
> So looks like I might have been wrong about the high CPU, and your few 
> percent is actually spot on.  I still suspect however, that the 
> resampled audio quality is fair bit lower than if I play it back at the 
> correct rate (which there is no reason for it to be), but I will do some 
> better testing first.
> 
> Thanks for the thoughts.  However, I am still interested in your 
> thoughts on how to use the lavc resampler?

i don't know how to use it since i haven't examined the code. but i'm
fairly sure it will be both faster and and same or better quality than
both mplayer's current code and libsamplerate.

rich