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

Svante Signell svante.signell at telia.com
Thu Oct 28 23:36:19 CEST 2004


I have a few questions. Maybe it would be a good exercise to write a SW
implementation of a resampler, if there is any interest for mplayer.

1) How does the interface look like in mplayer? Any code example?
2) Which rate conversions? 44.1kHz to 48 kHz and vice versa?
3) Has anybody made an exact, i.e. rational number conversion?
4) Which algorithms are used in libsamplerate, mplayer, lame etc?
5) Any good references?

Thanks,
Svante

On Thu, 2004-10-28 at 11:48 -0400, D Richard Felker III wrote:
> On Thu, Oct 28, 2004 at 12:18:42PM +0100, Ed Wildgoose wrote:
> > 
> > >blackman nuttall windowed sinc, its trivial to change it to ANY other 
> > >linear resampling algorithm, and ive never seen a non-linear one used for 
> > >audio, and  u dont even seem to know what linear means ...
> > > 
> > >
> > 
...
> > non-linear one used" is slightly misleading.  First, many of the better 
> > resampling routines use sinc based interpolation between samples.  
> 
> > However, whilst the sinc function is non-linear (and infinitely long), 
> > it turns out that you can approximate it using only (finite) linear 
> > functions to a high degree of accuracy.  This is the technique used in 
> > libsamplerate.
> 
> huh? i really doubt this... i don't think it could improve speed or
> quality at all. whether the kernel function is linear or not doesn't
> have any bearing on speed, since any kernel function is just a vector
> with finitely many components as far as the computer is concerned.
> 
> rich
> 
> 
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-- 
Svante Signell <svante.signell at telia.com>




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