Re: Sound slow/transposed down in pitch

Tue Dec 23 2003, [email protected] wrote:
> > 2. Obtain a card that can do 48000.  I use the SoundBlaster Live since
> > it is supported in Solaris/x86 (via Jurgen Keil's drivers) and Linux,
> > and can do 48000.  (With an ancient SoundBlaster vibra, I get the
> > behavior you describe.)
> 
> So what does MPlayer do? Real-time down-sampling?
> 
> Answer: Yes, as witnessed by these lines when running MPlayer in verbose mode;
> 
> Building audio filter chain for 48000Hz/2ch/16bit -> 44100Hz/2ch/16bit...
> [dummy] Was reinitialized, rate=48000Hz, nch = 2, format = 0x00000001 and bps 
> = 2
> [libaf] Adding filter resample
> [resample] Changing sample rate to 44100Hz
> [resample] Using integer processing and inexact frequecy conversion.
> [resample] New filter designed up: 147 down: 160
> [dummy] Was reinitialized, rate=48000Hz, nch = 2, format = 0x00000001 and bps 
> = 2
> [resample] Using integer processing and inexact frequecy conversion.
> 
> Can I take it that my card is considered to be obsolete then? And that there 
> is no intention to create downsampling in Ogle alongside the downmixing?
> 
> Ah. Damn. Since it does an otherwise perfect job, I don't think I'll be 
> upgrading my card purely to run Ogle, and I don't fancy paying for the 4Front 
> drivers. I want the moon on a stick, don't I?
> 
Well, when we last looked at this there wasn't any good libraries
around for doing software resampling.  They either sounded like crap
or were way to expensive (in cpu processing needed) to be of much use.
This might have changed or people might simply find the poor audio quality
acceptable.  A patch to re-add this to Ogle would certainly be accepted.
Either stand alon code or useing some audio processing library. 
That output from mplayer looks like it is using something called 'libaf'.

-- 
Håkan Hjort