[MPlayer-dev-eng] [patch] prefer ALSA over OSS

[Rich Felker]

On Sat, May 05, 2007 at 04:50:17PM +0400, Vladimir Mosgalin wrote:
> Hi Rich Felker!
> 
>  On 2007.05.04 at 20:57:33 -0400, Rich Felker wrote next:
> 
> > > Well this is completely OT. The original problem is that it doesn't
> > > happen with oss interface in alsa, because modern hardware in a way is
> > > even more limited than old one, despite being better. The lack of
> > > hardware mixing and random sample rate/sample format support in hardware
> > > is a very good thing, quality-wise.
> > 
> > No, it's a bad thing for quality. No degree of digital signal
> > processing can give the correct result you'd get from correctly timing
> > the output clock to the samplerate of your recording; any resampling
> 
> You are wrong. There are _no_ problems from good digital resampling in
> high resolution (move to 24 bits resolution to save original original
> 16-bit precision - and of course all audio processing must be at least
> 24-bit, most likely float though).

There are. Resampling involves tradeoffs between using lowpass filters
(losing high frequency content), large windows (latency and/or
echo/preecho), etc. The number of bits per sample is utterly
irrelevant to these issues; it's a fundamental mathematical fact even
if you had unlimited precision.

Why not try learning some math before trolling about something you
know nothing about.

> As a matter or fact, most DACs resample digital input once more, to some
> higher frequency, like 96khz or 192khz and it makes quality better.
> Because of two reasons: first, it doesn't make original digital stream
> any worse and second, the DAC unit by itself is designed such way
> so it produces better analog output when feeded by hi-resolution signal.

This is new crap. Good classic hardware does it the straightforward
and lossless way.

> > involves tradeoffs between artifacts, destruction of high frequency
> > content, etc.
> 
> Then stop using some kind of very broken resampler and try real one.

It's provable that one does not exist. I'm using the best available,
libavcodec's.

Rich