[vorbis] Low bitrate encoding

[jaromil]

On Tue, Jan 09, 2001 at 01:31:39PM +0100, Olaf van der Spek wrote:
> >
> > that's not exact... more than averaging it's a stretching operation.
> > assuming 16bit samples i would do it like that:
> 
> This means you just discard half of the samples.

yes
there's some better way to do it, but it's cpu intensive and imho it's not
worthwhile

on my side, i take care of performance: muse is a live engine

> >
> > /* downsampling >>1 */
> >
> > for(i=src_length>>2;i;--i) {
> > dst[0] = src[0];
> > dst[1] = src[1];
> > src += 4;
> > dst += 2;
> > }
> 
> What about this?
> for(i=src_length>>1;i;--i) {
> dst[0] = src[0] + src[1];
> src += 2;
> dst++;
> }

uhm. i guess we should simply try those. i cannot atm, i'm not at home far
from my machines. keep me informed about what you get if you try.
i'll be testing this starting from next monday.

> >
> > /* upsampling <<1 */
> >
> > for(i=src_lenght>>1;i;--i) {
> > src -= 1;
> > dst -= 2;
> > dst[0] = src[0];
> > dst[1] = src[0];
> > }
> 
> Would it be better to interpolate the second value?

don't really know, how does it looks like? :)

jrml

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