[Mplayer-users] mp3 downsampling/mixing? (again)
atmosfear at users.sourceforge.net
Wed Aug 15 00:40:56 CEST 2001
On Tuesday, 14. August 2001 23:20, you wrote:
> > A while ago, I asked about a feature of
> > 1) changing samplingrate of MP3 streams (e.g from 44100 to 22050 kHz,
> > only supported and easy ratios, like 1/2 or so) at play
> > 2) downmixing to mono (or playing only single channel in joint-stereo)
> > both ways work e.g. with mpg123 to speed up mp3 output (no, that's _NOT_
> > only 2% on my machine)
> > It might be possible with a registry entry in DLL, or by not too much
> > work in mp3-library.
> > But somehow that idea fell asleep. If this is possible, can somebody
> > comment on this?
> yes, i did it...
> in mp3lib/sr1.c change:
> fr.down_sample=0; //2;
> to value of 1 (1:2) or 2 (1:4) downsampling of freq.
1:4 downsample gives 10% speedup for audiodecoding (1.8313% vs. 1.6664%).
> for getting mono output, change the last parameter of MP3_Decode()
> in dec_audio.c from -1 to 1 (left only) or 2(right only) or 3 (mixed)
> but i got only a few percent of speedup...
> A'rpi / Astral & ESP-team
Ever tried? Ever failed? - Try again! Fail better!
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