[FFmpeg-devel] Some ideas for a tiny set of audio conversion functions..

Michael Niedermayer michaelni
Sun Nov 18 02:10:01 CET 2007


On Sat, Nov 17, 2007 at 05:56:45PM +0100, Andreas ?man wrote:
> Benjamin Larsson wrote:
> > Andreas ?man wrote:
> >> ... or a replacement of DSPContext->float_to_int16()
> >>
> >> I've been given this some thought and I've come up with
> >> some thoughts that I realized into code.
> >>
> >> The idea is to support
> >>
> >> * any number of channels
> >> * both planar and interleaved data
> >> * mixing of multiple sources into one output channel
> >>
> >> If this is the right way to go i'll continue to write some
> >> convenience functions, SSE-implementations and make some test
> >> with the current codecs that output floats internally.
> >>
> >> The file is currently just standalone.
> >>
> >> Comments?
> >>
> > 
> > We need support for fixed point down mixing also. Otherwise ffmpeg will
> > be to slow for embedded platforms. 
> 
> Is it okay to still represent 'gain' as a float or do we
> need to get rid of the 'float' concept entirely for the
> fixed point case. (I was thinking the fixed-point versions
> could convert 'gain' to its internal multipliers)

float is ok IMHO
AVRational wont be accurate anyway with the use of sqrt(2) and the like

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The misfortune of the wise is better than the prosperity of the fool.
-- Epicurus
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