[FFmpeg-devel] Float vs. fixed-point audio codecs

Reimar Döffinger Reimar.Doeffinger
Fri May 14 18:17:18 CEST 2010

On Fri, May 14, 2010 at 04:20:44PM +0100, M?ns Rullg?rd wrote:
> Systems we care
> about can be broadly divided into three categories:
> 1. No hardware FPU
> 2. Slow FPU
> 3. Fast FPU

Maybe I'm wrong, but I would expect it might also depend on which
SIMD features are available on some CPUs (something like a borderline FPU
and optional integer-only SIMD).

> In all of the above cases it may be desirable to enable both versions,
> even if one is faster, letting the user choose.  This brings us to the
> question of how to choose implementation in the API as well as on the
> command line.  One possibility is to introduce a flag which when set
> causes the float version to be chosen, the default depending on
> configure options.  Whatever the default, the flag could be set or
> cleared from the command line.

Is just one flag going to work out? The default would then have to be
set during codec opening I guess and changing it later would be hard.
I'd expect a prefer_float and a prefer_int flag might work better...

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