[Ffmpeg-devel] (minor) performance improvement suggestions

Måns Rullgård mru
Sat Jun 4 12:10:06 CEST 2005

"Robert Lippmann" <rlippmann at imsventures.com> writes:

> hi all,
> been looking at some minor optimizations during some of the initialization
> functions.  due to the sheer number of format/codecs, i think some
> improvements can be made.  not on the scale of improving a couple
> milliseconds on a decoder loop, but every little bit counts, right?
> anyway, here's my suggestions:
> 1) in av_probe_input_format, it does an exhaustive search over a large
> number of input format types.  some probes return AVPROBE_SCORE_MAX.
> shouldn't the loop just break there?
> 2) in a similar vein, perhaps some of the lesser used formats (ie westwood,
> sierra, etc) shouldn't be enabled (and registered ) by default.
> 3) similarly, avcodec_find_encoder and avcodec_find_decoder look through a
> long linked list.  seems like there's a natural hash key using the codec id
> and encode/decode.  but, finding a minimal perfect hash function generator
> in a friday night is making my head hurt :)
> comments/suggestions?

What are suggesting adds complexity to gain at most a few milliseconds
once per run.  I can't imagine any application where that would make a
significant difference.

M?ns Rullg?rd
mru at inprovide.com

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