[FFmpeg-devel] [PATCH] configure: add command flag to disable yasm use

Art Clarke aclarke
Thu Feb 5 04:58:46 CET 2009

> What functionality currently uses yasm code?

Among others, if yasm is found, then FFMPEG uses a yasm based fft mmx
implementation, and I think some different assembly for h.264
decoding.  Arguably faster though I haven't seen metrics.

>  Is it likely that
> someone might want to build with a set of options that wouldn't use
> any of the yasm code?

Well for one, without the other patch I submitted today, you need to
disable yasm to get FFMPEG to build on Mac-OS 64-bit shared libraries

But in general given that libx264 already requires yasm (build fails
if it can't find yasm or you don't pass --disable-asm), more and more
people are using FFMPEG for h.264 encoding, and slowly but surely Yasm
code is increasing in FFMPEG, I think some change re: YASM
configuration is a good idea.

I suggest giving a rude WARNING on configure if yasm can't be found on
the current system to give folks a heads up, and then in three months
or so change configure to require yasm.

If folks agree, I'm happy to submit a patch.

- Art

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