[FFmpeg-user] Rotate 180 degrees

Moritz Barsnick barsnick at gmx.net
Tue May 20 11:22:50 CEST 2014

Hi Cecil,

On Tue, May 20, 2014 at 11:05:33 +0200, Cecil Westerhof wrote:
>     file-size   620.4 MB
>     file-size   876.1 MB

I've seen much bigger differences. Of course, mileage varies according
to input material. I did tests on some example material of mine, and
found that "veryfast" (or was is "fast") gave me an acceptable ratio.
"Acceptable" remains to be defined. ;-) I just noticed that the slower
presets hadn't given me any "significant" file size reduction, related
to the added hours of wait time. (I have a very slow CPU.)

What DID help _very much_ was ensuring that my libx264 was compiled
with assembler support. Originally, my yasm was too old, and x264
dropped the assembler-optimized routines. Recompiling with the proper
yasm actually made H.264 encoding more than 4x faster for me!!!

(I don't know how to check x264's ASM routines in the runtimes - in the
compile tree, you can examine its "config.log".)

> And because I need to do ten other operations (at the moment I do not
> know how to do it in one) it is very welcome indeed. :-D

Please do ask - there's always some way to combine and optimize, that
can save you even more time.


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