[Ffmpeg-devel] Differences between mencoder and ffmpeg whenencoding using x264

Loren Merritt lorenm
Tue Feb 21 23:15:02 CET 2006

On Tue, 21 Feb 2006, Robert Swain wrote:
> On Tuesday 21 February 2006 21:23, Loren Merritt wrote:
>> Warning: some options are both supported by ffmpeg.c and auto generated
>> from avcodec.h, but only one of the copies works.
>> e.g. "-g 250" works, but "-gop_size 250" does nothing.
>> This applies to any option printed by `ffmpeg` that has a version without
>> the "EDV.." field.
> Hmm, OK. Why are such options present? Should they be removed if they are
> naught but placebos? :)

The versions from ffmpeg.c are there because ffmpeg does some 
additional processing to them, which can't be done if they're in a 
avctx. Or something.
The placebo options do actually set the corresponding value in the avctx, 
they just get overwritten by the ffmpeg.c version.
Solution: either fix them to not require global variables, or add support 
in AVOption to not export some list of options.
And, for that matter, to distinguish between toplevel options and 
arguments to other options in the printed list.

--Loren Merritt

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