[FFmpeg-user] formula for transcoding to ogv, shrinking an mkv
Carl Eugen Hoyos
cehoyos at ag.or.at
Fri Jan 18 09:51:51 CET 2013
James Miller <gajs-f0el <at> dea.spamcon.org> writes:
> > If you have a target filesize, don't use a constant
> > quantiser, but specify a bit-rate (calculated by you)
> > and use 2-pass encoding.
> Thank you for your response, which I am trying to interpret. According to
> some research I've done in that effort, the -crf option in my formula is
> probably what you're referring to as a "constant quantizer"; is that
> correct? I've also gathered that, instead of using this, I should use the
> -b option followed by some numerals in order to get a certain bit-rate.
> Correct? Can you recommend any basic documentation on 2-pass encoding?
The MEncoder documentation is old and therefore by
definition a bit out-dated but it contains many
information to basic strategies:
> > Please note that for all questions on this mailing
> > list, you should add complete, uncut console output
> > together with your command line.
> Hmmm. I'm a little puzzled by this stipulation. When I run my command in
> the console, I get several lines that give specifics about the
> characteristics of the file being processed and about what ffmpeg is
> preparing to perform on it. That, on successful attempts (like the one I
> posted about), is followed by a sort of progress meter that runs until the
> transcoding is finished. Are you saying I should copy and paste all that
> into any query I make to this list?
(This is of course a little simplified and there
probably are situations where it is unneeded but
it is a good idea to always post it.)
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