[FFmpeg-user] formula for transcoding to ogv, shrinking an mkv

[Liam Condron-Farnos]

The ffmpeg community wiki page on x264 encoding
<https://ffmpeg.org/trac/ffmpeg/wiki/x264EncodingGuide#twopass>has a
section on two-pass encoding, which can be generalised to other video
encoders.

On 18 January 2013 08:51, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:

> 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:
>
> http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-dvd-mpeg4.html#menc-feat-dvd-mpeg4-2pass
>
> > > 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?
>
> Yes.
> (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.)
>
> Carl Eugen
>
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