[Libav-user] Encoding with variable frame rate

[Claudio Freire]

On Wed, May 22, 2013 at 12:28 PM, Brad O'Hearne
<brado at bighillsoftware.com> wrote:
>> The capabilities of container formats
>> _and_ muxers vary a lot. So this can only really be discussed in a
>> useful way when were talking about the same thing.
>
> Yes, but these are facilitated through a common code layer. Quite frankly, it is hard to tell where common behavior and muxer-specific behavior starts / ends.


This is true at many levels, I faced similar woes in the past with
codecs, and options that codecs ignored or interpreted in varied ways.

It would be nice to have detailled:
 * Documentation about those codec/muxer/format-specific behaviors
 * Machine-readable capabilities descriptions. There's already some of
it in CODEC_CAP bits, perhaps it should be expanded. Especially audio,
those cap bits seem to care only for video stuff.

Example: VBR, ABR, CBR. One has to guess whether a particular codec
supports any of those in any meaningful way. Multipass. Maybe there's
some facility for that I missed, in that case I would love to be
enlightened ;)