[FFmpeg-devel] [PATCH 0/4] User controllable padding

[Timothy Gu]

On Jan 1, 2014 6:46 AM, "Michael Niedermayer" <michaelni at gmx.at> wrote:
>
> On Wed, Jan 01, 2014 at 01:01:24PM +0100, James Darnley wrote:
> > On 2013-12-30 20:16, James Almer wrote:
> > > Bump lavf minor in the first patch.
> >
> > Oh yes, done.
> >
> > > -1 for default value, 0 for no padding. Muxers can and should clip
the value if needed.
> > > Ideally look up the corresponding limit for both flac and id3v2.
> >
> > > You need to keep the default of 8192 if there's no user provided
value.
> > > Same with the value in the id3v2 patch.
> >
>
> > Why should there be a "default value" value?  Why would different
> > formats have different defaults for a feature intended to do the same
> > thing on them all?
>
> different formats have different requirements. different
> recommanditions, differnt constraints due to compatibility with
> various software.
> Having per format defaults is the easy solution.
> If you want to change the default padding used by some format then
> theres the question if that breaks any software or hardware that reads
> that format. This would have to be tested ...
>
> but its a bit worse then that, even if for the current formats
> theres a common default that would work for all, a format added
> in the future might have different requirements, like the padding
> being a multiple of 12345
>
> also it might make sense to instead use private options for each
> muxer that supports this, as that way it would be clear which
> muxers support it and what is the valid range of padding for each
> format, as well as the default, its not clear if this or a common
> field in AVFormatContext is better

Or maybe port AVCodecDefault to lavf or lavu.

[...]

Timothy