[FFmpeg-devel] [Bulk] Re: [Bulk] [PATCH] avformat/mxfdec: dont truncate packets

[Tim Nicholson]

On 03/02/14 21:14, Tomas Härdin wrote:
> On Mon, 2014-02-03 at 16:32 +0100, Michael Niedermayer wrote:
> [..].
> 
>> maybe someone can figure out how to seperate them with a minimum of
>> code. Might even make a good gsoc qualification task
> 
> Good idea
> 
>> Also can this not be done without using the UL ?
> 
> Nope :)
> 
> Example: the OPAtom spec mandates clip wrapping (all audio/video in one
> huge KLV chunk). But the OP1a spec is vague on the subject - OP1a files
> are usually frame wrapped (audio/video interleaved, like sane formats),
> but they can also be clip wrapped since the spec doesn't forbid it.
> That's how I interpret the specs at least
> 
> /Tomas
> [..]

>From a man who knows more than I do....


"OP-Atom doesn't mandate clip wrapping. See for example D-Cinema files
which use frame wrapping. OP-1A doesn't mandate frame wrapping. See for
example AS-02 which uses clip wrapping in OP-1A for audio.

I see the context for this is from the FFmpeg forums. I'm not on the
email list, so you might want to point them to a libMXF commit I made
fairly recently:
http://sourceforge.net/p/bmxlib/libmxf/ci/fb7c9f74b7a93c4f70b21986534987565def42d3/
This commit should provide some guidance in how the essence container
labels can be summarised to extract the clip/frame wrapping information.
bmx has some extra analysis beyond that, but the libMXF function should
cover most cases."


-- 
Tim