[FFmpeg-devel] [PATCH] h264 bitstream filter

Reimar Döffinger Reimar.Doeffinger
Wed Sep 5 21:06:38 CEST 2007

On Wed, Sep 05, 2007 at 07:07:29PM +0100, M?ns Rullg?rd wrote:
> Benoit Fouet <benoit.fouet at purplelabs.com> writes:
> > Michael Niedermayer wrote:
> >> patch ok if it works
> >>
> >> [...]
> >>   
> >
> > i have one remaining question: should mp4 files contain AUD nal units
> > too or have i missed something (again :) ) ?
> > if i'm right, it seems that our muxer doesn't handle it, as i don't get
> > the aud frames...
> > if i'm wrong, i'll have to add the aud in the filter too.
> AUD (Access Unit Delimiter) is an optional NAL unit with the sole
> purpose of marking the start of a new frame (access unit).  There
> would be no sense in using it in formats like mp4 that signal frame
> boundaries by other means.

But as I understood the spec this NAL is never needed to detect the
start of a new access unit (though the rules to detect it without are
very complex), so IMO at least for this filter there is no reason to
generate it, if anything it should be a different filter.

Reimar D?ffinger

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