[FFmpeg-devel] [PATCH] lavf/matroskaenc: Fix Cues on Audio for WebM DASH

Reimar Döffinger Reimar.Doeffinger at gmx.de
Sun Jun 8 11:53:18 CEST 2014

On Fri, Jun 06, 2014 at 12:25:30PM -0700, Vignesh Venkatasubramanian wrote:
> On Fri, Jun 6, 2014 at 12:17 PM, James Almer <jamrial at gmail.com> wrote:
> > On 06/06/14 3:26 PM, Vignesh Venkatasubramanian wrote:
> >> Fix a change that was broken by [1]. Cues must be added for audio frames
> >> on cluster start for WebM when the DASH flag is passed. Restoring
> >> correct functionality.
> >>
> >> [1] http://goo.gl/xYLq7Z
> >>
> >> Signed-off-by: Vignesh Venkatasubramanian <vigneshv at google.com>
> >> ---
> >>  libavformat/matroskaenc.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > Maybe you could add a fate test to make sure muxing of WebM DASH is not broken
> > by future unrelated work with the cues or other parts of the code.
> > Adding cues for audio in general is a TODO after all.
> there was a discussion about adding a fate test in [1]. turns out the
> only way to add a fate test it to verify the checksum of the whole
> file. that seemed too fragile and could easily break with other
> unrelated changes. do you have any idea as to how it can be done?

No _new_ ideas. As mentioned there, extending the demuxer to be able
to do the checking is possible.
You can avoid having to add a option to the demuxer by e.g. adding
"DASH" to the "encoder/muxer application" string.
I understand that it seems messy/a lot of effort, but long-term it's
likely to be less effort than having to manually debug and fix these
kind of bugs.

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