[FFmpeg-devel] [mov] Fix trampling of ctts during seeks when sidx support is enabled.

Michael Niedermayer michael at niedermayer.cc
Thu Jul 20 15:00:59 EEST 2017


On Wed, Jul 19, 2017 at 07:30:01PM -0700, Dale Curtis wrote:
> Thanks will take a look. Is this test not part of fate? make fate passed

no, we should have tests for all (fixed) tickets in fate ideally
but in reality most tickets lack a corresponding test
I tried both in outreachy and as well in GSoC to improve this situation
with student projects but both only moved this forward by a small
step. Its a large amount of work to create robust, portable and
practical tests for "all" tickets and everything else.
The way out to get this actually done would be to pay a developer to
create tests for "all" tickets in fate. I belive carl would be the
ideal one to do this work as he has since a very long time always tested
and kept track of all our tickets.
I did suggest a while ago to someone at google that funding such
project would make sense but IIRC i never heared back.
if some company would fund something like this, i belive this would be
very usefull in the long run for code quality

> for me. The attached patch fixes this; the issue was that the index entries
> are 1 to 1 with ctts values. When samples are added without ctts entries
> we'd just initialize a single ctts entry with a count of 5. This left a gap
> in the ctts table; the fix is to use only 1-count entries when this case is
> hit.
> Note: This made me realize the presence of a ctts box and a trun box with
> ctts samples has always been broken. If the ctts box comes second it'll
> wipe the trun's generated table, but if the trun box comes after the ctts
> box it will try to insert samples at incorrect positions. Prior to my patch
> they would be looked up at incorrect positions, so there shouldn't be any
> new bad behavior here.
> - dale


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Opposition brings concord. Out of discord comes the fairest harmony.
-- Heraclitus
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