[FFmpeg-devel] [RFC] Exporting virtual timelines as stream side data

Derek Buitenhuis derek.buitenhuis at gmail.com
Tue Mar 27 22:44:00 EEST 2018

So, I know we have edit list "support" in mov.c, but I am steadfast in my
belief that it is incorrect to implement it at the demuxing layer. By the
ISOBMFF spec, it is supposed to be applied at the presenattion layer. I'm
aware we probably cannot remove the current implementation very easily
(or at all?) because many will argue it is "removing a feature". Thus, for
ISOBMFF and mov support, this will likely have to live under a movflag,
I assume?

Anyway, this is my proposal for generic stream side data for virtual timelines.
This is also meant to cover Matroska ordered chapters and editions, though I
am not entirely sure how segment linking would work into this, if I am honest.

If/once I have the side data structs and API (in the following RFC patch) agreed
upon, I am willing to write:

    * Support for exporting MOV/ISOBMFF edit lists via side data
    * Support for exporting Matroska edit lists via side data
    * Porting the fftools to use it (if wanted)

As a side note, I would appreciate input from someone who unerstands Matroska
better than I do on this. I haven't included e.g. the Hidden/Enabled flags in
AVtimelineEntry since they don't seem to actually be useful to the actual
timeline (they seem to be mostly related to displaying chapter names or not).

The side data structs and API are based off of the recently pushed encryption
side data changes. The media rate is a rational, because exporting a float
would change on different platforms, and would make adding regression tests

So, everyone, rev up your diesel powered bikesheds and drive them full steam
into this thread's back yard, over my daffodils.

Derek Buitenhuis (1):
  avcodec/avutil: Add timeline side data

 libavcodec/avcodec.h |   8 +++
 libavutil/timeline.h | 160 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 168 insertions(+)
 create mode 100644 libavutil/timeline.h


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