[FFmpeg-devel] [PATCH 25/25] avformat/matroskaenc: Redo handling of FlagDefault

[Carl Eugen Hoyos]

Am Sa., 18. Jan. 2020 um 09:46 Uhr schrieb Andreas Rheinhardt
<andreas.rheinhardt at gmail.com>:
>
> Up until now, the Matroska muxer would mark a track as default if it had
> the disposition AV_DISPOSITION_DEFAULT or if there was no track with
> AV_DISPOSITION_DEFAULT set; in the latter case even more than one track
> of a kind (audio, video, subtitles) was marked as default which is not
> sensible.

It would not help only to change this strange behaviour?

> This commit changes the logic used to mark tracks as default. There are
> now three modes for this:
> a) In the "infer" mode the first track of every type (audio, video,
> subtitles) with default disposition set will be marked as default; if
> there is no such track (for a given type), then the first track of this
> type (if existing) will be marked as default. This behaviour is inspired
> by mkvmerge. It ensures that the default flags will be set in a sensible
> way even if the input comes from containers that lack the concept of
> default flags. This mode is the default mode.
> b) The "infer_no_subs" mode is similar to the "infer" mode; the
> difference is that if no subtitle track with default disposition exists,
> no subtitle track will be marked as default at all.
> c) The "passthrough" mode: Here the track will be marked as default if
> and only the corresponding input stream had disposition default.
>
> This fixes ticket #8173 (the passthrough mode is ideal for this) as
> well as ticket #8416 (the "infer_no_subs" mode leads to the desired
> output).

Doesn't this duplicate the cli option for disposition?
(Just asking, I know this is a can of worms)

I am wondering if a new option is necessary and useful.

Carl Eugen