[FFmpeg-devel] [PATCH 11/14] lavfi/vf_paletteuse: convert to framesync2.

Nicolas George george at nsup.org
Thu Aug 10 12:33:31 EEST 2017

Le tridi 23 thermidor, an CCXXV, Clement Boesch a écrit :
> But unless it's API documented, that's implementation specific. I'd prefer
> if you keep that as a safe guard. It also has a documentation purpose.

I will do it if you insist, but before that, let me correct a little

> If the frame is already writable it will be a noop.

Before it is used for its contents, frames are used for their timestamp.
The frame could be read-only at the time it is dequeued by
framesync but have become writable by the time it is ready for
processing by the filter. And I think it is not that unlikely: a graph
with split sending to overlay and scale would have that effect.

Instead of .needs_writable (I am not sure this flag should be relevant
with the activate callback), I can propose the following solution that
make the need for a writable explicit:

	 * Like ff_framesync2_dualinput_get, but make sure f0 is
	 * writable.
	ff_framesync2_dualinput_get_writable(fs, &f0, &f1);


	ff_framesync2_dualinput_get(fs, &f0, &f1,

(whichever people prefer), and probably the same options for the
individual ff_inlink_consume_frame().


  Nicolas George

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