[FFmpeg-devel] [PATCH 1/4] lavfi: add filter messages infrastructure.

Clément Bœsch u at pkh.me
Tue Jul 29 17:30:15 CEST 2014

On Tue, Jul 29, 2014 at 05:14:22PM +0200, Nicolas George wrote:
> Le primidi 11 thermidor, an CCXXII, Clément Bœsch a écrit :
> > What other kind of messages do you have in mind?
> I had thought about something to handle timestamps discontinuities / lost
> frames, but not very deeply.
> > "messages" sounds very user specific though. Like, it makes almost believe
> > that it's similar to the command system, and that we could maybe introduce
> > stuff like seeking through this. Said differently, it's just extremely
> > confusing to get the purpose.
> In my mind, commands are an extra feature to change the filtering process
> while these messages are necessary for normal encoding (the current system
> is broken wrt the duration of the last frame). Do you have an inkling about
> a better name? Metaframe?

metaframe sounds good, it carries the type of object it actually is. I
prefer considering a frame with a special flag a "metaframe" than a

> Also, I would like your advice on the avframe-on-stack micro-optimization.

av_frame_free() does more than just av_free() the AVFrame*. I would guess
that in the future it might do even more assuming that rest the code base
is doing av_frame_alloc() ("AVFrame must be allocated using
av_frame_alloc()"). I would be more comfortable with being a correct user
of the API here.

If you need to close multiple time, maybe you can allocate it once in the
AVFilterLink or wherever it would fit and use that one.


Clément B.
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