[FFmpeg-devel] [PATCH] lavfi: add asendcmd and sendcmd filters

[Stefano Sabatini]

On date Monday 2012-09-03 17:35:05 +0200, Clément Bœsch encoded:
> On Mon, Sep 03, 2012 at 04:04:30PM +0200, Stefano Sabatini wrote:
> > On date Monday 2012-09-03 13:32:04 +0200, Clément Bœsch encoded:
> > > On Mon, Sep 03, 2012 at 12:28:11PM +0200, Stefano Sabatini wrote:
> > > [...]
> > > > > Even if "filter class" and "specific filter instance" sounds more correct
> > > > > from a developer perspective, would it make more sense to say that it's
> > > > > just the filter name?
> > > > > 
> > > > 
> > > > > And by the way, how do you identify the different target instances of the
> > > > > same filter? ("volume", "volume1", "volume2", ...?)
> > > > 
> > > > Different filters have different instance name (parsed_...), it is not
> > > > still possible to specify the name of an instance in the filter graph.
> > > > 
> > > > > > + at var{time} specify the time when the filter command is sent, expressed
> > > > > > +as a time duration.
> > > > > > +
> > > > > 
> > > > > Note: as I said on IRC, I really think this should allow frame accurate
> > > > > timing range at some point.
> > > > 
> > > > Mixing times and frames is really hard if not impossible.
> > > >  
> > > 
> > > :(
> > 
> > When I was working on an extended fade filter I tried to mix frame
> > count and time interval, and it was a mess. For example:
> > #100-100
> > 
> > depending on the timestamps the interval could be negative (end <
> > start). I also tried to handle special interval like:
> > 10+#100
> > 
> > (starting from 10 and continuing for 100 frames).
> > 
> > Dealing with frame-count interval e.g. #100-#200 should be feasible,
> > but again that won't work with seeking, since the frame counter will
> > always increase.
> > 
> 
> Well OK, mixing both might be a problem (and I don't think users need
> that), but allowing timestamp-only or frame-only should be possible,
> right?

Yes. Of course anything which works with framecount won't be accurate
when seeking is performed.

Other variants:
TIME+FRAME_COUNT
FRAME_COUNT+TIME

suffer of the same problem (but should be possible otherwise).

Patch updated, with some added checks.
-- 
FFmpeg = Fantastic and Fancy Majestic Power EntanGlement
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