[Interest] mirroring and reversing QMovie
Thiago Macieira
thiago.macieira at intel.com
Tue Jul 12 07:38:11 CEST 2016
On terça-feira, 12 de julho de 2016 15:48:47 PDT Frank Rueter | OHUfx wrote:
> Hi all,
>
> I am wondering how to mirror a cached QMovie object horizontally and
> vertically and how to play it in reverse.
> Is this even achievable with QMovie? If not could it be achieved by
> manipulating the IODevice somehow?
> I can't find a single thing online about this sort of thing.
Forget about playing it in reverse. Movie files are encoded in such a way that
the frame N+1 depends on the rendering of frame N. To play in reverse, you
need to render all of the non-key frames, store them in memory, then display
them.
That's why rewinding on moving players is usually choppy, while fast-forward
can be smooth: rewinding often simply displays the key frames.
--
Thiago Macieira - thiago.macieira (AT) intel.com
Software Architect - Intel Open Source Technology Center
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