[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 

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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