On Friday, July 15, 2016 4:27:04 AM CEST, Brian Matherly wrote: > JB, > > I think this optimization could be made in frei0r.cairoblend. > > Could you compare the performance of frei0r.cairoblend with > transition_qtblend when the top frame has transparency? > > Seems like the transition_qtblend would be worth keeping > regardless of whether its performance is better.
I did make some further optimisations to my qtblend transition, and performance seems quite similar to cairoblend when doing a composite operation. qtblend can easily be modified to also use opacity and affine like transformations by applying a QTransform to the QPainter. I did spend some more time looking at cairoblend, composite and affine transitions though, and here are my quick thoughts: * composite transition: like Dan said, using the Kdenlive's monitor zoom I can clearly see the luma bleed * affine transition: when used as a filter, it does not correctly handle alpha channel (see picture in http://j-b-m.ch/affine-bug.png ). I tried to fix it but non trivial to fix for all cases * frei0r.cairoblend: if we want to optimize it as I did for qtblend, it would require modifications to transition_frei0r.c, since this helper always requests RGBA images for the A and B frames. Making it retrieve only B frame if it has no transparency does not seem easy since as Dan noted some frei0r transition might want to use A frame even when B frame is fully opaque, so it would require some kind rules depending on which transition/parameters. So in conclusion, despite the fact that I agree it's better to fix the problems rather than adding a new solution, in this case - thinking about Kdenlive - I think the best option would be to enhance my current implementation of qtblend to allow affine like transform and use it as a replacement for composite/affine/cairoblend in Kdenlive. Regards jb ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports.http://sdm.link/zohodev2dev _______________________________________________ Mlt-devel mailing list Mlt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mlt-devel
