[Cin] Playback slowdown

[Andrea paz]

>
> I am having a little trouble keeping problems categorized and did not yet look at the previous report of the PNG problem (not MKV though)  If you could open an issue in MantisBT for just the PNGs, it will not as easily get lost there.
>
I'm sorry, it's my fault for the chaos of my messages.
Like Andrew said, PNG aren't a real problem. So I'm not going to open
an issue. When I had problems with playback I noticed that transitions
between two PNGs slowed down even more than usual. Associating this
with the terminal's message:
"FFMPEG::open_decoder: some stream have bad times:
/home/paz/video_editing/prova/1080/background.png"
I thought the slowdowns were similar to those with mkv. But Andrew
clarified the ideas to me and it's not worth wasting time on PNG.
I will instead open an issue on mkv, because I think it is important
to be able to use them without problems. Their codecs are now very
widespread and have great potential.