Comment 106 for bug 520941

I have also found that PNG sequences cause this issue. See the attached example project "Openshot PNG sequence issue.tar.gz", which demonstates the issue using a PNG sequence generated via "New Animated Title".

There are two issues I can see:-

1. The final frame of the animation is not mixed correctly and so you see a flash.
2. Fades will be broken for any clips after the PNG sequence on the same track (in the example I attached, you hear a blip at the end)

Looking at the generated MLT XML, you can see a difference between image sequence "out" attribute which is "79". Whereas the transition which is added along with the image sequence has "out" set to "78".

If you change the 78 to 79 and run the XML directly with melt, then that at least fixes the flash you see at the end of the animation. But does not resolve the blip at the end of the fade.

I have played with the ins and outs, but cannot find a way to resolve the blip.

So back to the 78 vs 79 issue. I think this is a rounding error within OpenShot. I since noticed that I used the default profile NTSC, I usually use PAL, but lets investigate this anyway:

The image sequence is 80 frames. NTSC is 29.97 frames per second.
So I expect OpenShot to calculate a duration of 2.669336003 and round this to 2.67.
But OpenShot shows a length of 2.64, which happens to be what you would round to if OpenShot was calculating based on 79 frames (79/29.97 = 2.635969303)

So possibly OpenShot is getting the number of frames in a sequence out by 1?