This is an aborted project from when I was thinking of manually implementing a dissolve feature.
kino can do this!
My idea ∞
- Take 10 frames from source a as PNG images. (FFmpeg?, MPlayer?)
- Take 10 frames from source b as PNG images.
- Apply transparency effects to those 20 images, from 0% transparency to 100% transparency in source a, and 100% to 0% in source b.
- Merge the 10 source a and 10 source b images together. (1-10 a with 10-1 b)
- Create a video out of those 10 images.
- Cut 10 frames from the end of video source a.
- Cut 10 frames from the beginning of video source b.
- Calculate how many frames equals how many seconds.
- Clip the audio from the two sources.
- Use SoX to cross-fade the two sound sources.
- Apply the cross-faded sound to the transparency-picture video.
Merge the new source a, the transparency-picture-video, and the new source b.
cross-fade the sound too.