Feature request: option to crossfade between chunks when merging

[bascurtiz]

Great handy tool!
Thanks for writing it (and making it cross-platform)

Feature request: option to crossfade between chunks when merging
https://trac.ffmpeg.org/wiki/AfadeCurves

I believe just the default slope would do, and ask the user how many mm/ss/ms.

If not, stuff can result in clicks/glitches on the chunks, hence crossfading would be a life-savior :)
Example: https://pillowcase.su/f/53abaca280e4a5980fe3574c5f7ec8fc

[thp]

Patches gladly accepted.