Ad -F+i option to allow setting ffmpeg options that apply to input only.

[joa-quim]

No description provided.

[Esteban82]

I think that there is something missing.

I got these messages:

movie [WARNING]: Modifier +i detected but not a valid modifier! - ignored
movie [ERROR]: Option -F: Unrecognized format mp4+i-thread_queue_size 4096
movie [ERROR]: Must select at least one output product (-F, -M

I think that this issue (#8327) can help.

[joa-quim]

Please try again.

[Esteban82]

Please try again.

Ok, I will try.

[Esteban82]

Now it works. @joa-quim do you want me to add something in the docs ?

[joa-quim]

Yes, you can update the movie.rst file and I'll add the online doc to movie.c