If both ffmpeg and extpipe are on - both are executed and write to the same file

[tosiara]

To reproduce, enable extpipe as follow:

extpipe cat > video.raw

And also enable ffmpeg movies:

ffmpeg_output_movies on

Start motion, generate some movenets to trigger motion and see there are 2 files created: an avi file and video.raw. Both will contain same video.

So if you just enable default extpipe which has %f.avi for file name - the same video will be written to the same file twice.

Since extpipe is used as a replacement for internal ffmpeg encoding - it should have higher priority and disable internal encoding if use_extpipe is on