Update ffmpeg.py

[gcurtis79]

If using "video_input_format=mjpeg" then disable '-video_size'
Otherwise, normal operation.
Should make it a list of incompatible input_formats, but I'm only aware of mjpeg.

[gcurtis79]

Just a note:

This change will have absolutely no effect on anyone not using mjpeg input format, and requires no additional config options.

With this simple patch to ffmpeg.py, you can now stream from a Pi Zero to LetsRobot.tv with another machine (in my case a Ubuntu Server) with normal config settings.

In my case, I use the following in the standard config file:

[camera]
# Camera stream on my Pi Zero
camera_device = http://192.168.136.199:8080/stream/video.mjpeg
[ffmpeg]
# RSH to remote machine and activate ffmpeg there
ffmpeg_location = rsh <user>@<host> ffmpeg
# The trouble making input format
video_input_format = mjpeg

[gcurtis79]

Checking in to see if this should be dropped, or if it's going to be merged. I've been using it for weeks now.

[Nocturnal42]

It's because there are already several conditionals added to the ffmpeg command line builds, and it makes sense that they should all be handled in a consistent fashion. I've been meaning to go over it and pick a method to go with. I just haven't got around to it.

[gcurtis79]

Gotcha. I didn't know if there were any already. I would have made it a list check, but I only knew of the one that caused the error so far.

[Nocturnal42]

They are mostly in the ffmpeg audio stuff, from memory.