Workaround for iOS 12.2 playback issues

[Supereg]

As discussed in #50

FFmpeg now takes the raw video stream from the camera and encodes it via h264_omx (hardware accelerated).

I removed to v4l2ctl call (which previously would set the bitrate). I don't if there is any effect on the picture when using the raw yuv420p video stream from the camera. Most people will have the video_bitrate setting set to 300.000 (default 10.000.000). Don't know if that's an issue.

[moritzmhmk]

Thanks for the pull request! I will not be able to review/test/merge this until July. (See #50 for more on this)

[h0lz]

Works! Thank you very much! :)

[smeathers]

This also solve my problem of live video not working.