framerate improvement

[JamesKrieger]

Tesla video source are at generate between 35 to 36 fps.
during the conversation, the video is down sample to 25 fps.
Propose to keep same rate as the source. (or take the higher frame rate.)

[JamesKrieger]

instead of the default 25fps, the new framerate can be specify on the first stream to the FFMPEG.

Below the example to set the framerate to 60

'-filter_complex', "color=duration=58.48:s=3840x1920:c=black ,fps=60 [base];

Tested and confirm to work. (but probably need a better integration in the code)

[ehendrix23]

Added in release 0.1.16