ffmpeg, first second of cut video part freezed
The order of the parameters is very important on ffmpeg.
Try this:

ffmpeg -ss 00:36:18 -i input.mp4 -vcodec copy -acodec copy -to 00:39:50 output.mp4


It seems that setting the -ss parameter before -i sets a keyframe at the beginning of the newly generated video.
Or so I understand from the Wiki page here.