Correct FFMPEG WRITER_WARNING on SDS_tools.make_animation_mp4

[thekester]

Hello, I noticed that the generation of mp4 videos was generating a few warnings, so I've tried to correct some of them in a pull request. However, i still encounter the warning [rawvideo @ 0x5cfe700] Stream #0: not enough frames to estimate rate; consider increasing probesize but these warnings do not prevent the video from being generated