command line convert .dat to .mp4
ffmpeg -i input.dat -c:v libx264 -crf 20 -c:a aac -b:a 128k -movflags +faststart output.mp4
# If input is interlaced
ffmpeg -i input.dat -vf yadif -c:v libx264 -crf 20 -c:a aac -b:a 128k -movflags +faststart output.mp4
# Use mkv for archival purposes
ffmpeg -i input_video.dat -c:a pcm_s16le -c:v ffv1 -level 3 -coder 1 -context 1 -g 1 output.mkv