ffmpeg -i <input> c:v libx264 -crf 23 -profile:v baseline -level 3.0 -pix_fmt yuv420p -c:a aac -ac 2 -strict experimental -b:a 128k -movflags faststart output.mp4

ffmpeg -i <input> -c:v libx264 -profile:v baseline -c:a libfaac -ar 44100 -ac 2 -b:a 128k -movflags faststart output.mp4

ffmpeg -i input.mp4 -vcodec libx264 -profile:v main -level 3.1 -preset veryslow -crf 23 -x264-params ref=4 -acodec copy -movflags +faststart output.mp4

ffmpeg -i source_video.avi input -acodec aac -ab 128kb -vcodec mpeg4 -b 1200k -mbd 2 -flags +4m -aic 2 -cmp 2 -subcmp 2 -s 320x180 -title X final_video.mp4