I\’m not an expert in Video Editing but what I want to understand the logic of Whatsapp video processing. First of all I have noticed that whatever the file is, Whatsapp sets the limit of Uploaded videos to 16MB, after which whatsapp crops the video to not exceed the limit. is this a convention or it\’s a personal choice ? Secondly, When a video is recorded using the Camera it\’s not compressed by default, so whatsapp gb compresses it using FFMPEG I guess, and it takes no time. (tried for a video of 1min 1920×1080 with 125MB of size, becomes 640×360 with 5MB of size in no time, and the upload starts automatically).. how may they do this ? and why the choice of 640×360, It seems to me very fast for 2 asynchronous tasks : Compression + Upload. When I run the compression command ffmpeg -y -i in.mp4 -codec:v libx264 -crf 23 -preset medium -codec:a libfdk_aac -vbr 4 -vf scale=-1:640,format=yuv420p out.mp4 it takes approximatively 1 min and the video is being rotated !! 😀 Finally, when we download a video from Youtube it\’s already compressed (I guess) and whatsapp doesn\’t even try to compress it. So I think that it automatically detects thats the video is compressed. How can we detect this ?