Be sure to not confuse a container with codecs.
Mp4 is a
container, and can have two streams inside (unlike mkv which can have unlimited video, audio, subtitle streams);
1. Video stream (determined by a video codec, usually mpeg-4)
2. Audio stream (determined by an audio codec, youtube uses AAC among other)
Other containers are; mkv, avi, mov, flv, ogg (ogg vorbis is both a container and a codec) et al
Video codecs examples (for decoding and encoding); MPEG-2 (DVD), vp6, HEVC x265, xvid/divx.
https://en.wikipedia.org/wiki/Comparison_of_video_codecs Some codecs can only be used in certain container formats.
But yes, what you already have in an
mp4 file is generally
compressed, both the video stream and the audio stream. That's where uncompressed and compressed (lossy and lossless) comes in.
wav for example is the main format used on Wndows for raw and typically uncompressed audio. ogg and mp3 (and those under videos) are compressed. Compressed usually means lower file size.
To make the file size smaller you can decrease the audio quality and video quality in several ways, example by lower sampling rate, lower fps, lower bit rate, lower resolution etc.
BeatriceElysia: are you saying uploading mp4 video and compressing it to be of smaller size is futile?
It all depends on what you already have, what you want, and what you are willing to sacrifice just for the sake of a few kb or mb...
Only 2 minutes of video? I personally wouldn't bother. Use vlc to check what the mp4 contains and decide from there.
If you have a 2000 megabyte big mp4 file for only 2 minutes of video then something is not right...
