.mp4 files are typically used to store MPEG4 AVC video files with high quality audio. .mp4 is just a container format, it can hold content encoded in a variety of audio and video formats.
avidemux is the most user-friendly choice when you need to make .mp4 files.
.mp4 files used on the web (as HTML5 video) should contain MPEG4 AVC video with AAC (faac) audio.
 Recommended bitrates
The 720p x264 TV Releasing Standards specifies the following bitrates for MP4 x264 video:
- 720p: Minimum 4000 kbit, maximum 8000 kbit. Minimum bitrate for animation is 2300 kbit.
- 1080p: Minimum 8000 kbit, maximum 14000 kbit, though not more than source-2000kbit. Minimum bitrate for animation is 5000 kbit.