MP4
MPEG-4 Part 14 or MP4 is a digital multimedia container format most commonly used to
store video and audio. Like most modern container formats, it allows streaming over
the Internet. The only official filename extension for MPEG-4 Part 14 files is .mp4, but
many have other extensions, most commonly .m4a and .m4p. M4A (audio only) is often
compressed using AAC encoding (lossy), but can also be in Apple Lossless format. M4P
is a protected format which employs DRM technology to restrict copying.
In MP4 file, the widely supported codecs and additional data streams are MPEG-4 Part
10 (H.264) for video and Advanced Audio Coding for audio.
WebM
WebM is a video file format.
[3]
It is primarily intended to offer a royalty-free alternative to
use in the HTML5 videotag. It has a sister project WebP for images. The development of
the format is sponsored by Google, and the corresponding software is distributed under
a BSD license.