WebM is a video file format intended primarily for royalty-free use in the HTML5 video tag. The WebM Project releases WebM-related software under a BSD license and all users are granted a worldwide, non-exclusive, no-charge, royalty-free patent license. The project is sponsored by Google and has a sister project WebP. The WebM container is based on a profile of Matroska. WebM initially supported VP8 video and Vorbis audio streams. In 2013 it was updated to accommodate VP9 video and Opus audio. WebM Project licenses VP8 hardware accelerators (RTL IP) to semiconductor companies for 1080p encoding and decoding at zero cost. AMD, ARM and Broadcom have announced support for hardware acceleration of the WebM format.
MPEG-4 Part 14 or MP4 is a digital multimedia format most commonly used to store video and audio, but can also be used to store other data such as subtitles and still images. 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. MPEG-4 Part 14 (formally ISO/IEC 14496-14:2003) is a standard specified as a part of MPEG-4. Some devices advertised as "MP4 Players" are simply MP3 Players that also play AMV video or some other video format, and do not necessarily play the MPEG-4 Part 14 format.