WebM

WebM is a video and audio container format released by Google, used with content encoded under the VP8 or VP9 codecs for video, and Vorbis and Opus for audio. It is a variant of Matroska, based on EBML.

Identification
A WebM file begins with, as do all EBML files.

It contains an EMBL "DocType" element whose value is the string "webm". This means that the byte sequence will appear in the file, normally near the beginning.

Sample files

 * Test video
 * https://telparia.com/fileFormatSamples/video/webmVideo/

Links

 * Wikipedia article
 * The WebM Project
 * Container Guidelines

Software

 * FFmpeg
 * Konvertor