Interesting about the relation between WebM and MKV found in google search: "Many Web browsers support WebM, which is a restricted version of MKV. The most imp

Interesting about the relation between WebM and MKV found in google search: "Many Web browsers support WebM, which is a restricted version of MKV. The most important restriction is in the allowed video codecs. WebM video uses only the VP8 and VP9 codecs, which are open and royalty-free. All WebM files are MKV files, but not all MKV files are consistent with WebM" So the question comes back to supported codec moreso than container format.