Is a new media container format from Google. Based on video codecs line VP8(9). Its main task is a replacing the old standard MPEG-4. The format is supported by all browsers and is integrated in Adobe Flash technology. For audio codec Vorbis is used; for subtitles and metadata is a the Matroska container.
this is a lossless-format (and encoding algorithm) for Apple platforms. M4A is widely used in iPod players and as a component in QuickTime media-players. The m4a codecs decoder is found in open sources - this allows third party users to open files in that format.