OPUS is an audio file that is encoded using the Ogg Opus format (lossy coding). It was created for online audio streaming, that is, in order to transmit sound through a global network. The format is being developed by the Internet Engineering Task Force (IETF) and Xiph.Org communities. Applies SILK codecs when used in Skype and CELT (from Xiph.Org), provides support for variable bitrate. Most often, the OPUS codec is used for video conferencing, game chats, VoIP telephony. OPUS is a free audio codec that has international standard status (IETF RFC 6716). Its main advantages are a low coding delay (from 2.5 to 60 ms) and its significant speed, an increased degree of compression of audio data with high-quality sound, as well as support for multi-channel audio (within 255 channels). In 2011, J. Skeglund of Google conducted two series of tests, during which OPUS coding and decoding were compared, taking into account the assessments of experts and ordinary listeners. Studies have shown that OPUS provides stereo music with the same quality as MP3 and better quality than G.719 64 kbps. OPUS offers great streaming capabilities with dynamic tweaking and very low latency. This is always high sound quality and excellent data compression. Full support for OPUS is provided by Mozilla applications. He is the key Skype audio codec.
MKA is an audio container format. It supports some types of audio compression algorithms. The .mka file extension belongs to the Matroska format (Matröška, Matryoshka). Thus, it serves to specifically designate the file type "Matroska Audio File" (Matroska Audio File). Matroska is an open cross-platform standard. It is a modern extensible multimedia container format. It is error resistant. It is suitable for streaming HTTP / RTP. Supports multiple subtitle tracks, audio, video. The Matroska standard is supported in the native mode by many software players and hardware devices, including, for example, receivers, televisions, smartphones, etc. A .mka file is a regular Matroska container that has one or more audio tracks. They are encoded by any of the supported codecs. In most cases, AAC and AC3 (Dolby Digital) codecs are used. Playing a .mka file needs the support of the standard Matroska container format. But not only. There must also be a specific audio codec with which the tracks are encoded. Often, MKA files are used as external audio tracks for movies in other languages. Or with other content, or with sound quality. Say multi-channel sound, director’s comments. .Mka audio files are used as containers for high-quality multi-channel music.