MPC is one of the files of the Audio category. This unlicensed file format is intended to store audio information. The MPC format (i.e. Musepack Compressed Audio File) was created by Musepack. Musepack is a lossy compression scheme developed by German programmer Andree Buschmann. He started creating the codec in 1997. At that time he had the name MP +. The developer was not satisfied with the existing quality of MP3 coding. The algorithm is based on MP2 (MPEG-1 Layer 2), where there are 32 frequency bands, but with significant improvements. Over the past years, it has undergone revision and has become much better. It is currently at a more advanced stage, which contains highly optimized and unpatented source code. The MPC encoding quality at high bitrates (160 Kbps and more) is much higher than the quality that MP3 provides. During coding, a different psychoacoustic compression algorithm is used. In MPC, frequencies that ignore MP3 encoders do not disappear. The specificity of MPC is the fine tuning of psychoacoustics. This provides the ability to operate with pure VBR encoding (variable bit rate encoding). The main task of Musepack is to obtain the highest transparency of sound.
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.