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.
VOC is an audio file category format. File format VOC (or Creative Labs Audio File) was created by Creative Labs. Creative Labs was involved in the development of the audio file format in order to store and transfer audio data for its 8-bit and then 16-bit Sound Blaster sound cards. The format is a sound effect, sound clip and instrumental sound, referred to as a voice. To reduce the size, VOC files are compressed. Since this format has already been thoroughly investigated, its file structures have already been described in detail. A .voc file is a digital audio file in VOC format. In the title, it can be easily identified by the text line “Creative Voice File”. The file includes a header, as well as one or more blocks of audio data. Due to PCM / ADPCM audio encoding, VOC files can be easily converted to WAV format. VOC audio files can be played by several universal multimedia players. Sound editors import them. Using many utility converters, you can convert other audio formats to WAV. In many cases, the .voc file type becomes associated with some kind of multimedia processor that is installed on the system.