QCP is an audio file category format. It has the full name Qualcomm PureVoice Audio File, since the format was developed by Qualcomm. The main application is the preservation of various types of recorded sound. The development of this format was in the company specifically for recording, storage and playback of all frequencies of the human voice. Files with the .QCP extension are most often used specifically for recording human voices, as well as for processing pauses that are natural for human speech. QCP files are also widely used for recording ringtones for mobile phones. They are very often applied as a sound attachment to emails. The standard plugin for many email programs is the PureVoice Player-Recorder program, which allows you to listen to the email application as a file with the .QCP extension. Also on any device, you can install the PureVoice SDK plugin, which allows you to listen to sound files with the extension .QCP. QCP belongs to the category of container formats. He can not independently set the encoding parameters of sound files. Inside the file with the extension .QCP there are files that use the EVRC or QCELP method for encoding.
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.