Is a media data format created by Apple. Named 'Quicktime' and is opened by a program with the same name. This format contains several tracks, each of which can store audio, video or text. Supported by a large number of encodings and in a single file, each element can use its own codec.
An SPX file is a Speex audio file saved within an Ogg Vorbis container. Speex is an open source patent-free audio format designed for speech compression. It supports variable bitrate (VBR) encoding and several features not found in other audio codecs. Some examples include embedded encoding, intensity stereo encoding, and voice activity detection.