ตัวแปลงไฟล์ออนไลน์ฟรี VMS เป็น SPX

Used in Germany to compress speech audio for voice mail. A self-describing variant of cvsd (Continuously Variable Slope Delta modulation).

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.