ตัวแปลงไฟล์ออนไลน์ฟรี M4A เป็น SPX

This is a lossless-format (and encoding algorithm) for Apple platforms. M4A is widely used in iPod players and as a component in QuickTime media-players. The m4a codecs decoder is found in open sources - this allows third party users to open files in that format.

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.