Convert M4A to MP4 — Free Online Converter

M4A and MP4 are the same container format — MPEG-4 Part 14 (ISO 14496-14). The only difference is the file extension: Apple uses .m4a for audio-only files and .mp4 for video or general multimedia. Converting M4A to MP4 is the simplest possible operation: renaming the extension or performing a stream copy that updates the ftyp brand code. The audio bitstream is completely unchanged.

Some systems, platforms, and APIs only accept .mp4 files and reject .m4a even though the container is identical. HTML5 audio elements sometimes have MIME type configurations that recognize audio/mp4 but not the .m4a extension. Certain CMS platforms, video hosting services, and media processing APIs validate file extensions and refuse .m4a uploads. Converting to .mp4 resolves these purely administrative compatibility issues.