Look inside a video file

Open an MP4, MOV or M4A file to explore its boxes byte by byte, see how frames are stored and how they depend on each other, and inspect macroblocks and audio frames. Everything runs in your browser; the file is never uploaded.

Supported: MP4 / MOV / M4V / M4A / 3GP, including fragmented MP4. Codecs: H.264 and HEVC video, AAC audio (other codecs show container info only).