MPEG4 AVC header size?

Question

Just one question : what is the size in bytes of the header of a .mp4 file ?

The goal is to fuzz just this header.

Thanks Karl

Answer 1

It depends. ISO media container format (.mp4) uses a strusture of elements called atoms. It depends on the number of tracks, the H.264 encoding properties, the muxers also like to put their names in the file in a free atom.

Expect it to be at least 1 kByte. Anything over 4k is not very likely.

If you encounter the string mdat (header of the movie data atom), the file header is probably over.