Parsing H264 in mdat MP4

Question

I have a file that only contains the mdat atom in a MP4 container. The data in the mdat contains AVC data. I know the encoding parameters for the data. The format does not appea

Answer 1

I found what michael was talking about defined in section 5.2.3 of ISO 14496-15.

Sebastian's answer refers to section 5.2.4.1.1 and 5.3.4.1.2.

You will not be able to parse the slices in the 'mdat' box without copies of the SPS and PPS from the 'avcC' box (defined in section 5.2.4.1.1)

Answer 2

AVC NAL units are in the following format in MDAT section: [4 bytes] = NAL length, network order; [NAL bytes] Shortly, start codes are simply replaced by lengths.

Answer 3

Be careful! The NAL Length is not required to be 4! The AvcConfigurationBox ('moov/trak/mdia/minf/stbl/stsd/avc1/avcC') contains a field 'lengthSizeMinusOne' specifying the length. But the default is 4.