h264 bitstream types

Question

I am trying to inspect h264 bitstream coming from hardware encoder on TI Davinci board.

00 00 0b c8 25 88 84 27 e4 a2 8e 32 77 87 ec 16 86 37 d7 8e 99 e1 8c 3b 8b ce fe a5 fc e9 9c f3 34 87 9f d7 ff 66 7d c1 ce ed 62 18 05 35 00 08 0f f6 69 12 08 a8 32 5e c7 fe c8 bf 77 e4 62 e4 9e 8b b0 6e f0 39 60 5b e8 26 78 52 d8 24 75 5c 2f 06 ce 71 04 aa cb e3 19 d0 dd 02 b5 e7 0e a7 ce 77 70 a9 7c 46 1e 65 b3 7b 02 c9 d4 72 d7 97 36 f3 59 93 e5 e6 92 ff 8f ba 29 03 d5 da 0a 7a 14 1f 19 b5 88 b1 98 7a 3b e1 58 a2 88 a1 5a 4a

The first 4 bytes seams to be size of the trailing chunk ...

What is the format of this bitstream?

How to extract nal_unit_type and slice_type/pict_type ?

Is there forbidden zero bit present ?

this source states that stream does not need to contain start codes, sequence parameter set NALUs and picture parameter set NALUs. And in that case decoder must obtain SPS and PPS NALUs externally (Some kind of extradata parameter to decoder..).

Answer 1

The ITU-T H.264 standard and the ISO/IEC MPEG-4 AVC standard (formally, ISO/IEC 14496-10 – MPEG-4 Part 10, Advanced Video Coding) are jointly maintained so that they have identical technical content. (http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC)

The H.264 spec can be downloaded for free at: http://www.itu.int/rec/T-REC-H.264/en

The ISO version costs currently CHF 323.00 at http://webstore.iec.ch/

Answer 2

The bitstream format is defined in ISO/IEC 14496-10 :

Information technology — Coding of audio-visual objects — Part 10: Advanced Video Coding

You can download the standard from itu.int website .

The data you provided looks like NAL Unit 5 (lower 5 bits of first byte of payload, after first 4 bytes with length are skipped) and it does not carry SPS/PPS units.

See also previous topics on H.264 decoding, eg H.264 stream header