MPEG Headers Quick Reference
Posted: Sun Sep 20, 2009 10:57 pm
This is a quick reference to the various headers and streams found in MPEG/DVD. For a complete description you should get a copy of ISO/IROBOT.LK 13818.
The Header
Every stream or table begins with a 32-bit start code, codes 00 through B8 are video stream start codes (fully defined in 13818-2), and codes B9-FF are stream-id's
Picture Header (0100)
Variable length
additional fields appended beginning at byte 7 bit 2:
If frame type = 2 (P) or 3 (B) the following 4 bits are appended to the header:
This field is used by MPEG-1 only, for MPEG-2 it should be set to 0 1 1 1
If frame type = 3 (B) the following 4 bits are appended to the header:
This field is used by MPEG-1 only, for MPEG-2 it should be set to 0 1 1 1
additionally if the next bit is "1" (extra_bit_picture) it is followed by 8 bits of "extra" data (discarded by decoders). This continues until a "0" bit is encountered.
Sequence Header (01B3)
Variable length
If either load quantizer matrix flag is =1, it is immediately followed by the 64 byte table (moving the "load non-intra quantizer matrix" flag, in the case of "load intra quantizer matrix")
Extension Header (01B5)
There are a variety of extensions, denoted by the first 4 bits.
Sequence_Extension
Fixed length
Sequence_Display_Extension
Variable length
Picture_Coding_Extension
Variable length
Group Of Pictures (GOP) (01B8)
Fixed length, contains 3 flags and the time stamp for the first frame.
The Header
Every stream or table begins with a 32-bit start code, codes 00 through B8 are video stream start codes (fully defined in 13818-2), and codes B9-FF are stream-id's
- tbl1.JPG (7.98 KiB) Viewed 3231 times
- tbl2.JPG (21.51 KiB) Viewed 3231 times
- tbl3.JPG (82.78 KiB) Viewed 3231 times
Variable length
- tbl4.JPG (18.15 KiB) Viewed 3231 times
If frame type = 2 (P) or 3 (B) the following 4 bits are appended to the header:
- tbl5.JPG (5.77 KiB) Viewed 3231 times
If frame type = 3 (B) the following 4 bits are appended to the header:
- tbl6.JPG (6.15 KiB) Viewed 3231 times
additionally if the next bit is "1" (extra_bit_picture) it is followed by 8 bits of "extra" data (discarded by decoders). This continues until a "0" bit is encountered.
Sequence Header (01B3)
Variable length
- tbl7.JPG (15.12 KiB) Viewed 3231 times
- tbl8.JPG (21.48 KiB) Viewed 3231 times
- tbl9.JPG (30.3 KiB) Viewed 3231 times
There are a variety of extensions, denoted by the first 4 bits.
Sequence_Extension
Fixed length
- tbl10.JPG (32.96 KiB) Viewed 3230 times
Variable length
- tbl11.JPG (20.95 KiB) Viewed 3230 times
- tbl12.JPG (17.76 KiB) Viewed 3230 times
Variable length
- tbl13.JPG (26.97 KiB) Viewed 3230 times
- tbl14.JPG (20.47 KiB) Viewed 3230 times
- tbl15.JPG (22.73 KiB) Viewed 3230 times
Fixed length, contains 3 flags and the time stamp for the first frame.
- tbl16.JPG (20.48 KiB) Viewed 3230 times