From: Wilson Woo To: submit@wotsit.demon.co.uk Subject: MPEG Video THIS TEXT CONTAINS ONLY MPEG VIDEO HEADER INFO - BY WILSON WOO It's only what I know. Please feel free to update it. Below is information got from someone. /*****************************************************************/ Sequence Header This contains information related to one or more "group-of-pictures" Byte# Data Details =================================================================== 1-4 Sequence header In Hex 000001B3 code 12 bits Horizontal size In pixels 12 bits Vertical size In pixels 4 bits Pel aspect ratio See below 18 bits Picture rate See below 1 bit Marker bit Always 1 10 bits VBV buffer size Minimum buffer needed to decode this sequence of pictures; in 16KB units 1 bit Constrained parameter flag 1 bit Load intra 0: false; 1: true (matrix follows) quantizer matrix 64 bytes Intra quantizer Optional matrix 1 bit Load nonintra 0: false; 1: true (matrix follows) quantizer matrix 64 bytes Nonintra quantizer Optional matrix - Squence extension Optional Data - User data Optional application-dependent data =================================================================== Aspect raios are defined by a code which represents the height and width of the Video image. Picture rates are also defined by a code that represents the number of pictures that may be displayed each second. Each group of pictures has a header that contains one "I picture" and zero or more B and P pictures. The header is concerned with the time synchronisation for the first picture in this group, and the closeness of the previous group to this one. /*****************************************************************/ For picture rate: 1 = 23.976 frames/sec 2 = 24 3 = 25 4 = 29.97 5 = 30 6 = 50 7 = 59.94 8 = 60 Here gives an example. Below is Hex dump of first 256 bytes of the first Video frame of TEST.MPG from XingMPEG. 00 00 01 B3 16 00 F0 C4 02 A3 20 A5 10 12 12 14 14 14 16 16 16 16 18 18 19 18 18 1A 1B 1B 1B 1B 1A 1C 1D 1E 1E 1E 1D 1C 1E 1F 20 21 21 20 1F 1E 21 23 23 24 23 23 21 25 26 27 27 26 25 29 2A 2A 2A 29 2D 2D 2D 2D 30 31 30 34 34 38 16 00 F0 C4 00 00 01 B8 00 08 00 00 00 00 01 00 00 0A 72 00 00 00 01 01 13 F9 50 02 BC B2 B8 BE 68 8B A4 9F C5 B5 CA 00 56 76 39 65 F2 30 8B A6 9D 50 69 E7 DA FE 13 CF B7 FF 8F F4 CE 7B FA 0E F0 66 AE 1C 5D E7 00 C8 0A 92 B9 29 3C 21 23 F1 D6 40 13 06 F0 10 10 C6 27 80 A0 34 E1 C8 E4 0F 74 91 DA C4 03 A0 DC 03 12 60 18 49 27 1D D4 BC 67 0E 54 8C 96 FC 5D C0 06 E0 1A 72 11 7C 9A 8D C9 45 89 6D CD C4 0B 63 DC 90 18 24 00 EC 84 90 18 10 C9 3B 1E A7 60 3C 9D 74 80 76 05 0B 02 81 A9 29 39 68 53 8F 59 F1 BF 93 FB A0 04 01 BC B0 CE 18 E1 25 Sequence header = (Hex) 00 00 01 B3 Horizontal size = 0x160 = 352 Vertical size = 0x0F0 = 240 Pel aspect ratio = [I don't know] Picture rate = 4 = 29.97 frames/sec Marker bit = 1