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Pack Header

byte 0byte 1byte 2byte 3
76543210765432107654321076543210
0000 0000 0000 0000 0000 0001
start code		 1011 1010
PACK identifier
byte 4byte 5byte 6byte 7byte 8byte 9
765432107654321076543210765432107654321076543210
01 SCR 32..30 1 SCR 29..15 1 SCR 14..00 1 SCR_ext 1
byte 10byte 11byte 12byte 13
76543210765432107654321076543210
Program_Mux_Rate 11 reserved pack_stuffing_length

PACK identifier -- 0xBA

  • SCR and SCR_ext together are the System Clock Reference, a counter driven at 27MHz, used as a reference to synchronize streams. The clock is divided by 300 (to match the 90KHz clocks such as PTS/DTS), the quotient is SCR (33 bits), the remainder is SCR_ext (9 bits)
  • Program_Mux_Rate -- This is a 22 bit integer specifying the rate at which the program stream target decoder receives the Program Stream during the pack in which it is included. The value of program_mux_rate is measured in units of 50 bytes/second. The value 0 is forbidden.
  • pack_stuffing_length -- A 3 bit integer specifying the number of stuffing bytes which follow this field.
  • stuffing byte -- This is a fixed 8-bit value equal to '1111 1111' that can be inserted by the encoder, for example to meet the requirements of the channel. It is discarded by the decoder.

Packetized Elementary Stream Headers

Depending on the Stream ID, a Packetized Elementary Stream (PES) header may contain various components.

The header

byte 0byte 1byte 2byte 3byte 4byte 5
0000 0000 0000 0000 0000 0001
Start code		 Stream ID PES packet length

Stream ID's which pertain to DVD

Stream IDStream typeextension present?
1011 1101
0xBD		 Private stream 1 (non MPEG audio, subpictures) Yes
1011 1110
0xBE		 Padding stream No
1011 1111
0xBF		 Private stream 2 (navigation data) No
110x xxxx
0xC0 - 0xDF		 MPEG-1 or MPEG-2 audio stream number x xxxx
note: DVD allows only 8 audio streams		 Yes
1110 xxxx
0xE0 - 0xEF		 MPEG-1 or MPEG-2 video stream number xxxx
note: DVD allows only 1 video stream		 Yes

The extension

byte 6byte 7byte 8
765432107654321076543210
10 PES scrambling control PES priority data alignment indicator copyright original or copy PTS DTS flags ESCR flag ES rate flag DSM trick mode flag additional copy info flag PES CRC flag PES extension flag PES header data length

The bit fields of the basic extension:

PES scrambling control -- 00 = not scrambled, others are user defined.

PES priority -- provides 2 priority levels, 0 and 1.

data alignment indicator -- if set to 1 indicates that the PES packet header is immediately followed by the video start code or audio syncword.

copyright -- 1 = packet contains copyrighted material.

original or copy -- 1 = original, 0 = copy.

PTS DTS flags -- Presentation Time Stamp / Decode Time Stamp. 00 = no PTS or DTS data present, 01 is forbidden.
if set to 10 the following data is appended to the header data field:

7654321076543210765432107654321076543210
0010 PTS 32..30 1 PTS 29..15 1 PTS 14..00 1
PTS DTS flags -- if set to 11 the following data is appended to the header data field:
7654321076543210765432107654321076543210
0011 PTS 32..30 1 PTS 29..15 1 PTS 14..00 1
0001 DTS 32..30 1 DTS 29..15 1 DTS 14..00 1
presentation and decoder time stamps use the 90KHz clock (SCR / 300)

ESCR -- if set to 1 the following data is appended to the header data field:

765432107654321076543210765432107654321076543210
00 ESCR base 32..30 1 ESCR base 29..15 1 ESCR base 14..00 1 ESCR ext 1
This is the Elementary Stream Clock Reference, used if the stream and system levels are not synchronized (i.e. ESCR differs from SCR in the PACK header).

ES rate -- if set to 1 the following data is appended to the header data field:

765432107654321076543210
1 ES rate 1
The rate at which data is delivered for this stream, in units of 50 bytes/second.

DSM trick mode - not used by DVD

additional copy info -- if set to 1 the following data is appended to the header data field:

76543210
1 additional copy info

PES CRC flag -- if set to 1 the following data is appended to the header data field:

7654321076543210
previous PES packet CRC
The polynomial used is X16 + X12 + X5 + 1

PES extension flag -- if set to 1 the following data is appended to the header data field:

76543210
PES private data flag pack header field flag program packet sequence counter flag P-STD buffer flag 111 PES extension flag 2
The bit fields of the first extension:

PES private data flag -- if set to 1 16 bytes of user defined data is appended to the header data field.

pack header field flag -- if set to 1 the 8-bit pack field length value is appended to the header data field.

program packet sequence counter flag -- if set to 1 the following data is appended to the header data field:

7654321076543210
1 packet sequence counter 1 MPEG1_MPEG2 identifier original stuffing length

P-STD buffer flag -- if set to 1 the following data is appended to the header data field:

7654321076543210
01 P-STD buffer scale
0 = 128 bytes
1 = 1024 bytes		 P-STD buffer size

PES extension flag 2 -- if set to 1 the following data is appended to the header data field:

7654321076543210
1 PES extension field length reserved
Which is then followed by the indicated number of bytes.

The rest of the packet

Following all the extension data are optional stuffing bytes (0xFF), which are included in the header data length, and then the payload.
In the case of private streams the first byte of the payload is the sub-stream number.

參考來源
http://dvd.sourceforge.net/dvdinfo/packhdr.html
http://dvd.sourceforge.net/dvdinfo/pes-hdr.html

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