http://blog.chinaunix.NET/uid-24322243-id-2620180.html
下面針對解復用程序詳細分析一下PAT,PMT和SDT三類表格的格式．
PAT---Program Association Table,節目關聯表?。PAT表攜帶以下信息:?
(1)?TS流ＩＤ--- transport_stream_id,該ＩＤ標志唯一的流ＩＤ
(2)節目頻道號-- program_number,該號碼標志ＴＳ流中的一個頻道，該頻道可以包含很多的節目(即可以包含多個Video PID和Audio PID)
(3)?PMT的PID--- program_map_PID,表示本頻道使用的哪個PID做為PMT的ＰＩＤ，因為可以有很多的頻道，因此ＤＶＢ規定PMT的PID可以由用戶自己定義．
PAT表定義如下:?各字段含義如下:
table_id:8 bits,標志本表格的類型，應該是0x00
section_syntax_indicator:1 bit,段語法標志，應該是''1'' ''0'':固定的''0''，這是為了防止和ISO13818Video流格式中的控制字沖突而設置的．
Reserved:保留的2bits,保留位一般都是''0''
section_length:12bits的段大小，單位是Bytes.
transport_stream_id:16bits的當前流ＩＤ，ＤＶＢ內唯一.(事實上很多都是自定義的TS ID)version_number:5bits版本號碼，標注當前節目的版本．這是個非常有用的參數，當檢測到這個字段改變時，說明ＴＳ流中的節目已經變化?了，程序必須重新搜索節目．
current_next_indicator:1bit:當前還是未來使用標志符,一般情況下為''0''
section_number:8bits當前段號碼
last_section_number:8bits最后段號碼(section_number和?last_section_number的功能是當PAT內容>184字節時，PAT表會分成多個段(sections),解復用程序必須在全部接?收完成后再進行PAT的分析)
從for()開始，就是描述了當前流中的頻道數目(N),每一個頻道對應的PMT PID是什么．解復用程序需要和上圖類似的循環來接收所有的頻道號碼和對應的PMT PID,并把這些信息在緩沖區中保存起來．在后部的處理中需要使用到PMT PID.
CRC_32:本段的CRC校驗值，一般是會忽略的．N是一個變量，計算方法是N=(section_length-9)/4.
從以上分析我們可以發現,PAT表主要包含頻道號碼和每一個頻道對應的PMT的PID號碼,這些信息我們在處理PAT表格的時候會保存起來,以后會使用到?這些數據.例如我們可以定義這樣的數據結構保存這些信息:
typedef struct
{
int channel_number;
int pmt_pid;
}PMT_ITEM;
PMT_ITEM pmt[64];
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PMT, Program Map Table,節目影射表?如果一個TS流中含有多個頻道,
那么就會包含多個PID不同的PMT表.檢測是否PMT的偽代碼如下:
void Process_Packet(unsigned char*buff)
{ int I;
int PID=GETPID(buff);
if(PID==0x0000)
{
Process_PAT(buff+4);
?}
else if(PID==.....)
{ }
else
{ for(i=0;i<64;i++)
{ if(PID==pmt[i].pmt_pid)
{ Process_PMT(buff+4); break; }
} } }
PMT表中包含的數據如下:
(1)?當前頻道中包含的所有Video數據的PID
(2)?當前頻道中包含的所有Audio數據的PID
(3)?和當前頻道關聯在一起的其他數據的PID(如數字廣播,數據通訊等使用的PID)
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PMT定義如下:?各字段含義如下:
table_id:8bits的ID,應該是0x02
section_syntax_indicator:1bit的段語法標志,應該是''1'' ''0'':固定是''0'',如果不是說明數據有錯.
reserved:2bits保留位,應該是''00''
section_length:16bits段長度,從program_number開始,到CRC_32(包含)的字節總數.?program_number:16bits的頻道號碼,表示當前的PMT關聯到的頻道.換句話就是說,當前描述的是program_number頻道的?信息.
reserved:2bits保留位,應該是''00''
version_number:版本號碼,如果PMT內容有更新,則version_number會遞增1通知解復用程序需要重新接收節目信息,否則?version_number是固定不變的.
current_next_indicator:當前未來標志符,一般是0
section_number:當前段號碼
last_section_number:最后段號碼,含義和PAT中的對應字段相同,請參考PAT部分.?reserved:3bits保留位,一般是''000''.
PCR_PID:13bits的PCR PID,具體請參考ISO13818-1,解復用程序不使用該參數.
reserved:4bits保留位,一般是''0000''
program_info_length:節目信息長度(之后的是N個描述符結構,一般可以忽略掉,這個字段就代表描述符總的長度,單位是Bytes)?緊接著就是頻道內部包含的節目類型和對應的PID號碼了.
stream_type:8bits流類型,標志是Video還是Audio還是其他數據.
reserved:3 bits保留位.
elementary_PID:13bits對應的數據PID號碼(如果stream_type是Video,那么這個PID就是Video PID,如果stream_type標志是Audio,那么這個PID就是Audio PID)
reserved:4 bits保留位.
ES_info_length:和program_info_length類似的信息長度(其后是N2個描述符號)?CRC_32:32bits段末尾是本段的CRC校驗值,一般忽略.
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從以上的分析可以看出,只要我們處理了PMT,那么我們就可以獲取頻道中所有的PID信息,例如當前頻道包含多少個Video,共多少個Audio,和其?他數據,還能知道每種數據對應的PID分別是什么.?這樣如果我們要選擇其中一個Video和Audio收看,那么只需要把要收看的節目的Video PID和Audio PID保存起來,在處理Packet的時候進行過濾即可實現.?比較全面實現解復用的偽代碼如下:
int Video_PID=0x07e5,Audio_PID=0x07e6;
void Process_Packet(unsigned char*buff)
{ int I; int PID=GETPID(buff);
if(PID==0x0000) { Process_PAT(buff+4); }
else if(PID==Video_PID) { SaveToVideoBuffer(buff+4); }
else if(PID==Audio_PID) { SaveToAudioBuffer(buff+4); }
else
{ for( i=0;i<64;i++)
{ if(PID==pmt[i].pmt_pid) { Process_PMT(buff+4); Break; }
} } }
以上偽代碼可以實現基本的解復用:檢測所有的頻道,檢測所有stream的PID,選擇特定的節目進行播放.只要讀取每個Packet的188字節的內?容,然后每次都調用Process_Packet()即可實現簡單的解復用.?介紹到這里,我們就可以總結一下DVB搜臺的原理了.(好!洗耳恭聽!)?機?頂盒先調整高頻頭到一個固定的頻率(如498MHZ),如果此頻率有數字信號,則COFDM芯片(如MT352)會自動把TS流數據傳送給MPEG- 2 decoder. MPEG-2 decoder先進行數據的同步,也就是等待完整的Packet的到來.然后循環查找是否出現PID== 0x0000的Packet,如果出現了,則馬上進入分析PAT的處理,獲取了所有的PMT的PID.接著循環查找是否出現PMT,如果發現了,則自動進?入PMT分析,獲取該頻段所有的頻道數據并保存.如果沒有發現PAT或者沒有發現PMT,說明該頻段沒有信號,進入下一個頻率掃描.?從以上描述可以看出,機頂盒搜索頻率是隨機發生的,要使每次機頂盒都能搜索到信號,則要求TS流每隔一段時間就發送一?次PAT和PMT.事實上DVB傳輸系統就是這么做的.因此無論何時接入終端系統,系統都能馬上搜索到節目并正確解復用實現播放.不僅僅如此,其他數據也?都是交替傳送的.比如第一個Packet可能是PAT,第二個Packet可能是PMT,而第三個Packet可能是Video 1,第四個Packet可能是Video 2,?只要系統傳輸速度足夠快(就是稱之為"碼率"的東東),實現實時播放是沒有任何問題的.?到這里雖然實現了解復用,但可以看出,使用的PID都是枯燥的數字,如果調臺要用戶自己輸入數字那可是太麻煩了,而且還容易輸入錯?誤,操作非常不直觀,即使做成一個菜單讓用戶選擇也是非常的呆板.針對這個問題,DVB系統提出了一個SDT表格,該表格標志一個節目的名稱,并且能和?PMT中的PID聯系起來,這樣用戶就可以通過直接選擇節目名稱來選擇節目了.
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SDT, Service description section,服務描述段
SDT可以提供的信息包括:
(1)?該節目是否在播放中
(2)?該節目是否被加密
(3)?該節目的名稱
SDT定義如下:?各字段定義如下:
table_id:8bits的ID,可以是0x42,表示描述的是當前流的信息,也可以是0x46,表示是其他流的信息(EPG使用此參數)
section_syntax_indicator:段語法標志,一般是''1''
reserved_future_used:2bits保留未來使用
reserved:1bit保留位,防止控制字沖突,一般是''0'',也有可能是''1''
section_length:12bits的段長度,單位是Bytes,從transport_stream_id開始,到CRC_32結束(包含)
transport_stream_id:16bits當前描述的流ID
reserved:2bits保留位
version_number:5bits的版本號碼,如果數據更新則此字段遞增1
current_next_indicator:當前未來標志,一般是''0'',表示當前馬上使用.?original_netword_id:16bits的原始網絡ID號
reserved_future_use:8bits保留未來使用位?接下來是N個節目信息的循環:
service_id:16 bits的服務器ID,實際上就是PMT段中的program_number.?reserved_future_used:6bits保留未來使用位
EIT_schedule_flag:1bit的EIT信息,1表示當前流實現了該節目的EIT傳送?EIT_present_following_flag:1bits的EIT信息,1表示當前流實現了該節目的EIT傳送?running_status:3bits的運行狀態信息:1-還未播放?2-幾分鐘后馬上開始,3-被暫停播出,4-正在播放,其他---保留
free_CA_mode:1bits的加密信息,''1''表示該節目被加密.?緊?接著的是描述符,一般是Service descriptor,分析此描述符可以獲取servive_id指定的節目的節目名稱.具體格式請參考?EN300468中的Service descriptor部分.
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分析完畢,則節目名稱和節目號碼已經聯系起來了.機頂盒程序就可以用這些節目名稱代替?PID讓用戶選擇,從而實現比較友好的用戶界面!?下面參考一下<>中的界面和顯示信息.?上?圖是<>打開三個不同的碼流文件(*.ts)形成的PID信息和節目名稱.用戶?可以通過切換節目名稱的下拉列表框切換節目,也可以通過"視頻流"和"音頻流"下拉列表框切換Video和Audio!這些數據都是通過分析PAT, PMT和SDT得到的.?（轉載自網路）
http://blog.csdn.net/blackboyofsnp/article/details/4665409
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對TS流的分析， 涉及到對PAT，PMT等等的分析， 具體內容見iso/iec 13838系列文檔，
本文只給出自己寫的一些和TS分析想關的代碼， 簡單的分析足夠了， 不考慮復雜情況：
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//??//??//??TS流結構定義??//??//????#ifndef?ZZQ_TS_H_??#define?ZZQ_TS_H_????#include?<vector>??using?namespace?std;??typedef??unsigned?char??byte;??typedef??unsigned?int???bits;????#define??TSPKT_LENGTH??188????//-----------------------------------------------------------------------------??//?結構體??//-----------------------------------------------------------------------------??//?TS包構成偽代碼????//?TS包頭部??//?WARNING!!!??暫時沒有考慮修改區以及修改區內可選字段的處理??struct?ts_header??{??????bits??sync_byte????????????????????:?8;??????bits??transport_error_indicator????:?1;??????bits??payload_unit_start_indicator?:?1;??????bits??transport_priority???????????:?1;??????bits??PID??????????????????????????:?13;??????bits??transport_scrambling_control?:?2;??????bits??adaptation_field_control?????:?2;??????bits??continuity_counter???????????:?4;??};??//?TS包中的修改字段(adaptation?field)??struct?ts_adaptation_field??{??????bits??adaptation_field_length?:?8;??????bits??discontinuity_idicator??:?1;??????bits??random_access_indicator?:?1;??????bits??elementary_stream_priority_indicator?:?1;??????bits??flags???????????????????:?5;?//?5?flags??};????//?PAT中的可變段??struct?ts_pat_section??{??????bits??program_number?:?16;??????bits??reserved???????:?3;??????bits??PID????????????:?13;??};??typedef?vector<ts_pat_section>??vec_pat_section;??//?PAT表,?P138-PAT的結構,?文檔P61??struct?ts_pat??{??????bits??table_id?????????????????:?8;??//?0x00??????bits??section_syntax_indicator?:?1;??//?1??????bits??zero?????????????????????:?1;??//?0??????bits??reserved_1???????????????:?2;??//?11??????bits??section_length???????????:?12;???????bits??transport_stream_id??????:?16;?//?傳輸數據流識別??????bits??reserved_2???????????????:?2;??//?"11"??????bits??version_number???????????:?5;??????bits??current_next_indicator???:?1;??????bits??section_number???????????:?8;??????bits??last_section_number??????:?8;??????//?....?TODO??????vec_pat_section?network_section;??????vec_pat_section?pmt_section;??????bits??crc32????????????????????:?32;??};????//?Stream_type分配表,?P85??#define??ST_Reserved????????0x00?//?ITU-T?|?ISO/IEC?Reserved??#define??ST_VIDEO_1?????????0x01?//?ISO/IEC?11172?Video??#define??ST_VIDEO_2?????????0x02?//?ITU-T?Rec.?H.262?|?ISO/IEC?13818-2?Video?or?ISO/IEC?11172-2?constrained?parameter?video?stream??#define??ST_AUDIO_1?????????0x03?//?ISO/IEC?11172?Audio??#define??ST_AUDIO_2?????????0x04?//?ISO/IEC?13818-3?Audio??#define??ST_PRIVATE_SECTIONS????????0x05?//?ITU-T?Rec.?H.222.0?|?ISO/IEC?13818-1?private_sections??#define??ST_PES_PKT_PRIVATE_DATA????0x06?//?ITU-T?Rec.?H.222.0?|?ISO/IEC?13818-1?PES?packets?containing?private?data??#define??ST_MHEG????????????0x07?//?ISO/IEC?13522?MHEG??#define??ST_DSMCC???????????0x08?//?ITU-T?Rec.?H.222.0?|?ISO/IEC?13818-1?Annex?A?DSM?CC??#define??ST_H2221???????????0x09?//?ITU-T?Rec.?H.222.1??#define??ST_TYPEA???????????0x0A?//?ISO/IEC?13818-6?type?A??#define??ST_TYPEB???????????0x0B?//?ISO/IEC?13818-6?type?B??#define??ST_TYPEC???????????0x0C?//?ISO/IEC?13818-6?type?C??#define??ST_TYPED???????????0x0D?//?ISO/IEC?13818-6?type?D??#define??ST_AUXILIARY???????0x0E?//?ISO/IEC?13818-1?auxiliary??//?0x0F-0x7F:?ITU-T?Rec.?H.222.0?|?ISO/IEC?13818-1?Reserved??//?0x80-0xFF:?User?Private??//?PMT表中的ES段??struct?ts_pmt_es_section??{??????bits??stream_type??????????????:?8;??????bits??reserved_1???????????????:?3;??????bits??elementary_PID???????????:?13;??????bits??reserved_2???????????????:?4;??????bits??ES_info_length???????????:?12;??};??typedef?vector<ts_pmt_es_section>??vec_pmt_section;????//?PMT表,?書P138?-?PMT的結構??struct?ts_pmt??{??????bits??table_id?????????????????:?8;??//?0x02??????bits??section_syntax_indicator?:?1;??//?1??????bits??zero?????????????????????:?1;??//?0??????bits??reserved_1???????????????:?2;??//?11??????bits??section_length???????????:?12;??????bits??program_number???????????:?16;??????bits??reserved_2???????????????:?2;??//?11??????bits??version_number???????????:?5;??????bits??current_next_indicator???:?1;??????bits??section_number???????????:?8;??????bits??last_section_number??????:?8;??????bits??reserved_3???????????????:?3;??//?111??????bits??PCR_PID??????????????????:?13;??????bits??reserved_4???????????????:?4;??//?1111??????bits??program_info_length??????:?12;??????vec_pmt_section??es_section;??????bits??crc32????????????????????:?32;??};????//?PES包構成偽代碼??P43??????//?Steam?ID分配表,??文檔P47??#define??SID_PROGRAM_STREAM_MAP?????0xBC??#define??SID_PRIVATE_STREAM_1???????0xBD??#define??SID_PADDING_STREAM?????????0xBE??#define??SID_PRIVATE_STREAM_2???????0xBF??#define??SID_AUDIO_STREAM???????????0xC0?//?110x?xxxx,?stream?number?x?xxxx??#define??SID_VIDEO_STREAM???????????0xE0?//?1110?xxxx,?stream?number?xxxx??#define??SID_ECM_STREAM?????????????0xF0??#define??SID_EMM_STREAM?????????????0xF1??#define??SID_DSMCC_STREAM???????????0xF2??#define??SID_13522_STREAM???????????0xF3??#define??SID_TYPEA??????????????????0xF4??#define??SID_TYPEB??????????????????0xF5??#define??SID_TYPEC??????????????????0xF6??#define??SID_TYPED??????????????????0xF7??#define??SID_TYPEE??????????????????0xF8??#define??SID_ANCILLARY_STREAM???????0xF9??//?1111?1010?~?1111?1110,?reserved?data?stream??#define??SID_PROGRAM_STREAM_DIRECTORY???0xFF????//?PES包中的可選包頭部??struct?optional_pes_header??{??????bits??prefix???????????????????:?2;?//?"10"??????bits??pes_scrambling_control???:?2;??????bits??pes_priority?????????????:?1;??????bits??data_alignment_indicator?:?1;??????bits??copyright????????????????:?1;??????bits??original_or_copy?????????:?1;??????//?7?flags?start??????bits??PTS_DTS_flags????????????:?2;??????bits??ESCR_flag????????????????:?1;??????bits??ES_rate_flag?????????????:?1;??????bits??DSM_trick_mode_flag??????:?1;??????bits??additional_copy_info_flag:?1;??????bits??PES_CRC_flag?????????????:?1;??????bits??PES_extension_flag???????:?1;??????//?7?flags?end??????bits??pes_header_data_length???:?8;??????//?WARNING!!!?目前只使用?PTS,?DTS??????bits??PTS_H????????????????????:?3;??//?32..30??????bits??PTS_M????????????????????:?15;?//?29..15??????bits??PTS_L????????????????????:?15;?//?14..0??????bits??DTS_H????????????????????:?3;??//?32..30??????bits??DTS_M????????????????????:?15;?//?29..15??????bits??DTS_L????????????????????:?15;?//?14..0??};????//?PES包頭部,?文檔P43,?書P131??struct?pes_header??{??????bits??packet_start_code_prefix?:?24;??????bits??stream_id????????????????:?8;??????bits??pes_packet_length????????:?16;??????//?之后是optional?PES?header,?即任意包頭,?它的有無由stream_id決定??????bool??ophdr_flag;??????optional_pes_header?ophdr;??//?如果聲明為指針,?會帶來一些內存問題??????//byte*??es_data;???//?實際數據指針??????int???offset;???//?實際數據偏移????????????pes_header()??????{??????????ophdr_flag?=?false;??????????offset?=?-1;??????}??????~pes_header()??????{}??};????//-----------------------------------------------------------------------------??//?位段結構調整函數??//-----------------------------------------------------------------------------??int?adjust_ts_header(ts_header*?pkt,?byte*?buff);??int?adjust_ts_pat(ts_pat*?pkt,?byte*?buff);??int?adjust_ts_pmt(ts_pmt*?pkt,?byte*?buff);??int?adjust_ts_pes_header(pes_header*?pkt,?byte*?buff);??__int64??get_pts_from_pes(pes_header&?pkt);??__int64??get_dts_from_pes(pes_header&?pkt);??#endif?? 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//??//??//??TS流相關函數??//??//??#include?<stdio.h>??#include?"zzq_TS.h"????int?adjust_ts_header(ts_header*?pkt,?byte*?buff)??{??????if(pkt?==?NULL?||?buff?==?NULL)??????{???return?1;???}??????pkt->sync_byte?=?buff[0];??????pkt->transport_error_indicator?=?buff[1]?>>?7;??????pkt->payload_unit_start_indicator?=?buff[1]?>>?6?&?0x01;??????pkt->transport_priority?=?buff[1]?>>?5?&?0x01;??????pkt->PID?=?(buff[1]?&?0x1f)<<8?|?buff[2];??????pkt->transport_scrambling_control?=?buff[3]?>>?6;??????pkt->adaptation_field_control?=?buff[3]?>>?4?&?0x03;??????pkt->continuity_counter?=?buff[3]?&?0x03;??????return?0;??}????int?adjust_ts_pat(ts_pat*?pkt,?byte*?buff)??{??????if(pkt?==?NULL?||?buff?==?NULL)??????{???return?1;???}??????pkt->table_id?=?buff[0];??????pkt->section_syntax_indicator?=?buff[1]?>>?7;??????pkt->zero?=?buff[1]?>>?6?&?0x1;??????pkt->reserved_1?=?buff[1]?>>?4?&?0x3;??????pkt->section_length?=?(buff[1]?&?0x0f)?<<?8?|?buff[2];??????pkt->transport_stream_id?=?buff[3]?<<?8?|?buff[4];??????pkt->reserved_2?=?buff[5]?>>?6;??????pkt->version_number?=?buff[5]?>>?1?&?0x1f;??????pkt->current_next_indicator?=?(buff[5]?<<?7)?>>?7;??????pkt->section_number?=?buff[6];??????pkt->last_section_number?=?buff[7];??????//?get?crc32??????int?len?=?3?+?pkt->section_length;??????pkt->crc32?=?(buff[len-4]?&?0x000000ff)?<<?24?|???????????????????(buff[len-3]?&?0x000000ff)?<<?16?|???????????????????(buff[len-2]?&?0x000000ff)?<<?8??|???????????????????(buff[len-1]?&?0x000000ff);??????//?get?variable?section??????for(int?i=0;?i<pkt->section_length-4-8;?i+=4?)??????{??????????ts_pat_section?sec;??????????sec.program_number?=?buff[8+i]?<<?8?|?buff[9];??????????sec.reserved?=?buff[10+i]?>>?5;??????????sec.PID?=?(buff[10+i]?<<?3)?<<?5?|?buff[11+i];??????????if(sec.program_number?==?0x0)??????????????pkt->network_section.push_back(sec);??????????else??????????????pkt->pmt_section.push_back(sec);??????}??????return?0;??}????int?adjust_ts_pmt(ts_pmt*?pkt,?byte*?buff)??{??????if(pkt?==?NULL?||?buff?==?NULL)???????{???return?1;???}??????pkt->table_id?=?buff[0];??????pkt->section_syntax_indicator?=?buff[1]?>>?7;??????pkt->zero?=?buff[1]?>>?6;??????pkt->reserved_1?=?buff[1]?>>?4;??????pkt->section_length?=?(buff[1]?&?0x0f)?<<?8?|?buff[2];??????pkt->program_number?=?buff[3]?<<?8?|?buff[4];??????pkt->reserved_2?=?buff[5]?>>?6;??????pkt->version_number?=?buff[5]?>>?1?&?0x1f;??????pkt->current_next_indicator?=?(buff[5]?<<?7)?>>?7;??????pkt->section_number?=?buff[6];??????pkt->last_section_number?=?buff[7];??????pkt->reserved_3?=?buff[8]?>>?5;??????pkt->PCR_PID?=?((buff[8]?<<?8)?|?buff[9])?&?0x1fff;??????pkt->reserved_4?=?buff[10]?>>?4;??????pkt->program_info_length?=?(buff[10]?&?0x0f)?<<?8?|?buff[11];??????//?get?crc32??????int?len?=?pkt->section_length?+?3;??????pkt->crc32?=?(buff[len-4]?&?0x000000ff)?<<?24?|???????????????????(buff[len-3]?&?0x000000ff)?<<?16?|???????????????????(buff[len-2]?&?0x000000ff)?<<?8??|???????????????????(buff[len-1]?&?0x000000ff);??????//?skip?program?description??????int?pos?=?12?+?pkt->program_info_length;??????for(?;?pos?<=?(pkt->section_length-4);?pos+=5)??????{??????????ts_pmt_es_section?sec;??????????sec.stream_type?=?buff[pos];??????????sec.reserved_1?=?buff[pos+1]?>>?5;??????????sec.elementary_PID?=?((buff[pos+1]?<<?8)?|?buff[pos+2])?&?0x1fff;??????????sec.ES_info_length?=?(buff[pos+3]?&?0x0f)?<<?8?|?buff[pos+4];??????????pkt->es_section.push_back(sec);??????????pos?+=?sec.ES_info_length;??????}??????return?0;??}????int?adjust_ts_pes_header(pes_header*?pkt,?byte*?buff)??{??????if(pkt?==?NULL?||?buff?==?NULL)???????{???return?1;???}??????//?0000?0000?0000?0000?0000?0001?:?0x000001??????pkt->packet_start_code_prefix?=?(buff[0]?&?0x0000ff)?<<?16?|??????????????????????????????????????(buff[1]?&?0x0000ff)?<<?8??|??????????????????????????????????????(buff[2]?&?0x0000ff);??????//if(pkt->packet_start_code_prefix?!=?0x000001)??return?2;??????byte?sid?=?buff[3];?//?aux??????pkt->stream_id?=?buff[3];??????pkt->pes_packet_length?=?buff[4]?<<?8?|?buff[5];??????if(sid?!=?SID_PROGRAM_STREAM_MAP?&&?????????sid?!=?SID_PADDING_STREAM?&&?????????sid?!=?SID_PRIVATE_STREAM_2?&&?????????sid?!=?SID_ECM_STREAM?&&?????????sid?!=?SID_EMM_STREAM?&&?????????sid?!=?SID_PROGRAM_STREAM_DIRECTORY?&&?????????sid?!=?SID_DSMCC_STREAM?&&?????????sid?!=?SID_TYPEE????????)??????{??????????pkt->ophdr_flag?=?true;??????????pkt->ophdr.prefix?=?buff[6]?>>?6;?//?"10"?:?2??????????//if(pkt->ophdr->prefix?!=?2)?return?2;??????????pkt->ophdr.pes_scrambling_control?=?buff[6]?>>?4?&?0x03;??????????pkt->ophdr.pes_priority?=?buff[6]?>>?3?&?0x01;??????????pkt->ophdr.data_alignment_indicator?=?buff[6]?>>?2?&?0x01;??????????pkt->ophdr.copyright?=?buff[6]?>>?1?&?0x01;??????????pkt->ophdr.original_or_copy?=?buff[6]?&?0x01;??????????pkt->ophdr.PTS_DTS_flags?=?buff[7]?>>?6?&?0x03;??????????pkt->ophdr.ESCR_flag?=?buff[7]?>>?5?&?0x01;??????????pkt->ophdr.ES_rate_flag?=?buff[7]?>>?4?&?0x01;??????????pkt->ophdr.DSM_trick_mode_flag?=?buff[7]?>>?3?&?0x01;??????????pkt->ophdr.additional_copy_info_flag?=?buff[7]?>>?2?&?0x01;??????????pkt->ophdr.PES_CRC_flag?=?buff[7]?>>?1?&?0x01;??????????pkt->ophdr.PES_extension_flag??=?buff[7]?&?0x01;??????????pkt->ophdr.pes_header_data_length?=?buff[8];??????????if(pkt->ophdr.PTS_DTS_flags?==?0x2)?//?"10"??????????{??????????????//?以下移位操作,?都將各位串靠左對齊??????????????pkt->ophdr.PTS_H?=?buff[9]?<<?3?&?0xe0;?//?3?bits??????????????pkt->ophdr.PTS_M?=?(buff[10]?<<?8)?|?(buff[11]?&?0xfe);?//?15?bits??????????????pkt->ophdr.PTS_L?=?(buff[12]?<<?8)?|?(buff[13]?&?0xfe);?//?15?bits??????????}??????????else?if(pkt->ophdr.PTS_DTS_flags?==?0x3)?//?"11"??????????{??????????????//?以下移位操作,?都將各位串靠左對齊??????????????pkt->ophdr.PTS_H?=?buff[9]?<<?3?&?0xe0;?//?3?bits??????????????pkt->ophdr.PTS_M?=?(buff[10]?<<?8)?|?(buff[11]?&?0xfe);?//?15?bits??????????????pkt->ophdr.PTS_L?=?(buff[12]?<<?8)?|?(buff[13]?&?0xfe);?//?15?bits??????????????pkt->ophdr.DTS_H?=?buff[14]?<<?3?&?0xe0;??????????????pkt->ophdr.DTS_M?=?(buff[15]?<<?8)?|?(buff[16]?&?0xfe);?//?15?bits??????????????pkt->ophdr.DTS_L?=?(buff[17]?<<?8)?|?(buff[18]?&?0xfe);?//?15?bits??????????}??????????//??????????//??ESCR,?ES_rate之類的目前不處理??????????//?6?+?3:?(24+8+16)?+?(2+2+1+1+1+1+8+8)??????????pkt->offset?=?6?+?3?+?pkt->ophdr.pes_header_data_length;??????}??????else?if(sid?==?SID_PROGRAM_STREAM_MAP?||??????????????sid?==?SID_PRIVATE_STREAM_2?||??????????????sid?==?SID_ECM_STREAM?||??????????????sid?==?SID_EMM_STREAM?||??????????????sid?==?SID_PROGRAM_STREAM_DIRECTORY?||??????????????sid?==?SID_DSMCC_STREAM?||??????????????sid?==?SID_TYPEE?????????????)??????{??????????pkt->offset?=?6;??????}??????else?if(sid?==?SID_PADDING_STREAM)??????{??????????pkt->offset?=?-1;??????}????????????return?0;??}????__int64??get_pts_from_pes(pes_header&?pkt)??{??????if(pkt.ophdr_flag?==?false)?return?-1;??????if(pkt.ophdr.PTS_DTS_flags?!=?0x2?&&?pkt.ophdr.PTS_DTS_flags?!=?0x3)??????????return?-1;??????__int64?H?=?0,?M?=?0,?L?=?0;??????L?=?pkt.ophdr.PTS_L?>>?1?|?pkt.ophdr.PTS_M?<<?14;??????M?=?pkt.ophdr.PTS_M?>>?2?|?pkt.ophdr.PTS_H?<<?13;??????L?=?pkt.ophdr.PTS_H?>>?3;??????return?(H<<32)?|?(M<<16)?|?L;??}??__int64??get_dts_from_pes(pes_header&?pkt)??{??????if(pkt.ophdr_flag?==?false)?return?-1;??????if(pkt.ophdr.PTS_DTS_flags?!=?0x3)??????????return?-1;??????__int64?H?=?0,?M?=?0,?L?=?0;??????L?=?pkt.ophdr.DTS_L?>>?1?|?pkt.ophdr.DTS_M?<<?14;??????M?=?pkt.ophdr.DTS_M?>>?2?|?pkt.ophdr.DTS_H?<<?13;??????L?=?pkt.ophdr.DTS_H?>>?3;??????return?(H<<32)?|?(M<<16)?|?L;??}?
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