1. mpeg sectoin parser

MPEG-2 Part 1, Analyzer를 c++ 공부 차원에서 한번 만들어 보기로 하자.

첫번째 클래스는 ts파일에서 188 바이트씩 읽어와서 section을 넘겨주는 section parser이다.

완전 단순하게 adaptation field을 보고 PID와 PID에 해당하는 section을 단순히 넘기는 클래스이다.

다음에 이어질 PSI (PAT, PMT, SDT ...)에서 사용하기 위함.

사실 셋탑박스나 TV단에서는 system decoder 블록이 별도로 존재하고 chip 자체적으로

PID만 주면 해당 PID에 대한 첫번째 section부터 마지막 setion까지 수신 후,

callback function으로 section을 return해 준다. 기본 길이는 1024 ~ 4096 Byte이다.

이 동작은 네가 경험한 chip에서는 모두 동작이 동일하다.

블로그에 올릴 떄는 현재 기준으로 파일만 대응했는데, IP에서도 가능하도록 도전해 볼 생각이다.

1 소스트리

.

├── CMakeLists.txt

├── SGP.ts

├── psi_glob.h

├── remove.sh

├── section.cpp

├── section.h

├── test.cpp

└── types.h

2. section class header

#ifndef __SECTION_H__ #define __SECTION_H__ #include <cstdio> #include <cstring> #include <cstdlib> #include <iostream> #include <fstream> #include <string> #include "types.h" /* ------------------------------------------------------------------------------------------------------------------- declare define ------------------------------------------------------------------------------------------------------------------- */ #define PRINT_SECTION #ifdef PRINT_SECTION #define PRINT_SECTION_INFO(x) std::printf("%3s = %10d [%#10x]\n", #x, x, x); #else #define PRINT_SECTION_INFO(x) #endif /* ------------------------------------------------------------------------------------------------------------------- declare class data ------------------------------------------------------------------------------------------------------------------- */ typedef struct { UINT16 pid; UINT8 section[188]; } SECTION_INFO_T; typedef enum { MEDIA_TYPE_FILE, MEDIA_TYPE_SOCKET, MEDIA_TYPE_NOTSUPPORT } MEDIA_TYPE_T; class CSection { public : CSection(); ~CSection(); MEDIA_TYPE_T getCurrentMediaType(void); RESULT_T openMedia(std::string media); RESULT_T readMedia(SECTION_INFO_T* sectionInfo); RESULT_T readMediaFromFile(SECTION_INFO_T* sectionInfo); private : std::ifstream fin; std::string mediaInPath; MEDIA_TYPE_T currentOpenedMediaType; }; #endif

3. section class

/** This is free and unencumbered software released into the public domain. Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a compiled binary, for any purpose, commercial or non-commercial, and by any means. In jurisdictions that recognize copyright laws, the author or authors of this software dedicate any and all copyright interest in the software to the public domain. We make this dedication for the benefit of the public at large and to the detriment of our heirs and successors. We intend this dedication to be an overt act of relinquishment in perpetuity of all present and future rights to this software under copyright law. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. For more information, please refer to <http://unlicense.org> */ /** -------------------------------------------------------------------- file : section.cpp get section raw data from TS stream version : 1.0 data : 2016.06.01 author : HeeSoon Kim(chipmaker0304@gmail.com) -----------------------------------------------------------------------*/ #include "section.h" CSection::CSection() { currentOpenedMediaType = MEDIA_TYPE_NOTSUPPORT; std::cout << __FUNCTION__ << std::endl; } CSection::~CSection() { if(currentOpenedMediaType == MEDIA_TYPE_FILE) { fin.close(); } std::cout << __FUNCTION__ << std::endl; } MEDIA_TYPE_T CSection::getCurrentMediaType(void) { return currentOpenedMediaType; } RESULT_T CSection::openMedia(std::string media) { if(media.compare(0, std::strlen("file://"), "file://") == 0) { currentOpenedMediaType = MEDIA_TYPE_FILE; mediaInPath = media; mediaInPath.erase(0, std::strlen("file://")); std::cout << "current media type : FILE " << std::endl; fin.open(mediaInPath.c_str(), std::ios_base::in | std::ios_base::binary); if(fin.is_open() == false) { std::cout << "File Open Error" << std::endl; return RESULT_NOTOK; } } else if(media.compare(0, std::strlen("udp://"), "udp://") == 0) { currentOpenedMediaType = MEDIA_TYPE_SOCKET; mediaInPath = media; mediaInPath.erase(0, std::strlen("udp://")); std::cout << "current media type : SOCKET " << std::endl; // To do ... } else { currentOpenedMediaType = MEDIA_TYPE_NOTSUPPORT; std::cout << "current media type : Not Supported " << std::endl; return RESULT_NOTOK; } std::cout << "mediaInPath : " << mediaInPath << std::endl; return RESULT_OK; } RESULT_T CSection::readMediaFromFile(SECTION_INFO_T* sectionInfo) { int cnt; char buffer[188]; bool transport_error_indicator; bool payload_unit_start_indicator; UINT16 pid; UINT8 scrambling_control; UINT8 adaptation_field_control; UINT8 continuity_counter; UINT8 moveSize; fin.read(buffer, 188); cnt = fin.gcount(); if(cnt == 0) { std::cout << "No Data !! " << std::endl; return RESULT_NOTOK; } if(buffer[0] != 0x47) { std::cout << "Not Header Start " << std::endl; return RESULT_INVALID; } transport_error_indicator = (buffer[1] >> 7) & 0x01; payload_unit_start_indicator = (buffer[1] >> 6) & 0x01; pid = ((buffer[1] & 0x1f) << 8) | buffer[2]; PRINT_SECTION_INFO(pid); scrambling_control = (buffer[3] >> 6) & 0x03; adaptation_field_control = (buffer[3] >> 4) & 0x03; continuity_counter = buffer[3] & 0x0f; if(adaptation_field_control == 0x01) { std::memset(sectionInfo->section, 0x00, 188); std::memcpy(sectionInfo->section, buffer+4, 184); } else if(adaptation_field_control == 0x03) // adapation + Payload { moveSize = 0; moveSize = buffer[4] + 4 + 1; std::memset(sectionInfo->section, 0x00, 188); std::memcpy(sectionInfo->section, buffer + moveSize, 188 - moveSize); } else { sectionInfo->pid = 0x1FFF; // default PID return RESULT_INVALID; } sectionInfo->pid = pid; return RESULT_OK; } RESULT_T CSection::readMedia(SECTION_INFO_T* sectionInfo) { RESULT_T retval; switch(currentOpenedMediaType) { case MEDIA_TYPE_FILE: retval = readMediaFromFile(sectionInfo); return retval; break; default: break; } return RESULT_NOTOK; }

4. test을 위한 main

test는 단순하다. 단순하게 파일해서 188Byte씩 읽어 들이고 setion이라는 구조를 선언하고 이 구조체에

현재 ts에 대한 pid값과 ts header를 제거한 부분을 구조체 버퍼에 넣어서 올려준다.

#include <thread> #include "section.h" int main(int argc, char* argv[]) { SECTION_INFO_T sec; CSection* section = new CSection(); // open media test, media is file section->openMedia("file://SGP.ts"); // create task to read continously std::thread tr = std::thread([&]() { while(1) { if(section->readMedia(&sec) == RESULT_NOTOK) break; } }); tr.join(); delete section; return 0; }

5. 전체 소스 (github 아래 링크에 존재)

https://github.com/heesoon/mpeg/tree/master/test/section