FLV文件格式解析部分代码

转自：http://www.lougoo.com/blog/article.asp?id=856

前面在FLV文件格式大揭秘中介绍了FLV文件格式，其中也谈到了曾经编写的代码解析flv文件。应网友要求，现在把代码贴出来，仅供大家参考。因为这代码还是在2006年写的，现在看来有些地方还不够准确，解析的也不够完全，所以仅供参考。

flvheadpacket.h

#include "packet.h"

class CFlvHeadPacket : public CPacket

{

public:

CFlvHeadPacket(void);

CFlvHeadPacket(UInt8* pContent, UInt32 nLength);

~CFlvHeadPacket(void);

};

flvheadpacket.cpp

#include "stdafx.h"

#include "flvheadpacket.h"

CFlvHeadPacket::CFlvHeadPacket(void)

{

m_nType = FLV_HEAD;

}

CFlvHeadPacket::CFlvHeadPacket(UInt8* pContent, UInt32 nLength)

{

m_nType = FLV_HEAD;

m_pContent = pContent;

m_nLength = nLength;

}

CFlvHeadPacket::~CFlvHeadPacket(void)

{

}

flvmetapacket.h

#include "packet.h"

class CFlvMetaPacket : public CPacket

{

public:

CFlvMetaPacket(void);

CFlvMetaPacket(UInt8* pContent, UInt32 nLength);

~CFlvMetaPacket(void);

};

flvmetapacket.cpp

#include "stdafx.h"

#include "flvmetapacket.h"

CFlvMetaPacket::CFlvMetaPacket(void)

{

m_nType = FLV_META;

}

CFlvMetaPacket::CFlvMetaPacket(UInt8* pContent, UInt32 nLength)

{

m_nType = FLV_META;

m_pContent = pContent;

m_nLength = nLength;

}

CFlvMetaPacket::~CFlvMetaPacket(void)

{

}

flvdatapacket.h

#include "packet.h"

enum{

FLV_UNKNOWN_FRAME,

FLV_VIDEO_FRAME,

FLV_AUDIO_FRAME

};

class CFlvDataPacket : public CPacket

{

public:

CFlvDataPacket(void);

CFlvDataPacket(UInt8* pContent, UInt32 nLength);

~CFlvDataPacket(void);

void Print();

UInt8 m_nDataType;

UInt32 m_nTime;

UInt8 m_nFlag;

};

flvdatapacket.cpp

#include "stdafx.h"

#include "flvdatapacket.h"

CFlvDataPacket::CFlvDataPacket(void)

{

m_nType = FLV_DATA;

m_nDataType = FLV_UNKNOWN_FRAME;

}

CFlvDataPacket::CFlvDataPacket(UInt8* pContent, UInt32 nLength)

{

m_nType = FLV_DATA;

m_pContent = pContent;

m_nLength = nLength;

if ( m_pContent[0] == 8 )

m_nDataType = FLV_AUDIO_FRAME;

else if ( m_pContent[0] == 9 )

m_nDataType = FLV_VIDEO_FRAME;

else

m_nDataType = FLV_UNKNOWN_FRAME;

m_nTime = FOUR_CHARS_TO_INT(0,m_pContent[4],m_pContent[5],m_pContent[6]);

m_nFlag = m_pContent[11];

}

CFlvDataPacket::~CFlvDataPacket(void)

{

}

void CFlvDataPacket::Print()

{

printf("Type:%d,DataType=%d,Time=%d,Flag=%d,Length=%d/n",m_nType,m_nDataType,m_nTime,m_nFlag,m_nLength);

}

flvreader.h

#ifndef __FLVREADER_H__

#define __FLVREADER_H__

#define FLV_HEAD_LENGTH 13

#define FLV_DATA_HEAD_LENGTH 11

class CFlvDataPacket;

class CFlvHeadPacket;

class CFlvMetaPacket;

class CFlvReader

{

public:

CFlvReader(void);

~CFlvReader(void);

public:

SInt8* m_sFile;

FILE* m_pFile;

UInt32 m_nOffset;

BOOL SetFile(SInt8* sFile);

FILESTAT64 GetFileStat64();

FILESTAT GetFileStat();

CFlvHeadPacket* ReadHeader();

CFlvMetaPacket* ReadMeta();

CFlvDataPacket* GetNextDataPacket();

};

#endif

flvreader.cpp

#include "stdafx.h"

#include "flvreader.h"

#include "flvdatapacket.h"

#include "flvheadpacket.h"

#include "flvmetapacket.h"

CFlvReader::CFlvReader(void)

{

m_sFile = NULL;

m_pFile = NULL;

m_nOffset = 0;

}

CFlvReader::~CFlvReader(void)

{

if ( m_pFile != NULL )

{

fclose( m_pFile );

m_pFile = NULL;

}

}

BOOL CFlvReader::SetFile(SInt8* sFile)

{

if ( m_pFile != NULL )

{

fclose( m_pFile );

m_pFile = NULL;

}

m_sFile = sFile;

m_pFile = fopen( m_sFile, "rb" );

return m_pFile != NULL;

}

CFlvHeadPacket* CFlvReader::ReadHeader()

{

UInt8* pContent = new UInt8[FLV_HEAD_LENGTH];

UInt32 nRead = fread( pContent, sizeof(SInt8), FLV_HEAD_LENGTH, m_pFile );

if ( nRead == FLV_HEAD_LENGTH )

{

return new CFlvHeadPacket(pContent, FLV_HEAD_LENGTH);

}

else

{

delete pContent;

return NULL;

}

}

CFlvMetaPacket* CFlvReader::ReadMeta()

{

UInt8 buf[FLV_DATA_HEAD_LENGTH];

UInt32 nRead = fread( buf, sizeof(UInt8), FLV_DATA_HEAD_LENGTH, m_pFile );

if ( nRead == FLV_DATA_HEAD_LENGTH )

{

if ( buf[0] == 18 )//meta

{

UInt32 nSize = FOUR_CHARS_TO_INT(0,buf[1],buf[2],buf[3]);

UInt8* pContent = new UInt8[nSize+FLV_DATA_HEAD_LENGTH+4];

memcpy(pContent,buf,FLV_DATA_HEAD_LENGTH);

nRead = fread(&pContent[FLV_DATA_HEAD_LENGTH],sizeof(UInt8), nSize+4, m_pFile);

if ( nRead = (nSize+4) )

{

return new CFlvMetaPacket(pContent,nSize+FLV_DATA_HEAD_LENGTH+4);

}

else

{

delete pContent;

return NULL;

}

}

}

return NULL;

}

CFlvDataPacket* CFlvReader::GetNextDataPacket()

{

UInt8 buf[FLV_DATA_HEAD_LENGTH];

UInt32 nRead = fread( buf, sizeof(UInt8), FLV_DATA_HEAD_LENGTH, m_pFile );

if ( nRead == FLV_DATA_HEAD_LENGTH )

{

if ( buf[0] == 8 || buf[0] == 9 )

{

UInt32 nSize = FOUR_CHARS_TO_INT(0,buf[1],buf[2],buf[3]);

UInt8* pContent = new UInt8[nSize+FLV_DATA_HEAD_LENGTH+4];

memcpy(pContent,buf,FLV_DATA_HEAD_LENGTH);

nRead = fread(&pContent[FLV_DATA_HEAD_LENGTH],sizeof(UInt8), nSize+4,m_pFile);

if ( nRead = (nSize+4) )

{

return new CFlvDataPacket(pContent,nSize+FLV_DATA_HEAD_LENGTH+4);

}

else

{

delete pContent;

return NULL;

}

}

}

return NULL;

}

FILESTAT CFlvReader::GetFileStat()

{

FILESTAT fileStat;

memset(&fileStat,0,sizeof(FILESTAT));

if ( m_pFile != NULL )

{

if ( _stat(m_sFile,&fileStat) != 0 )

{

printf( "/nGetFileStat Error!/n" );

}

}

return fileStat;

}

FILESTAT64 CFlvReader::GetFileStat64()

{

FILESTAT64 fileStat;

memset(&fileStat,0,sizeof(FILESTAT64));

if ( m_pFile != NULL )

{

if ( _stat64(m_sFile,&fileStat) != 0 )

{

printf( "/nGetFileStat64 Error!/n" );

}

}

return fileStat;

}