H264視訊編碼成MP4檔案
阿新 • • 發佈：2018-12-30
最近需要將H264視訊編碼成MP4格式。研究了一下，一種方法是採用ffmpeg庫，可以先將H264檔案解碼，再編碼生成MP4檔案，但這種方式效率較低，10M的視訊可能需要幾秒鐘才能完成。另一種方式根據MP4檔案協議直接將H264包封裝成MP4格式，由於是直接基於MP4的封裝，因而效率很高。H264可以很方便的封裝成FLV檔案，但MP4格式格式相對比較複雜，封裝起來會比較麻煩。由於沒時間研究MP4協議，在Google Code上找到一個開源的MP4編解碼庫Mp4v2（https://code.google.com/p/mp4v2/），通過Mp4v2可以很方便的將H264編碼成MP4格式檔案。為了方便使用，基於該庫封裝了一個MP4Encoder類，MP4Encoder封裝的介面如下。目前僅支援將H264檔案或資料幀編碼成MP4檔案。
class MP4Encoder { public: MP4Encoder(void); ~MP4Encoder(void); public: // open or creat a mp4 file. MP4FileHandle CreateMP4File(const char *fileName,int width,int height,int timeScale = 90000,int frameRate = 25); // wirte 264 metadata in mp4 file. bool Write264Metadata(MP4FileHandle hMp4File,LPMP4ENC_Metadata lpMetadata); // wirte 264 data, data can contain multiple frame. int WriteH264Data(MP4FileHandle hMp4File,const unsigned char* pData,int size); // close mp4 file. void CloseMP4File(MP4FileHandle hMp4File); // convert H264 file to mp4 file. // no need to call CreateMP4File and CloseMP4File,it will create/close mp4 file automaticly. bool WriteH264File(const char* pFile264,const char* pFileMp4); // Prase H264 metamata from H264 data frame static bool PraseMetadata(const unsigned char* pData,int size,MP4ENC_Metadata &metadata); };
客戶端呼叫示例程式碼：
#include <stdio.h>
#include "MP4Encoder\MP4Encoder.h"
int main(int argc, char** argv)
{
MP4Encoder mp4Encoder;
// convert H264 file to mp4 file
mp4Encoder.WriteH264File("test.264","test.mp4");
}/******************************************************************** filename: MP4Encoder.h created: 2013-04-16 author: firehood purpose: MP4編碼器，基於開源庫mp4v2實現（https://code.google.com/p/mp4v2/）。 *********************************************************************/ #pragma once #include "mp4v2\mp4v2.h" // NALU單元 typedef struct _MP4ENC_NaluUnit { int type; int size; unsigned char *data; }MP4ENC_NaluUnit; typedef struct _MP4ENC_Metadata { // video, must be h264 type unsigned int nSpsLen; unsigned char Sps[1024]; unsigned int nPpsLen; unsigned char Pps[1024]; } MP4ENC_Metadata,*LPMP4ENC_Metadata; class MP4Encoder { public: MP4Encoder(void); ~MP4Encoder(void); public: // open or creat a mp4 file. MP4FileHandle CreateMP4File(const char *fileName,int width,int height,int timeScale = 90000,int frameRate = 25); // wirte 264 metadata in mp4 file. bool Write264Metadata(MP4FileHandle hMp4File,LPMP4ENC_Metadata lpMetadata); // wirte 264 data, data can contain multiple frame. int WriteH264Data(MP4FileHandle hMp4File,const unsigned char* pData,int size); // close mp4 file. void CloseMP4File(MP4FileHandle hMp4File); // convert H264 file to mp4 file. // no need to call CreateMP4File and CloseMP4File,it will create/close mp4 file automaticly. bool WriteH264File(const char* pFile264,const char* pFileMp4); // Prase H264 metamata from H264 data frame static bool PraseMetadata(const unsigned char* pData,int size,MP4ENC_Metadata &metadata); private: // read one nalu from H264 data buffer static int ReadOneNaluFromBuf(const unsigned char *buffer,unsigned int nBufferSize,unsigned int offSet,MP4ENC_NaluUnit &nalu); private: int m_nWidth; int m_nHeight; int m_nFrameRate; int m_nTimeScale; MP4TrackId m_videoId; };
MP4Encoder.cpp
/********************************************************************
filename: MP4Encoder.cpp
created: 2013-04-16
author: firehood
purpose: MP4編碼器，基於開源庫mp4v2實現（https://code.google.com/p/mp4v2/）。
*********************************************************************/
#include "MP4Encoder.h"
#include <string.h>
#define BUFFER_SIZE (1024*1024)
MP4Encoder::MP4Encoder(void):
m_videoId(NULL),
m_nWidth(0),
m_nHeight(0),
m_nTimeScale(0),
m_nFrameRate(0)
{
}
MP4Encoder::~MP4Encoder(void)
{
}
MP4FileHandle MP4Encoder::CreateMP4File(const char *pFileName,int width,int height,int timeScale/* = 90000*/,int frameRate/* = 25*/)
{
if(pFileName == NULL)
{
return false;
}
// create mp4 file
MP4FileHandle hMp4file = MP4Create(pFileName);
if (hMp4file == MP4_INVALID_FILE_HANDLE)
{
printf("ERROR:Open file fialed.\n");
return false;
}
m_nWidth = width;
m_nHeight = height;
m_nTimeScale = 90000;
m_nFrameRate = 25;
MP4SetTimeScale(hMp4file, m_nTimeScale);
return hMp4file;
}
bool MP4Encoder::Write264Metadata(MP4FileHandle hMp4File,LPMP4ENC_Metadata lpMetadata)
{
m_videoId = MP4AddH264VideoTrack
(hMp4File,
m_nTimeScale,
m_nTimeScale / m_nFrameRate,
m_nWidth, // width
m_nHeight,// height
lpMetadata->Sps[1], // sps[1] AVCProfileIndication
lpMetadata->Sps[2], // sps[2] profile_compat
lpMetadata->Sps[3], // sps[3] AVCLevelIndication
3); // 4 bytes length before each NAL unit
if (m_videoId == MP4_INVALID_TRACK_ID)
{
printf("add video track failed.\n");
return false;
}
MP4SetVideoProfileLevel(hMp4File, 0x01); // Simple Profile @ Level 3
// write sps
MP4AddH264SequenceParameterSet(hMp4File,m_videoId,lpMetadata->Sps,lpMetadata->nSpsLen);
// write pps
MP4AddH264PictureParameterSet(hMp4File,m_videoId,lpMetadata->Pps,lpMetadata->nPpsLen);
return true;
}
int MP4Encoder::WriteH264Data(MP4FileHandle hMp4File,const unsigned char* pData,int size)
{
if(hMp4File == NULL)
{
return -1;
}
if(pData == NULL)
{
return -1;
}
MP4ENC_NaluUnit nalu;
int pos = 0, len = 0;
while (len = ReadOneNaluFromBuf(pData,size,pos,nalu))
{
if(nalu.type == 0x07) // sps
{
// 新增h264 track
m_videoId = MP4AddH264VideoTrack
(hMp4File,
m_nTimeScale,
m_nTimeScale / m_nFrameRate,
m_nWidth, // width
m_nHeight, // height
nalu.data[1], // sps[1] AVCProfileIndication
nalu.data[2], // sps[2] profile_compat
nalu.data[3], // sps[3] AVCLevelIndication
3); // 4 bytes length before each NAL unit
if (m_videoId == MP4_INVALID_TRACK_ID)
{
printf("add video track failed.\n");
return 0;
}
MP4SetVideoProfileLevel(hMp4File, 1); // Simple Profile @ Level 3
MP4AddH264SequenceParameterSet(hMp4File,m_videoId,nalu.data,nalu.size);
}
else if(nalu.type == 0x08) // pps
{
MP4AddH264PictureParameterSet(hMp4File,m_videoId,nalu.data,nalu.size);
}
else
{
int datalen = nalu.size+4;
unsigned char *data = new unsigned char[datalen];
// MP4 Nalu前四個位元組表示Nalu長度
data[0] = nalu.size>>24;
data[1] = nalu.size>>16;
data[2] = nalu.size>>8;
data[3] = nalu.size&0xff;
memcpy(data+4,nalu.data,nalu.size);
if(!MP4WriteSample(hMp4File, m_videoId, data, datalen,MP4_INVALID_DURATION, 0, 1))
{
return 0;
}
delete[] data;
}
pos += len;
}
return pos;
}
int MP4Encoder::ReadOneNaluFromBuf(const unsigned char *buffer,unsigned int nBufferSize,unsigned int offSet,MP4ENC_NaluUnit &nalu)
{
int i = offSet;
while(i<nBufferSize)
{
if(buffer[i++] == 0x00 &&
buffer[i++] == 0x00 &&
buffer[i++] == 0x00 &&
buffer[i++] == 0x01
)
{
int pos = i;
while (pos<nBufferSize)
{
if(buffer[pos++] == 0x00 &&
buffer[pos++] == 0x00 &&
buffer[pos++] == 0x00 &&
buffer[pos++] == 0x01
)
{
break;
}
}
if(pos == nBufferSize)
{
nalu.size = pos-i;
}
else
{
nalu.size = (pos-4)-i;
}
nalu.type = buffer[i]&0x1f;
nalu.data =(unsigned char*)&buffer[i];
return (nalu.size+i-offSet);
}
}
return 0;
}
void MP4Encoder::CloseMP4File(MP4FileHandle hMp4File)
{
if(hMp4File)
{
MP4Close(hMp4File);
hMp4File = NULL;
}
}
bool MP4Encoder::WriteH264File(const char* pFile264,const char* pFileMp4)
{
if(pFile264 == NULL || pFileMp4 == NULL)
{
return false;
}
MP4FileHandle hMp4File = CreateMP4File(pFileMp4,352,288);
if(hMp4File == NULL)
{
printf("ERROR:Create file failed!");
return false;
}
FILE *fp = fopen(pFile264, "rb");
if(!fp)
{
printf("ERROR:open file failed!");
return false;
}
fseek(fp, 0, SEEK_SET);
unsigned char *buffer = new unsigned char[BUFFER_SIZE];
int pos = 0;
while(1)
{
int readlen = fread(buffer+pos, sizeof(unsigned char), BUFFER_SIZE-pos, fp);
if(readlen<=0)
{
break;
}
readlen += pos;
int writelen = 0;
for(int i = readlen-1; i>=0; i--)
{
if(buffer[i--] == 0x01 &&
buffer[i--] == 0x00 &&
buffer[i--] == 0x00 &&
buffer[i--] == 0x00
)
{
writelen = i+5;
break;
}
}
writelen = WriteH264Data(hMp4File,buffer,writelen);
if(writelen<=0)
{
break;
}
memcpy(buffer,buffer+writelen,readlen-writelen+1);
pos = readlen-writelen+1;
}
fclose(fp);
delete[] buffer;
CloseMP4File(hMp4File);
return true;
}
bool MP4Encoder:: PraseMetadata(const unsigned char* pData,int size,MP4ENC_Metadata &metadata)
{
if(pData == NULL || size<4)
{
return false;
}
MP4ENC_NaluUnit nalu;
int pos = 0;
bool bRet1 = false,bRet2 = false;
while (int len = ReadOneNaluFromBuf(pData,size,pos,nalu))
{
if(nalu.type == 0x07)
{
memcpy(metadata.Sps,nalu.data,nalu.size);
metadata.nSpsLen = nalu.size;
bRet1 = true;
}
else if((nalu.type == 0x08))
{
memcpy(metadata.Pps,nalu.data,nalu.size);
metadata.nPpsLen = nalu.size;
bRet2 = true;
}
pos += len;
}
if(bRet1 && bRet2)
{
return true;
}
return false;
}