ffmpeg学习4--ffmpeg类的简单封装，包含解码和定时录像功能
ffmpeg学习4--ffmpeg类的简单封装，包含解码和定时录像功能
参考网上的资料，简单封装了一下ffmpeg，这里记录一下，其它传感器编码及项目中用到的已经抽离，这里只包含解码和录像部分。这只是个玩具级别的测试。完整测试代码下载：代码下载
ffmpegDeCode.h
#pragma once
#include "stdafx.h"
#include<iostream>
using namespace std;
extern char *VideoPath;
extern int CameraIndex;
extern int fps;
extern "C"
{
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libswscale/swscale.h"
#include <libavdevice/avdevice.h>
};
class ffmpegDeCode
{
public:
ffmpegDeCode();
~ffmpegDeCode();
bool DecoderInit(const char *sdpurl);
void DecodeFrame();
void DecodeLastFrame();
void StopDecodeFrame();
void GetopencvFrame();
//////////解码部分////////
AVFrame *pFrame;//解码后的帧数据
AVFormatContext *pFormatCtx ;//视频流编码上下文的指针
int videoindex;//视频流索引
AVCodecContext *pCodecCtx;//用于编解码器的类型（视频，音频...）及设置
AVCodec *pCodec ;//解码器指针
long m_framenums;//帧序号
SwsContext *img_convert_ctx;//根据编码信息设置渲染格式
AVPacket *packet;////是存储压缩编码数据相关信息的结构体,数据流分包(一帧的分包)
//1个AVPacket的data通常对应一个NAL。
IplImage * pCVFrame ;
char datatime[60];
char Recordname[100];
//////录像部分/////////
AVStream *i_video_stream;
AVFormatContext *opFormatCtx;
AVStream *o_video_stream;
void WriteVideoHead();
void WriteVideoTail();
int m_recordframenums;
int m_Toatlframenums;
int last_pts ;
int last_dts;
int64_t pts, dts;
int count;//录像文件计数
};
ffmpegDeCode.cpp
#include "stdafx.h"
#include"stdio.h"
#include"ffmpegDeCode.h"
#include "sqlite/sqlite3.h"
#include <fstream>
#include <windows.h>
SYSTEMTIME sys; //系统时间
char systime[50];
ofstream outfile;//打印异常信息
ffmpegDeCode :: ffmpegDeCode()
{
pFrame = NULL/**pFrameRGB = NULL*/;
pFormatCtx = NULL;
videoindex=0;
pCodecCtx = NULL;
pCodec = NULL;
m_framenums = 0;
img_convert_ctx = NULL;
packet = NULL;
pCVFrame = NULL;
//////////////
i_video_stream= NULL;
opFormatCtx= NULL;
o_video_stream= NULL;
m_recordframenums=1;
last_pts = 0;
last_dts = 0;
pts=0;
dts=0;
count=1;
m_Toatlframenums=fps*60*60;//fps*3600
memset(datatime, 0, 100*sizeof(char));
memset(Recordname, 0, 100*sizeof(char));
}
ffmpegDeCode :: ~ffmpegDeCode()
{
WriteVideoTail();
if(pCVFrame)
cvReleaseImage(&pCVFrame);
if(pCodecCtx)
avcodec_close(pCodecCtx);
if(pFormatCtx)
avformat_close_input(&pFormatCtx);
m_framenums=0;
}
void ffmpegDeCode::StopDecodeFrame()//WriteVideoTail()手动
{
WriteVideoTail();//关闭
if(pCVFrame)
cvReleaseImage(&pCVFrame);
if(pCodecCtx)
{
avcodec_close(pCodecCtx);
pCodecCtx=NULL;
}
if(pFormatCtx)
{
avformat_close_input(&pFormatCtx);
pFormatCtx=NULL;
}
m_framenums=0;
}
/*ffmpeg及相关变量初始化*/
bool ffmpegDeCode::DecoderInit(const char *sdpurl)
{
//1)ffmpeg注册复用器，编码器等的函数。
av_register_all();
avformat_network_init();//需要播放网络视频
//avdevice_register_all();//打开摄像头时需要
pFormatCtx = avformat_alloc_context();
//打开视频文件,通过参数filepath来获得文件名。这个函数读取文件的头部并且把信息保存到我们给的AVFormatContext结构体中。
//最后2个参数用来指定特殊的文件格式，缓冲大小和格式参数，但如果把它们设置为空NULL或者0，libavformat将自动检测这些参数。
/////2)打开文件或摄像头或网络流
if(avformat_open_input(&pFormatCtx,sdpurl,NULL,NULL)!=0)
//avformat_open_input(&pFormatCtx,url,NULL,&avdic)
{
GetLocalTime( &sys );
sprintf(systime,"\n%4d-%02d-%02d-%02d:%02d:%02d.%03d",sys.wYear,sys.wMonth,sys.wDay,sys.wHour,sys.wMinute, sys.wSecond,sys.wMilliseconds);
outfile<<systime<<"-->Couldn't open stream！";
StopDecodeFrame();
return false;
}
//3）查找文件的流信息,avformat_open_input函数只是检测了文件的头部，接着要检查在文件中的流的信息
if(av_find_stream_info(pFormatCtx)<0)
{
GetLocalTime( &sys );
sprintf(systime,"\n%4d-%02d-%02d-%02d:%02d:%02d.%03d",sys.wYear,sys.wMonth,sys.wDay,sys.wHour,sys.wMinute, sys.wSecond,sys.wMilliseconds);
outfile<<systime<<"-->Couldn't find stream information！";
StopDecodeFrame();
return false;
}
//遍历文件的各个流，找到第一个视频流，并记录该流的编码信息
videoindex=-1;
for(int i=0; i<pFormatCtx->nb_streams; i++)
{
if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO)
{
videoindex=i;
i_video_stream = pFormatCtx->streams[i];
break;
}
}
if(videoindex==-1)
{
GetLocalTime( &sys );
sprintf(systime,"\n%4d-%02d-%02d-%02d:%02d:%02d.%03d",sys.wYear,sys.wMonth,sys.wDay,sys.wHour,sys.wMinute, sys.wSecond,sys.wMilliseconds);
outfile<<systime<<"-->Couldn't find a video stream！";
StopDecodeFrame();
return false;
}
pCodecCtx=pFormatCtx->streams[videoindex]->codec;
//4）在库里面查找支持该格式的解码器
pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
if(pCodec==NULL)
{
GetLocalTime( &sys );
sprintf(systime,"\n%4d-%02d-%02d-%02d:%02d:%02d.%03d",sys.wYear,sys.wMonth,sys.wDay,sys.wHour,sys.wMinute, sys.wSecond,sys.wMilliseconds);
outfile<<systime<<"-->Couldn't find Codec！";
StopDecodeFrame();
return false;
}
//5）打开解码器
if(avcodec_open2(pCodecCtx, pCodec,NULL)<0)//avcodec_open2(pCodecCtx, pCodec,NULL)
{
GetLocalTime( &sys );
sprintf(systime,"\n%4d-%02d-%02d-%02d:%02d:%02d.%03d",sys.wYear,sys.wMonth,sys.wDay,sys.wHour,sys.wMinute, sys.wSecond,sys.wMilliseconds);
outfile<<systime<<"-->Couldn't open codec！";
StopDecodeFrame();
return false;
}
int y_size = pCodecCtx->width * pCodecCtx->height;
packet=(AVPacket *)malloc(sizeof(AVPacket));//分配（一帧的分包）内存
av_new_packet(packet, y_size);
if (NULL==pCVFrame)
{
pCVFrame=cvCreateImage(cvSize(pCodecCtx->width, pCodecCtx->height),8,3);
}
return true;
}
/*将解码后的RGB转化成opencv的帧结构*/
void ffmpegDeCode::GetopencvFrame()
{
AVFrame *pFrameRGB = avcodec_alloc_frame();//分配一个帧指针，指向解码后的转换帧
uint8_t * out_bufferRGB=new uint8_t[avpicture_get_size( PIX_FMT_RGB24,
pCodecCtx->width, pCodecCtx->height)];//给out_bufferRGB帧分配内存;
avpicture_fill((AVPicture *)pFrameRGB,
out_bufferRGB, PIX_FMT_RGB24, pCodecCtx->width, pCodecCtx->height);
//(RGB转换成opencv的BGR)
uchar *p = NULL;
p = pFrame->data[1];
pFrame->data[1] = pFrame->data[2];
pFrame->data[2] = p;
//设置图像转换上下文
sws_scale(img_convert_ctx,
pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
pFrameRGB->data, pFrameRGB->linesize);//格式转换，YUV420转换成RGB
memcpy(pCVFrame->imageData,out_bufferRGB,pCodecCtx->width*pCodecCtx->height*3);
pCVFrame->widthStep=pCodecCtx->width*3;// (3通道的)
pCVFrame->origin=0;
delete[] out_bufferRGB;
av_free(pFrameRGB);
}
void ffmpegDeCode::DecodeFrame()
{
int decode_result=0;
int got_picture=0;//
pFrame=avcodec_alloc_frame();//分配一个帧指针，指向解码后的帧
///一个AVPacket最多只包含一个AVFrame，而一个AVFrame可能包含好几个AVPacket，
///AVPacket是种数据流分包的概念。记录一些音视频相关的属性值，如pts,dts等
if(pFormatCtx==NULL)
exit(1);
if(av_read_frame(pFormatCtx,packet)<0)
exit(1);
//SavedSensorData();//解析传感器数据
if(packet->stream_index==videoindex)
{
decode_result = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
////////分时段录像//////////////////
if(m_framenums==30)//避免开始传感器数据不正常或没有
WriteVideoHead();//写视频头，第一段视频头
if(m_framenums>=30)
{
packet->flags|=AV_PKT_FLAG_KEY;
pts = packet->pts;
packet->pts += last_pts;
dts = packet->dts;
packet->dts += last_dts;
packet->stream_index = 0;
m_recordframenums++;
av_interleaved_write_frame(opFormatCtx,packet);
if(m_recordframenums==m_Toatlframenums)
{
WriteVideoTail();
WriteVideoHead();
}
}
//////////////////////
if(decode_result<0)
{
GetLocalTime( &sys );
sprintf(systime,"\n%4d-%02d-%02d-%02d:%02d:%02d.%03d",sys.wYear,sys.wMonth,sys.wDay,sys.wHour,sys.wMinute, sys.wSecond,sys.wMilliseconds);
outfile<<systime<<"\n-->解码错误！\n";
return ;
}
if(got_picture)//got_picture标志解码出完整一帧
{
////////////////////
//printf("帧号: %d,帧大小：%d,关键帧标志：%d,显示时间戳:%d,解码时间戳%d\n",
// m_framenums,packet->size,packet->data,packet->pts,packet->dts);
////printf("帧号: %d,帧大小：%d,关键帧标志：%d,显示时间戳:%d,解码时间戳%d\n",
// //m_framenums,pFrame->data,pFrame->key_frame);
//////////////////////
m_framenums++;
img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,
pCodecCtx->width, pCodecCtx->height, PIX_FMT_RGB24, SWS_BICUBIC, NULL, NULL, NULL);
if(img_convert_ctx != NULL)
{
GetopencvFrame();
sws_freeContext(img_convert_ctx);
}
}
}
if(pFrame)
av_free(pFrame);
if(packet)
av_free_packet(packet);
}
void ffmpegDeCode ::WriteVideoHead()
{
sprintf(Recordname,"%sCam%d-%s.mp4",VideoPath,CameraIndex+1,datatime);
avformat_alloc_output_context2(&opFormatCtx, NULL, NULL, Recordname);
//int y_size = pCodecCtx->width * pCodecCtx->height;
//packet2=(AVPacket *)malloc(sizeof(AVPacket));//分配（一帧的分包）内存
//av_new_packet(packet2, y_size);
o_video_stream = avformat_new_stream(opFormatCtx, NULL);
AVCodecContext *c;
c = o_video_stream->codec;
//c->bit_rate = 900000;
c->bit_rate = i_video_stream->codec->bit_rate;
c->codec_id = i_video_stream->codec->codec_id;
c->codec_type = i_video_stream->codec->codec_type;
c->time_base.num = i_video_stream->time_base.num;
c->time_base.den = i_video_stream->time_base.den;
//fprintf(stderr, "time_base.num = %d time_base.den = %d\n", c->time_base.num, c->time_base.den);
c->width = i_video_stream->codec->width;
c->height = i_video_stream->codec->height;
c->pix_fmt = i_video_stream->codec->pix_fmt;
//printf("%d %d %d", c->width, c->height, c->pix_fmt);
c->flags = i_video_stream->codec->flags;
c->flags |= CODEC_FLAG_GLOBAL_HEADER;
c->me_range = i_video_stream->codec->me_range;
c->max_qdiff = i_video_stream->codec->max_qdiff;
c->qmin = i_video_stream->codec->qmin;
c->qmax = i_video_stream->codec->qmax;
c->qcompress = i_video_stream->codec->qcompress;
avio_open(&opFormatCtx->pb,Recordname, AVIO_FLAG_WRITE);
if(avformat_write_header(opFormatCtx, NULL)>=0)
{
GetLocalTime( &sys );
sprintf(systime,"\n%4d-%02d-%02d-%02d:%02d:%02d.%03d",sys.wYear,sys.wMonth,sys.wDay,sys.wHour,sys.wMinute, sys.wSecond,sys.wMilliseconds);
outfile<<systime<<"-->写入视频头文件成功！";
}
}
void ffmpegDeCode ::WriteVideoTail()
{
last_dts += dts;
last_pts += pts;
if(opFormatCtx)
{
if(av_write_trailer(opFormatCtx)>=0)
{
GetLocalTime( &sys );
sprintf(systime,"\n%4d-%02d-%02d-%02d:%02d:%02d.%03d",sys.wYear,sys.wMonth,sys.wDay,sys.wHour,sys.wMinute, sys.wSecond,sys.wMilliseconds);
outfile<<systime<<"-->写入视频尾文件成功！";
}
avcodec_close(opFormatCtx->streams[0]->codec);
av_freep(&opFormatCtx->streams[0]->codec);
av_freep(&opFormatCtx->streams[0]);
avio_close(opFormatCtx->pb);
av_free(opFormatCtx);
}
/*if(packet2)
av_free_packet(packet2);*/
m_recordframenums=1;
last_pts = 0;
last_dts = 0;
}
测试代码：
#include "stdafx.h"
#include "ffmpegDecode.h"
#include "highgui.h"
#include "cv.h"
#include "cxcore.h"
#include <windows.h>
char *VideoPath="D:\\";
int CameraIndex=3;//测试数据存在Cam4_SensorData
int fps=25;
char *sdpurl1 = "test1.sdp";//test.sdp D:\\DataSaved\\HC_Record_ch04_20160410145430.mp4
ffmpegDeCode deCode1;
int _tmain(int argc, _TCHAR* argv[])
{
///////////初始化///////
if(!deCode1.DecoderInit(sdpurl1))
{
cout<<"播放失败!"<<endl;
}
cvNamedWindow("Decode1");
//////解码播放//////////
while(1)
{
deCode1.DecodeFrame();
cout<<"------->第1路第"<<deCode1.m_framenums<<"帧"<<endl;
if(deCode1.pCVFrame)
{
cvShowImage("Decode1",deCode1.pCVFrame);
cvWaitKey(5);//标准1000/fps
}
}
return 0;
}
测试截图：
解码rtp流：
这里的rtp流以笔记本自带的摄像头发送rtp流来测试，具体有发送端的板子或另外一台电脑也可以来发送rtp流也可以。
ffmpeg -f dshow -i video="Integrated Camera" -b 1500000 -r 25 -s 320*240 -pix_fmt yuv420p -vcodec libx264 -preset:v ultrafast -tune:v zerolatency -f rtp rtp://127.0.0.1:9988>test1.sdp
