目录
[5. 写文件头信息，写到formatContex中](#5. 写文件头信息，写到formatContex中)
一、编码分析
想要编码必须是解码时获取的YUV格式------> H264 ------>mp4等格式
1.解码线程：
2.编码线程：
二、ffmpeg编码
1.注册所有组件
av_register_all();
2.编码初始化函数
（1）选择文件后缀
AVOutputFormat* outputFormat=
av_guess_format(nullptr,"../fileout/Warcraft3_End.H264",nullptr);
if(outputFormat==nullptr)
{
qDebug()<<"av_guess_format fail";
}
else {
qDebug()<<"av_guess_format success";
}
//1.1 设置格式
this->formatContext->oformat=outputFormat;
（2）打开视频流
int res=avio_open(
&(this->formatContext->pb),"../fileout/Warcraft3_End.H264",AVIO_FLAG_WRITE);
if(res<0)
{
qDebug()<<"avio_open fail";
}
else {
qDebug()<<"avio_open success";
}
（3）新建视频流
//2.1 新建视频流
AVStream *newStream=avformat_new_stream(this->formatContext,nullptr);
if(newStream==nullptr)
{
qDebug()<<"avformat_new_stream fail";
}
else {
qDebug()<<"avformat_new_stream success";
}
//2.2 编码器上下文环境
this->codecContext=newStream->codec;
//2.3 设置信息
this->codecContext->width=800;//编码视频文件宽 (根据实际宽高改变)
this->codecContext->height=368;//编码视频文件高
this->codecContext->bit_rate=579000;//编码视频文件码率
this->codecContext->framerate={24,1};//编码视频文件帧率
this->codecContext->time_base={1,24};//编码视频文件时间基
//2.4 设置高级信息
this->codecContext->gop_size=10;//I/P/B 以10帧为一组
this->codecContext->qmax=51;//清晰度
this->codecContext->qmin=10;//清晰度
this->codecContext->max_b_frames=0;//B压缩为0
this->codecContext->pix_fmt=AV_PIX_FMT_YUV420P;
this->codecContext->codec_type=AVMEDIA_TYPE_VIDEO;
this->codecContext->codec_id=outputFormat->video_codec;
4.查找编码器
AVCodec *codec=avcodec_find_encoder(this->codecContext->codec_id);
//4.1 打开编码器
res=avcodec_open2(this->codecContext,codec,nullptr);
if(res!=0)
{
qDebug()<<"avcodec_open2 fail";
}else {
qDebug()<<"avcodec_open2 success";
}
5. 写文件头信息，写到formatContex中
//4. 写文件头信息，写到formatContex中
res=avformat_write_header(this->formatContext,nullptr);
if(res<0)
{
qDebug()<<"avformat_write_header fail";
}else {
qDebug()<<"avformat_write_header success";
}
6.发送一帧数据给编码器
int res=avcodec_send_frame(this->codecContext,yuv);
if(res!=0)
{
qDebug()<<"avcodec_send_frame fail";
}else {
qDebug()<<"avcodec_send_frame success";
}
7.将像素数据转码压缩码流数据
res=avcodec_receive_packet(this->codecContext,this->pkt);
if(res!=0)
{
qDebug()<<"avcodec_receive_packet fail";
break;
}else {
qDebug()<<"avcodec_receive_packet success";
}
8.写一帧数据到文件
res=av_interleaved_write_frame(this->formatContext,this->pkt);
if(res!=0)
{
qDebug()<<"av_interleaved_write_frame fail";
}else {
qDebug()<<"av_interleaved_write_frame success"<<page;
}
9.写尾帧
void EncodeVideo::writeTailter()
{
//写尾帧信息
av_write_trailer(this->formatContext);
//关闭视频流
avio_close(this->formatContext->pb);
//关闭视频流上下文
avformat_free_context(this->formatContext);
}
cpp
#include "encodevideo.h"
EncodeVideo::EncodeVideo():QThread()
{
this->register_all();
this->formatContext=avformat_alloc_context();
this->pkt=av_packet_alloc();
this->pktIndex=0;
}
EncodeVideo::~EncodeVideo()
{
}
void EncodeVideo::register_all()
{
//注册所有组件
av_register_all();
}
void EncodeVideo::initEncode()
{
//1.通过文件后缀得到最佳输出格式
AVOutputFormat* outputFormat=av_guess_format(nullptr,"../fileout/Warcraft3_End.H264",nullptr);
if(outputFormat==nullptr)
{
qDebug()<<"av_guess_format fail";
}
else {
qDebug()<<"av_guess_format success";
}
//1.1 设置格式
this->formatContext->oformat=outputFormat;
//2.打开视频流
int res=avio_open(&(this->formatContext->pb),"../fileout/Warcraft3_End.H264",AVIO_FLAG_WRITE);
if(res<0)
{
qDebug()<<"avio_open fail";
}
else {
qDebug()<<"avio_open success";
}
//2.1 新建视频流
AVStream *newStream=avformat_new_stream(this->formatContext,nullptr);
if(newStream==nullptr)
{
qDebug()<<"avformat_new_stream fail";
}
else {
qDebug()<<"avformat_new_stream success";
}
//2.2 编码器上下文环境
this->codecContext=newStream->codec;
//2.3 设置信息
this->codecContext->width=800;//编码视频文件宽
this->codecContext->height=368;//编码视频文件高
this->codecContext->bit_rate=579000;//编码视频文件码率
this->codecContext->framerate={24,1};//编码视频文件帧率
this->codecContext->time_base={1,24};//编码视频文件时间基
//2.4 设置高级信息
this->codecContext->gop_size=10;//I/P/B 以10帧为一组
this->codecContext->qmax=51;//清晰度
this->codecContext->qmin=10;//清晰度
this->codecContext->max_b_frames=0;//B压缩为0
this->codecContext->pix_fmt=AV_PIX_FMT_YUV420P;
this->codecContext->codec_type=AVMEDIA_TYPE_VIDEO;
this->codecContext->codec_id=outputFormat->video_codec;
//3. 查找编码器
AVCodec *codec=avcodec_find_encoder(this->codecContext->codec_id);
//3.1 打开编码器
res=avcodec_open2(this->codecContext,codec,nullptr);
if(res!=0)
{
qDebug()<<"avcodec_open2 fail";
}else {
qDebug()<<"avcodec_open2 success";
}
//4. 写文件头信息，写到formatContex中
res=avformat_write_header(this->formatContext,nullptr);
if(res<0)
{
qDebug()<<"avformat_write_header fail";
}else {
qDebug()<<"avformat_write_header success";
}
}
void EncodeVideo::run()
{
//队列有两帧画面在取第一帧，可以避免资源争抢
while(1)
{
if(YuvQueue.size()==0)
{
continue;
}
//从队列取一帧数据
AVFrame *yuv=YuvQueue.dequeue();
//5.发送一帧数据给编码器
int res=avcodec_send_frame(this->codecContext,yuv);
if(res!=0)
{
qDebug()<<"avcodec_send_frame fail";
}else {
qDebug()<<"avcodec_send_frame success";
}
while(res>=0)
{
//下标
yuv->pts=this->pktIndex++;
qDebug()<<"this->pktIndex="<<this->pktIndex;
//6.将像素数据转码压缩码流数据
res=avcodec_receive_packet(this->codecContext,this->pkt);
if(res!=0)
{
qDebug()<<"avcodec_receive_packet fail";
break;
}else {
qDebug()<<"avcodec_receive_packet success";
}
//7.写一帧数据到文件
res=av_interleaved_write_frame(this->formatContext,this->pkt);
if(res!=0)
{
qDebug()<<"av_interleaved_write_frame fail";
}else {
qDebug()<<"av_interleaved_write_frame success"<<page;
}
}
//释放
av_packet_unref(this->pkt);
}
}
void EncodeVideo::reciverYUV(AVFrame *fram)
{
//队列入队
YuvQueue.enqueue(fram);
}
void EncodeVideo::CloseFile()
{
this->writeTailter();
qDebug()<<"writeTailter";
}
void EncodeVideo::writeTailter()
{
//写尾帧信息
av_write_trailer(this->formatContext);
//关闭视频流
avio_close(this->formatContext->pb);
//关闭视频流上下文
avformat_free_context(this->formatContext);
}