ffmpeg实现windows屏幕录制YUV420P并实现H264编码

完整工程下载

https://download.csdn.net/download/iot_shun/10313142

首先之前我们的代码利用gdigrab已经实现了屏幕录制功能，可是我们发现，保存的YYU42OP文件实现太大，100张150M，在音视频实时传输的过程中我们需要利用软硬件实现编码压缩，视频编码的方式有很多，例如h263，MPEG-2, H264等，这里我么采用的是H264编码实现效果:        YYU音视频文件（150M）压缩成只有491k视频录制效果：    首先看Yvu文件----->下载一个yuv播放器然后看h264文件两者效果一致；比之前屏幕录制YYU240P，这里只需要配置H264的编码器        //查找h264编码器        pH264Codec = avcodec_find_encoder(AV_CODEC_ID_H264);        if(!pH264Codec)        {          fprintf(stderr, "---------h264 codec not found----\n");          exit(1);        }        pH264CodecCtx = avcodec_alloc_context3(pH264Codec);        pH264CodecCtx->codec_id = AV_CODEC_ID_H264;        pH264CodecCtx->codec_type = AVMEDIA_TYPE_VIDEO;        pH264CodecCtx->pix_fmt = PIX_FMT_YUV420P;        pH264CodecCtx->width = pCodecCtx->width;        pH264CodecCtx->height = pCodecCtx->height;        pH264CodecCtx->time_base.num = 1;        pH264CodecCtx->time_base.den = 15;//帧率(既一秒钟多少张图片)        pH264CodecCtx->bit_rate = 400000; //比特率(调节这个大小可以改变编码后视频的质量)        pH264CodecCtx->gop_size=12;        //H264 还可以设置很多参数 自行研究吧        pH264CodecCtx->qmin = 10;        pH264CodecCtx->qmax = 51;        // some formats want stream headers to be separate        if (pH264CodecCtx->flags & AVFMT_GLOBALHEADER)            pH264CodecCtx->flags |= CODEC_FLAG_GLOBAL_HEADER;        // Set Option        AVDictionary *param = 0;        //H.264        av_dict_set(¶m, "preset", "superfast", 0);        av_dict_set(¶m, "tune", "zerolatency", 0);  //实现实时编码        if (avcodec_open2(pH264CodecCtx, pH264Codec,¶m) < 0){          printf("Failed to open video encoder1! 编码器打开失败！\n");          return false;        }------------------------------------------------分割线------------------------------------------------------然后再获取屏幕视频流后用H264编码sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameYUV->data, pFrameYUV->linesize);

int y_size=pCodecCtx->width*pCodecCtx->height;

fwrite(pFrameYUV->data[0],1,y_size,fp_yuv);    //Y

fwrite(pFrameYUV->data[1],1,y_size/4,fp_yuv);  //U

fwrite(pFrameYUV->data[2],1,y_size/4,fp_yuv);  //V

//编码成h264文件

int ret1 = avcodec_encode_video2(pH264CodecCtx, packet,pFrameYUV, &got_picture);

if(ret1 < 0){

printf("Failed to encode! \n");

return -1;

}

ret1 = fwrite(packet->data,1 , packet->size, fp_h264 );

if (0 > ret1)

{

printf("write into output.h264 fail\n");

}

--------------------------------------------以下为完整代码---------------------------------------

#include <stdio.h>

extern "C"

{

#include "libavcodec/avcodec.h"

#include "libavformat/avformat.h"

#include "libswscale/swscale.h"

#include "libavdevice/avdevice.h"

}

//'1' Use Dshow

//'0' Use VFW

#define USE_DSHOW 0

//Show Dshow Device

void show_dshow_device()

{

AVFormatContext *pFormatCtx = avformat_alloc_context();

AVDictionary* options = NULL;

av_dict_set(&options,"list_devices","true",0);

AVInputFormat *iformat = av_find_input_format("dshow");

printf("========Device Info=============\n");

avformat_open_input(&pFormatCtx,"video=dummy",iformat,&options);

printf("================================\n");

}

//Show Dshow Device Option

void show_dshow_device_option()

{

AVFormatContext *pFormatCtx = avformat_alloc_context();

AVDictionary* options = NULL;

av_dict_set(&options,"list_options","true",0);

AVInputFormat *iformat = av_find_input_format("dshow");

printf("========Device Option Info======\n");

avformat_open_input(&pFormatCtx,"video=Integrated Camera",iformat,&options);

printf("================================\n");

}

//Show VFW Device

void show_vfw_device()

{

AVFormatContext *pFormatCtx = avformat_alloc_context();

AVInputFormat *iformat = av_find_input_format("vfwcap");

printf("========VFW Device Info======\n");

avformat_open_input(&pFormatCtx,"list",iformat,NULL);

printf("=============================\n");

}

//Show AVFoundation Device

void show_avfoundation_device()

{

AVFormatContext *pFormatCtx = avformat_alloc_context();

AVDictionary* options = NULL;

av_dict_set(&options,"list_devices","true",0);

AVInputFormat *iformat = av_find_input_format("avfoundation");

printf("==AVFoundation Device Info===\n");

avformat_open_input(&pFormatCtx,"",iformat,&options);

printf("=============================\n");

}

#define USE_DSHOW 1

int main(int argc, char* argv[])

{

AVFormatContext	*pFormatCtx;

int				i, videoindex;

AVCodecContext	*pCodecCtx;

AVCodec			*pCodec;

AVCodecContext	*pH264CodecCtx;

AVCodec			*pH264Codec;

av_register_all();

avformat_network_init();

avdevice_register_all();//Register Device

pFormatCtx = avformat_alloc_context();

//抓取屏幕

AVInputFormat *ifmt=av_find_input_format("gdigrab");

if(avformat_open_input(&pFormatCtx,"desktop",ifmt,NULL)!=0){

printf("Couldn't open input stream. ");

return -1;

}

if(avformat_find_stream_info(pFormatCtx,NULL)<0)

{

printf("Couldn't find stream information.\n");

return -1;

}

videoindex=-1;

for(i=0; i<pFormatCtx->nb_streams; i++)

    {

            if(pFormatCtx->str1207feams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO)

{

videoindex=i;

}

}

if(videoindex==-1)

    {

printf("Couldn't find a video stream.\n");

return -1;

}

//根据视频中的流打开选择解码器

pCodecCtx=pFormatCtx->streams[videoindex]->codec;

pCodec=avcodec_find_decoder(pCodecCtx->codec_id);

if(pCodec==NULL)

    {

printf("Codec not found.\n");

return -1;

}

//打开解码器

if(avcodec_open2(pCodecCtx, pCodec,NULL)<0)

    {

printf("Could not open codec.\n");

return -1;

}

AVFrame	*pFrame,*pFrameYUV;

pFrame=av_frame_alloc();

pFrameYUV=av_frame_alloc();

uint8_t *out_buffer=(uint8_t *)av_malloc(avpicture_get_size(PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height));

avpicture_fill((AVPicture *)pFrameYUV, out_buffer, PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height);

int ret, got_picture;

AVPacket *packet=(AVPacket *)av_malloc(sizeof(AVPacket));

AVPacket *packetH264=(AVPacket *)av_malloc(sizeof(AVPacket));

FILE *fp_yuv=fopen("output.yuv","wb");

FILE *fp_h264=fopen("output.h264","wb");

struct SwsContext *img_convert_ctx;

img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);

///这里打印出视频的宽高

fprintf(stderr,"w= %d h= %d\n",pCodecCtx->width, pCodecCtx->height);

///我们就读取100张图像

//查找h264编码器

pH264Codec = avcodec_find_encoder(AV_CODEC_ID_H264);

if(!pH264Codec)

    {

fprintf(stderr, "---------h264 codec not found----\n");

exit(1);

}

pH264CodecCtx = avcodec_alloc_context3(pH264Codec);

pH264CodecCtx->codec_id = AV_CODEC_ID_H264;

pH264CodecCtx->codec_type = AVMEDIA_TYPE_VIDEO;

pH264CodecCtx->pix_fmt = PIX_FMT_YUV420P;

pH264CodecCtx->width = pCodecCtx->width;

pH264CodecCtx->height = pCodecCtx->height;

pH264CodecCtx->time_base.num = 1;

pH264CodecCtx->time_base.den = 15;//帧率(既一秒钟多少张图片)

pH264CodecCtx->bit_rate = 400000; //比特率(调节这个大小可以改变编码后视频的质量)

pH264CodecCtx->gop_size=12;

//H264 还可以设置很多参数 自行研究吧

pH264CodecCtx->qmin = 10;

pH264CodecCtx->qmax = 51;

// some formats want stream headers to be separate

if (pH264CodecCtx->flags & AVFMT_GLOBALHEADER)

pH264CodecCtx->flags |= CODEC_FLAG_GLOBAL_HEADER;

// Set Option

AVDictionary *param = 0;

//H.264

av_dict_set(¶m, "preset", "superfast", 0);

av_dict_set(¶m, "tune", "zerolatency", 0);  //实现实时编码

if (avcodec_open2(pH264CodecCtx, pH264Codec,¶m) < 0){

printf("Failed to open video encoder1! 编码器打开失败！\n");

return false;

}

for(int i=0;i<100;i++)

    {

//读取截屏中的数据--->packet

if(av_read_frame(pFormatCtx, packet) < 0)

{

break;

}

if(packet->stream_index==videoindex)

{

ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);

if(ret < 0){

printf("Decode Error.\n");

return -1;

    }

if(got_picture)

    {

sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameYUV->data, pFrameYUV->linesize);

int y_size=pCodecCtx->width*pCodecCtx->height;

fwrite(pFrameYUV->data[0],1,y_size,fp_yuv);    //Y

fwrite(pFrameYUV->data[1],1,y_size/4,fp_yuv);  //U

fwrite(pFrameYUV->data[2],1,y_size/4,fp_yuv);  //V

//编码成h264文件

int ret1 = avcodec_encode_video2(pH264CodecCtx, packet,pFrameYUV, &got_picture);

if(ret1 < 0){

printf("Failed to encode! \n");

return -1;

}

ret1 = fwrite(packet->data,1 , packet->size, fp_h264 );

if (0 > ret1)

{

printf("write into output.h264 fail\n");

}

    }

}

av_free_packet(packet);

}

sws_freeContext(img_convert_ctx);

fclose(fp_yuv);

av_free(out_buffer);

av_free(pFrameYUV);

avcodec_close(pCodecCtx);

avformat_close_input(&pFormatCtx);

return 0;

}