ffmpeg获取摄像头数据保存成YUV420P格式

编译之前得下载好ffmpeg库文件

pro文件

SOURCES += \

    ffmpeg_libavdevice.cpp

INCLUDEPATH += $$PWD/ffmpeg/include

LIBS += $$PWD/ffmpeg/lib/avcodec.lib \

        $$PWD/ffmpeg/lib/avdevice.lib \

        $$PWD/ffmpeg/lib/avfilter.lib \

        $$PWD/ffmpeg/lib/avformat.lib \

        $$PWD/ffmpeg/lib/avutil.lib \

        $$PWD/ffmpeg/lib/postproc.lib \

        $$PWD/ffmpeg/lib/swresample.lib \

        $$PWD/ffmpeg/lib/swscale.lib

INCLUDEPATH += $$PWD/ffmpeg/include

ffmpeg_libavdevice.cpp

#include 

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;

    av_register_all();

    avformat_network_init();

    avdevice_register_all();//Register Device

    show_dshow_device();

    pFormatCtx = avformat_alloc_context();

#if 0

    AVInputFormat *ifmt=av_find_input_format("dshow");

    //Set own video device's name

    if(avformat_open_input(&pFormatCtx,"video=e2eSoft VCam",ifmt,NULL)!=0){

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

        return -1;

    }

#else

    AVInputFormat *ifmt=av_find_input_format("vfwcap");

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

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

        return -1;

    }

#endif

    if(avformat_find_stream_info(pFormatCtx,NULL)<0)

    {

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

        return -1;

    }

    videoindex=-1;

    for(i=0; inb_streams; i++)

    {

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

        {

            videoindex=i;

        }

    }

    if(videoindex==-1)

    {

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

        return -1;

    }

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

    pCodec=avcodec_find_decoder(pCodecCtx->codec_id);

    if(pCodec==NULL)

    {

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

        return -1;

    }

    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));

    FILE *fp_yuv=fopen("output.yuv","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

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

    {

        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

            }

        }

        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;

}