Question

我能够将图像从AV_PIX_FMT_YUVJ422P转换为jpeg格式（在代码下方），但是在完整的下半部分上具有绿色阴影的结果图像表明我做错了。我已经采取了以下步骤

最初我有来自相机的AV_PIX_FMT_UYVY422图像，我已将其转换为AV_PIX_FMT_YUVJ422P格式，并且能够在http://rawpixels.net/上看到此图像，网站显示的参数大小为2448X2050，Bpp1 = 8，Bpp2 = 8， Bpp3 = 8，对齐1，SubSampling H = 2，SubSampling V = 1，格式：YUV422P 所以输入图像是正确的AV_PIX_FMT_YUVJ422P格式。＆安培;还能看到＆＃34; YUV图像查看器软件＆＃34;使用YUV422格式。

现在我正在尝试使用下面的代码以jpeg格式转换它，附加的是在整个下半部分有绿色阴影的结果图像。

    AVFormatContext*    pFormatCtx;
    AVOutputFormat*     fmt;
    AVStream*           video_st;
    AVCodecContext*     pCodecCtx;
    AVCodec*            pCodec;

    uint8_t*            picture_buf;
    AVFrame*            picture;
    AVPacket            pkt;
    int                 y_size;
    int                 size;
    int                 got_picture=0;  
    int                 ret=0;

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

    FILE *in_file                       =   NULL;   
    unsigned int        in_width        =   2448;    
    unsigned int        in_height       =   2050;   
    const char* out_file                =   "encoded_pic.jpg";    


        in_file =   fopen("c:\\test_Planar.yuv","rb");
        if(in_file == NULL) { printf("\n\tFile Opening error...!!"); exit(1); }
        else printf("\n\tYUV File Open Sucessfully...!!\n\n");

        av_register_all();  // Loads the whole database of available codecs and formats.

        pFormatCtx          =   avformat_alloc_context();           
        fmt             =   NULL;
        fmt             =   av_guess_format("mjpeg",NULL,NULL);
        pFormatCtx->oformat     =   fmt;

//------Output URL-------------------------
if (avio_open(&pFormatCtx->pb,out_file, AVIO_FLAG_READ_WRITE) < 0)
{
    printf("Couldn't open output file.");
    return -1;
}

video_st = avformat_new_stream(pFormatCtx, 0);    
if (video_st==NULL)        return -1;


pCodecCtx               =   video_st->codec;
pCodecCtx->codec_id     =   fmt->video_codec;
pCodecCtx->codec_type   =   AVMEDIA_TYPE_VIDEO;
pCodecCtx->pix_fmt      =   AV_PIX_FMT_YUVJ422P;

//--------------------------MY SOURCE PIXEL FORMAT--------------

pCodecCtx->width        =   in_width;
pCodecCtx->height       =   in_height;

pCodecCtx->time_base.num = 1;
pCodecCtx->time_base.den = 1;//25;

//Output some information
av_dump_format(pFormatCtx, 0, out_file, 1);

// Determine if desired video encoder is installed 
pCodec = avcodec_find_encoder(pCodecCtx->codec_id);

if (!pCodec)
{
    printf("Codec not found.");
    return -1;
}

printf("\nCodec Identified done\n");

if (avcodec_open2(pCodecCtx, pCodec,NULL) < 0){
    printf("Could not open codec.\n");
    return -1;
}
picture     =   av_frame_alloc();
size            =   avpicture_get_size(pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
picture_buf     =   (uint8_t *)av_malloc(size);
if (!picture_buf)    return -1;

avpicture_fill((AVPicture *)picture, picture_buf, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);

printf("\t\nWrite Header..");
avformat_write_header(pFormatCtx,NULL);
y_size = pCodecCtx->width * pCodecCtx->height;
av_new_packet(&pkt,y_size*3);


//Read YUV
if (fread(picture_buf, 1, y_size*3/2, in_file) <=0)
{
    printf("Could not read input file.");
    return -1;
}
 //--------------------------------------------input image format UYVY
picture->data[0] = picture_buf;             // Y
picture->data[1] = picture_buf+ y_size;         // U
picture->data[2] = picture_buf+ y_size*5/4;     // V
//-----------------------------------------------

printf("\t\n Encode the image..\n");
ret = avcodec_encode_video2(pCodecCtx, &pkt,picture, &got_picture);
if(ret < 0)
{
    printf("Encode Error.\n");
    return -1;
}

if (got_picture==1)
{
    pkt.stream_index = video_st->index;
    ret = av_write_frame(pFormatCtx, &pkt);
}

av_free_packet(&pkt);
//Write Trailer
av_write_trailer(pFormatCtx);    
printf("Encode Successful.\n");

if (video_st)
{
    avcodec_close(video_st->codec);
    av_free(picture);
    av_free(picture_buf);
}

avio_close(pFormatCtx->pb);
avformat_free_context(pFormatCtx);    

    fclose(in_file);
    printf("\n\tYUV File Close Sucessfully...!!");    
}

Resultant output jpeg encoded image from yuvj422p image having green shade

Answer 1

将输入像素格式从AV_PIX_FMT_YUVJ422P更改为AV_PIX_FMT_YUVJ 420 P解决问题。

AV_PIX_FMT_YUVJ422P转换为jpeg

1 个答案: