Próbuję pobrać piksele z ekranu i zakodować zrzut ekranu w wideo za pomocą ffmpeg. Widziałem kilka przykładów, ale albo zakładają, że masz już dane w pikselach, albo używasz wejścia do pliku obrazu. Wygląda na to, że używam sws_scale () lub nie (który jest zawarty w przykładach, które widziałem), czy też mam zamiar nadpisywać HBITMAP lub RGBQUAD *, mówiąc mi, że dane src obrazu są złe i koduje puste obraz zamiast zrzutu ekranu. Czy czegoś tu brakuje?

AVCodec* codec;
AVCodecContext* c = NULL;
AVFrame* inpic;
uint8_t* outbuf, *picture_buf;
int i, out_size, size, outbuf_size;
HBITMAP hBmp;
//int x,y;

avcodec_register_all();

printf("Video encoding\n");

// Find the mpeg1 video encoder
codec = avcodec_find_encoder(CODEC_ID_H264);
if (!codec) {
    fprintf(stderr, "Codec not found\n");
    exit(1);
}
else printf("H264 codec found\n");

c = avcodec_alloc_context3(codec);
inpic = avcodec_alloc_frame();

c->bit_rate = 400000;
c->width = screenWidth;                                     // resolution must be a multiple of two
c->height = screenHeight;
c->time_base.num = 1;
c->time_base.den = 25;
c->gop_size = 10;                                           // emit one intra frame every ten frames
c->max_b_frames=1;
c->pix_fmt = PIX_FMT_YUV420P;
c->codec_id = CODEC_ID_H264;
//c->codec_type = AVMEDIA_TYPE_VIDEO;

//av_opt_set(c->priv_data, "preset", "slow", 0);
//printf("Setting presets to slow for performance\n");

// Open the encoder
if (avcodec_open2(c, codec,NULL) < 0) {
    fprintf(stderr, "Could not open codec\n");
    exit(1);
}
else printf("H264 codec opened\n");

outbuf_size = 100000 + 12*c->width*c->height;           // alloc image and output buffer
//outbuf_size = 100000;
outbuf = static_cast<uint8_t *>(malloc(outbuf_size));
size = c->width * c->height;
picture_buf = static_cast<uint8_t*>(malloc((size*3)/2));
printf("Setting buffer size to: %d\n",outbuf_size);

FILE* f = fopen("example.mpg","wb");
if(!f) printf("x  -  Cannot open video file for writing\n");
else printf("Opened video file for writing\n");

/*inpic->data[0] = picture_buf;
inpic->data[1] = inpic->data[0] + size;
inpic->data[2] = inpic->data[1] + size / 4;
inpic->linesize[0] = c->width;
inpic->linesize[1] = c->width / 2;
inpic->linesize[2] = c->width / 2;*/


//int x,y;
// encode 1 second of video
for(i=0;i<c->time_base.den;i++) {
    fflush(stdout);


    HWND hDesktopWnd = GetDesktopWindow();
    HDC hDesktopDC = GetDC(hDesktopWnd);
    HDC hCaptureDC = CreateCompatibleDC(hDesktopDC);
    hBmp = CreateCompatibleBitmap(GetDC(0), screenWidth, screenHeight);
    SelectObject(hCaptureDC, hBmp);
    BitBlt(hCaptureDC, 0, 0, screenWidth, screenHeight, hDesktopDC, 0, 0, SRCCOPY|CAPTUREBLT);
    BITMAPINFO bmi = {0}; 
    bmi.bmiHeader.biSize = sizeof(bmi.bmiHeader); 
    bmi.bmiHeader.biWidth = screenWidth; 
    bmi.bmiHeader.biHeight = screenHeight; 
    bmi.bmiHeader.biPlanes = 1; 
    bmi.bmiHeader.biBitCount = 32; 
    bmi.bmiHeader.biCompression = BI_RGB;
    RGBQUAD *pPixels = new RGBQUAD[screenWidth*screenHeight];
    GetDIBits(hCaptureDC,hBmp,0,screenHeight,pPixels,&bmi,DIB_RGB_COLORS);

inpic->pts = (float) i * (1000.0/(float)(c->time_base.den))*90;
    avpicture_fill((AVPicture*)inpic, (uint8_t*)pPixels, PIX_FMT_BGR32, c->width, c->height);                   // Fill picture with image
    av_image_alloc(inpic->data, inpic->linesize, c->width, c->height, c->pix_fmt, 1);
    //printf("Allocated frame\n");
    //SaveBMPFile(L"screenshot.bmp",hBmp,hDc,screenWidth,screenHeight);
    ReleaseDC(hDesktopWnd,hDesktopDC);
    DeleteDC(hCaptureDC);
    DeleteObject(hBmp);

    // encode the image
    out_size = avcodec_encode_video(c, outbuf, outbuf_size, inpic);
    printf("Encoding frame %3d (size=%5d)\n", i, out_size);
    fwrite(outbuf, 1, out_size, f);
}

// get the delayed frames
for(; out_size; i++) {
    fflush(stdout);

    out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
    printf("Writing frame %3d (size=%5d)\n", i, out_size);
    fwrite(outbuf, 1, out_size, f);
}

// add sequence end code to have a real mpeg file
outbuf[0] = 0x00;
outbuf[1] = 0x00;
outbuf[2] = 0x01;
outbuf[3] = 0xb7;
fwrite(outbuf, 1, 4, f);
fclose(f);
free(picture_buf);
free(outbuf);

avcodec_close(c);
av_free(c);
av_free(inpic);
printf("Closed codec and Freed\n");