libVPX convert VPX_IMG_FMT_I420 -> RGB

Question

Как я могу конвертировать VPX_IMG_FMT_I420 vpx_image_t в RGB?

Пример кода:

int DecodeFrame() 
{ 
    vpx_video_reader_read_frame(reader); 
    vpx_codec_iter_t iter = NULL; 
    vpx_image_t *img = NULL; 
    size_t frame_size = 0; 
    const unsigned char *frame = vpx_video_reader_get_frame(reader, &frame_size); 
    if (vpx_codec_decode(&codec, frame, (unsigned int)frame_size, NULL, 0)) return 0; 

    img = vpx_codec_get_frame(&codec, &iter); 

// here I need to convert img to RGB array 

    return 1; 
}; 

Answer 1

код из uTox:

void yuv420tobgr(uint16_t width, uint16_t height, 
       const uint8_t *y, const uint8_t *u, const uint8_t *v, 
       unsigned int ystride, 
       unsigned int ustride, 
       unsigned int vstride, 
       uint8_t *out) 
{ 
    unsigned long int i, j; 
    for (i = 0; i < height; ++i) { 
     for (j = 0; j < width; ++j) { 
      uint8_t *point = out + 4 * ((i * width) + j); 
      int t_y = y[((i * ystride) + j)]; 
      int t_u = u[(((i/2) * ustride) + (j/2))]; 
      int t_v = v[(((i/2) * vstride) + (j/2))]; 
      t_y = t_y < 16 ? 16 : t_y; 

      int r = (298 * (t_y - 16) + 409 * (t_v - 128) + 128) >> 8; 
      int g = (298 * (t_y - 16) - 100 * (t_u - 128) - 208 * (t_v - 128) + 128) >> 8; 
      int b = (298 * (t_y - 16) + 516 * (t_u - 128) + 128) >> 8; 

      point[2] = r>255? 255 : r<0 ? 0 : r; 
      point[1] = g>255? 255 : g<0 ? 0 : g; 
      point[0] = b>255? 255 : b<0 ? 0 : b; 
      point[3] = ~0; 
     } 
    } 
}