enum AVPixelFormat pix_fmt = dshow_pixfmt(bih->biCompression, bih->biBitCount);
if (pix_fmt == AV_PIX_FMT_NONE) {
enum AVCodecID codec_id = av_codec_get_id(tags, bih->biCompression);
enum AVPixelFormat pix_fmt = dshow_pixfmt(bih->biCompression, bih->biBitCount);
if (pix_fmt == AV_PIX_FMT_NONE) {
enum AVCodecID codec_id = av_codec_get_id(tags, bih->biCompression);