rotate_find_format
const struct rotate_format *rotate_find_format(u32 pixelformat);
fmt = rotate_find_format(ctx->dst_fmt.pixelformat);
fmt = rotate_find_format(pix_fmt->pixelformat);
fmt = rotate_find_format(fsize->pixel_format);
fmt = rotate_find_format(ctx->src_fmt.pixelformat);
if (!rotate_find_format(f->fmt.pix.pixelformat))
fmt = rotate_find_format(ctx->src_fmt.pixelformat);