// Y'CbCr output (see below for details).
void add_output(const ImageFormat &format, OutputAlphaFormat alpha_format);
// Y'CbCr output (see below for details).
void add_output(const ImageFormat &format, OutputAlphaFormat alpha_format);
// Currently, only 4:4:4 output is supported, so chroma_subsampling_x
// and chroma_subsampling_y must both be 1.
//
// Currently, only 4:4:4 output is supported, so chroma_subsampling_x
// and chroma_subsampling_y must both be 1.
//