asset->png_use_alpha ? PNG_COLOR_TYPE_RGB_ALPHA : PNG_COLOR_TYPE_RGB,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
// does not work (gg 2020/03/17 libpng16 fc31)
asset->png_use_alpha ? PNG_COLOR_TYPE_RGB_ALPHA : PNG_COLOR_TYPE_RGB,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
// does not work (gg 2020/03/17 libpng16 fc31)
png_write_info(png_ptr, info_ptr);
png_write_image(png_ptr, output_frame->get_rows());
png_write_end(png_ptr, info_ptr);
png_write_info(png_ptr, info_ptr);
png_write_image(png_ptr, output_frame->get_rows());
png_write_end(png_ptr, info_ptr);