_color_trc = get_optional_enum<AVColorTransferCharacteristic>(node, "ColorTransferCharacteristic");
_colorspace = get_optional_enum<AVColorSpace>(node, "Colorspace");
_bits_per_pixel = node->optional_number_child<int> ("BitsPerPixel");
_color_trc = get_optional_enum<AVColorTransferCharacteristic>(node, "ColorTransferCharacteristic");
_colorspace = get_optional_enum<AVColorSpace>(node, "Colorspace");
_bits_per_pixel = node->optional_number_child<int> ("BitsPerPixel");