On 9/18/2020 6:05 PM, Jan Ekström wrote:
> As it was brought up that the current documentation leaves things
> as specific to YCbCr only, ICtCp and RGB are now mentioned.
> Additionally, the specifications on which these definitions of
> narrow and full range are defined are mentioned.
>
> This way, the documentation of AVColorRange should now match how
> most people seem to read interpret it at this point, and thus
> flagging RGB AVFrames as full range is valid not only according to
> common sense, but also the enum definition.
> ---
> libavutil/pixfmt.h | 40 +++++++++++++++++++++++++++++++++++++---
> 1 file changed, 37 insertions(+), 3 deletions(-)
>
> diff --git a/libavutil/pixfmt.h b/libavutil/pixfmt.h
> index a46acf3c5e..68051bf4b9 100644
> --- a/libavutil/pixfmt.h
> +++ b/libavutil/pixfmt.h
> @@ -530,12 +530,46 @@ enum AVColorSpace {
> };
>
> /**
> - * MPEG vs JPEG YUV range.
> + * Visual content value range.
> + *
> + * These values are based on definitions that can be found in multiple
> + * specifications, such as ITU-T BT.709 (3.4 - Quantization of RGB, luminance
> + * and colour-difference signals), ITU-T BT.2020 (Table 5 - Digital
> + * Representation) as well as ITU-T BT.2100 (Table 9 - Digital 10- and 12-bit
> + * integer representation). At the time of writing, the BT.2100 one is
> + * recommended, as it also defines the full range representation.
> + *
> + * Common definitions:
> + * - For luminance planes such as Y in YCbCr and I in ICtCp, 'E' is the
> + * original value in range of 0.0 to 1.0.
> + * - For chrominance planes such as Cb,Cr and Ct,Cp, 'E' is the original
> + * value in range of -0.5 to 0.5.
> + * - 'n' is the output bit depth.
> + * - For additional definitions such as rounding and clipping to valid n
> + * bit unsigned integer range, please refer to BT.2100 (Table 9).
> */
> enum AVColorRange {
> AVCOL_RANGE_UNSPECIFIED = 0,
> - AVCOL_RANGE_MPEG = 1, ///< the normal 219*2^(n-8) "MPEG" YUV
> ranges
> - AVCOL_RANGE_JPEG = 2, ///< the normal 2^n-1 "JPEG" YUV
> ranges
> + AVCOL_RANGE_MPEG = 1, ///< Narrow or limited range content.
> + ///
> + /// For RGB and luminance planes:
> + /// (219 * E + 16) * 2^(n-8)
> + /// F.ex. the range of 16-235 for 8 bits
> + ///
> + /// For chrominance planes:
> + /// (224 * E + 128) * 2^(n-8)
> + /// F.ex. the range of 16-240 for 8 bits
Is this parsed right by doxygen? Because if not you may want to use /**
*/ for multi-line descriptions, and placed above each value instead of
next to them.
> +
> + AVCOL_RANGE_JPEG = 2, ///< Full range content
> + ///
> + /// For RGB and luminance planes:
> + /// (2^n - 1) * E
> + /// F.ex. the range of 0-255 for 8 bits
> + ///
> + /// For chrominance planes:
> + /// (2^n - 1) * E + 2^(n - 1)
> + /// F.ex. the range of 1-255 for 8 bits
> +
> AVCOL_RANGE_NB ///< Not part of ABI
> };
>
>
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
