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authorHans Verkuil <hansverk@cisco.com>2017-07-27 05:09:10 -0400
committerMauro Carvalho Chehab <mchehab@s-opensource.com>2017-08-08 06:08:50 -0400
commitfb98531e8916c65c1db0434b343d335574431843 (patch)
treed1b67ed767e6b29ba684b72ee9458a26c5a7ff3b /Documentation/media
parent5dcd7c66bca7f9863f497345c114dc36ea3f3084 (diff)
media: media/doc: improve bt.2020 documentation
Add a note stating that bt.2020 is often used in combination with the smpte 2084 transfer function. Also use the right references to the documentation of that transfer function. Signed-off-by: Hans Verkuil <hansverk@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'Documentation/media')
-rw-r--r--Documentation/media/uapi/v4l/colorspaces-defs.rst2
-rw-r--r--Documentation/media/uapi/v4l/colorspaces-details.rst5
2 files changed, 6 insertions, 1 deletions
diff --git a/Documentation/media/uapi/v4l/colorspaces-defs.rst b/Documentation/media/uapi/v4l/colorspaces-defs.rst
index 7ae7dcf73f63..e67ed1e0b3fa 100644
--- a/Documentation/media/uapi/v4l/colorspaces-defs.rst
+++ b/Documentation/media/uapi/v4l/colorspaces-defs.rst
@@ -97,7 +97,7 @@ whole range, 0-255, dividing the angular value by 1.41. The enum
* - ``V4L2_XFER_FUNC_DCI_P3``
- Use the DCI-P3 transfer function.
* - ``V4L2_XFER_FUNC_SMPTE2084``
- - Use the SMPTE 2084 transfer function.
+ - Use the SMPTE 2084 transfer function. See :ref:`xf-smpte-2084`.
diff --git a/Documentation/media/uapi/v4l/colorspaces-details.rst b/Documentation/media/uapi/v4l/colorspaces-details.rst
index 128b2acbe824..47d7d1915284 100644
--- a/Documentation/media/uapi/v4l/colorspaces-details.rst
+++ b/Documentation/media/uapi/v4l/colorspaces-details.rst
@@ -418,6 +418,11 @@ Inverse Transfer function:
L = \left( \frac{L' + 0.099}{1.099}\right) ^{\frac{1}{0.45} }\text{, for } L' \ge 0.081
+Please note that while Rec. 709 is defined as the default transfer function
+by the :ref:`itu2020` standard, in practice this colorspace is often used
+with the :ref:`xf-smpte-2084`. In particular Ultra HD Blu-ray discs use
+this combination.
+
The luminance (Y') and color difference (Cb and Cr) are obtained with
the following ``V4L2_YCBCR_ENC_BT2020`` encoding: