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| author |   Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-14 06:29:21 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-14 06:29:21 -0800 |
| commit | 747ae0a96f1a78b35c5a3d93ad37a16655e16340 (patch) | |
| tree | 880b33cf70674a5cccc6508cc327f01e93971017 /Documentation | |
| parent | Linux 4.10-rc8 (diff) | |
| parent | [media] cec: initiator should be the same as the destination for, poll (diff) | |
| download | linux-dev-747ae0a96f1a78b35c5a3d93ad37a16655e16340.tar.xz linux-dev-747ae0a96f1a78b35c5a3d93ad37a16655e16340.zip | |
Merge tag 'media/v4.10-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media fixes from Mauro Carvalho Chehab:
"A colorspace regression fix in V4L2 core and a CEC core bug that makes
it discard valid messages"
* tag 'media/v4.10-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
[media] cec: initiator should be the same as the destination for, poll
[media] videodev2.h: go back to limited range Y'CbCr for SRGB and, ADOBERGB
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/media/uapi/v4l/pixfmt-007.rst | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/Documentation/media/uapi/v4l/pixfmt-007.rst b/Documentation/media/uapi/v4l/pixfmt-007.rst index 44bb5a7059b3..95a23a28c595 100644 --- a/Documentation/media/uapi/v4l/pixfmt-007.rst +++ b/Documentation/media/uapi/v4l/pixfmt-007.rst @@ -211,7 +211,13 @@ Colorspace sRGB (V4L2_COLORSPACE_SRGB) The :ref:`srgb` standard defines the colorspace used by most webcams and computer graphics. The default transfer function is ``V4L2_XFER_FUNC_SRGB``. The default Y'CbCr encoding is -``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is full range. +``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is limited range. + +Note that the :ref:`sycc` standard specifies full range quantization, +however all current capture hardware supported by the kernel convert +R'G'B' to limited range Y'CbCr. So choosing full range as the default +would break how applications interpret the quantization range. + The chromaticities of the primary colors and the white reference are: @@ -276,7 +282,7 @@ the following ``V4L2_YCBCR_ENC_601`` encoding as defined by :ref:`sycc`: Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range [-0.5…0.5]. This transform is identical to one defined in SMPTE -170M/BT.601. The Y'CbCr quantization is full range. +170M/BT.601. The Y'CbCr quantization is limited range. .. _col-adobergb: @@ -288,10 +294,15 @@ The :ref:`adobergb` standard defines the colorspace used by computer graphics that use the AdobeRGB colorspace. This is also known as the :ref:`oprgb` standard. The default transfer function is ``V4L2_XFER_FUNC_ADOBERGB``. The default Y'CbCr encoding is -``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is full -range. The chromaticities of the primary colors and the white reference -are: +``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is limited +range. + +Note that the :ref:`oprgb` standard specifies full range quantization, +however all current capture hardware supported by the kernel convert +R'G'B' to limited range Y'CbCr. So choosing full range as the default +would break how applications interpret the quantization range. +The chromaticities of the primary colors and the white reference are: .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| @@ -344,7 +355,7 @@ the following ``V4L2_YCBCR_ENC_601`` encoding: Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range [-0.5…0.5]. This transform is identical to one defined in SMPTE -170M/BT.601. The Y'CbCr quantization is full range. +170M/BT.601. The Y'CbCr quantization is limited range. .. _col-bt2020: |