Re: [PATCH v4 02/13] media: v4l: add some definition of v4l2 colorspace/xfer_func/ycbcr_encoding
From: Hans Verkuil <hidden>
Date: 2021-07-21 10:18:46
Also in:
linux-arm-kernel, linux-media, lkml
On 20/07/2021 03:43, Ming Qian wrote:
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Some definition of colorspace/xfer_func/ycbcr_encoding are defined in ISO, but missed in V4L2, so add some definition according VPU driver's requirement Signed-off-by: Ming Qian <ming.qian@nxp.com> Signed-off-by: Shijie Qin <redacted> Signed-off-by: Zhou Peng <eagle.zhou@nxp.com> --- include/uapi/linux/videodev2.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h index 534eaa4d39bc..545f2c329bc9 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h@@ -247,6 +247,12 @@ enum v4l2_colorspace { /* DCI-P3 colorspace, used by cinema projectors */ V4L2_COLORSPACE_DCI_P3 = 12, + + /* Generic film (colour filters using Illuminant C) */ + V4L2_COLORSPACE_GENERIC_FILM = 13, + + /* SMPTE ST 428-1 */ + V4L2_COLORSPACE_ST428 = 14, }; /*@@ -276,6 +282,20 @@ enum v4l2_xfer_func { * V4L2_COLORSPACE_RAW: V4L2_XFER_FUNC_NONE * * V4L2_COLORSPACE_DCI_P3: V4L2_XFER_FUNC_DCI_P3 + * + * V4L2_XFER_FUNC_LINEAR: Linear transfer characteristics
This exists already: V4L2_XFER_FUNC_NONE
+ * + * V4L2_XFER_FUNC_GAMMA22: Assumed display gamma 2.2 + * + * V4L2_XFER_FUNC_GAMMA28: Assumed display gamma 2.8 + * + * V4L2_XFER_FUNC_HLG: STD-B67, Rec. ITU-R BT.2100-2 hybrid-log-gamma + * + * V4L2_XFER_FUNC_XVYCC: IEC 61966-2-4
This exists already, it is signaled through V4L2_YCBCR_ENC_XV709 and V4L2_YCBCR_ENC_XV601. It's not actually a different transfer function, it's the YCbCr encoding that's different (the transfer function is still V4L2_XFER_FUNC_709).
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+ * + * V4L2_XFER_FUNC_BT1361: Rec. ITU-R BT.1361-0 extended colour gamut + * + * V4L2_XFER_FUNC_ST428: SMPTE ST 428-1 */ V4L2_XFER_FUNC_DEFAULT = 0, V4L2_XFER_FUNC_709 = 1,@@ -285,6 +305,13 @@ enum v4l2_xfer_func { V4L2_XFER_FUNC_NONE = 5, V4L2_XFER_FUNC_DCI_P3 = 6, V4L2_XFER_FUNC_SMPTE2084 = 7, + V4L2_XFER_FUNC_LINEAR = 8, + V4L2_XFER_FUNC_GAMMA22 = 9, + V4L2_XFER_FUNC_GAMMA28 = 10, + V4L2_XFER_FUNC_HLG = 11, + V4L2_XFER_FUNC_XVYCC = 12, + V4L2_XFER_FUNC_BT1361 = 13,
This appears to be a variant of xvYCC, it should probably be a YCBCR_ENC variant since the transfer function defined in bt.1361 is REC709.
+ V4L2_XFER_FUNC_ST428 = 14,
Not sure what this one is about.
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}; /*@@ -345,6 +372,9 @@ enum v4l2_ycbcr_encoding { /* SMPTE 240M -- Obsolete HDTV */ V4L2_YCBCR_ENC_SMPTE240M = 8, + + /* KR=0.30, KB=0.11 or equivalent */ + V4L2_YCBCR_ENC_BT470_6M = 9, }; /*
I'm not opposed to this, but it has to be documented in Documentation/userspace-api/media/v4l/colorspaces-details.rst. I would recommend for an initial submission to only add those new colorimetries that are actually needed, and others can be added later. uAPI additions take a lot of time, esp. getting the documentation correct. Regards, Hans