On 05/06/2020 19:26, Dafna Hirschfeld wrote:
> From: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
>
> For video capture it is the driver that reports the colorspace,
> Y'CbCr/HSV encoding, quantization range and transfer function
> used by the video, and there is no way to request something
> different, even though many HDTV receivers have some sort of
> colorspace conversion capabilities.
>
> For output video this feature already exists since the application
> specifies this information for the video format it will send out, and
> the transmitter will enable any available CSC if a format conversion has
> to be performed in order to match the capabilities of the sink.
>
> For video capture we propose adding new v4l2_pix_format flag:
> V4L2_PIX_FMT_FLAG_SET_CSC. The flag is set by the application,
> the driver will interpret the ycbcr_enc/hsv_enc, and quantization fields
> as the requested colorspace information and will attempt to
> do the conversion it supports.
>
> Drivers set the flags
> V4L2_FMT_FLAG_CSC_YCBCR_ENC,
> V4L2_FMT_FLAG_CSC_HSV_ENC,
> V4L2_FMT_FLAG_CSC_QUANTIZATION,
> in the flags field of the struct v4l2_fmtdesc during enumeration to
> indicate that they support colorspace conversion for the respective field.
> Currently the conversion of the fields 'colorspace' and 'xfer_func' is not
> supported since there are no drivers that support it.
>
> The same API is added for the subdevices. With the flag
> V4L2_MBUS_FRAMEFMT_SET_CSC set by the application in VIDIOC_SUBDEV_S_FMT
> ioctl and the flags V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC,
> V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION set by the driver in the
> VIDIOC_SUBDEV_ENUM_MBUS_CODE ioctl.
>
> For subdevices, new 'flags' fields were added to the structs
> v4l2_subdev_mbus_code_enum, v4l2_mbus_framefmt which are borrowed from the
> 'reserved' field
>
> Drivers do not have to actually look at the flagsr. If the flags are not
flagsr -> flags
> set, then the colorspace, ycbcr_enc and quantization fields are set to
> the default values by the core, i.e. just pass on the received format
> without conversion.
>
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
> ---
> .../media/v4l/pixfmt-v4l2-mplane.rst | 16 ++----
> .../userspace-api/media/v4l/pixfmt-v4l2.rst | 46 ++++++++++++++--
> .../media/v4l/subdev-formats.rst | 52 +++++++++++++++++--
> .../media/v4l/vidioc-enum-fmt.rst | 22 +++++++-
> .../v4l/vidioc-subdev-enum-mbus-code.rst | 28 ++++++++++
> .../media/videodev2.h.rst.exceptions | 3 ++
> include/uapi/linux/v4l2-mediabus.h | 5 +-
> include/uapi/linux/v4l2-subdev.h | 5 +-
> include/uapi/linux/videodev2.h | 4 ++
> 9 files changed, 160 insertions(+), 21 deletions(-)
>
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-v4l2-mplane.rst b/Documentation/userspace-api/media/v4l/pixfmt-v4l2-mplane.rst
> index 444b4082684c..66f3365d7b72 100644
> --- a/Documentation/userspace-api/media/v4l/pixfmt-v4l2-mplane.rst
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-v4l2-mplane.rst
> @@ -105,29 +105,21 @@ describing all planes of that format.
> * - __u8
> - ``ycbcr_enc``
> - Y'CbCr encoding, from enum :c:type:`v4l2_ycbcr_encoding`.
> - This information supplements the ``colorspace`` and must be set by
> - the driver for capture streams and by the application for output
> - streams, see :ref:`colorspaces`.
> + See struct :c:type:`v4l2_pix_format`.
> * - __u8
> - ``hsv_enc``
> - HSV encoding, from enum :c:type:`v4l2_hsv_encoding`.
> - This information supplements the ``colorspace`` and must be set by
> - the driver for capture streams and by the application for output
> - streams, see :ref:`colorspaces`.
> + See struct :c:type:`v4l2_pix_format`.
> * - }
> -
> * - __u8
> - ``quantization``
> - Quantization range, from enum :c:type:`v4l2_quantization`.
> - This information supplements the ``colorspace`` and must be set by
> - the driver for capture streams and by the application for output
> - streams, see :ref:`colorspaces`.
> + See struct :c:type:`v4l2_pix_format`.
> * - __u8
> - ``xfer_func``
> - Transfer function, from enum :c:type:`v4l2_xfer_func`.
> - This information supplements the ``colorspace`` and must be set by
> - the driver for capture streams and by the application for output
> - streams, see :ref:`colorspaces`.
> + See struct :c:type:`v4l2_pix_format`.
> * - __u8
> - ``reserved[7]``
> - Reserved for future extensions. Should be zeroed by drivers and
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst b/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst
> index ffa539592822..f23404efd90f 100644
> --- a/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst
> @@ -148,13 +148,29 @@ Single-planar format structure
> - Y'CbCr encoding, from enum :c:type:`v4l2_ycbcr_encoding`.
> This information supplements the ``colorspace`` and must be set by
> the driver for capture streams and by the application for output
> - streams, see :ref:`colorspaces`.
> + streams, see :ref:`colorspaces`. If the application sets the
> + flag ``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set
> + this field for a capture stream to request a specific Y'CbCr encoding
> + for the captured image data. If the driver cannot handle requested
> + conversion, it will return another supported encoding.
> + This field is ignored for HSV pixelformats. The driver indicates that
> + ycbcr_enc conversion is supported by setting the flag
> + V4L2_FMT_FLAG_CSC_YCBCR_ENC in the corresponding struct
> + :c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`
Missing period at the end.
> * - __u32
> - ``hsv_enc``
> - HSV encoding, from enum :c:type:`v4l2_hsv_encoding`.
> This information supplements the ``colorspace`` and must be set by
> the driver for capture streams and by the application for output
> - streams, see :ref:`colorspaces`.
> + streams, see :ref:`colorspaces`. If the application sets the flag
> + ``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set this
> + field for a capture stream to request a specific HSV encoding for the
> + captured image data. If the driver cannot handle requested
> + conversion, it will return another supported encoding.
> + This field is ignored for non-HSV pixelformats. The driver indicates
> + that hsv_enc conversion is supported by setting the flag
> + V4L2_FMT_FLAG_CSC_HSV_ENC in the corresponding struct
> + :c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`
Missing period at the end.
> * - }
> -
> * - __u32
> @@ -162,7 +178,14 @@ Single-planar format structure
> - Quantization range, from enum :c:type:`v4l2_quantization`.
> This information supplements the ``colorspace`` and must be set by
> the driver for capture streams and by the application for output
> - streams, see :ref:`colorspaces`.
> + streams, see :ref:`colorspaces`. If the application sets the flag
> + ``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set
> + this field for a capture stream to request a specific quantization
> + range for the captured image data. If the driver cannot handle requested
> + conversion, it will return another supported encoding.
> + The driver indicates that quantization conversion is supported by setting
> + the flag V4L2_FMT_FLAG_CSC_QUANTIZATION in the corresponding struct
> + :c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`
Missing period at the end.
> * - __u32
> - ``xfer_func``
> - Transfer function, from enum :c:type:`v4l2_xfer_func`.
> @@ -186,3 +209,20 @@ Single-planar format structure
> by RGBA values (128, 192, 255, 128), the same pixel described with
> premultiplied colors would be described by RGBA values (64, 96,
> 128, 128)
> + * .. _`v4l2-pix-fmt-flag-set-csc`:
> +
> + - ``V4L2_PIX_FMT_FLAG_SET_CSC``
> + - 0x00000002
> + - Set by the application. It is only used for capture and is
> + ignored for output streams. If set, then request the device to do
> + colorspace conversion from the received colorspace to the requested
> + colorspace values. If colorimetry field (``ycncr_enc``, ``hsv_enc``
ycncr_enc -> ycbcr_enc
> + or ``quantization``) is set to 0, then that colorimetry setting will
> + remain unchanged from what was received. So to change the quantization
> + only the ``quantization`` field shall be set to non-zero values
> + (``V4L2_QUANTIZATION_FULL_RANGE`` or ``V4L2_QUANTIZATION_LIM_RANGE``)
> + and all other colorimetry fields shall be set to 0. The API does not
does not -> does not (yet)
> + support the conversion of the fields ``colorspace`` and ``xfer_func``
Missing period at the end.
> +
> + To check which conversions are supported by the hardware for the current
> + pixel format, see :ref:`fmtdesc-flags`.
> diff --git a/Documentation/userspace-api/media/v4l/subdev-formats.rst b/Documentation/userspace-api/media/v4l/subdev-formats.rst
> index 9a4d61b0d76f..75eb7f8bb4c5 100644
> --- a/Documentation/userspace-api/media/v4l/subdev-formats.rst
> +++ b/Documentation/userspace-api/media/v4l/subdev-formats.rst
> @@ -49,13 +49,32 @@ Media Bus Formats
> - Y'CbCr encoding, from enum :c:type:`v4l2_ycbcr_encoding`.
> This information supplements the ``colorspace`` and must be set by
> the driver for capture streams and by the application for output
> - streams, see :ref:`colorspaces`.
> + streams, see :ref:`colorspaces`. If the application sets the
> + flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set
> + this field for a capture stream to request a specific Y'CbCr encoding
> + for the media bus data. If the driver cannot handle requested
> + conversion, it will return another supported encoding.
> + This field is ignored for HSV media bus formats. The driver indicates
> + that ycbcr_enc conversion is supported by setting the flag
> + V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC in the corresponding struct
> + :c:type:`v4l2_subdev_mbus_code_enum` during enumeration.
> + See :ref:`v4l2-subdev-mbus-code-flags`
Missing period at the end.
> +
> * - __u16
> - ``quantization``
> - Quantization range, from enum :c:type:`v4l2_quantization`.
> This information supplements the ``colorspace`` and must be set by
> the driver for capture streams and by the application for output
> - streams, see :ref:`colorspaces`.
> + streams, see :ref:`colorspaces`. If the application sets the
> + flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set
> + this field for a capture stream to request a specific quantization
> + encoding for the media bus data. If the driver cannot handle requested
> + conversion, it will return another supported encoding.
> + The driver indicates that quantization conversion is supported by
> + setting the flag V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION in the
> + corresponding struct :c:type:`v4l2_subdev_mbus_code_enum`
> + during enumeration. See :ref:`v4l2-subdev-mbus-code-flags`
Missing period at the end.
> +
> * - __u16
> - ``xfer_func``
> - Transfer function, from enum :c:type:`v4l2_xfer_func`.
> @@ -63,10 +82,37 @@ Media Bus Formats
> the driver for capture streams and by the application for output
> streams, see :ref:`colorspaces`.
> * - __u16
> - - ``reserved``\ [11]
> + - ``flags``
> + - flags See: :ref:v4l2-mbus-framefmt-flags
> + * - __u16
> + - ``reserved``\ [10]
> - Reserved for future extensions. Applications and drivers must set
> the array to zero.
>
> +.. _v4l2-mbus-framefmt-flags:
> +
> +.. flat-table:: v4l2_mbus_framefmt Flags
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 3 1 4
> +
> + * .. _`mbus-framefmt-set-csc`:
> +
> + - ``V4L2_MBUS_FRAMEFMT_SET_CSC``
> + - 0x0001
> + - Set by the application. It is only used for capture and is
> + ignored for output streams. If set, then request the subdevice to do
> + colorspace conversion from the received colorspace to the requested
> + colorspace values. If colorimetry field (``ycbcr_enc`` or
> + ``quantization``) is set to 0, then that colorimetry setting will remain
> + unchanged from what was received. So to change the quantization, only the
> + ``quantization`` field shall be set to non-zero values
> + (``V4L2_QUANTIZATION_FULL_RANGE`` or ``V4L2_QUANTIZATION_LIM_RANGE``)
> + and all other colorimetry fields shall be set to 0. The API does not
> + support the conversion of the fields ``colorspace`` and ``xfer_func``.
> +
> + To check which conversions are supported by the hardware for the current
> + media bus frame format, see :ref:`v4l2-mbus-framefmt-flags`.
>
>
> .. _v4l2-mbus-pixelcode:
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> index a53dd3d7f7e2..11323755d41b 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> @@ -178,7 +178,27 @@ the ``mbus_code`` field is handled differently:
> parameters are detected. This flag can only be used in combination
> with the ``V4L2_FMT_FLAG_COMPRESSED`` flag, since this applies to
> compressed formats only. It is also only applies to stateful codecs.
> -
> + * - ``V4L2_FMT_FLAG_CSC_YCBCR_ENC``
> + - 0x0010
> + - The driver allows the application to try to change the default
> + Y'CbCr encoding. This flag is relevant only for capture devices.
> + The application can ask to configure the ycbcr_enc of the capture device
> + when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with
> + :ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
> + * - ``V4L2_FMT_FLAG_CSC_HSV_ENC``
> + - 0x0010
> + - The driver allows the application to try to change the default
> + HSV encoding. This flag is relevant only for capture devices.
> + The application can ask to configure the hsv_enc of the capture device
> + when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with
> + :ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
> + * - ``V4L2_FMT_FLAG_CSC_QUANTIZATION``
> + - 0x0020
> + - The driver allows the application to try to change the default
> + quantization. This flag is relevant only for capture devices.
> + The application can ask to configure the quantization of the capture
> + device when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with
> + :ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
>
> Return Value
> ============
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst b/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst
> index 35b8607203a4..3d3430bdd71f 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst
> @@ -78,12 +78,40 @@ information about the try formats.
> - ``which``
> - Media bus format codes to be enumerated, from enum
> :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
> + * - __u32
> + - ``flags``
> + - See :ref:`v4l2-subdev-mbus-code-flags`
> * - __u32
> - ``reserved``\ [8]
'[8]' should now be changed to '[7]'.
> - Reserved for future extensions. Applications and drivers must set
> the array to zero.
>
>
> +
> +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{7.7cm}|
> +
> +.. _v4l2-subdev-mbus-code-flags:
> +
> +.. flat-table:: Subdev Media Bus Code Enumerate Flags
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 1 1 2
> +
> + * - V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC
> + - 0x00000001
> + - The driver allows the application to try to change the default Y'CbCr
> + encoding. The application can ask to configure the ycbcr_enc of the
> + subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
> + ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
> + See :ref:`v4l2-mbus-format` on how to do this.
> + * - V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION
> + - 0x00000002
> + - The driver allows the application to try to change the default
> + quantization. The application can ask to configure the quantization of
> + the subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
> + ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
> + See :ref:`v4l2-mbus-format` on how to do this.
> +
> Return Value
> ============
>
> diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> index 564a3bf5bc6d..f7be008cd479 100644
> --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> @@ -187,6 +187,9 @@ replace define V4L2_FMT_FLAG_COMPRESSED fmtdesc-flags
> replace define V4L2_FMT_FLAG_EMULATED fmtdesc-flags
> replace define V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM fmtdesc-flags
> replace define V4L2_FMT_FLAG_DYN_RESOLUTION fmtdesc-flags
> +replace define V4L2_FMT_FLAG_CSC_YCBCR_ENC fmtdesc-flags
> +replace define V4L2_FMT_FLAG_CSC_HSV_ENC fmtdesc-flags
> +replace define V4L2_FMT_FLAG_CSC_QUANTIZATION fmtdesc-flags
>
> # V4L2 timecode types
> replace define V4L2_TC_TYPE_24FPS timecode-type
> diff --git a/include/uapi/linux/v4l2-mediabus.h b/include/uapi/linux/v4l2-mediabus.h
> index 123a231001a8..0f916278137a 100644
> --- a/include/uapi/linux/v4l2-mediabus.h
> +++ b/include/uapi/linux/v4l2-mediabus.h
> @@ -16,6 +16,8 @@
> #include <linux/types.h>
> #include <linux/videodev2.h>
>
> +#define V4L2_MBUS_FRAMEFMT_SET_CSC 0x0001
> +
> /**
> * struct v4l2_mbus_framefmt - frame format on the media bus
> * @width: image width
> @@ -36,7 +38,8 @@ struct v4l2_mbus_framefmt {
> __u16 ycbcr_enc;
> __u16 quantization;
> __u16 xfer_func;
> - __u16 reserved[11];
> + __u16 flags;
> + __u16 reserved[10];
> };
>
> #ifndef __KERNEL__
> diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
> index 5d2a1dab7911..972e64d8b54e 100644
> --- a/include/uapi/linux/v4l2-subdev.h
> +++ b/include/uapi/linux/v4l2-subdev.h
> @@ -65,6 +65,8 @@ struct v4l2_subdev_crop {
> __u32 reserved[8];
> };
>
> +#define V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC 0x00000001
> +#define V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION 0x00000002
> /**
> * struct v4l2_subdev_mbus_code_enum - Media bus format enumeration
> * @pad: pad number, as reported by the media API
> @@ -77,7 +79,8 @@ struct v4l2_subdev_mbus_code_enum {
> __u32 index;
> __u32 code;
> __u32 which;
> - __u32 reserved[8];
> + __u32 flags;
> + __u32 reserved[7];
> };
>
> /**
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index c3a1cf1c507f..15824316e0ca 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -774,6 +774,7 @@ struct v4l2_pix_format {
>
> /* Flags */
> #define V4L2_PIX_FMT_FLAG_PREMUL_ALPHA 0x00000001
> +#define V4L2_PIX_FMT_FLAG_SET_CSC 0x00000002
>
> /*
> * F O R M A T E N U M E R A T I O N
> @@ -792,6 +793,9 @@ struct v4l2_fmtdesc {
> #define V4L2_FMT_FLAG_EMULATED 0x0002
> #define V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM 0x0004
> #define V4L2_FMT_FLAG_DYN_RESOLUTION 0x0008
> +#define V4L2_FMT_FLAG_CSC_YCBCR_ENC 0x0010
> +#define V4L2_FMT_FLAG_CSC_HSV_ENC 0x0010
> +#define V4L2_FMT_FLAG_CSC_QUANTIZATION 0x0020
>
> /* Frame Size and frame rate enumeration */
> /*
>
Regards,
Hans
