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_HSV_QUANTIZATION,
That last define should be 'V4L2_FMT_FLAG_CSC_QUANTIZATION' without 'HSV_'.
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, 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_HAS_CSC
Should also be REQUEST_CSC.
set by the application in the 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 flags: if the flags are not
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>
---
This is v3 of the RFC suggested originaly by Hans Verkuil:
https://patchwork.linuxtv.org/patch/28847/
And then a v2 from Philipp Zabel:
https://patchwork.kernel.org/project/linux-media/list/?series=15483
changes in v3:
I added the API to subdevices as well and added fixes according to
comments from Hans.
I also added a usecase for the new API for the rkisp1 driver.
changes in v2 (reported by Philipp Zabel):
- convert to rst
- split V4L2_PIX_FMT_FLAG_REQUEST_CSC into four separate flags for
colorspace, ycbcr_enc/hsv_enc, quantization, and xfer_func
- let driver set flags to indicate supported features
[1] https://patchwork.linuxtv.org/patch/28847/
.../media/v4l/pixfmt-reserved.rst | 6 +++
.../media/v4l/pixfmt-v4l2-mplane.rst | 16 ++-----
.../userspace-api/media/v4l/pixfmt-v4l2.rst | 36 +++++++++++++---
.../media/v4l/subdev-formats.rst | 42 +++++++++++++++++--
.../media/v4l/vidioc-enum-fmt.rst | 18 ++++++++
.../v4l/vidioc-subdev-enum-mbus-code.rst | 23 ++++++++++
drivers/media/v4l2-core/v4l2-ioctl.c | 19 ++++++++-
drivers/media/v4l2-core/v4l2-subdev.c | 7 ++++
include/uapi/linux/v4l2-mediabus.h | 5 ++-
include/uapi/linux/v4l2-subdev.h | 5 ++-
include/uapi/linux/videodev2.h | 4 ++
11 files changed, 158 insertions(+), 23 deletions(-)
diff --git a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
index 59b9e7238f90..fa8dada69f8c 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
Why on earth did the documentation of these pixel format flags end up in
pixfmt-reserved.rst?
Can you make a patch that moves this to pixfmt-v4l2.rst?
@@ -280,3 +280,9 @@ please make a proposal on the linux-media mailing list.
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_HAS_CSC``
+ - 0x00000002
+ - Set by the application. It is only used for capture and is
+ ignored for output streams. If set, then request the driver to do
+ colorspace conversion from the received colorspace, only conversions
+ of Ycbcr encoding, HSV encoding and quantization are supported.
I'd replace the part "If set..." with this:
----------
If set, then request the driver to do colorspace conversion from the received
colorspace to the requested colorspace values. If a colorimetry field
(``colorspace``, ``xfer_func``, ``ycncr_enc`` or ``quantization``) is set to 0,
then that colorimetry setting will remain unchanged from what was received.
So to just change the quantization only the ``quantization`` field shall be set
to a non-zero value (``V4L2_QUANTIZATION_FULL_RANGE`` or
``V4L2_QUANTIZATION_LIM_RANGE``) and all other colorimetry fields shall be set to 0.
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/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 759420a872d6..ce57718cd66b 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst
@@ -110,8 +110,8 @@ Single-planar format structure
- ``colorspace``
- Image colorspace, from enum :c:type:`v4l2_colorspace`.
This information supplements the ``pixelformat`` and must be set
- by the driver for capture streams and by the application for
- output streams, see :ref:`colorspaces`.
+ by the driver for capture streams and by the application for output
+ streams, see :ref:`colorspace`.
This doesn't appear to change anything.
* - __u32
- ``priv``
- This field indicates whether the remaining fields of the
@@ -148,13 +148,31 @@ 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_HAS_CSC`` then the application can set
+ this field for a capture stream to request a specific Y'CbCr encoding
+ for the captured image data. The driver will attempt to do the
+ conversion to the specified Y'CbCr encoding or return the encoding it
+ will use if it can't do the conversion. This field is ignored for
+ non-Y'CbCr pixelformats. The driver indicates that ycbcr_enc conversion
+ is supported by setting the flag V4L2_FMT_FLAG_CSC_YCBCR_ENC on the
+ on the corresponding struct :c:type:`v4l2_fmtdesc` during enumeration.
on the on the -> in the
+ See :ref:`fmtdesc-flags`
* - __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_HAS_CSC`` then the application can set this
+ field for a capture stream to request a specific HSV encoding for the
+ captured image data. The driver will attempt to do the conversion to
+ the specified HSV encoding or return the encoding it will use if it
+ can't do the conversion. 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 on the
+ on the corresponding struct :c:type:`v4l2_fmtdesc` during enumeration.
Ditto.
+ See :ref:`fmtdesc-flags`
* - }
-
* - __u32
@@ -162,7 +180,15 @@ 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_HAS_CSC`` then the application can set
+ this field for a capture stream to request a specific quantization
+ range for the captured image data. The driver will attempt to do the
+ conversion to the specified quantization range or return the
+ quantization it will use if it can't do the conversion. The driver
+ indicates that quantization conversion is supported by setting the flag
+ V4L2_FMT_FLAG_CSC_QUANTIZATION on the on the corresponding struct
Ditto
+ :c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`
* - __u32
- ``xfer_func``
- Transfer function, from enum :c:type:`v4l2_xfer_func`.
diff --git a/Documentation/userspace-api/media/v4l/subdev-formats.rst b/Documentation/userspace-api/media/v4l/subdev-formats.rst
index 9a4d61b0d76f..f1d4ca29a3e8 100644
--- a/Documentation/userspace-api/media/v4l/subdev-formats.rst
+++ b/Documentation/userspace-api/media/v4l/subdev-formats.rst
@@ -49,13 +49,33 @@ 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_HAS_CSC`` the the application can set
+ this field for a capture stream to request a specific Y'CbCr encoding
+ for the mbus data. The driver will attempt to do the
mbus -> media bus
+ conversion to the specified Y'CbCr encoding or return the encoding it
+ will use if it can't do the conversion. This field is ignored for
+ non-Y'CbCr pixelformats. The driver indicates that ycbcr_enc conversion
This is a media bus format, not a pixelformat.
+ is supported by setting the flag V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC on
on -> in
+ the corresponding struct c:type:`v4l2_subdev_mbus_code_enum` during
+ enumeration. See :ref:`vidioc-subdev-enum-mbus-code.rst <v4l2-subdev-mbus-code-flags>`
+
* - __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_HAS_CSC`` the the application can set
+ this field for a capture stream to request a specific quantization
+ encoding for the mbus data. The driver will attempt to do the
mbus -> media bus
+ conversion to the specified quantization or return the quantization it
+ will use if it can't do the conversion. The driver indicates that
+ quantization conversion is supported by setting the flag
+ V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION on the corresponding struct
on -> in
+ c:type:`v4l2_subdev_mbus_code_enum` during enumeration.
+ See :ref:`vidioc-subdev-enum-mbus-code.rst <v4l2-subdev-mbus-code-flags>`
+
* - __u16
- ``xfer_func``
- Transfer function, from enum :c:type:`v4l2_xfer_func`.
@@ -63,10 +83,26 @@ 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
flags see: -> See:
+ * - __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
+
+ * - ``V4L2_MBUS_FRAMEFMT_HAS_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, only conversions
+ of Ycbcr encoding, and quantization are supported.
Replace by a similar text as for V4L2_PIX_FMT_FLAG_HAS_CSC.
.. _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 7e3142e11d77..125f074543af 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
@@ -145,6 +145,24 @@ formats in preference order, where preferred formats are returned before
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
+ ycbcr 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 :c:func:`VIDIOC_S_FMT` ioctl.
add: ...ioctl with ``V4L2_FMT_FLAG_REQUEST_CSC`` set. (this should probably be
a reference to the REQUEST_CSC flag documentation).
+ * - ``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 :c:func:`VIDIOC_S_FMT` ioctl.
Ditto. Also: hsv -> HSV.
+ * - ``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 :c:func:`VIDIOC_S_FMT` ioctl.
Ditto.
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..4ad87cb74f57 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
@@ -78,11 +78,34 @@ 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`
see -> See
* - __u32
- ``reserved``\ [8]
- Reserved for future extensions. Applications and drivers must set
the array to zero.
+.. _v4l2-subdev-mbus-code-flags:
+
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{7.7cm}|
+
+.. flat-table:: flags in struct v4l2_subdev_mbus_code_enum
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 1 1 2
+
+ * - V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC
+ - 0x00000001
+ - The driver supports setting the ycbcr encoding by the application
+ when calling the VIDIOC_SUBDEV_S_FMT ioctl. see :ref:`v4l2-mbus-format`
see -> See
+ on how to do this.
+ * - V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION
+ - 0x00000002
+ - The driver supports setting the quantization by the application
+ when calling the VIDIOC_SUBDEV_S_FMT ioctl. see :ref:`v4l2-mbus-format`
see -> See
+ on how to do this.
Return Value
============
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index b2ef8e60ea7d..3c7ffb6b15cb 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -1029,6 +1029,15 @@ static void v4l_sanitize_format(struct v4l2_format *fmt)
fmt->fmt.pix_mp.num_planes = min_t(u32, fmt->fmt.pix_mp.num_planes,
VIDEO_MAX_PLANES);
+ if (fmt->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE) {
+ if (fmt->fmt.pix_mp.flags & V4L2_PIX_FMT_FLAG_HAS_CSC)
+ return;
+ fmt->fmt.pix_mp.colorspace = V4L2_COLORSPACE_DEFAULT;
+ fmt->fmt.pix_mp.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
+ fmt->fmt.pix_mp.quantization = V4L2_QUANTIZATION_DEFAULT;
+ fmt->fmt.pix_mp.xfer_func = V4L2_XFER_FUNC_DEFAULT;
+ }
+
/*
* The v4l2_pix_format structure has been extended with fields that were
* not previously required to be set to zero by applications. The priv
@@ -1043,8 +1052,16 @@ static void v4l_sanitize_format(struct v4l2_format *fmt)
fmt->type != V4L2_BUF_TYPE_VIDEO_OUTPUT)
return;
- if (fmt->fmt.pix.priv == V4L2_PIX_FMT_PRIV_MAGIC)
+ if (fmt->fmt.pix.priv == V4L2_PIX_FMT_PRIV_MAGIC) {
+ if (fmt->type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
+ fmt->fmt.pix.flags & V4L2_PIX_FMT_FLAG_HAS_CSC)
+ return;
+ fmt->fmt.pix.colorspace = V4L2_COLORSPACE_DEFAULT;
+ fmt->fmt.pix.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
+ fmt->fmt.pix.quantization = V4L2_QUANTIZATION_DEFAULT;
+ fmt->fmt.pix.xfer_func = V4L2_XFER_FUNC_DEFAULT;
return;
+ }
fmt->fmt.pix.priv = V4L2_PIX_FMT_PRIV_MAGIC;
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index a376b351135f..51e009936aad 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -477,6 +477,13 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
case VIDIOC_SUBDEV_S_FMT: {
struct v4l2_subdev_format *format = arg;
+ if (!(format->format.flags & V4L2_MBUS_FRAMEFMT_HAS_CSC)) {
+ format->format.colorspace = V4L2_COLORSPACE_DEFAULT;
+ format->format.xfer_func = V4L2_XFER_FUNC_DEFAULT;
+ format->format.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
+ format->format.quantization = V4L2_QUANTIZATION_DEFAULT;
+ }
