Re: [PATCH v2 1/4] v4l: Add metadata buffer type and format
Hi Laurent, On Fri, Sep 02, 2016 at 12:40:18AM +0300, Laurent Pinchart wrote: ... > > >> +Data Format Negotiation > > >> +=== > > >> + > > >> +The metadata device uses the :ref:`format` ioctls to select the capture > > >> format. +The metadata buffer content format is bound to that selected > > >> format. In addition +to the basic :ref:`format` ioctls, the > > >> > > >> :ref:`VIDIOC_ENUM_FMT` ioctl must be +supported as well. > > >> > > >> + > > >> +To use the :ref:`format` ioctls applications set the ``type`` of the > > >> +:ref:`v4l2_format ` structure to > > >> ``V4L2_BUF_TYPE_META_CAPTURE`` +and use the :ref:`v4l2_meta_format > > >> ` ``meta`` member of the +``fmt`` union as needed per > > >> the desired operation. The :ref:`v4l2-meta-format` +structure contains > > >> two fields, ``dataformat`` is set by applications to the V4L2 > > > > > > I might not specify the number of number of fields here. It has high > > > chances of not getting updated when more fields are added. Up to you. > > > > This has been copied from dev-sdr.rst. I can drop the last sentence > > completely as the parameters are described in the table below. Hans, any > > opinion ? > > How about this ? > > To use the :ref:`format` ioctls applications set the ``type`` of the s/of/field of/ ? > :ref:`v4l2_format ` structure to ``V4L2_BUF_TYPE_META_CAPTURE`` > and use the :ref:`v4l2_meta_format ` ``meta`` member of the > ``fmt`` union as needed per the desired operation. Both drivers and > applications must set the remainder of the :ref:`v4l2_format ` > structure to 0. -- Sakari Ailus e-mail: sakari.ai...@iki.fi XMPP: sai...@retiisi.org.uk
Re: [PATCH v2 1/4] v4l: Add metadata buffer type and format
Huomenta! On Fri, Sep 02, 2016 at 12:22:42AM +0300, Laurent Pinchart wrote: > Hi Sakari, > > On Monday 29 Aug 2016 12:13:40 Sakari Ailus wrote: > > On Wed, Aug 17, 2016 at 03:20:27PM +0300, Laurent Pinchart wrote: > > > The metadata buffer type is used to transfer metadata between userspace > > > and kernelspace through a V4L2 buffers queue. It comes with a new > > > metadata capture capability and format description. > > > > > > Signed-off-by: Laurent Pinchart > > > > > > Tested-by: Guennadi Liakhovetski > > > --- > > > Changes since v1: > > > > > > - Rebased on top of the DocBook to reST conversion > > > > > > Documentation/media/uapi/v4l/buffer.rst | 8 +++ > > > Documentation/media/uapi/v4l/dev-meta.rst| 69 +++ > > > Documentation/media/uapi/v4l/devices.rst | 1 + > > > Documentation/media/uapi/v4l/vidioc-querycap.rst | 14 +++-- > > > Documentation/media/videodev2.h.rst.exceptions | 2 + > > > drivers/media/v4l2-core/v4l2-compat-ioctl32.c| 19 +++ > > > drivers/media/v4l2-core/v4l2-dev.c | 16 +++--- > > > drivers/media/v4l2-core/v4l2-ioctl.c | 41 ++ > > > drivers/media/v4l2-core/videobuf2-v4l2.c | 3 ++ > > > include/media/v4l2-ioctl.h | 17 ++ > > > include/uapi/linux/videodev2.h | 14 + > > > 11 files changed, 195 insertions(+), 9 deletions(-) > > > create mode 100644 Documentation/media/uapi/v4l/dev-meta.rst > > [snip] > > > > diff --git a/Documentation/media/uapi/v4l/dev-meta.rst > > > b/Documentation/media/uapi/v4l/dev-meta.rst new file mode 100644 > > > index ..252ed05b4841 > > > --- /dev/null > > > +++ b/Documentation/media/uapi/v4l/dev-meta.rst > > > @@ -0,0 +1,69 @@ > > > +.. -*- coding: utf-8; mode: rst -*- > > > + > > > +.. _metadata: > > > + > > > +** > > > +Metadata Interface > > > +** > > > + > > > +Metadata refers to any non-image data that supplements video frames with > > > +additional information. This may include statistics computed over the > > > image +or frame capture parameters supplied by the image source. This > > > interface is +intended for transfer of metadata to userspace and control > > > of that operation. + > > > +The metadata interface is implemented on video capture device nodes. The > > > device +can be dedicated to metadata or can implement both video and > > > metadata capture +as specified in its reported capabilities. > > > + > > > +.. note:: > > > + > > > +This is an :ref:`experimental` interface and may > > > +change in the future. > > > + > > > +Querying Capabilities > > > += > > > + > > > +Device nodes supporting the metadata interface set the > > > ``V4L2_CAP_META_CAPTURE`` +flag in the ``device_caps`` field of the > > > +:ref:`v4l2_capability ` structure returned by the > > > +:ref:`VIDIOC_QUERYCAP` ioctl. That flag means the device can capture > > > +metadata to memory. > > > + > > > +At least one of the read/write or streaming I/O methods must be > > > supported. > > > + > > > + > > > +Data Format Negotiation > > > +=== > > > + > > > +The metadata device uses the :ref:`format` ioctls to select the capture > > > format. +The metadata buffer content format is bound to that selected > > > format. In addition +to the basic :ref:`format` ioctls, the > > > :ref:`VIDIOC_ENUM_FMT` ioctl must be +supported as well. > > > + > > > +To use the :ref:`format` ioctls applications set the ``type`` of the > > > +:ref:`v4l2_format ` structure to > > > ``V4L2_BUF_TYPE_META_CAPTURE`` +and use the :ref:`v4l2_meta_format > > > ` ``meta`` member of the +``fmt`` union as needed per > > > the desired operation. The :ref:`v4l2-meta-format` +structure contains > > > two fields, ``dataformat`` is set by applications to the V4L2 > > > > I might not specify the number of number of fields here. It has high chances > > of not getting updated when more fields are added. Up to you. > > This has been copied from dev-sdr.rst. I can drop the last sentence > completely > as the parameters are described in the table below. Hans, any opinion ? > > > > +FourCC code of the desired format, and ``buffersize`` set by drivers to > > > the +maximum buffer size (in bytes) required for data transfer. > > > + > > > +.. _v4l2-meta-format: > > > +.. flat-table:: struct v4l2_meta_format > > > +:header-rows: 0 > > > +:stub-columns: 0 > > > +:widths: 1 1 2 > > > + > > > +* - __u32 > > > + - ``dataformat`` > > > + - The data format, set by the application. This is a little endian > > > +:ref:`four character code `. V4L2 defines metadata > > > formats +in :ref:`meta-formats`. > > > +* - __u32 > > > + - ``buffersize`` > > > + - Maximum buffer size in bytes required for data. The value is set > > > by the +driver. > > > > We'll need to add width and heigth as well but it could be done lat
Re: [PATCH v2 1/4] v4l: Add metadata buffer type and format
On Friday 02 Sep 2016 00:22:42 Laurent Pinchart wrote: > On Monday 29 Aug 2016 12:13:40 Sakari Ailus wrote: > > On Wed, Aug 17, 2016 at 03:20:27PM +0300, Laurent Pinchart wrote: > >> The metadata buffer type is used to transfer metadata between userspace > >> and kernelspace through a V4L2 buffers queue. It comes with a new > >> metadata capture capability and format description. > >> > >> Signed-off-by: Laurent Pinchart > >> > >> Tested-by: Guennadi Liakhovetski > >> --- > >> Changes since v1: > >> > >> - Rebased on top of the DocBook to reST conversion > >> > >> Documentation/media/uapi/v4l/buffer.rst | 8 +++ > >> Documentation/media/uapi/v4l/dev-meta.rst| 69 + > >> Documentation/media/uapi/v4l/devices.rst | 1 + > >> Documentation/media/uapi/v4l/vidioc-querycap.rst | 14 +++-- > >> Documentation/media/videodev2.h.rst.exceptions | 2 + > >> drivers/media/v4l2-core/v4l2-compat-ioctl32.c| 19 +++ > >> drivers/media/v4l2-core/v4l2-dev.c | 16 +++--- > >> drivers/media/v4l2-core/v4l2-ioctl.c | 41 ++ > >> drivers/media/v4l2-core/videobuf2-v4l2.c | 3 ++ > >> include/media/v4l2-ioctl.h | 17 ++ > >> include/uapi/linux/videodev2.h | 14 + > >> 11 files changed, 195 insertions(+), 9 deletions(-) > >> create mode 100644 Documentation/media/uapi/v4l/dev-meta.rst > > [snip] > > >> diff --git a/Documentation/media/uapi/v4l/dev-meta.rst > >> b/Documentation/media/uapi/v4l/dev-meta.rst new file mode 100644 > >> index ..252ed05b4841 > >> --- /dev/null > >> +++ b/Documentation/media/uapi/v4l/dev-meta.rst > >> @@ -0,0 +1,69 @@ > >> +.. -*- coding: utf-8; mode: rst -*- > >> + > >> +.. _metadata: > >> + > >> +** > >> +Metadata Interface > >> +** > >> + > >> +Metadata refers to any non-image data that supplements video frames > >> with > >> +additional information. This may include statistics computed over the > >> image +or frame capture parameters supplied by the image source. This > >> interface is +intended for transfer of metadata to userspace and control > >> of that operation. + > >> +The metadata interface is implemented on video capture device nodes. > >> The > >> device +can be dedicated to metadata or can implement both video and > >> metadata capture +as specified in its reported capabilities. > >> + > >> +.. note:: > >> + > >> +This is an :ref:`experimental` interface and may > >> +change in the future. > >> + > >> +Querying Capabilities > >> += > >> + > >> +Device nodes supporting the metadata interface set the > >> ``V4L2_CAP_META_CAPTURE`` +flag in the ``device_caps`` field of the > >> +:ref:`v4l2_capability ` structure returned by the > >> +:ref:`VIDIOC_QUERYCAP` ioctl. That flag means the device can capture > >> +metadata to memory. > >> + > >> +At least one of the read/write or streaming I/O methods must be > >> supported. > >> + > >> + > >> +Data Format Negotiation > >> +=== > >> + > >> +The metadata device uses the :ref:`format` ioctls to select the capture > >> format. +The metadata buffer content format is bound to that selected > >> format. In addition +to the basic :ref:`format` ioctls, the > >> > >> :ref:`VIDIOC_ENUM_FMT` ioctl must be +supported as well. > >> > >> + > >> +To use the :ref:`format` ioctls applications set the ``type`` of the > >> +:ref:`v4l2_format ` structure to > >> ``V4L2_BUF_TYPE_META_CAPTURE`` +and use the :ref:`v4l2_meta_format > >> ` ``meta`` member of the +``fmt`` union as needed per > >> the desired operation. The :ref:`v4l2-meta-format` +structure contains > >> two fields, ``dataformat`` is set by applications to the V4L2 > > > > I might not specify the number of number of fields here. It has high > > chances of not getting updated when more fields are added. Up to you. > > This has been copied from dev-sdr.rst. I can drop the last sentence > completely as the parameters are described in the table below. Hans, any > opinion ? How about this ? To use the :ref:`format` ioctls applications set the ``type`` of the :ref:`v4l2_format ` structure to ``V4L2_BUF_TYPE_META_CAPTURE`` and use the :ref:`v4l2_meta_format ` ``meta`` member of the ``fmt`` union as needed per the desired operation. Both drivers and applications must set the remainder of the :ref:`v4l2_format ` structure to 0. > >> +FourCC code of the desired format, and ``buffersize`` set by drivers to > >> the > >> +maximum buffer size (in bytes) required for data transfer. > >> + > >> +.. _v4l2-meta-format: > >> +.. flat-table:: struct v4l2_meta_format > >> +:header-rows: 0 > >> +:stub-columns: 0 > >> +:widths: 1 1 2 > >> + > >> +* - __u32 > >> + - ``dataformat`` > >> + - The data format, set by the application. This is a little > >> endian > >> +:ref:`four character code `. V4L2 defines metadata > >> formats > >> +
Re: [PATCH v2 1/4] v4l: Add metadata buffer type and format
Hi Sakari, On Monday 29 Aug 2016 12:13:40 Sakari Ailus wrote: > On Wed, Aug 17, 2016 at 03:20:27PM +0300, Laurent Pinchart wrote: > > The metadata buffer type is used to transfer metadata between userspace > > and kernelspace through a V4L2 buffers queue. It comes with a new > > metadata capture capability and format description. > > > > Signed-off-by: Laurent Pinchart > > > > Tested-by: Guennadi Liakhovetski > > --- > > Changes since v1: > > > > - Rebased on top of the DocBook to reST conversion > > > > Documentation/media/uapi/v4l/buffer.rst | 8 +++ > > Documentation/media/uapi/v4l/dev-meta.rst| 69 +++ > > Documentation/media/uapi/v4l/devices.rst | 1 + > > Documentation/media/uapi/v4l/vidioc-querycap.rst | 14 +++-- > > Documentation/media/videodev2.h.rst.exceptions | 2 + > > drivers/media/v4l2-core/v4l2-compat-ioctl32.c| 19 +++ > > drivers/media/v4l2-core/v4l2-dev.c | 16 +++--- > > drivers/media/v4l2-core/v4l2-ioctl.c | 41 ++ > > drivers/media/v4l2-core/videobuf2-v4l2.c | 3 ++ > > include/media/v4l2-ioctl.h | 17 ++ > > include/uapi/linux/videodev2.h | 14 + > > 11 files changed, 195 insertions(+), 9 deletions(-) > > create mode 100644 Documentation/media/uapi/v4l/dev-meta.rst [snip] > > diff --git a/Documentation/media/uapi/v4l/dev-meta.rst > > b/Documentation/media/uapi/v4l/dev-meta.rst new file mode 100644 > > index ..252ed05b4841 > > --- /dev/null > > +++ b/Documentation/media/uapi/v4l/dev-meta.rst > > @@ -0,0 +1,69 @@ > > +.. -*- coding: utf-8; mode: rst -*- > > + > > +.. _metadata: > > + > > +** > > +Metadata Interface > > +** > > + > > +Metadata refers to any non-image data that supplements video frames with > > +additional information. This may include statistics computed over the > > image +or frame capture parameters supplied by the image source. This > > interface is +intended for transfer of metadata to userspace and control > > of that operation. + > > +The metadata interface is implemented on video capture device nodes. The > > device +can be dedicated to metadata or can implement both video and > > metadata capture +as specified in its reported capabilities. > > + > > +.. note:: > > + > > +This is an :ref:`experimental` interface and may > > +change in the future. > > + > > +Querying Capabilities > > += > > + > > +Device nodes supporting the metadata interface set the > > ``V4L2_CAP_META_CAPTURE`` +flag in the ``device_caps`` field of the > > +:ref:`v4l2_capability ` structure returned by the > > +:ref:`VIDIOC_QUERYCAP` ioctl. That flag means the device can capture > > +metadata to memory. > > + > > +At least one of the read/write or streaming I/O methods must be > > supported. > > + > > + > > +Data Format Negotiation > > +=== > > + > > +The metadata device uses the :ref:`format` ioctls to select the capture > > format. +The metadata buffer content format is bound to that selected > > format. In addition +to the basic :ref:`format` ioctls, the > > :ref:`VIDIOC_ENUM_FMT` ioctl must be +supported as well. > > + > > +To use the :ref:`format` ioctls applications set the ``type`` of the > > +:ref:`v4l2_format ` structure to > > ``V4L2_BUF_TYPE_META_CAPTURE`` +and use the :ref:`v4l2_meta_format > > ` ``meta`` member of the +``fmt`` union as needed per > > the desired operation. The :ref:`v4l2-meta-format` +structure contains > > two fields, ``dataformat`` is set by applications to the V4L2 > > I might not specify the number of number of fields here. It has high chances > of not getting updated when more fields are added. Up to you. This has been copied from dev-sdr.rst. I can drop the last sentence completely as the parameters are described in the table below. Hans, any opinion ? > > +FourCC code of the desired format, and ``buffersize`` set by drivers to > > the +maximum buffer size (in bytes) required for data transfer. > > + > > +.. _v4l2-meta-format: > > +.. flat-table:: struct v4l2_meta_format > > +:header-rows: 0 > > +:stub-columns: 0 > > +:widths: 1 1 2 > > + > > +* - __u32 > > + - ``dataformat`` > > + - The data format, set by the application. This is a little endian > > +:ref:`four character code `. V4L2 defines metadata > > formats +in :ref:`meta-formats`. > > +* - __u32 > > + - ``buffersize`` > > + - Maximum buffer size in bytes required for data. The value is set > > by the +driver. > > We'll need to add width and heigth as well but it could be done later on. Unless you have a use case you can upstream now for those fields we'll have to add them later. > > +* - __u8 > > + - ``reserved[24]`` > > + - This array is reserved for future extensions. Drivers and > > applications +must set it to zero. > > struct v4l2_pix_format has grown
Re: [PATCH v2 1/4] v4l: Add metadata buffer type and format
Hi Laurent, Thanks for the patchset! On Wed, Aug 17, 2016 at 03:20:27PM +0300, Laurent Pinchart wrote: > The metadata buffer type is used to transfer metadata between userspace > and kernelspace through a V4L2 buffers queue. It comes with a new > metadata capture capability and format description. > > Signed-off-by: Laurent Pinchart > Tested-by: Guennadi Liakhovetski > --- > Changes since v1: > > - Rebased on top of the DocBook to reST conversion > > Documentation/media/uapi/v4l/buffer.rst | 8 +++ > Documentation/media/uapi/v4l/dev-meta.rst| 69 > > Documentation/media/uapi/v4l/devices.rst | 1 + > Documentation/media/uapi/v4l/vidioc-querycap.rst | 14 +++-- > Documentation/media/videodev2.h.rst.exceptions | 2 + > drivers/media/v4l2-core/v4l2-compat-ioctl32.c| 19 +++ > drivers/media/v4l2-core/v4l2-dev.c | 16 +++--- > drivers/media/v4l2-core/v4l2-ioctl.c | 41 ++ > drivers/media/v4l2-core/videobuf2-v4l2.c | 3 ++ > include/media/v4l2-ioctl.h | 17 ++ > include/uapi/linux/videodev2.h | 14 + > 11 files changed, 195 insertions(+), 9 deletions(-) > create mode 100644 Documentation/media/uapi/v4l/dev-meta.rst > > diff --git a/Documentation/media/uapi/v4l/buffer.rst > b/Documentation/media/uapi/v4l/buffer.rst > index 5deb4a46f992..b5177cc63b86 100644 > --- a/Documentation/media/uapi/v4l/buffer.rst > +++ b/Documentation/media/uapi/v4l/buffer.rst > @@ -499,6 +499,14 @@ enum v4l2_buf_type > - Buffer for Software Defined Radio (SDR) output stream, see > :ref:`sdr`. > > +- .. row 13 > + > + - ``V4L2_BUF_TYPE_META_CAPTURE`` > + > + - 13 > + > + - Buffer for metadata capture, see :ref:`metadata`. > + > > > .. _buffer-flags: > diff --git a/Documentation/media/uapi/v4l/dev-meta.rst > b/Documentation/media/uapi/v4l/dev-meta.rst > new file mode 100644 > index ..252ed05b4841 > --- /dev/null > +++ b/Documentation/media/uapi/v4l/dev-meta.rst > @@ -0,0 +1,69 @@ > +.. -*- coding: utf-8; mode: rst -*- > + > +.. _metadata: > + > +** > +Metadata Interface > +** > + > +Metadata refers to any non-image data that supplements video frames with > +additional information. This may include statistics computed over the image > +or frame capture parameters supplied by the image source. This interface is > +intended for transfer of metadata to userspace and control of that operation. > + > +The metadata interface is implemented on video capture device nodes. The > device > +can be dedicated to metadata or can implement both video and metadata capture > +as specified in its reported capabilities. > + > +.. note:: > + > +This is an :ref:`experimental` interface and may > +change in the future. > + > +Querying Capabilities > += > + > +Device nodes supporting the metadata interface set the > ``V4L2_CAP_META_CAPTURE`` > +flag in the ``device_caps`` field of the > +:ref:`v4l2_capability ` structure returned by the > +:ref:`VIDIOC_QUERYCAP` ioctl. That flag means the device can capture > +metadata to memory. > + > +At least one of the read/write or streaming I/O methods must be supported. > + > + > +Data Format Negotiation > +=== > + > +The metadata device uses the :ref:`format` ioctls to select the capture > format. > +The metadata buffer content format is bound to that selected format. In > addition > +to the basic :ref:`format` ioctls, the :ref:`VIDIOC_ENUM_FMT` ioctl must be > +supported as well. > + > +To use the :ref:`format` ioctls applications set the ``type`` of the > +:ref:`v4l2_format ` structure to ``V4L2_BUF_TYPE_META_CAPTURE`` > +and use the :ref:`v4l2_meta_format ` ``meta`` member of the > +``fmt`` union as needed per the desired operation. The > :ref:`v4l2-meta-format` > +structure contains two fields, ``dataformat`` is set by applications to the > V4L2 I might not specify the number of number of fields here. It has high chances of not getting updated when more fields are added. Up to you. > +FourCC code of the desired format, and ``buffersize`` set by drivers to the > +maximum buffer size (in bytes) required for data transfer. > + > +.. _v4l2-meta-format: > +.. flat-table:: struct v4l2_meta_format > +:header-rows: 0 > +:stub-columns: 0 > +:widths: 1 1 2 > + > +* - __u32 > + - ``dataformat`` > + - The data format, set by the application. This is a little endian > +:ref:`four character code `. V4L2 defines metadata > formats > +in :ref:`meta-formats`. > +* - __u32 > + - ``buffersize`` > + - Maximum buffer size in bytes required for data. The value is set by > the > +driver. We'll need to add width and heigth as well but it could be done later on. > +* - __u8 > + - ``reserved[24]`` > + - This array is reserved for future extens
