From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001 From: root Date: Fri, 25 Dec 2015 04:40:36 +0000 Subject: initial_commit --- .../DocBook/v4l/vidioc-enum-framesizes.xml | 282 +++++++++++++++++++++ 1 file changed, 282 insertions(+) create mode 100644 Documentation/DocBook/v4l/vidioc-enum-framesizes.xml (limited to 'Documentation/DocBook/v4l/vidioc-enum-framesizes.xml') diff --git a/Documentation/DocBook/v4l/vidioc-enum-framesizes.xml b/Documentation/DocBook/v4l/vidioc-enum-framesizes.xml new file mode 100644 index 00000000..6afa4542 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-enum-framesizes.xml @@ -0,0 +1,282 @@ + + + + ioctl VIDIOC_ENUM_FRAMESIZES + &manvol; + + + + VIDIOC_ENUM_FRAMESIZES + Enumerate frame sizes + + + + + + int ioctl + int fd + int request + struct v4l2_frmsizeenum *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENUM_FRAMESIZES + + + + argp + + Pointer to a &v4l2-frmsizeenum; that contains an index +and pixel format and receives a frame width and height. + + + + + + + Description + + + Experimental + + This is an experimental +interface and may change in the future. + + + This ioctl allows applications to enumerate all frame sizes +(&ie; width and height in pixels) that the device supports for the +given pixel format. + The supported pixel formats can be obtained by using the +&VIDIOC-ENUM-FMT; function. + The return value and the content of the +v4l2_frmsizeenum.type field depend on the +type of frame sizes the device supports. Here are the semantics of the +function for the different cases: + + + + Discrete: The function +returns success if the given index value (zero-based) is valid. The +application should increase the index by one for each call until +EINVAL is returned. The +v4l2_frmsizeenum.type field is set to +V4L2_FRMSIZE_TYPE_DISCRETE by the driver. Of the +union only the discrete member is +valid. + + + Step-wise: The function +returns success if the given index value is zero and +EINVAL for any other index value. The +v4l2_frmsizeenum.type field is set to +V4L2_FRMSIZE_TYPE_STEPWISE by the driver. Of the +union only the stepwise member is +valid. + + + Continuous: This is a +special case of the step-wise type above. The function returns success +if the given index value is zero and EINVAL for +any other index value. The +v4l2_frmsizeenum.type field is set to +V4L2_FRMSIZE_TYPE_CONTINUOUS by the driver. Of +the union only the stepwise member is valid +and the step_width and +step_height values are set to 1. + + + + When the application calls the function with index zero, it +must check the type field to determine the +type of frame size enumeration the device supports. Only for the +V4L2_FRMSIZE_TYPE_DISCRETE type does it make +sense to increase the index value to receive more frame sizes. + Note that the order in which the frame sizes are returned +has no special meaning. In particular does it not say anything about +potential default format sizes. + Applications can assume that the enumeration data does not +change without any interaction from the application itself. This means +that the enumeration data is consistent if the application does not +perform any other ioctl calls while it runs the frame size +enumeration. + + + + Structs + + In the structs below, IN denotes a +value that has to be filled in by the application, +OUT denotes values that the driver fills in. The +application should zero out all members except for the +IN fields. + + + struct <structname>v4l2_frmsize_discrete</structname> + + &cs-str; + + + __u32 + width + Width of the frame [pixel]. + + + __u32 + height + Height of the frame [pixel]. + + + +
+ + + struct <structname>v4l2_frmsize_stepwise</structname> + + &cs-str; + + + __u32 + min_width + Minimum frame width [pixel]. + + + __u32 + max_width + Maximum frame width [pixel]. + + + __u32 + step_width + Frame width step size [pixel]. + + + __u32 + min_height + Minimum frame height [pixel]. + + + __u32 + max_height + Maximum frame height [pixel]. + + + __u32 + step_height + Frame height step size [pixel]. + + + +
+ + + struct <structname>v4l2_frmsizeenum</structname> + + + + + + + + __u32 + index + + IN: Index of the given frame size in the enumeration. + + + __u32 + pixel_format + + IN: Pixel format for which the frame sizes are enumerated. + + + __u32 + type + + OUT: Frame size type the device supports. + + + union + + + OUT: Frame size with the given index. + + + + &v4l2-frmsize-discrete; + discrete + + + + + &v4l2-frmsize-stepwise; + stepwise + + + + __u32 + reserved[2] + + Reserved space for future use. + + + +
+ + + + Enums + + + enum <structname>v4l2_frmsizetypes</structname> + + &cs-def; + + + V4L2_FRMSIZE_TYPE_DISCRETE + 1 + Discrete frame size. + + + V4L2_FRMSIZE_TYPE_CONTINUOUS + 2 + Continuous frame size. + + + V4L2_FRMSIZE_TYPE_STEPWISE + 3 + Step-wise defined frame size. + + + +
+ + + + &return-value; + + See the description section above for a list of return +values that errno can have. + + + + -- cgit v1.2.3