From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001 From: root Date: Fri, 25 Dec 2015 04:40:36 +0000 Subject: initial_commit --- Documentation/DocBook/v4l/vidioc-enum-fmt.xml | 166 ++++++++++++++++++++++++++ 1 file changed, 166 insertions(+) create mode 100644 Documentation/DocBook/v4l/vidioc-enum-fmt.xml (limited to 'Documentation/DocBook/v4l/vidioc-enum-fmt.xml') diff --git a/Documentation/DocBook/v4l/vidioc-enum-fmt.xml b/Documentation/DocBook/v4l/vidioc-enum-fmt.xml new file mode 100644 index 00000000..71d373b6 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-enum-fmt.xml @@ -0,0 +1,166 @@ + + + ioctl VIDIOC_ENUM_FMT + &manvol; + + + + VIDIOC_ENUM_FMT + Enumerate image formats + + + + + + int ioctl + int fd + int request + struct v4l2_fmtdesc +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENUM_FMT + + + + argp + + + + + + + + + Description + + To enumerate image formats applications initialize the +type and index +field of &v4l2-fmtdesc; and call the +VIDIOC_ENUM_FMT ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL;. All formats are enumerable by beginning at index zero and +incrementing by one until EINVAL is +returned. + + + struct <structname>v4l2_fmtdesc</structname> + + &cs-str; + + + __u32 + index + Number of the format in the enumeration, set by +the application. This is in no way related to the +pixelformat field. + + + &v4l2-buf-type; + type + Type of the data stream, set by the application. +Only these types are valid here: +V4L2_BUF_TYPE_VIDEO_CAPTURE, +V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE, +V4L2_BUF_TYPE_VIDEO_OUTPUT, +V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE, +V4L2_BUF_TYPE_VIDEO_OVERLAY, and custom (driver +defined) types with code V4L2_BUF_TYPE_PRIVATE +and higher. + + + __u32 + flags + See + + + __u8 + description[32] + Description of the format, a NUL-terminated ASCII +string. This information is intended for the user, for example: "YUV +4:2:2". + + + __u32 + pixelformat + The image format identifier. This is a +four character code as computed by the v4l2_fourcc() +macro: + + + +#define v4l2_fourcc(a,b,c,d) (((__u32)(a)<<0)|((__u32)(b)<<8)|((__u32)(c)<<16)|((__u32)(d)<<24)) +Several image formats are already +defined by this specification in . Note these +codes are not the same as those used in the Windows world. + + + __u32 + reserved[4] + Reserved for future extensions. Drivers must set +the array to zero. + + + +
+ + + Image Format Description Flags + + &cs-def; + + + V4L2_FMT_FLAG_COMPRESSED + 0x0001 + This is a compressed format. + + + V4L2_FMT_FLAG_EMULATED + 0x0002 + This format is not native to the device but emulated +through software (usually libv4l2), where possible try to use a native format +instead for better performance. + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-fmtdesc; type +is not supported or the index is out of +bounds. + + + + + + + -- cgit v1.2.3