2.1. Single-planar format structure¶
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v4l2_pix_format
¶
__u32 | width |
Image width in pixels. |
__u32 | height |
Image height in pixels. If field is one of V4L2_FIELD_TOP ,
V4L2_FIELD_BOTTOM or V4L2_FIELD_ALTERNATE then height
refers to the number of lines in the field, otherwise it refers to
the number of lines in the frame (which is twice the field height
for interlaced formats). |
Applications set these fields to request an image
size, drivers return the closest possible values. In case of
planar formats the width and height applies to the largest
plane. To avoid ambiguities drivers must return values rounded up
to a multiple of the scale factor of any smaller planes. For
example when the image format is YUV 4:2:0, width and
height must be multiples of two. |
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__u32 | pixelformat |
The pixel format or type of compression, set by the application. This is a little endian four character code. V4L2 defines standard RGB formats in Packed RGB Image Formats, YUV formats in YUV Formats, and reserved codes in Reserved Image Formats |
__u32 | field |
Field order, from enum v4l2_field .
Video images are typically interlaced. Applications can request to
capture or output only the top or bottom field, or both fields
interlaced or sequentially stored in one buffer or alternating in
separate buffers. Drivers return the actual field order selected.
For more details on fields see Field Order. |
__u32 | bytesperline |
Distance in bytes between the leftmost pixels in two adjacent lines. |
Both applications and drivers can set this field to request
padding bytes at the end of each line. Drivers however may ignore
the value requested by the application, returning Video hardware may access padding bytes, therefore they must reside in accessible memory. Consider cases where padding bytes after the last line of an image cross a system page boundary. Input devices may write padding bytes, the value is undefined. Output devices ignore the contents of padding bytes. When the image format is planar the For compressed formats the |
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__u32 | sizeimage |
Size in bytes of the buffer to hold a complete image, set by the
driver. Usually this is bytesperline times height . When
the image consists of variable length compressed data this is the
maximum number of bytes required to hold an image. |
__u32 | colorspace |
Image colorspace, from enum 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 Colorspaces. |
__u32 | priv |
This field indicates whether the remaining fields of the
struct Applications that wish to use the pixel format extended fields must first ensure that the feature is supported by querying the device for the V4L2_CAP_EXT_PIX_FORMAT capability. If the capability isn’t set the pixel format extended fields are not supported and using the extended fields will lead to undefined results. To use the extended fields, applications must set the When the |
__u32 | flags |
Flags set by the application or driver, see Format Flags. |
union { | (anonymous) | |
__u32 | ycbcr_enc |
Y’CbCr encoding, from enum 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 Colorspaces. |
__u32 | hsv_enc |
HSV encoding, from enum 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 Colorspaces. |
} | ||
__u32 | quantization |
Quantization range, from enum 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 Colorspaces. |
__u32 | xfer_func |
Transfer function, from enum 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 Colorspaces. |