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| Home › Support › Breeze Help > "File formats: YUV" options dialog box
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This dialog allows you to specify parameters of YUV format file / stream.
For additional information about YUV formats please visit section FAQ
(Frequently Asked Questions) at the Breeze support web site
www.DiscoveryBiz.Net
The following options allow you to specify YUV file / stream:
"Data format" combo box
This combo box allows specifying YUV image format entirely.
If you know exactly the name of required format then you can select it from the
full list in this combo box.
The list of displayed YUV formats depends on the filter values selected in the
other combo boxes, placed under "Data format" combo box.
All available formats are displayed in the list when values of filters are set
to "Any" value. It means that YUV format is specified in general only.
To make specification more definite, filters have to be set to the concrete
values. As a result, a list of YUV formats displayed in the "Data format" combo
box becomes shorter. The more filters are set to the definite values, the more
precisely YUV format is defined.
"RGB-YUV conversion base" combo box
This combo box specifies an RGB-YUV conversion base.
Conversion base is defined, first of all, by the formulae coefficients. Breeze
supports major international standards specifying RGB - YUV conversion.
"YUV color components" combo box
This combo box specifies YUV color componets as they are defined in the
concrete YUV color spaces.
"Sub sampling ratio" combo box
This combo box specifies sub sampling ratio for chroma color components.
"Color planes" combo box
This combo box specifies a structure of color planes and how individual colors
of each pixel placed in the color planes.
There are two major variants, planar and interleaved. In the first variant data
describing a color component are saved in one continious array. For 3 color
components 3 color planes are used. In the second variant all color componets
describing one pixel are kept together, one after another. In this variant only
one inteleaved color plane is used.
"Progressive / Interlaced" combo box
This combo box specifies a frame scan structure.
Entire horizontal line of pixels is called image scan line. Hardware equipment
usually scans images line by line; in a whole scan line units. There are two
major variants of scanning image, progressive and interlaced.
In the progressive scan scheme an image is scanned entirely, line by line.
In the interlaced scheme an image is scanned in two stages, even and odd. At
the even stage all even lines of image are scanned; then at the odd stage all
odd lines are scanned. These two sub groups of scan lines are usually saved
separately. When image is restored for displaying to a user, scan lines from
the even and odd sub groups are joint in one image by the special procedure
called "deinterlacing"
"Bits per luma" combo box
This combo box specifies how many bits per luma color component is used to
represent data for one pixel.
"Bits per chroma" combo box
This combo box specifies how many bits per chroma color component is used to
represent data for one pixel.
"Data range" combo box
This combo box specifies the range of values used to represent luma and chroma
withing limits of minimum and maximum values.
For example, if 8 bits is reserved for luma and chroma color components, then
the minimum value is 0, and maximum value is 255. At the same time concrete YUV
format may require using more narrow range of values, for example 16 - 235 for
luma, 16 - 240 for both chromas.
"Sub sampling pattern" combo box
This combo box specifies a pattern of sub sampled chroma components.
"Single image in file" combo box
This combo box specifies how a sequence of YUV images is organized, as a one
file / stream with multiple images in it, or as a multiple file with the single
image in each file.
"Size of the image" group box
This group box allow you to specify size (resolution) of the YUV image.
"Resolution" combo box
This combo box allows you to make a selection from the list of major standard
resolutions, or to specify custom sizes of the image.
"Width" and "Height" edit boxes
These edit boxes allow you to specify width and height of the image if you have
selected a "custom resolution" in the "Resolution" combo box.
Remarks
YUV files / streams are specified by the following main parameters:
1. YUV image format itself:
• RGB - YUV conversion base (formulae coefficients)
• Type of YUV color components
• Sub sampling ratio
• Structure of color planes, planar or interleaved
• Frame scan structure, progressive or interlaced
• Luma bit depth
• Chroma bit depth
• Data range for each color component
• Sub sampling pattern
2. Size of YUV image, width and height
3. Number of images in file / stream, single or multiple).
What is YUV?
YUV color model imitates a human vision. Humans are able to recognize (discern)
the contents of a color RGB (Red / Green / Blue) image presented in the two
main forms, as an original RGB color image or as a gray (black / white) image.
Historically, YUV color space was developed to provide compatibility between
color and black /white analog television systems. YUV color image information
transmitted in the TV signal allows proper reproducing an image contents at the
both types of TV receivers, at the color TV sets as well as at the black /
white TV sets.
Term YUV itself is not defined precisely in the technical and scientific
literature. In general it designates a whole family of so called luminance /
chrominance color spaces. The best way to avoid ambiguity associated with the
term YUV is to refer to the concrete variant of YUV colors space well defined
in the internationally recognized standard documents.
YCbCr color space is defined in the ITU-R BT.601-5 and ITU-R BT.709-5 standards
of ITU (International Telecommunication Union). These documents define YCbCr as
a color space for digital television systems. These documents give concrete
definitions for coefficients of conversion between RGB and YCbCr color spaces,
for normalization and quantization of digital signals. A majority of parameters
defined for the digital YCbCr color space remains the same for the YPbPr color
space used in the analog television systems. YCbCr and YPbPr color spaces are
closely related.
Individual color components of YCbCr color space are luma Y, chroma Cb and
chroma Cr. Chroma Cb corresponds to the U color component, and chroma Cr
corresponds to the V component of a general YUV color space.
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