COMPRO Y-C User manual

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Compro
Y/C Separation
User’s Guide
Introduction
Compro has always focused on developing products with great picture quality. Some
VideoMate TV models now feature Y/C Separation and digital noise reduction hardware for
unprecedented quality. This manual tells you how to optimize the Y/C separation settings to
the type of TV programs you care most about.
Y/C Separation
Television signals actually contain two signals, Luminance and Chrominance. By convention,
Y represents Luminance and C represents Chrominance. The Y signal describes the
brightness of the picture and C represents the color information. Black and white TV signals
contain only the Y signal. When color TV was introduced many years ago, the Y and C
signals were combined into a composite video signal. This has the advantages of being
compatible with black and white TV set and using less bandwidth. All TV sets must separate
the Y and C signals before presenting a picture.
This is analogous to using a glass prism to separate colors from a beam of white light.
Composite video
or TV signal
Luminance
(brightness)
Chrominance
(color)
Y/C separation

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The disadvantage of this scheme is that it is impossible to perfectly separate the Y and C
signals. If part of the Y signal is treated as C signal, the picture will show rainbow-like color
pattern as known as the Cross-Color Artifact phenomenon. If part of the C signal is treated
as Y signal, the picture will show the vertical or horizontal dot lines color as known as the
Cross-Luminance phenomenon. [Examples are shown later in this guide.]
In other words, better separation of the Y and C signals results in a clearer, sharper picture
with brighter and more accurate color.
Benefits of Y/C Separation
Incomplete separation of the Y and C signals results in Cross-Color Artifact and
Cross-Luminance phenomena. Scientists developed many algorithms trying to solve these
problems. Among them, 2D and 3D Y/C separation algorithms have been widely adopted.
These algorithms are superior to the simple comb filters found on most TV sets today.
Some versions of VideoMate TV incorporate the Y/C separation chip to process Y/C
separation and noise reduction. The chip provides 2D Y/C separation, Digital Noise
Reduction (DNR), and 3D Y/C separation calculations in hardware, greatly reducing
Cross-Color Artifacts and Cross-Luminance problems. Combined with the deinterlacing
technology in ComproPVR, you can enjoy crystal clear video and less eyestrain, giving you
greater enjoyment of TV programs.
Different algorithms are optimal for different types of TV programs, for example, action,
news, or drama shows. 2D Y/C separation, for example, has the side effect of turning
oblique lines into hanging dots while 3D algorithms can cause blurring in action videos.
VideoMate TV can automatically choose the optimal algorithm or you can select the Y/C
separation algorithm that you prefer.
Note
In S-Video, the Y and C signals are already separated and VideoMate TV will automatically
apply noise reduction for better picture quality.
3D Y/C separation algorithm is only available in NTSC system. 2D algorithm and noise
reduction function will automatically be used in PAL system.
Using the Y/C Separation program
Compro Y/C Separation program provides three preset profiles that let you quickly adjust
the picture to your preferences without knowing the details of Y/C separation. Additionally,
TV enthusiasts can configure the Y/C separation settings, in minute detail, to achieve
ultimate picture quality.

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Note
Compro Y/C Separation program is both a standalone program and part of the ComproPVR
setup dialogs.
The primary dialog in the program lets you choose one of three preset profiles or choose to
enter the custom settings dialog.
TV Mode
This is the standard mode. In this mode, the appropriate Y/C separation algorithm is
automatically selected. This is a good setting for most people.

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Noise Reduction Mode
This setting enables 2D Y/C separation and noise reduction modes. Choose this setting if
your TV signal contains is weak or the program contains lots of motion. This mode is
recommended for sports and action programs.
Detail Mode
This mode enables the 3D Y/C separation algorithm. This mode gives you crystal clear text
and beautiful color on videos with little motion and complex scenes. This mode is
recommended when you have a strong video signal and are watching programs with lots of
detail, such as financial programs or news. However, 3D Y/C separation algorithm is only
available in NTSC system.
Custom Mode
The video enthusiast can control every nuance of the Y/C separation chip in Custom Mode.
When you choose this mode, a dialog window will appear and let you fine tune to your
satisfaction. The graph in middle is updated as you move the slider bars so you can better
understand the effects of your adjustments. Pressing the Default button restores the settings
in this dialog, so feel free to explore and experiment.
First, select your desired “Y/C Separation Mode.” Then you can fine-tune the parameters
relating to the selected mode.

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Y/C Separation Mode
First, you must choose among the three modes.
2D+3D Mode: This is the same as “TV Mode” described above. Selecting this mode lets you
adjust when the Y/C separation chip switches between 2D and 3D separation modes.
3D Only Mode: This is the same as “Detail Mode” described above. Choosing this mode
sets VideoMate TV to use 3D Y/C separation only. Here, you can adjust the Motion
Detection Threshold.
2D+Noise Reduction Mode: This is the same as “Noise Reduction Mode” described above.
Here, you can adjust the Noise Reduction Threshold.
Note
Here, “noise” is defined as the ratio of changing luminance or chrominance signal strength.
This kind noise may not be visible to the naked eye.
3D Y/C separation algorithm is only available in NTSC system.
Y and C Signal Settings
Regardless of which mode you choose, you can always adjust the Y Signal Output
Correction and C Signal Delay settings, which fine-tune how the signals are separated.
Y Signal Output Correction
Use Y Signal Correction: Checking this box lets you modify the Y signal output correction
algorithm. You can adjust the following two parameters to have better result on the video. If
not checked, default settings will be used.
Aperture Compensation Level: Adjusting aperture compensation level can sharpen the
edges of objects in the video. If set incorrectly, you may see unwanted shadows.
Y Peaking Filter: Adjusting Y peaking filter can brighten the picture in the video. If set
incorrectly, you may see darker pictures.
C Signal Delay
Depending on your local TV broadcaster, there are minute differences in the delay of C
signal relative to the Y signal. This adjustment lets you compensate for this difference. The
result will be more accurate separation of the Y and C signals.
Motion Detection Threshold
If you choose 2D+3D Mode in Y/C Separation Mode, VideoMate TV automatically switches
between 2D and 3D separation. Here, you can adjust when the transitions are made.

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DY: Adjusting this value will set the luminance change threshold for switching modes.
DC: Adjusting this value will set the chrominance change threshold for switching modes.
Noise Reduction Threshold
If you choose 2D+Noise Reduction Mode in Y/C Separation Mode, here you can change
when Noise Reduction Mode is activated.
Y Noise: Adjusting this value will set the luminance change threshold for activating Noise
Reduction Mode.
C Noise: Adjusting this value will set the chrominance change threshold for activating Noise
Reduction Mode.
Signal Status
Here are three fields to show signal status. No adjustments can be made here.
Noise Level: This field shows the ratio of normal signal and noise signal.
WCV-ID Decoding Result: This field shows if your TV signal includes WCV-ID. This ID
signal is used in Japan only. This information is not normally used by end-users.
ID-1Decoding Result: This field shows if your TV signal includes ID-1. This ID signal
depends on local TV provider. This information is not normally used by end-users.
Saving Your Settings
Changes made on this dialog do not take effect until you press the OK button.
After setting your choices, press OK will apply the parameters to process your video
immediately.
If you wish to use the default settings, press the Default button to reset the parameters.
Then press OK to apply the default settings immediately.
Press the Cancel button to undo any changes and return to the Y/C Separation tab page.
Benefits of Y/C Separation
The following page graphically explain the benefits of Y/C Separation. Please look closely.
These pictures were shot at the Taichung Scientific Museum in Taiwan.

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Without Y/C separation
In these pictures, the texts should be very clear and sharp. Without Y/C separation, however,
the text displays the Cross-Color Artifact phenomenon. Also, the line between the black and
white bars shows the vertical or horizontal dot lines color as known as the Cross-Luminance
phenomenon. This error is also avoided by the Y/C Separation process. Y/C Separation
returns sharpness to edges and clarifies text. You no longer need to suffer from blurry
pictures.
After Y/C separation

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Summary
The Y/C Separation process brings superior quality of video into your life. It eliminates
Cross-Color Artifacts and Cross-Luminance problems. When combined with ComproPVR
deinterlacing technology, you get sharper pictures with more vivid and accurate colors. Give
you eyes a treat and experiment a bit the Y/C separation settings.
Copyright © 2001-2004. Compro Technology, Inc. No part of this document may be copied
or reproduced in any form or by any means without the prior written consent of Compro
Technology, Inc.
Compro, VideoMate, Poladyne, Play with Power, and the Compro logo are trademarks of
Compro Technology, Inc. Other names and marks are trademarks of their respective
owners.
Compro makes no warranties with respect to this documentation and disclaims any implied
warranties of merchantability, quality, or fitness for any particular purpose. The information in
this document is subject to change without notice. Compro reserves the right to make
revisions to this publication without obligation to notify any person or entity of any such
changes.
Compro Technology, Inc.
Tel. [phone], Fax [phone]
3/F, No.12, Alley 6, Lane 45, Pao Shin Road
Hsintein City, Taipei, Taiwan.
www.comprousa.com
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