User`s guide

Digital Rapids TouchStream
Page 20
Temporal Noise Reduction
Temporal noise reduction is commonly used to remove low level noise such as
film grain, tape noise or noise caused by low lighting levels. Note that Temporal
Noise Reduction will only be used if hardware deinterlacing is enabled in the
project.
Temporal noise reduction compares images in sequence over a predetermined
period of time, blending the images between fields or frames. The theory is that
by blending data over time you can reduce the overall noise content of the
resulting image. Successive samples of the same scene are blended together
which will effectively cancel out the noise found in any individual frame. The
problem with typical noise reduction algorithms is that if there is any motion in the
individual scene you will get a motion blur (trails) artifact in the processed frame.
TouchStream uses a very advanced form of temporal noise processing called
motion adaptive 3D noise reduction. Motion adaptive 3D noise reduction
combines the information in multiple frames of video using the information
obtained from the motion adaptive de-interlacing in order to decide how much
processing is applied to each pixel in the final frame. Because each pixel is
calculated individually the result will be more precise noise reduction with less
motion blurring artifacts than would otherwise normally be possible.
The Temporal noise reduction can be adjusted using the slider, or by pressing
one of the three buttons (None, Optimal, Extreme) to move the slider to a pre-set
position.
Cropping
Cropping controls how much video is removed from the top, bottom, and sides of
the incoming video. Typical uses of cropping:
 remove the black areas which often surround a video image (known as
‗underscan‘)
 remove the letterbox black (the black bars above and below the image
found in letterboxed material) off a 4x3 input that will be encoded at 16x9
 crop the sides of a 16x9 input to fit a 4x3 encode session, provided the
production was done 4x3 safe
Keep in mind that when you remove lines from the video, you are not changing
the size that will be used by the video output. For example, if you crop 20 lines
from the height of your video, the picture will be ―stretched‖ to fit the size that was
specified as the video output size in the project. If you don‘t want this to happen,
you must also modify the project to reduce the vertical height of the output by 20
lines.