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Edge blanking (often called "edge noise") is actually part of the video signal outside the image area. Depending on your capture card and system configuration, various amounts of this black area may be captured. This is normal, but you generally should remove these black edges.
When you activate cropping, you have two options: manual cropping (with or without constraints) and numeric cropping.
The Video tab allows you to specify how you want to crop, scale, and filter your video image, as well as attach or create color palettes.
Select the desired constraints, then simply click and drag on the Source Movie window to create your cropping rectangle. While you are cropping, the dimensions of your cropping rectangle show up in the Status Bar. To remove a cropping rectangle, click without dragging.
Depending on the options you select, the rectangle may be constrained as follows:
Aspect Ratio
To keep the cropping rectangle the same ratio as the output movie, mark the
"Aspect Ratio" box. When you click and drag on
the Source Movie window, the cropping rectangle will be the same proportions as what
is specified in the scaling subsection for the output movie. This is very handy if you
are trying to remove the vertical edge blanking (the black areas around the image), but
don't want to distort the final image by making it too tall or wide.
Multiples of 4
You may check the "Multiples of 4" box
to constrain your cropping rectangle to multiples of 4 pixels in each direction. This
is useful if you are going to crop a movie and not scale it, because many codecs
are optimized for movies with both dimensions that are multiples of 4.
NOTE: Manual cropping only applies to
the specific movie on which you have clicked and dragged; other movies with that settings
group don't have a cropping rectangle defined
until you click and drag on each one. The
cropping rectangle is automatically saved with the
source movie for future use.
To numerically crop your movie, select "Numeric" from the pop-up at the top of the cropping subsection. Select the number of pixels that you would like removed from each edge. You can scroll through the movie with the QuickTime controls underneath the Source Movie to make sure the cropping is correct for the whole movie.
NOTE: You may distort your image with the Numeric cropping option if you don't crop proportional amounts from at least two sides. For example, if you want to remove 20 pixels from the left of a 4:3 aspect ratio movie, you should also crop 15 pixels from the top or bottom to maintain the same ratio.
If you have a large number of movies in a batch, it is often easier to numerically specify a cropping setting that works for all of them, rather than manually cropping each movie numeric cropping is great for automation.
NOTE: "Numeric" cropping will be
applied identically to each movie processed with a "Numeric" setting. Unlike "Manual"
cropping, "Numeric" is not specific to each movie - it is
a global setting, just like a Fade or Blur. If
you want to process several movies with identical settings, but need to crop each differently,
the "Manual" option is usually the best solution.
You can change the final size of your movie
with the scaling feature. You may select two
different methods to specify the final movie size, and
three different quality settings for this scaling. If
you want to leave the movie the same size as the cropping rectangle, just leave the checkbox
next to the Scale option unmarked.
The first pop-up controls how you specify the dimensions of the final movie.
Source
The "Source" scaling option scales the
movie to the same size as your source movie. This is very useful if you are using cropping
and scaling to remove edge noise, but want the final movie to be the same size as
the original.
Numeric
The "Numeric" scaling option allows you
to set the size of your output movie numerically. The source movie will be scaled up
or down to the size you specify.
NOTE: You may introduce distortion into
the image if you select a ratio that is not the
same ratio as the original, and you do not crop
your movie to compensate.
To avoid this distortion, manually crop the movie with the "Aspect Ratio" option
selected after you have set a numeric output size.
The resulting cropping rectangle will be the same proportions as the specified output size.
Fast
"Fast" scaling uses a nearest
neighbor method, and is useful for quick previews, especially on slower machines.
Normal
"Normal" scaling uses a sub-pixel
interpolated, bicubic method that is recommended for scaling your video up to a factor of
two (either up or down). For example, if your
source was 320x240 and your output was to be 240x180, this would be a good method
of scaling.
Accurate
"Accurate" scaling uses a
sine-algorithm method that gives significantly better
results than "Normal" when scaling greater than
two times (either up or down). For example, "Accurate" is a good choice if your source
is 640x480 and your output will be 240x180.
"Accurate" is noticeably slower than the "Normal" or "Fast" method, but is the highest quality scaling method. It tends to produce sharper images than the "Normal" method when the image is being scaled more than two times.
NOTE: You don't always need to use
"Accurate" if you are scaling 2x or less, "Normal" is
often just as good, and significantly faster.
If you are capturing full screen video, you may need to deinterlace your image to remove
the video's interlacing. If you are capturing
half screen video, you normally won't need to deinterlace the image. See
Appendix A for more details on deinterlacing, and what settings
are best for your content.
Even
The "Even" option removes every even line
of the original source, and interpolates the remaining odd lines to create new even lines.
This interpolation is done with the scaling option specified in the "Scaling Quality"
pop-up.
Odd
Not surprisingly, the "Odd" option
removes every odd line of the original source, and interpolates new ones from the even lines.
In every other way it is identical to "Even."
Blend
The "Blend" option blurs together the
odd and even fields to produce a smooth, combined field. This is very useful
to preserve the interlacing "motion blur" effect.
Fast motion will appear smoother with the "Blend" option, but not as sharp as with
an "Even" or "Odd" option. "Blend" is
currently the best way to deal with content that
was shot on film and then translated to video
see Appendix A for more details.
The blur filter reduces the detail in an image, and therefore minimizes subtle differences from frame to frame. Blurring the entire image may help improve both the temporal and spatial compression, and therefore improve the final image quality.
However, the blur filter is not generally as effective as the Adaptive Noise Reduction filter, and tends to make the image look "fuzzy." (The Adaptive Noise Reduction filter does not normally reduce the sharpness of the overall image.)
There are three levels of blur: "mild", "medium", and "extreme." Generally, for 320 x 240 movies "mild" or "medium" blurs are useful. For larger movies, "extreme" blurs may be more appropriate. Experiment to find the right setting for your particular movie and settings.
NOTE: In case you're curious,
Media Cleaner uses a Gaussian blur. Gaussian blurs
are "center weighted" and usually produce
smoother images than other types of blur filters.
The Adaptive Noise Reduction filter allows you to selectively identify and remove just the noise from your video source without noticeably blurring the rest of the image. It smoothes out "flat field" noise ("blotchy" areas), as well as removes "stray pixels," while leaving the detail sharp.
The Adaptive Noise Reduction filter actually analyzes each pixel relative to the surrounding pixels. What is neat about this technique is that it doesn't apply the same filter to every pixel - different filters are applied only to identified "problem" pixels, and the "normal" pixels are left unaltered. Thus, the noise is removed but the overall image is not degraded, so you get better looking compressed movies.
You may select one of several pre-configured settings or manually select the parameters for the noise reduction. Your Noise Reduction options are:
Flat areas
This options looks for pixels that are similar,
but not identical, to the surrounding areas, and makes them as identical as possible by applying
a "mean" filter. This is useful for areas that
are "blotchy" but should be smooth, such as
the background of titles, flat backdrops, etc.
This minimizes detail that is significant to codecs,
but not to human eyes, so your image compresses better without noticeable image degradation.
This option normally makes the biggest difference in improving the compression of an image.
Stray pixels
Looks for single pixels that are
significantly different than those surrounding them
and replaces these stray pixels with the "most
typical" (median) surrounding pixel. This option
may eliminate very fine detail, such as highlights
in eyes, dots on "i" in your titles, etc.
You don't normally have stray pixels in your source movie unless your capture card introduces them. As such, you don't normally need to use this setting.
Flat & Stray
Uses both the "stray pixel" and "flat field"
noise reduction options above. This is a good setting
for video sources that suffer from both kinds of noise.
Custom
Allows you to manually specify what percentage difference between the center pixel and
the surrounding pixels defines each type of noise.
You may also control how many times the filter is
applied to the same image, as well as if the filter
is applied before or after the image has been resized.
See Appendix A for more details on how to
set the "Custom" option.
The Static Mask helps optimize movies with unchanging areas, such as a newscaster in front of a stationary background. It does this by compositing the defined areas of the first frame throughout the rest of the movie, thereby eliminating the video noise in areas that should be totally static.
Press the "Set" button in the Static Mask
section to specify the PICT image you wish to use for
the mask. For more details on using the Static
mask, including creating mask images, please see
Appendix A.
Media Cleaner allows you to create custom palettes to be associated with your movies, use
a common default palette (such as Navigator, Win 95, etc.), or attach existing palettes from
still images or movies. Attaching custom palettes
to movies is often a good idea if they may be
viewed on a 256 color monitor. Custom palettes
are especially important for web movies, given the
wide range of computers that will be used to view
them.
NOTE: Not all applications are aware of attached palettes, but some (like MoviePlayer) will use them.
To attach a palette to a movie, simply check the box next to the "Palette" option. A pop-up will appear that allows you to set standard default palettes (such as Netscape Navigator), as well as copy a palette from the original source movie or from a different source.
You can also create a new palette based on the actual movie. Creating a new palette often gives better results than using a standard palette, because this "custom" palette is specifically created to best represent the colors in your movie. Standard palettes were designed to represent a very wide range of colors, some of which may not be present in your movie.
If you wish to create a new palette, you may select how many colors it will contain.
NOTE: Attaching a palette to a movie does not reduce the movie to 256 colors. Instead, this feature leaves the image in whatever bit depth you select in the Compress dialog, but provides a palette as a "backup" in case your viewer only has a 256 color monitor. If you don't attach a palette to a movie, and your viewer has a 256 color monitor, the movie will be displayed in the system palette, which is usually not ideal.
For example, if you made a Millions of Colors Cinepak movie and attached a custom palette to it, this movie would be viewed in Millions of Colors on monitors that support that bit depth, and viewed with your special palette on monitors that only support 256 colors.
There is no harm in associating a palette with
a movie, so you should normally choose this option.