User Manual

Working with Color Spaces in HD Projects
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Setting the Project Format to Accommodate Variable Resolutions
Regardless of the project output format, you can still work with media of different frame sizes,
aspect ratios, and pixel aspect ratios in the same sequence. For example, you can mix SD 4:3,
HD 16:9, and 2K+ media formats. Your Avid editing application automatically resizes and
repositions these clips to match the project's format settings.
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The original media size, resolution and color properties are preserved in the metadata of the clip
in case the sequence needs to be conformed in other applications.
If you intend to output in multiple formats, e.g. broadcast in NTSC, PAL, and HD, then you can
edit your project format in the highest format which in this case would be HD. After outputting
to HD, you can then switch the project format to NTSC, and reformat and re-render any
necessary titles/effects before output. (See Mixing Frame Sizes and Aspect Ratios; Mixing
Frame Rates and Field Motion Types in the online help.)
Working with Color Spaces in HD Projects
In full HD projects, some Avid editing applications and Avid input/output hardware devices let
you work in either the YCbCr or the RGB color space. Your Avid editing application uses a
project’s color space setting to control how it displays video, processes most effects, and outputs
sequences.
RGB and YCbCr both separate colors into three channels, but they store color information
differently. When you choose which color space to work in, you need to take several factors into
consideration, including the color space of your media, your output needs, and your performance
expectations for your Avid editing application while editing.
The RGB color space is not available for 720p or NTSC/PAL SD projects.
Understanding the YCbCr Color Space
YCbCr performs better, but is of lesser quality.
YCbCr stores brightness (Y) separately from colors (Cb and Cr). Since humans are more
susceptible to changes in light than in color, YCbCr discards half the chrominance data
(one-third of the overall data) with little discernible difference to image quality. Media that uses
YCbCr takes up less disk space than media that uses RGB, and less bandwidth is required to play
it.
YCbCr is the only color space available for SD media, because SD requires lower bandwidths
and might need to maintain backwards compatibility with black-and-white displays. When you
only need SD output, you only need to work in the YCbCr color space.