Survey of Dirac: A Wavelet Based Video Codec for Multiparty Video Conferencing and Broadcasting - Intelligent Video Event Analysis and Understanding - page 217

Fig. 4 Dirac decoder architecture

5 Major Modules of Dirac

At this time, Dirac supports planar YUV format streams. YUV is a popular way of
representing color images. It separates the brightness information (Y) from the
color information (U and V). The Y component is a weighted average of the three
additive primaries - red, green and blue. The U component is the difference
between the blue primary and the Y component. The V component is the color
difference between the red primary and Y component. All three color primaries
can be reconstructed from the Y, U and V components. Because the human eye is
more sensitive to brightness than color, the chroma components generally are
recorded with fewer samples than the brightness data.
The supported YUV formats are:

Table 1 Different Supported Formats

Chroma
Format

YUV format Description

Planar 4:4:4 format. Full chroma resolution in both
vertical and horizontal directions.

format444

Planar 4:2:2 format. Full vertical chroma resolution
and 1/2 horizontal chroma resolution.

format422

format420 Planar 4:2:0 format. 1/2 chroma resolution in both
vertical and horizontal directions.
Dirac does not support any other input formats currently. The utility conversion
directory has a number of utilities to and from Dirac formats to other formats like
RGB and BMP.