Ultech Corporation DV2000 User Manual page 38

38 ULTECH DV2000 User's Manual
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UYC Compression
The UYC RLE (Run Length Encoding) compression is used to compress lines of alpha, Y,
and C data. The compression is applied to only one line of one type of data (alpha, Y, or C)
at a time. The RLE compression converts runs of the same value to a three word vector. The
first word is the vector indicator value (0x0FF1). The next word after the vector indicator
value is the run count, and the third word is the run value.
Word
Run Vector Insertion Rules
1. If a single instance of the vector indicator value (0x0FF1) appears in the data being
2. If a run of two or more instances of the vector indicator (0x0FF1) appears in the data
3. If a run of three or more instances of the same value appears in the data then a run
Ylo = (Y0 * 219) + 16
Yhi = (Y1 * 219) + 16
Clo = (CB * 112) + 128
Chi = (CR * 112) + 128
Alo = A0
Ahi = A1
put Ylo and Yhi into Yarray for line L and pixel P/2
put Clo and Chi into Carray for line L and pixel P/2
put Alo and Ahi into Aarray for line L and pixel P/2
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Description
0 Vector Indicator
1 Run Count
2 Run Value
compressed then it is duplicated.
being compressed then a run vector is inserted indicating the count (run length) and
the value (in this case 0x0FF1).
vector is inserted indicating the count (run length) and the value.
(final value 16 - 235)
(final value 16 - 235)
(final value 16 - 240 centered around 128)
(final value 16 - 240 centered around 128)
(value = 0 to 255)
(value = 0 to 255)
Value
0x0FF1
2 - 360
0x0000-0xFFFF