User`s manual

38 ULTECH DV2000 User’s Manual
Ylo = (Y0 * 219) + 16 (final value 16 - 235)
Yhi = (Y1 * 219) + 16 (final value 16 - 235)
Clo = (CB * 112) + 128 (final value 16 - 240 centered around 128)
Chi = (CR * 112) + 128 (final value 16 - 240 centered around 128)
Alo = A0 (value = 0 to 255)
Ahi = A1 (value = 0 to 255)
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
next P
next L
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 Description Value
0 Vector Indicator 0x0FF1
1 Run Count 2 - 360
2 Run Value 0x0000-0xFFFF
Run Vector Insertion Rules
1. If a single instance of the vector indicator value (0x0FF1) appears in the data being
compressed then it is duplicated.
2. If a run of two or more instances of the vector indicator (0x0FF1) appears in the data
being compressed then a run vector is inserted indicating the count (run length) and
the value (in this case 0x0FF1).
3. If a run of three or more instances of the same value appears in the data then a run
vector is inserted indicating the count (run length) and the value.