Difference between revisions of "Run-length encoding"
(→= Alterrnating black/white runs) |
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== Stack-run based ideas == | == Stack-run based ideas == | ||
| − | === | + | === Alternating runs and incompressible === |
00 - 0 | 00 - 0 | ||
11 - 1 | 11 - 1 | ||
| − | 10 - | + | 10 - 0 end |
| − | 01 - | + | 01 - 1 end |
| − | + | ||
=== Alternating black/white runs === | === Alternating black/white runs === | ||
00 - 0 | 00 - 0 | ||
Revision as of 00:30, 28 January 2011
Contents
Atari ST - Savage Paint - PAC compression
Single bit plane. The five most common bytes in the image was followed by a run length byte. It was simpler and gave higher a compression ratio than the run-length algorithm used in the .IFF format on the Amiga. The reason for using the 5 most common bytes was mainly because of the number of free registers in the MC68000 CPU.
Amiga - IFF - RLE compression
One or more bit planes. Runs longer than 2 bytes are encoded as -1 to -127 followed by the byte to be repeated (-n) + 1 times. Runs of different bytes are stored as 0 to 127 followed by n + 1 bytes of data. The byte code -128 is a no operation.
Head-On - BEAR3 compression
Indexed graphics, 8 bits per pixel. The range 0 to n was used by pixel data. The range n + 1 to 255 was the run lengths. Run-length = (byte - n) + 1. The main goals were fast, simple and compressible with ZIP for distribution.
Stack-run based ideas
Alternating runs and incompressible
00 - 0 11 - 1 10 - 0 end 01 - 1 end
Alternating black/white runs
00 - 0 11 - 1 10 - 0 end 01 - 1 end
