Simple RLE Compression | Handmade Hero Episode Guide

0:18Set the stage for the day

1:10Blackboard: RLE vs LZ

1:53Blackboard: On exploiting the properties of the data we want to compress

5:56Blackboard: Run-length Encoding

8:24Blackboard: Distinguishing between "literals" and "runs"

9:59Blackboard: Various formats developed by Electronic Arts: IFF, ILBM, PCX

11:53Blackboard: LZ (Lempel-Ziv) as a more heavy-duty form of compression

16:03Blackboard: Encoding an additional offset in LZ

20:07Blackboard: How LZ gives you RLE almost for free

25:50Blackboard: Replicating blocks

32:28Blackboard: Why LZ schemes use relative positioning, and choosing how many bits to allocate for the look-back distance

39:06Blackboard: LZ encoding

44:50Blackboard: Keeping a hash table and information of overlapping runs for the back catalogue

46:48Blackboard: Entropy encoding and backends, e.g. Huffman, Arithmetic, rANS / tANS

49:52Blackboard: Charting the frequency of values

53:10Blackboard: Huffman

1:01:21Blackboard: On the inefficiency, size-wise, of Huffman compared to Arithmetic

1:02:32"Please take it with a grain of salt, or even a cube of salt"^α

1:03:27Blackboard: rANS / tANS¹

1:06:43Determine to compress our art assets

1:08:16Save test_scene_layer_00.bmp as a png and compress it with 7zip for comparison

1:11:09simple_compressor.cpp: Setup the code to make an actual command-line compressor

1:14:56Run the compressor and view the documentation

1:15:16simple_compressor.cpp: Parse the Args

1:17:46simple_compressor.cpp: Introduce file_contents struct for ReadEntireFileIntoMemory() to return

1:20:39simple_compressor.cpp: Set up the call sites for Compress() and Decompress()

1:28:53simple_compressor.cpp: Introduce Compress(), Decompress() and Copy()

1:32:38Run the compressor on test1.hha

1:35:00simple_compressor.cpp: Introduce RLECompress() and RLEDecompress()

1:43:01simple_compressor.cpp: Implement RLEDecompress()

1:45:32simple_compressor.cpp: Enable RLECompress() to encode a run

1:51:33Run the compressor in the debugger

1:53:18simple_compressor.cpp: Make RLECompress() and RLEDecompress() more symmetric

1:54:59Step in to RLECompress() and inspect the values

1:58:20simple_compressor.cpp: Make RLECompress() correctly loop to the MAX_RUN_COUNT and compute the OutSize

1:59:41Run the compressor on test1.hha to find that it has output exactly the same size

2:01:08simple_compressor.cpp: Make Compress() use the MaxOutSize value, run the compressor on test1.hha and find that the output is much smaller

2:02:15Run the decompressor on test1.scp to find that it doesn't work at all

2:02:56simple_compressor.cpp: Correctly store the InFile.FileSize

2:05:02Step in to the compressor and inspect what it does

2:07:04Step in to the decompressor to find that it works fine, and diff the files it produced

2:08:39Run the compressor on intro_art.hha to see how it fares with that

2:10:34Q&A

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2:10:34Q&A

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2:10:34Q&A

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2:11:21Compress test1.hha and intro_art.hha with 7zip for comparison

2:12:38Miblo Awesome stuff! I hadn't been making the distinction between "literals" and "runs" in my thing. My test stuff has been just 0s and 1s, mind, so I was just storing the first Token and then the Counter values

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2:12:38Miblo Awesome stuff! I hadn't been making the distinction between "literals" and "runs" in my thing. My test stuff has been just 0s and 1s, mind, so I was just storing the first Token and then the Counter values

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2:12:38Miblo Awesome stuff! I hadn't been making the distinction between "literals" and "runs" in my thing. My test stuff has been just 0s and 1s, mind, so I was just storing the first Token and then the Counter values

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2:14:14magik603 Tomorrow you will show us what again?

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2:14:14magik603 Tomorrow you will show us what again?

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2:14:14magik603 Tomorrow you will show us what again?

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2:15:36ttbjm Are hardware image decompressors still a thing?

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2:15:36ttbjm Are hardware image decompressors still a thing?

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2:15:36ttbjm Are hardware image decompressors still a thing?

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2:22:54Conclude

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2:22:54Conclude

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2:22:54Conclude

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