Add deflate compression and crushed PCM audio to .glif format#3
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farkasmark merged 7 commits intomainfrom Feb 21, 2026
Merged
Add deflate compression and crushed PCM audio to .glif format#3farkasmark merged 7 commits intomainfrom
farkasmark merged 7 commits intomainfrom
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Implement channel-separated (planar) encoding and zlib-based compression for .glif files. The encoder tries all codecs per frame and picks the smallest: raw, RLE, delta, delta+RLE, planar RLE, planar delta+RLE, macroblock delta, deflate, and delta+deflate. Key techniques: - Planar encoding: deinterleave [ch,r,g,b] into 4 byte planes before compression — groups similar data for better pattern matching - Macroblock skip map: 8x8 cell blocks with a bitmap to skip unchanged regions entirely - Deflate (via vendored miniz): LZ77+Huffman compression that handles high-entropy data where RLE fails completely On mk421.glif (213x44 grid, 4633 frames): 122.5 MB -> 61.3 MB (2.0x). The RLE-based codecs couldn't compress this content at all (every cell has unique char+color, producing length-1 runs), but deflate with planar pre-processing halves the file size. New frame types: DEFLATE (0x04), PLANAR_DELTA_RLE (0x05), PLANAR_RLE (0x06), BLOCK_DELTA (0x07), DELTA_DEFLATE (0x09). v1/v2 files remain readable (backward compatible).
Drop all RLE-based codecs (RLE, delta, delta_RLE, byte_RLE, planar_RLE, planar_delta_RLE, block_delta) and collapse v1/v2/v3 versioning into a single format version. The project hasn't been released, so there's no backward compatibility to maintain. Seven deflate-based frame types remain (even=keyframe, odd=P-frame): DEFLATE, DELTA_DEFLATE, FILTERED_DEFLATE, DELTA_FILTERED_DEFLATE, PALETTE_DEFLATE, PLANAR_DEFLATE, DELTA_PLANAR_DEFLATE. Clean renumber frame types starting from 0x00. Update docs and tests. 153 tests pass (down from 204 — removed legacy codec tests).
…hold) Two encoder-side preprocessing steps that push compression from ~2x to ~5x: - Color quantization: drop N LSBs per RGB channel (default 2 bits with --compress) - Temporal thresholding: snap cells with tiny color diffs to previous frame values Defaults to --quant 6 --threshold 4 when --compress is active (122MB → 32MB on hk421). Remove gzip outer compression from glif-embed.sh since .glif frames are already deflate-compressed internally. Rebuild WASM player for current codecs.
Downsample and quantize original audio to 8-bit unsigned PCM at a configurable sample rate (default 8kHz), deflate-compress, and append as a BLIP v2 section after video frames. Sounds retro/lo-fi while preserving speech and music. Negligible file size overhead (~1MB for 2.5 min at 8kHz 8-bit). Encoder (blip.c): linear-interpolation resampling, stereo downmix, s16→u8/u4 quantization, incremental feeding. Decoder (glif.c): mz_uncompress + 4-bit nibble unpacking. Legacy BLIP v1 sections skipped gracefully. Backwards compatible — old decoders stop after video frames and never see the audio section. Web playback: crushed PCM read from WASM HEAPU8, converted to float32 AudioBuffer, played via AudioBufferSourceNode synced to video. Speed changes update playbackRate. Toggle with A key. CLI: --audio, --audio-pcm, --audio-rate, --audio-depth flags.
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Summary
Test plan
make test— 185 tests pass across 12 modules🤖 Generated with Claude Code