pco/pcodec is a high-performance lossless compression library specializing in numerical sequences (integers and floats). It implements a novel three-stage pipeline: mode selection (classic, dictionary, integer/float multiplier, float quantizer), delta encoding (consecutive, lookback, conv1), and binning with tANS entropy coding. The library achieves near-Shannon-entropy compression ratios, particularly for structured numeric data like time series, columnar store blocks, and scientific datasets. It provides multiple APIs: a core Rust crate (`pco`), Python bindings via PyO3 (`pcodec` on PyPI), Java bindings via JNI (`pco-jni` on Maven Central), a C API (`pco_c`), and a feature-rich CLI for compression, decompression, inspection, and benchmarking against many other codecs (zstd, snappy, parquet, blosc, etc.). The codebase includes a legacy predecessor (`quantile-compression/q_compress`) also maintained in the same workspace. The architecture is modular, with separate crates for bit I/O (`better_io`), type dispatch macros (`dtype_dispatch`), and extensive testing including format backward compatibility and corruption recovery. It is actively developed with CI pipelines for Rust, Python, and Java.
The GoPro CineForm SDK is a production-grade, wavelet-based video codec library (SMPTE VC-5 super-set) implementing the full CineForm compression pipeline: recursive spatial/temporal wavelet transforms, quantization with rate control, run-length + Huffman entropy coding, and tag/value bitstream framing. It exposes a layered architecture: a C core codec engine (Codec/), high-level EncoderSDK (with asynchronous encoder pools) and DecoderSDK (with thumbnail fast-paths and output format negotiation), plus supporting libraries for color space conversion and scaling (ConvertLib/), geometric mesh warping for GoPro lens correction (WarpLib/), and an Active Metadata engine handling 3D LUTs, CDL color corrections, and timecode. Both encoder and decoder C APIs (CFHD_OpenEncoder/CFHD_EncodeSample, CFHD_OpenDecoder/CFHD_DecodeSample) are the primary integration points, with TestCFHD and WaveletDemo as example tools. The codec is cross-platform (Windows, macOS, Linux) and built with CMake, with a GitHub Actions CI workflow. The codebase is mature and battle-tested in commercial video production, with heavy SIMD (MMX/SSE2) hand-optimization in the wavelet and color conversion paths. However, it carries significant technical debt: large monolithic translation units (e.g., ImageScaler.cpp, DemoasicFrames.cpp with thousands of lines), extensive #ifdef platform conditionals, large blocks of disabled #if 0 code, hardcoded debug paths, and dated SIMD (Pentium 3 MMX) that underutilizes modern AVX-512 hardware. Several latent bugs exist (e.g., a copy-paste index error in ScaleB64ARow), and the FSM/Huffman entropy tables (Common/table17.inc, table18.inc) are checked-in generated artifacts that may silently drift from their generator. Overall it is a strong, working codec with cleanly separable infrastructure components, but the surrounding code style shows its commercial origins and accumulated debt.