Pydub is a mature, high-level Python library for audio manipulation. It provides an immutable `AudioSegment` class that supports slicing, concatenation, overlaying, gain changes, fading, and format conversion using ffmpeg/avconv as a backend for non-WAV formats. The library includes a variety of DSP effects (normalize, speedup, compression, filters, equalization), silence detection/splitting, signal generators (sine, square, sawtooth, white noise), and optional playback via simpleaudio, pyaudio, or ffplay. Its architecture is modular, with core functionality in `audio_segment.py` and effects registered via a decorator pattern. The codebase demonstrates clean abstractions and is well-tested, though it carries some legacy Python 2 compatibility patterns.
Pinkfish is a Python library for backtesting equity trading strategies, primarily used via Jupyter notebooks. It provides a modular framework with components for data fetching (Yahoo Finance via yfinance), trade logging, portfolio management, performance statistics, and signal generation. The core architecture revolves around a Strategy class pattern, a Portfolio class for multi-symbol backtesting, and a TradeLog class for simulating trade entries/exits with realistic open/close fills. The library includes a wide range of technical indicators (both custom and TA-Lib wrappers), comprehensive performance metrics (Sharpe, Sortino, drawdown, etc.), and support for signal notifications via Pushover/email. The codebase is well-structured with clear separation of concerns, but uses some global state in TradeLog and relies on a static stock market calendar, introducing minor maintenance risks. The examples cover diverse strategies such as momentum, moving average crossovers, and sector rotation, serving as both documentation and reusable templates.