Support package: pydub

[ppenna]

Summary

Add support for the pydub package in the Nanvix Python distribution.

Category

E - Subprocess-dependent

Prerequisites

fork/exec + ffmpeg

Notes

Audio processing library. Requires process management support.

[ada-x64]

Keeping pure-python label with caveat (per #169).

Re-audited under stricter criteria. pydub 0.25.1 ships only .py files and has a clean setuptools.setup(...) build with no extensions, but its core public API shells out to external ffmpeg/avconv (and ffprobe/ffplay) binaries via subprocess.Popen:

• AudioSegment.from_file — pydub/audio_segment.py:616
• AudioSegment.export — pydub/audio_segment.py:766, :963
• pydub.utils.mediainfo / mediainfo_json — pydub/utils.py:274, :334, :339
• pydub.playback.play — pydub/playback.py:16 (uses ffplay)

The encoder/prober is resolved by shutil.which("avconv"/"ffmpeg") in pydub/utils.py:160-199.

Why caveat rather than native-extension:

AudioSegment.from_wav, AudioSegment.from_raw, and export(..., format='wav') go through the stdlib wave / audioop modules and do not spawn an external process. So pydub remains importable and offers a real (if narrow) pure-Python subset for raw-PCM and WAV workflows.

⚠️ Strong caveat — what does NOT work without ffmpeg/avconv on the host:

• Loading any non-WAV format (from_file, from_mp3, from_ogg, from_flac, from_mp4, …)
• Exporting to any non-WAV format (export(format='mp3'/'ogg'/'flac'/...))
• mediainfo / mediainfo_json (these always shell out to ffprobe)
• pydub.playback.play (always shells out to ffplay)

There is no opt-out flag to keep pydub in pure-Python mode — the library will attempt ffmpeg whenever called on non-WAV input and raise CouldntDecodeError if the binary is absent. Downstream packagers using pydub on a Nanvix-style target should restrict themselves to WAV/raw-PCM I/O.

Source-audit details: /tmp/audit_pydub/research.md.