macOS Opus Library Fix¶

Problem¶

On macOS (especially with Apple Silicon), ctypes.util.find_library('opus') fails to locate Homebrew's libopus even when installed:

Exception: Could not find Opus library. Make sure it is installed.

Root Cause¶

find_library() searches system paths only
Homebrew libs are in /opt/homebrew/lib (Apple Silicon) or /usr/local/lib (Intel)
SIP (System Integrity Protection) prevents DYLD_LIBRARY_PATH from working in most contexts

Solution¶

Patch opuslib to add Homebrew fallback paths:

File: .venv/lib/python3.11/site-packages/opuslib/api/__init__.py

lib_location = find_library('opus')

# Fallback for macOS Homebrew
if lib_location is None:
    import os
    homebrew_paths = ['/opt/homebrew/lib/libopus.dylib', '/usr/local/lib/libopus.dylib']
    for path in homebrew_paths:
        if os.path.exists(path):
            lib_location = path
            break

if lib_location is None:
    raise Exception('Could not find Opus library...')

Installation¶

# 1. Install Homebrew opus
brew install opus

# 2. Apply patch (automated script)
python scripts/patch_opuslib_macos.py

# 3. Verify
python -c "import opuslib; print('OK')"

Upstream¶

This workaround should be submitted as a PR to opuslib upstream: https://github.com/OnBeep/opuslib

Alternative Solutions¶

Install system-wide opus (requires sudo, not recommended)
Build wheels with bundled libopus (complex, maintenance burden)
Use PyOpus instead (different API, requires code changes)

Impact¶

Without this fix: - TX audio transcoding fails silently (transcoder=False) - Opus frames sent directly to IC-7610 → no modulation - RX audio works (no transcoding needed)

With this fix: - TX audio Opus→PCM16 transcoding works - IC-7610 receives correct PCM16 data - Modulation visible on waterfall