patch-torchcodec

Patch TorchCodec to use PyAV's bundled FFmpeg — one command, no system FFmpeg needed.

Problem

TorchCodec requires FFmpeg shared libraries (libavcodec.so.62, etc.), but installing FFmpeg system-wide can be complex and may cause version conflicts.

Solution

PyAV already bundles FFmpeg. patch-torchcodec patches TorchCodec's RPATH to find them — no environment variables needed!

Quick Start

pip install torchcodec          # install torchcodec (with PyTorch)
pip install patch-torchcodec    # install patcher (av & patchelf included)
patch-torchcodec                # patches RPATH — done!

That's it. TorchCodec now works:

from torchcodec.decoders import VideoDecoder  # ✓ just works

Command Line Options

patch-torchcodec               # Patch RPATH (default, recommended)
patch-torchcodec --env-only    # Symlinks only (requires LD_LIBRARY_PATH)
patch-torchcodec --status      # Check current setup status
patch-torchcodec --verify      # Verify TorchCodec works
patch-torchcodec --quiet       # Silent mode

Python API

from patch_torchcodec import setup_with_patchelf, verify_torchcodec, is_rpath_patched

# Patch RPATH (recommended) — persists across sessions
setup_with_patchelf(verbose=True)

# Verify
assert verify_torchcodec(require_env=False)

How It Works

1. Finds PyAV's bundled FFmpeg in site-packages/av.libs/
2. Creates symbolic links with standard names (e.g., libavcodec.so.62)
3. Patches TorchCodec's .so files with patchelf to include PyAV's library path in RPATH

Limitations

• Linux only (RPATH is Linux-specific)
• Same virtualenv: PyAV and TorchCodec must be in the same environment
• Re-run after reinstall: If you reinstall TorchCodec, run patch-torchcodec again

License

MIT