Voice cloning failed with 'Could not load libtorchcodec', whose message blames
FFmpeg and the torch version. It was neither: the CUDA build links against
NVIDIA Performance Primitives (libnppicc.so.12), torch does not use NPP, and
torchcodec arrives as a transitive dependency of f5-tts — so nothing ever
installed it.

Installing it is only half: torch preloads its own nvidia libs and NPP is not
among them, so the library sits in site-packages and the loader never looks
there. LD_LIBRARY_PATH covers the other half.

Verified in the built image: torch 2.11.0+cu128, torchcodec 0.11.1+cu128,
AudioDecoder imports. Two wrong theories preceded this — an FFmpeg major
mismatch and a torch/torchcodec ABI mismatch — both suggested by that error
message, and both disproved by loading each .so by hand with torch imported.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0182DhR1eFNPQyGmDrpHbedY