ModuleNotFoundError: No module named 'av' in ComfyUI

If ComfyUI logs ModuleNotFoundError: No module named 'av', install the package av. The project is commonly known as PyAV, but the pip package and import name are both av.

This dependency commonly matters for video, audio, frame extraction, and media helper workflows. In a broken portable environment, it can also appear during core startup repair after Torch and model-stack packages have been restored.

In the SEO Lab portable repair chain, missing av appeared after torchsde was installed. Installing av exposed the next dependency, aiohttp.

.\python_embeded\python.exe -s -m pip show av
.\python_embeded\python.exe -s -m pip install "av>=14.2.0"
.\python_embeded\python.exe -s -c "import av; print(av.__version__)"
.\python_embeded\python.exe -s ComfyUI\main.py --windows-standalone-build

What The Log Looks Like

ModuleNotFoundError: No module named 'av'

If the traceback points into a video custom node, repair that workflow's environment. If it appears during portable startup repair, treat it as the next core dependency in the chain.

Quick Diagnosis

Step 1: Install AV / PyAV

Windows portable:

.\python_embeded\python.exe -s -m pip install "av>=14.2.0"

Manual venv:

python -m pip install "av>=14.2.0"

Step 2: Verify The Import

.\python_embeded\python.exe -s -c "import av; print(av.__version__)"

Manual venv:

python -c "import av; print(av.__version__)"

Step 3: Restart And Check The Next Failure

.\python_embeded\python.exe -s ComfyUI\main.py --windows-standalone-build

If your original issue was a video custom node, verify that node now imports. If you are repairing a broken portable environment, continue with the new first traceback.

What Not To Do

• do not search for a package named pyav first; the pip package is av
• do not install into system Python when ComfyUI uses python_embeded
• do not move video files or model files for a Python import error
• do not keep stacking media packages before checking whether av imports

Related Guides

• No module named 'torchsde' in ComfyUI
• No module named 'aiohttp' in ComfyUI
• Repair ComfyUI Portable Dependencies One Missing Module At A Time
• Fix No module named errors in ComfyUI
• ComfyUI Dependency Conflicts

Source References

• Windows portable SEO Lab repair, May 18, 2026: ModuleNotFoundError: No module named 'av' appeared after torchsde repair
• Same lab ComfyUI\requirements.txt: av>=14.2.0
• av on PyPI