FFmpeg not found: test the executable in ComfyUI's process environment

Symptoms and scope

Determine whether the missing item is FFmpeg itself, an input file or an encoder. The appearance of ffmpeg in a log does not justify reinstalling the whole video stack.

Error fragments for search; IDs, values and filenames may vary:

ffmpeg not found
No such file or directory: 'ffmpeg'
ffmpeg

Source-supported context

VideoHelperSuite uses FFmpeg for media processing and advanced previews. Its current resolver first honors VHS_FORCE_FFMPEG_PATH; otherwise it considers imageio_ffmpeg, a system PATH candidate, and executable files in the process working directory, with VHS_USE_IMAGEIO_FFMPEG able to force the imageio candidate. When several candidates exist, the node scores them. A shell ffmpeg -version checks only that shell's PATH candidate; it does not identify the executable VHS selected. A file-not-found error also needs the actual failing path. VHS resolver Source 1 Source 2

Cases to distinguish

1. VHS resolves no usable FFmpeg candidate, or an explicit VHS_FORCE_FFMPEG_PATH points to a missing or unusable file.

2. A terminal, desktop app, virtual environment and container expose different PATH, working directory and VHS/imageio override settings; a terminal success may test another binary.

3. FFmpeg is found but rejects the media, codec or arguments at a later stage.

Diagnostic sequence

The sequence below is an editorial procedure based on the cited context, not a diagnosis already confirmed for your environment.

Step 1. Capture the full traceback/stderr and operation stage. Identify the path in the failure before assuming the missing file is FFmpeg rather than an input resource.

Step 2. Record the actual ComfyUI launch environment: VHS_FORCE_FFMPEG_PATH, VHS_USE_IMAGEIO_FFMPEG, PATH and working directory. Follow the installed VHS version's resolver to identify its selected executable, then run that exact path with -version; a separate terminal's ffmpeg -version only tests its PATH candidate.

Step 3. If no valid candidate is selected, use a trusted FFmpeg distribution or the supported VHS path override and restart the ComfyUI process after changing its launch environment. If FFmpeg starts but an encoder fails, inspect the selected binary's codec support instead of reinstalling blindly.

Step 4. Read and export a short known-good clip with the same node and launch conditions. Check both the exact selected binary and the output artifact; a version response alone does not prove encoding or input access.

Commands and request examples

Run these commands only after identifying the executable VHS selected. Replace ffmpeg with that exact path when it differs from the shell PATH candidate; these commands were not executed for your machine.

ffmpeg -version
ffmpeg -encoders

Completion check

The node invokes the selected executable and completes a small media read/export. A version check or encoder list alone does not prove the whole workflow or every format works.

Limitations and cautions

Avoid untrusted codec-repair executables. Python wrappers and the FFmpeg program are different components.

Original sources

• VideoHelperSuite README — checked 2026-09-26.
• Python errno — checked 2026-09-26.
• VideoHelperSuite FFmpeg resolver — checked 2026-09-26.

Source and English-language review: 2026-09-26. No site-run VHS process, media export or GPU test is claimed.

Related troubleshooting and guides

• Video export fails or plays incorrectly: check frames, encoding and audio separately
• VideoHelperSuite reference: frame loading, audio, composition and saved output