deepfakes/faceswap · error · ValueError

An unexpected FFRuntimeError occurred: {ffe}

Error message

An unexpected FFRuntimeError occurred: {ffe}

What it means

Wrapper error around ffmpeg-python's FFRuntimeError: the ffmpeg subprocess run by effmpeg exited with a code other than 255 (255 is tolerated as the post-SIGINT status) and not via KeyboardInterrupt. The original FFRuntimeError is chained (`from ffe`), so the real ffmpeg stderr is embedded in the message.

Source

Thrown at tools/effmpeg/effmpeg.py:507

                items_to_check.append("input")
            elif i == "o":
                items_to_check.append("output")

        return all(getattr(self, i).fps is None for i in items_to_check)

    @staticmethod
    def __run_ffmpeg(exe=str(ffmpeg.FFMPEG_PATH), inputs=None, outputs=None):
        """Run ffmpeg"""
        logger.debug("Running ffmpeg: (exe: '%s', inputs: %s, outputs: %s", exe, inputs, outputs)
        ffm = FFmpeg(executable=exe, inputs=inputs, outputs=outputs)
        try:
            ffm.run(stderr=subprocess.STDOUT)
        except FFRuntimeError as ffe:
            # After receiving SIGINT ffmpeg has a 255 exit code
            if ffe.exit_code == 255:
                pass
            else:
                raise ValueError(f"An unexpected FFRuntimeError occurred: {ffe}") from ffe
        except KeyboardInterrupt:
            pass  # Do nothing if voluntary interruption
        logger.debug("ffmpeg finished")

    @staticmethod
    def __convert_fps(fps):
        """Convert to Frames per Second"""
        if "/" in fps:
            _fps = fps.split("/")
            retval = float(_fps[0]) / float(_fps[1])
        else:
            retval = float(fps)
        logger.debug(retval)
        return retval

    @staticmethod
    def __get_duration(start_time, end_time):
        """Get the duration"""

View on GitHub (pinned to f530cb7508)

Solutions

1. Read the tail of the message — it contains ffmpeg's own stderr; fix the reported cause (codec, path, filter).
2. Test the same operation manually with the ffmpeg CLI to reproduce and isolate.
3. For codec issues, install full ffmpeg builds (e.g. from johnvansickle static builds or distro ffmpeg-full) rather than minimal ones.
4. For path issues, create the output directory and check write permissions.

Example fix

# before: fails because output dir does not exist
python tools.py effmpeg -a rescale -i in.mp4 -o newdir/out.mp4

# after
mkdir -p newdir
python tools.py effmpeg -a rescale -i in.mp4 -o newdir/out.mp4

import os, shutil

def ffmpeg_ready(input_path: str, output_dir: str) -> bool:
    return (shutil.which("ffmpeg") is not None
            and os.path.exists(input_path)
            and os.path.isdir(output_dir))

from ffmpy import FFRuntimeError
try:
    run_ffmpeg_action(...)
except ValueError as err:
    if "FFRuntimeError" in str(err):
        # original ffmpeg stderr is embedded — surface it verbatim for diagnosis
        print("ffmpeg failed:", err)
        raise SystemExit(1) from err
    raise

When it happens

Trigger: Any effmpeg action where the ffmpeg binary fails: unsupported/missing codec, unreadable input file, unwritable output path, invalid filter string, or a broken ffmpeg install — ffm.run() raises FFRuntimeError and it is re-raised as ValueError.

Common situations: Converting to a codec not compiled into the distro ffmpeg; output directory missing or no write permission; input file truncated; ffmpeg not on PATH / FFMPEG_PATH pointing to the wrong binary.

Related errors

• The chosen action requires a directory as its input, but you
• The chosen action requires a video as its input, but you ent
• The chosen action requires a directory as its output, but yo
• The chosen action requires a video as its output, but you en
• The file chosen as the reference video is not a video, eithe

AI-assisted analysis of deepfakes/faceswap@f530cb7508 (2026-08-15). Data as JSON: /api/errors/fd76a9fddb9ff913. Report an issue: GitHub.