calesthio/OpenMontage · error · ValueError

decoded {label} Data URI must be smaller than {max_bytes //

Error message

decoded {label} Data URI must be smaller than {max_bytes // (1024 * 1024)} MB

What it means

Error "decoded {label} Data URI must be smaller than {max_bytes // (1024 * 1024)} MB" thrown in calesthio/OpenMontage.

Source

Thrown at tools/video/seedance_ark.py:1120

        match = re.fullmatch(
            r"data:([a-z]+/[a-z0-9.+-]+);base64,([A-Za-z0-9+/=]+)",
            value,
            flags=re.IGNORECASE,
        )
        if not match:
            raise ValueError(
                f"{label} Data URI must use a supported MIME type and "
                "strict base64 encoding"
            )
        mime = match.group(1).lower()
        if mime not in set(suffix_to_mime.values()):
            raise ValueError(f"unsupported {label} Data URI MIME type: {mime}")
        try:
            decoded = base64.b64decode(match.group(2), validate=True)
        except (ValueError, binascii.Error) as exc:
            raise ValueError(f"invalid base64 in {label} Data URI") from exc
        if len(decoded) >= max_bytes:
            raise ValueError(
                f"decoded {label} Data URI must be smaller than "
                f"{max_bytes // (1024 * 1024)} MB"
            )
        return mime, decoded

    def _local_or_data_audio_duration(
        self, value: str, *, max_seconds: int = 15
    ) -> float | None:
        if value.startswith("data:"):
            mime, decoded = self._decode_data_uri(
                value,
                suffix_to_mime=self.AUDIO_SUFFIX_TO_MIME,
                max_bytes=self.MAX_AUDIO_BYTES,
                label="audio",
            )
            return self._probe_audio_bytes(decoded, mime, max_seconds=max_seconds)
        if self._is_remote_or_asset(value):
            return None

View on GitHub (pinned to 95e1c3d0ab)

Solutions

1. Reduce the decoded image size below the stated MB limit by resizing or recompressing before encoding.
2. Alternatively host the image at a URL and pass the URL instead of a Data URI.

When it happens

Trigger: The decoded bytes of a reference Data URI exceed the maximum allowed size in megabytes.

Common situations: See trigger scenarios.

AI-assisted analysis of calesthio/OpenMontage@95e1c3d0ab (2026-08-15). Data as JSON: /api/errors/c3cf6fc558f6e166. Report an issue: GitHub.