hpcaitech/Open-Sora · error · ValueError

shortcut {shortcut} is not supported for decoder project in

Error message

shortcut {shortcut} is not supported for decoder project in

What it means

The decoder project_in block supports only None and 'duplicating' shortcut modes. Any other shortcut value raises this ValueError when the Decoder is constructed.

Source

Thrown at opensora/models/dc_ae/models/dc_ae.py:333

    block = ConvLayer(
        in_channels=in_channels,
        out_channels=out_channels,
        kernel_size=3,
        stride=1,
        use_bias=True,
        norm=None,
        act_func=None,
        is_video=is_video,
    )
    if shortcut is None:
        pass
    elif shortcut == "duplicating":
        shortcut_block = ChannelDuplicatingPixelShuffleUpSampleLayer(
            in_channels=in_channels, out_channels=out_channels, factor=1
        )
        block = ResidualBlock(block, shortcut_block)
    else:
        raise ValueError(f"shortcut {shortcut} is not supported for decoder project in")
    return block


def build_decoder_project_out_block(
    in_channels: int,
    out_channels: int,
    factor: int,
    upsample_block_type: str,
    norm: Optional[str],
    act: Optional[str],
    is_video: bool,
):
    layers: list[nn.Module] = [
        build_norm(norm, in_channels),
        build_act(act),
    ]
    if factor == 1:
        layers.append(

View on GitHub (pinned to 7ad6a96a13)

Solutions

Set decoder project_in shortcut to null/None or 'duplicating'
Use an unmodified shipped config

Example fix

# before
shortcut: averaging   # decoder project_in
# after
shortcut: duplicating

Defensive patterns

Strategy: validation

Validate before calling

assert shortcut in (None, 'duplicating'), f'unsupported decoder project_in shortcut: {shortcut}'

Prevention

Validate shortcut per block kind
Use shipped configs

When it happens

Trigger: Setting decoder project_in shortcut to 'averaging', 'identity', or any string other than null/'duplicating' in the config.

Common situations: Mirroring encoder shortcut settings into the decoder; hand-modified configs.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

AI-assisted analysis of hpcaitech/Open-Sora@7ad6a96a13 (2026-08-28). Data as JSON: /api/errors/9ce747c3bfa8352a. Report an issue: GitHub.