espnet2.asr.encoder.abs_look_ahead_encoder.AbsLookAheadEncoder

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class espnet2.asr.encoder.abs_look_ahead_encoder.AbsLookAheadEncoder(*args: Any, **kwargs: Any)

Bases: AbsEncoder

An encoder whose output may read a chosen number of future frames.

One set of weights serves every look-ahead from 0 (online: an output frame depends on the current and past input frames only) to max_look_ahead (offline). set_look_ahead chooses it, for training as for inference. A convolutional encoder implements it by switching off future kernel taps; a self-attention encoder can implement it by masking the attention to keys after t + look_ahead.

Initialize internal Module state, shared by both nn.Module and ScriptModule.

abstract property look_ahead : int

Current look-ahead, in input frames.

abstract property max_look_ahead : int

Largest look-ahead, in input frames.

abstractmethod set_look_ahead(frames: int)

Make each output frame t read input frames up to t + frames.

• Raises:ValueError – frames is negative, larger than max_look_ahead, or not reachable by this encoder.