You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
PaddleSpeech/speechx/speechx/decoder/ctc_beam_search_decoder.h

73 lines
2.3 KiB

// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// used by deepspeech2
#pragma once
#include "decoder/ctc_beam_search_opt.h"
#include "decoder/ctc_decoders/path_trie.h"
#include "decoder/ctc_decoders/scorer.h"
#include "decoder/decoder_itf.h"
namespace ppspeech {
class CTCBeamSearch : public DecoderBase {
public:
explicit CTCBeamSearch(const CTCBeamSearchOptions& opts);
~CTCBeamSearch() {}
void InitDecoder();
void Reset();
void AdvanceDecode(
const std::shared_ptr<kaldi::DecodableInterface>& decodable);
void Decode(std::shared_ptr<kaldi::DecodableInterface> decodable);
std::string GetBestPath();
std::vector<std::pair<double, std::string>> GetNBestPath();
std::vector<std::pair<double, std::string>> GetNBestPath(int n);
std::string GetFinalBestPath();
std::string GetPartialResult() {
CHECK(false) << "Not implement.";
return {};
}
int DecodeLikelihoods(const std::vector<std::vector<BaseFloat>>& probs,
const std::vector<std::string>& nbest_words);
private:
void ResetPrefixes();
int32 SearchOneChar(const bool& full_beam,
const std::pair<size_t, BaseFloat>& log_prob_idx,
const BaseFloat& min_cutoff);
void CalculateApproxScore();
void LMRescore();
void AdvanceDecoding(const std::vector<std::vector<BaseFloat>>& probs);
CTCBeamSearchOptions opts_;
std::shared_ptr<Scorer> init_ext_scorer_; // todo separate later
std::vector<std::string> vocabulary_; // todo remove later
int space_id_;
std::shared_ptr<PathTrie> root_;
std::vector<PathTrie*> prefixes_;
DISALLOW_COPY_AND_ASSIGN(CTCBeamSearch);
};
} // namespace ppspeech