offline-stream.h
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// sherpa-onnx/csrc/offline-stream.h
//
// Copyright (c) 2023 Xiaomi Corporation
#ifndef SHERPA_ONNX_CSRC_OFFLINE_STREAM_H_
#define SHERPA_ONNX_CSRC_OFFLINE_STREAM_H_
#include <stdint.h>
#include <memory>
#include <string>
#include <vector>
#include "sherpa-onnx/csrc/parse-options.h"
namespace sherpa_onnx {
struct OfflineRecognitionResult {
// Recognition results.
// For English, it consists of space separated words.
// For Chinese, it consists of Chinese words without spaces.
std::string text;
// Decoded results at the token level.
// For instance, for BPE-based models it consists of a list of BPE tokens.
std::vector<std::string> tokens;
/// timestamps.size() == tokens.size()
/// timestamps[i] records the time in seconds when tokens[i] is decoded.
std::vector<float> timestamps;
};
struct OfflineFeatureExtractorConfig {
// Sampling rate used by the feature extractor. If it is different from
// the sampling rate of the input waveform, we will do resampling inside.
int32_t sampling_rate = 16000;
// Feature dimension
int32_t feature_dim = 80;
// Set internally by some models, e.g., paraformer
// This parameter is not exposed to users from the commandline
// If true, the feature extractor expects inputs to be normalized to
// the range [-1, 1].
// If false, we will multiply the inputs by 32768
bool normalize_samples = true;
std::string ToString() const;
void Register(ParseOptions *po);
};
class OfflineStream {
public:
explicit OfflineStream(const OfflineFeatureExtractorConfig &config = {});
~OfflineStream();
/**
@param sampling_rate The sampling_rate of the input waveform. If it does
not equal to config.sampling_rate, we will do
resampling inside.
@param waveform Pointer to a 1-D array of size n. It must be normalized to
the range [-1, 1].
@param n Number of entries in waveform
Caution: You can only invoke this function once so you have to input
all the samples at once
*/
void AcceptWaveform(int32_t sampling_rate, const float *waveform,
int32_t n) const;
/// Return feature dim of this extractor
int32_t FeatureDim() const;
// Get all the feature frames of this stream in a 1-D array, which is
// flattened from a 2-D array of shape (num_frames, feat_dim).
std::vector<float> GetFrames() const;
/** Set the recognition result for this stream. */
void SetResult(const OfflineRecognitionResult &r);
/** Get the recognition result of this stream */
const OfflineRecognitionResult &GetResult() const;
private:
class Impl;
std::unique_ptr<Impl> impl_;
};
} // namespace sherpa_onnx
#endif // SHERPA_ONNX_CSRC_OFFLINE_STREAM_H_