offline-transducer-decoder.h
1.5 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
// sherpa-onnx/csrc/offline-transducer-decoder.h
//
// Copyright (c) 2023 Xiaomi Corporation
#ifndef SHERPA_ONNX_CSRC_OFFLINE_TRANSDUCER_DECODER_H_
#define SHERPA_ONNX_CSRC_OFFLINE_TRANSDUCER_DECODER_H_
#include <vector>
#include "onnxruntime_cxx_api.h" // NOLINT
#include "sherpa-onnx/csrc/offline-stream.h"
namespace sherpa_onnx {
struct OfflineTransducerDecoderResult {
/// The decoded token IDs
std::vector<int64_t> tokens;
/// timestamps[i] contains the output frame index where tokens[i] is decoded.
/// Note: The index is after subsampling
std::vector<int32_t> timestamps;
/// durations[i] contains the duration for tokens[i] in output frames
/// (post-subsampling). It is converted to seconds by higher layers
/// (e.g., Convert() in offline-recognizer-transducer-impl.h).
std::vector<float> durations;
};
class OfflineTransducerDecoder {
public:
virtual ~OfflineTransducerDecoder() = default;
/** Run transducer beam search given the output from the encoder model.
*
* @param encoder_out A 3-D tensor of shape (N, T, joiner_dim)
* @param encoder_out_length A 1-D tensor of shape (N,) containing number
* of valid frames in encoder_out before padding.
*
* @return Return a vector of size `N` containing the decoded results.
*/
virtual std::vector<OfflineTransducerDecoderResult> Decode(
Ort::Value encoder_out, Ort::Value encoder_out_length,
OfflineStream **ss = nullptr, int32_t n = 0) = 0;
};
} // namespace sherpa_onnx
#endif // SHERPA_ONNX_CSRC_OFFLINE_TRANSDUCER_DECODER_H_