Add C++ and Python API for FireRedASR AED models (#1867)

@@ -133,3 +133,4 @@ lexicon.txt
 us_gold.json
 us_silver.json
 kokoro-multi-lang-v1_0
+sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16

+#!/usr/bin/env python3
+
+"""
+This file shows how to use a non-streaming FireRedAsr AED model from
+https://github.com/FireRedTeam/FireRedASR
+to decode files.
+
+Please download model files from
+https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+
+For instance,
+
+wget https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16.tar.bz2
+tar xvf sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16.tar.bz2
+rm sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16.tar.bz2
+"""
+
+from pathlib import Path
+
+import sherpa_onnx
+import soundfile as sf
+
+
+def create_recognizer():
+    encoder = "./sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16/encoder.int8.onnx"
+    decoder = "./sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16/decoder.int8.onnx"
+    tokens = "./sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16/tokens.txt"
+    test_wav = "./sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16/test_wavs/0.wav"
+    #  test_wav = "./sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16/test_wavs/1.wav"
+    #  test_wav = "./sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16/test_wavs/2.wav"
+    #  test_wav = "./sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16/test_wavs/3.wav"
+    #  test_wav = "./sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16/test_wavs/8k.wav"
+    #  test_wav = "./sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16/test_wavs/3-sichuan.wav"
+    #  test_wav = "./sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16/test_wavs/4-tianjin.wav"
+    #  test_wav = "./sherpa-onnx-fire-red-asr-large-zh_en-2025-02-16/test_wavs/5-henan.wav"
+
+    if (
+        not Path(encoder).is_file()
+        or not Path(decoder).is_file()
+        or not Path(test_wav).is_file()
+    ):
+        raise ValueError(
+            """Please download model files from
+            https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+            """
+        )
+    return (
+        sherpa_onnx.OfflineRecognizer.from_fire_red_asr(
+            encoder=encoder,
+            decoder=decoder,
+            tokens=tokens,
+            debug=True,
+        ),
+        test_wav,
+    )
+
+
+def main():
+    recognizer, wave_filename = create_recognizer()
+
+    audio, sample_rate = sf.read(wave_filename, dtype="float32", always_2d=True)
+    audio = audio[:, 0]  # only use the first channel
+
+    # audio is a 1-D float32 numpy array normalized to the range [-1, 1]
+    # sample_rate does not need to be 16000 Hz
+
+    stream = recognizer.create_stream()
+    stream.accept_waveform(sample_rate, audio)
+    recognizer.decode_stream(stream)
+    print(wave_filename)
+    print(stream.result)
+
+
+if __name__ == "__main__":
+    main()

@@ -27,6 +27,9 @@ set(sources
   offline-ctc-fst-decoder.cc
   offline-ctc-greedy-search-decoder.cc
   offline-ctc-model.cc
+  offline-fire-red-asr-greedy-search-decoder.cc
+  offline-fire-red-asr-model-config.cc
+  offline-fire-red-asr-model.cc
   offline-lm-config.cc
   offline-lm.cc
   offline-model-config.cc

+// sherpa-onnx/csrc/offline-fire-red-asr-decoder.h
+//
+// Copyright (c)  2025  Xiaomi Corporation
+
+#ifndef SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_DECODER_H_
+#define SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_DECODER_H_
+
+#include <cstdint>
+#include <vector>
+
+#include "onnxruntime_cxx_api.h"  // NOLINT
+
+namespace sherpa_onnx {
+
+struct OfflineFireRedAsrDecoderResult {
+  /// The decoded token IDs
+  std::vector<int32_t> tokens;
+};
+
+class OfflineFireRedAsrDecoder {
+ public:
+  virtual ~OfflineFireRedAsrDecoder() = default;
+
+  /** Run beam search given the output from the FireRedAsr encoder model.
+   *
+   * @param n_layer_cross_k       A 4-D tensor of shape
+   *                              (num_decoder_layers, N, T, d_model).
+   * @param n_layer_cross_v       A 4-D tensor of shape
+   *                              (num_decoder_layers, N, T, d_model).
+   *
+   * @return Return a vector of size `N` containing the decoded results.
+   */
+  virtual std::vector<OfflineFireRedAsrDecoderResult> Decode(
+      Ort::Value n_layer_cross_k, Ort::Value n_layer_cross_v) = 0;
+};
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_DECODER_H_

+// sherpa-onnx/csrc/offline-fire-red-asr-greedy-search-decoder.cc
+//
+// Copyright (c)  2025  Xiaomi Corporation
+
+#include "sherpa-onnx/csrc/offline-fire-red-asr-greedy-search-decoder.h"
+
+#include <algorithm>
+#include <tuple>
+#include <utility>
+
+#include "sherpa-onnx/csrc/macros.h"
+#include "sherpa-onnx/csrc/onnx-utils.h"
+
+namespace sherpa_onnx {
+
+// Note: this functions works only for batch size == 1 at present
+std::vector<OfflineFireRedAsrDecoderResult>
+OfflineFireRedAsrGreedySearchDecoder::Decode(Ort::Value cross_k,
+                                             Ort::Value cross_v) {
+  const auto &meta_data = model_->GetModelMetadata();
+
+  auto memory_info =
+      Ort::MemoryInfo::CreateCpu(OrtDeviceAllocator, OrtMemTypeDefault);
+
+  // For multilingual models, initial_tokens contains [sot, language, task]
+  //   - language is English by default
+  //   - task is transcribe by default
+  //
+  // For non-multilingual models, initial_tokens contains [sot]
+  std::array<int64_t, 2> token_shape = {1, 1};
+  int64_t token = meta_data.sos_id;
+
+  int32_t batch_size = 1;
+
+  Ort::Value tokens = Ort::Value::CreateTensor(
+      memory_info, &token, 1, token_shape.data(), token_shape.size());
+
+  std::array<int64_t, 1> offset_shape{1};
+  Ort::Value offset = Ort::Value::CreateTensor<int64_t>(
+      model_->Allocator(), offset_shape.data(), offset_shape.size());
+  *(offset.GetTensorMutableData<int64_t>()) = 0;
+
+  std::vector<OfflineFireRedAsrDecoderResult> ans(1);
+
+  auto self_kv_cache = model_->GetInitialSelfKVCache();
+
+  std::tuple<Ort::Value, Ort::Value, Ort::Value, Ort::Value, Ort::Value,
+             Ort::Value>
+      decoder_out = {Ort::Value{nullptr},
+                     std::move(self_kv_cache.first),
+                     std::move(self_kv_cache.second),
+                     std::move(cross_k),
+                     std::move(cross_v),
+                     std::move(offset)};
+
+  for (int32_t i = 0; i < meta_data.max_len; ++i) {
+    decoder_out = model_->ForwardDecoder(View(&tokens),
+                                         std::move(std::get<1>(decoder_out)),
+                                         std::move(std::get<2>(decoder_out)),
+                                         std::move(std::get<3>(decoder_out)),
+                                         std::move(std::get<4>(decoder_out)),
+                                         std::move(std::get<5>(decoder_out)));
+
+    const auto &logits = std::get<0>(decoder_out);
+    const float *p_logits = logits.GetTensorData<float>();
+
+    auto logits_shape = logits.GetTensorTypeAndShapeInfo().GetShape();
+    int32_t vocab_size = logits_shape[2];
+
+    int32_t max_token_id = static_cast<int32_t>(std::distance(
+        p_logits, std::max_element(p_logits, p_logits + vocab_size)));
+    if (max_token_id == meta_data.eos_id) {
+      break;
+    }
+
+    ans[0].tokens.push_back(max_token_id);
+
+    token = max_token_id;
+
+    // increment offset
+    *(std::get<5>(decoder_out).GetTensorMutableData<int64_t>()) += 1;
+  }
+
+  return ans;
+}
+
+}  // namespace sherpa_onnx

+// sherpa-onnx/csrc/offline-fire-red-asr-greedy-search-decoder.h
+//
+// Copyright (c)  2025  Xiaomi Corporation
+
+#ifndef SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_GREEDY_SEARCH_DECODER_H_
+#define SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_GREEDY_SEARCH_DECODER_H_
+
+#include <vector>
+
+#include "sherpa-onnx/csrc/offline-fire-red-asr-decoder.h"
+#include "sherpa-onnx/csrc/offline-fire-red-asr-model.h"
+
+namespace sherpa_onnx {
+
+class OfflineFireRedAsrGreedySearchDecoder : public OfflineFireRedAsrDecoder {
+ public:
+  explicit OfflineFireRedAsrGreedySearchDecoder(OfflineFireRedAsrModel *model)
+      : model_(model) {}
+
+  std::vector<OfflineFireRedAsrDecoderResult> Decode(
+      Ort::Value cross_k, Ort::Value cross_v) override;
+
+ private:
+  OfflineFireRedAsrModel *model_;  // not owned
+};
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_GREEDY_SEARCH_DECODER_H_

+// sherpa-onnx/csrc/offline-fire-red-asr-model-config.cc
+//
+// Copyright (c)  2023  Xiaomi Corporation
+
+#include "sherpa-onnx/csrc/offline-fire-red-asr-model-config.h"
+
+#include "sherpa-onnx/csrc/file-utils.h"
+#include "sherpa-onnx/csrc/macros.h"
+
+namespace sherpa_onnx {
+
+void OfflineFireRedAsrModelConfig::Register(ParseOptions *po) {
+  po->Register("fire-red-asr-encoder", &encoder,
+               "Path to onnx encoder of FireRedAsr");
+
+  po->Register("fire-red-asr-decoder", &decoder,
+               "Path to onnx decoder of FireRedAsr");
+}
+
+bool OfflineFireRedAsrModelConfig::Validate() const {
+  if (encoder.empty()) {
+    SHERPA_ONNX_LOGE("Please provide --fire-red-asr-encoder");
+    return false;
+  }
+
+  if (!FileExists(encoder)) {
+    SHERPA_ONNX_LOGE("FireRedAsr encoder file '%s' does not exist",
+                     encoder.c_str());
+    return false;
+  }
+
+  if (decoder.empty()) {
+    SHERPA_ONNX_LOGE("Please provide --fire-red-asr-decoder");
+    return false;
+  }
+
+  if (!FileExists(decoder)) {
+    SHERPA_ONNX_LOGE("FireRedAsr decoder file '%s' does not exist",
+                     decoder.c_str());
+    return false;
+  }
+
+  return true;
+}
+
+std::string OfflineFireRedAsrModelConfig::ToString() const {
+  std::ostringstream os;
+
+  os << "OfflineFireRedAsrModelConfig(";
+  os << "encoder=\"" << encoder << "\", ";
+  os << "decoder=\"" << decoder << "\")";
+
+  return os.str();
+}
+
+}  // namespace sherpa_onnx

+// sherpa-onnx/csrc/offline-fire-red-asr-model-config.h
+//
+// Copyright (c)  2023  Xiaomi Corporation
+#ifndef SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_MODEL_CONFIG_H_
+#define SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_MODEL_CONFIG_H_
+
+#include <string>
+
+#include "sherpa-onnx/csrc/parse-options.h"
+
+namespace sherpa_onnx {
+
+// see https://github.com/FireRedTeam/FireRedASR
+struct OfflineFireRedAsrModelConfig {
+  std::string encoder;
+  std::string decoder;
+
+  OfflineFireRedAsrModelConfig() = default;
+  OfflineFireRedAsrModelConfig(const std::string &encoder,
+                               const std::string &decoder)
+      : encoder(encoder), decoder(decoder) {}
+
+  void Register(ParseOptions *po);
+  bool Validate() const;
+
+  std::string ToString() const;
+};
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_MODEL_CONFIG_H_

+// sherpa-onnx/csrc/offline-fire-red-asr-model-meta-data.h
+//
+// Copyright (c)  2025  Xiaomi Corporation
+#ifndef SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_MODEL_META_DATA_H_
+#define SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_MODEL_META_DATA_H_
+
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+namespace sherpa_onnx {
+
+struct OfflineFireRedAsrModelMetaData {
+  int32_t sos_id;
+  int32_t eos_id;
+  int32_t max_len;
+
+  int32_t num_decoder_layers;
+  int32_t num_head;
+  int32_t head_dim;
+
+  std::vector<float> mean;
+  std::vector<float> inv_stddev;
+};
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_MODEL_META_DATA_H_

+// sherpa-onnx/csrc/offline-fire-red-asr-model.cc
+//
+// Copyright (c)  2025  Xiaomi Corporation
+
+#include "sherpa-onnx/csrc/offline-fire-red-asr-model.h"
+
+#include <algorithm>
+#include <cmath>
+#include <string>
+#include <tuple>
+#include <unordered_map>
+#include <utility>
+
+#if __ANDROID_API__ >= 9
+#include "android/asset_manager.h"
+#include "android/asset_manager_jni.h"
+#endif
+
+#if __OHOS__
+#include "rawfile/raw_file_manager.h"
+#endif
+
+#include "sherpa-onnx/csrc/macros.h"
+#include "sherpa-onnx/csrc/onnx-utils.h"
+#include "sherpa-onnx/csrc/session.h"
+#include "sherpa-onnx/csrc/text-utils.h"
+
+namespace sherpa_onnx {
+
+class OfflineFireRedAsrModel::Impl {
+ public:
+  explicit Impl(const OfflineModelConfig &config)
+      : config_(config),
+        env_(ORT_LOGGING_LEVEL_ERROR),
+        sess_opts_(GetSessionOptions(config)),
+        allocator_{} {
+    {
+      auto buf = ReadFile(config.fire_red_asr.encoder);
+      InitEncoder(buf.data(), buf.size());
+    }
+
+    {
+      auto buf = ReadFile(config.fire_red_asr.decoder);
+      InitDecoder(buf.data(), buf.size());
+    }
+  }
+
+  template <typename Manager>
+  Impl(Manager *mgr, const OfflineModelConfig &config)
+      : config_(config),
+        env_(ORT_LOGGING_LEVEL_ERROR),
+        sess_opts_(GetSessionOptions(config)),
+        allocator_{} {
+    {
+      auto buf = ReadFile(mgr, config.fire_red_asr.encoder);
+      InitEncoder(buf.data(), buf.size());
+    }
+
+    {
+      auto buf = ReadFile(mgr, config.fire_red_asr.decoder);
+      InitDecoder(buf.data(), buf.size());
+    }
+  }
+
+  std::pair<Ort::Value, Ort::Value> ForwardEncoder(Ort::Value features,
+                                                   Ort::Value features_length) {
+    std::array<Ort::Value, 2> inputs{std::move(features),
+                                     std::move(features_length)};
+
+    auto encoder_out = encoder_sess_->Run(
+        {}, encoder_input_names_ptr_.data(), inputs.data(), inputs.size(),
+        encoder_output_names_ptr_.data(), encoder_output_names_ptr_.size());
+
+    return {std::move(encoder_out[0]), std::move(encoder_out[1])};
+  }
+
+  std::tuple<Ort::Value, Ort::Value, Ort::Value, Ort::Value, Ort::Value,
+             Ort::Value>
+  ForwardDecoder(Ort::Value tokens, Ort::Value n_layer_self_k_cache,
+                 Ort::Value n_layer_self_v_cache, Ort::Value n_layer_cross_k,
+                 Ort::Value n_layer_cross_v, Ort::Value offset) {
+    std::array<Ort::Value, 6> decoder_input = {std::move(tokens),
+                                               std::move(n_layer_self_k_cache),
+                                               std::move(n_layer_self_v_cache),
+                                               std::move(n_layer_cross_k),
+                                               std::move(n_layer_cross_v),
+                                               std::move(offset)};
+
+    auto decoder_out = decoder_sess_->Run(
+        {}, decoder_input_names_ptr_.data(), decoder_input.data(),
+        decoder_input.size(), decoder_output_names_ptr_.data(),
+        decoder_output_names_ptr_.size());
+
+    return std::tuple<Ort::Value, Ort::Value, Ort::Value, Ort::Value,
+                      Ort::Value, Ort::Value>{
+        std::move(decoder_out[0]),   std::move(decoder_out[1]),
+        std::move(decoder_out[2]),   std::move(decoder_input[3]),
+        std::move(decoder_input[4]), std::move(decoder_input[5])};
+  }
+
+  std::pair<Ort::Value, Ort::Value> GetInitialSelfKVCache() {
+    int32_t batch_size = 1;
+    std::array<int64_t, 5> shape{meta_data_.num_decoder_layers, batch_size,
+                                 meta_data_.max_len, meta_data_.num_head,
+                                 meta_data_.head_dim};
+
+    Ort::Value n_layer_self_k_cache = Ort::Value::CreateTensor<float>(
+        Allocator(), shape.data(), shape.size());
+
+    Ort::Value n_layer_self_v_cache = Ort::Value::CreateTensor<float>(
+        Allocator(), shape.data(), shape.size());
+
+    auto n = shape[0] * shape[1] * shape[2] * shape[3] * shape[4];
+
+    float *p_k = n_layer_self_k_cache.GetTensorMutableData<float>();
+    float *p_v = n_layer_self_v_cache.GetTensorMutableData<float>();
+
+    memset(p_k, 0, sizeof(float) * n);
+    memset(p_v, 0, sizeof(float) * n);
+
+    return {std::move(n_layer_self_k_cache), std::move(n_layer_self_v_cache)};
+  }
+
+  OrtAllocator *Allocator() { return allocator_; }
+
+  const OfflineFireRedAsrModelMetaData &GetModelMetadata() const {
+    return meta_data_;
+  }
+
+ private:
+  void InitEncoder(void *model_data, size_t model_data_length) {
+    encoder_sess_ = std::make_unique<Ort::Session>(
+        env_, model_data, model_data_length, sess_opts_);
+
+    GetInputNames(encoder_sess_.get(), &encoder_input_names_,
+                  &encoder_input_names_ptr_);
+
+    GetOutputNames(encoder_sess_.get(), &encoder_output_names_,
+                   &encoder_output_names_ptr_);
+
+    // get meta data
+    Ort::ModelMetadata meta_data = encoder_sess_->GetModelMetadata();
+    if (config_.debug) {
+      std::ostringstream os;
+      os << "---encoder---\n";
+      PrintModelMetadata(os, meta_data);
+#if __OHOS__
+      SHERPA_ONNX_LOGE("%{public}s\n", os.str().c_str());
+#else
+      SHERPA_ONNX_LOGE("%s\n", os.str().c_str());
+#endif
+    }
+
+    Ort::AllocatorWithDefaultOptions allocator;  // used in the macro below
+    SHERPA_ONNX_READ_META_DATA(meta_data_.num_decoder_layers,
+                               "num_decoder_layers");
+    SHERPA_ONNX_READ_META_DATA(meta_data_.num_head, "num_head");
+    SHERPA_ONNX_READ_META_DATA(meta_data_.head_dim, "head_dim");
+    SHERPA_ONNX_READ_META_DATA(meta_data_.sos_id, "sos");
+    SHERPA_ONNX_READ_META_DATA(meta_data_.eos_id, "eos");
+    SHERPA_ONNX_READ_META_DATA(meta_data_.max_len, "max_len");
+
+    SHERPA_ONNX_READ_META_DATA_VEC_FLOAT(meta_data_.mean, "cmvn_mean");
+    SHERPA_ONNX_READ_META_DATA_VEC_FLOAT(meta_data_.inv_stddev,
+                                         "cmvn_inv_stddev");
+  }
+
+  void InitDecoder(void *model_data, size_t model_data_length) {
+    decoder_sess_ = std::make_unique<Ort::Session>(
+        env_, model_data, model_data_length, sess_opts_);
+
+    GetInputNames(decoder_sess_.get(), &decoder_input_names_,
+                  &decoder_input_names_ptr_);
+
+    GetOutputNames(decoder_sess_.get(), &decoder_output_names_,
+                   &decoder_output_names_ptr_);
+  }
+
+ private:
+  OfflineModelConfig config_;
+  Ort::Env env_;
+  Ort::SessionOptions sess_opts_;
+  Ort::AllocatorWithDefaultOptions allocator_;
+
+  std::unique_ptr<Ort::Session> encoder_sess_;
+  std::unique_ptr<Ort::Session> decoder_sess_;
+
+  std::vector<std::string> encoder_input_names_;
+  std::vector<const char *> encoder_input_names_ptr_;
+
+  std::vector<std::string> encoder_output_names_;
+  std::vector<const char *> encoder_output_names_ptr_;
+
+  std::vector<std::string> decoder_input_names_;
+  std::vector<const char *> decoder_input_names_ptr_;
+
+  std::vector<std::string> decoder_output_names_;
+  std::vector<const char *> decoder_output_names_ptr_;
+
+  OfflineFireRedAsrModelMetaData meta_data_;
+};
+
+OfflineFireRedAsrModel::OfflineFireRedAsrModel(const OfflineModelConfig &config)
+    : impl_(std::make_unique<Impl>(config)) {}
+
+template <typename Manager>
+OfflineFireRedAsrModel::OfflineFireRedAsrModel(Manager *mgr,
+                                               const OfflineModelConfig &config)
+    : impl_(std::make_unique<Impl>(mgr, config)) {}
+
+OfflineFireRedAsrModel::~OfflineFireRedAsrModel() = default;
+
+std::pair<Ort::Value, Ort::Value> OfflineFireRedAsrModel::ForwardEncoder(
+    Ort::Value features, Ort::Value features_length) const {
+  return impl_->ForwardEncoder(std::move(features), std::move(features_length));
+}
+
+std::tuple<Ort::Value, Ort::Value, Ort::Value, Ort::Value, Ort::Value,
+           Ort::Value>
+OfflineFireRedAsrModel::ForwardDecoder(Ort::Value tokens,
+                                       Ort::Value n_layer_self_k_cache,
+                                       Ort::Value n_layer_self_v_cache,
+                                       Ort::Value n_layer_cross_k,
+                                       Ort::Value n_layer_cross_v,
+                                       Ort::Value offset) const {
+  return impl_->ForwardDecoder(
+      std::move(tokens), std::move(n_layer_self_k_cache),
+      std::move(n_layer_self_v_cache), std::move(n_layer_cross_k),
+      std::move(n_layer_cross_v), std::move(offset));
+}
+
+std::pair<Ort::Value, Ort::Value>
+OfflineFireRedAsrModel::GetInitialSelfKVCache() const {
+  return impl_->GetInitialSelfKVCache();
+}
+
+OrtAllocator *OfflineFireRedAsrModel::Allocator() const {
+  return impl_->Allocator();
+}
+
+const OfflineFireRedAsrModelMetaData &OfflineFireRedAsrModel::GetModelMetadata()
+    const {
+  return impl_->GetModelMetadata();
+}
+
+#if __ANDROID_API__ >= 9
+template OfflineFireRedAsrModel::OfflineFireRedAsrModel(
+    AAssetManager *mgr, const OfflineModelConfig &config);
+#endif
+
+#if __OHOS__
+template OfflineFireRedAsrModel::OfflineFireRedAsrModel(
+    NativeResourceManager *mgr, const OfflineModelConfig &config);
+#endif
+
+}  // namespace sherpa_onnx

+// sherpa-onnx/csrc/offline-fire-red-asr-model.h
+//
+// Copyright (c)  2025  Xiaomi Corporation
+#ifndef SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_MODEL_H_
+#define SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_MODEL_H_
+
+#include <memory>
+#include <string>
+#include <tuple>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+#include "onnxruntime_cxx_api.h"  // NOLINT
+#include "sherpa-onnx/csrc/offline-fire-red-asr-model-meta-data.h"
+#include "sherpa-onnx/csrc/offline-model-config.h"
+
+namespace sherpa_onnx {
+
+class OfflineFireRedAsrModel {
+ public:
+  explicit OfflineFireRedAsrModel(const OfflineModelConfig &config);
+
+  template <typename Manager>
+  OfflineFireRedAsrModel(Manager *mgr, const OfflineModelConfig &config);
+
+  ~OfflineFireRedAsrModel();
+
+  /** Run the encoder model.
+   *
+   * @param features  A tensor of shape (N, T, C).
+   * @param features_len  A tensor of shape (N,) with dtype int64.
+   *
+   * @return Return a pair containing:
+   *  - n_layer_cross_k: A 4-D tensor of shape
+   *                     (num_decoder_layers, N, T, d_model)
+   *  - n_layer_cross_v: A 4-D tensor of shape
+   *                     (num_decoder_layers, N, T, d_model)
+   */
+  std::pair<Ort::Value, Ort::Value> ForwardEncoder(
+      Ort::Value features, Ort::Value features_length) const;
+
+  /** Run the decoder model.
+   *
+   * @param tokens A int64 tensor of shape (N, num_words)
+   * @param n_layer_self_k_cache  A 5-D tensor of shape
+   *                       (num_decoder_layers, N, max_len, num_head, head_dim).
+   * @param n_layer_self_v_cache  A 5-D tensor of shape
+   *                       (num_decoder_layers, N, max_len, num_head, head_dim).
+   * @param n_layer_cross_k       A 5-D tensor of shape
+   *                              (num_decoder_layers, N, T, d_model).
+   * @param n_layer_cross_v       A 5-D tensor of shape
+   *                              (num_decoder_layers, N, T, d_model).
+   * @param offset A int64 tensor of shape (N,)
+   *
+   * @return Return a tuple containing 6 tensors:
+   *
+   *  - logits A 3-D tensor of shape (N, num_words, vocab_size)
+   *  - out_n_layer_self_k_cache Same shape as n_layer_self_k_cache
+   *  - out_n_layer_self_v_cache Same shape as n_layer_self_v_cache
+   *  - out_n_layer_cross_k Same as n_layer_cross_k
+   *  - out_n_layer_cross_v Same as n_layer_cross_v
+   *  - out_offset Same as offset
+   */
+  std::tuple<Ort::Value, Ort::Value, Ort::Value, Ort::Value, Ort::Value,
+             Ort::Value>
+  ForwardDecoder(Ort::Value tokens, Ort::Value n_layer_self_k_cache,
+                 Ort::Value n_layer_self_v_cache, Ort::Value n_layer_cross_k,
+                 Ort::Value n_layer_cross_v, Ort::Value offset) const;
+
+  /** Return the initial self kv cache in a pair
+   *  - n_layer_self_k_cache A 5-D tensor of shape
+   *                       (num_decoder_layers, N, max_len, num_head, head_dim).
+   *  - n_layer_self_v_cache A 5-D tensor of shape
+   *                       (num_decoder_layers, N, max_len, num_head, head_dim).
+   */
+  std::pair<Ort::Value, Ort::Value> GetInitialSelfKVCache() const;
+
+  const OfflineFireRedAsrModelMetaData &GetModelMetadata() const;
+
+  /** Return an allocator for allocating memory
+   */
+  OrtAllocator *Allocator() const;
+
+ private:
+  class Impl;
+  std::unique_ptr<Impl> impl_;
+};
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_MODEL_H_

@@ -15,6 +15,7 @@ void OfflineModelConfig::Register(ParseOptions *po) {
   paraformer.Register(po);
   nemo_ctc.Register(po);
   whisper.Register(po);
+  fire_red_asr.Register(po);
   tdnn.Register(po);
   zipformer_ctc.Register(po);
   wenet_ctc.Register(po);
@@ -38,7 +39,7 @@ void OfflineModelConfig::Register(ParseOptions *po) {
   po->Register("model-type", &model_type,
                "Specify it to reduce model initialization time. "
                "Valid values are: transducer, paraformer, nemo_ctc, whisper, "
-               "tdnn, zipformer2_ctc, telespeech_ctc."
+               "tdnn, zipformer2_ctc, telespeech_ctc, fire_red_asr."
                "All other values lead to loading the model twice.");
   po->Register("modeling-unit", &modeling_unit,
                "The modeling unit of the model, commonly used units are bpe, "
@@ -84,6 +85,10 @@ bool OfflineModelConfig::Validate() const {
     return whisper.Validate();
   }
 
+  if (!fire_red_asr.encoder.empty()) {
+    return fire_red_asr.Validate();
+  }
+
   if (!tdnn.model.empty()) {
     return tdnn.Validate();
   }
@@ -125,6 +130,7 @@ std::string OfflineModelConfig::ToString() const {
   os << "paraformer=" << paraformer.ToString() << ", ";
   os << "nemo_ctc=" << nemo_ctc.ToString() << ", ";
   os << "whisper=" << whisper.ToString() << ", ";
+  os << "fire_red_asr=" << fire_red_asr.ToString() << ", ";
   os << "tdnn=" << tdnn.ToString() << ", ";
   os << "zipformer_ctc=" << zipformer_ctc.ToString() << ", ";
   os << "wenet_ctc=" << wenet_ctc.ToString() << ", ";

@@ -6,6 +6,7 @@
 
 #include <string>
 
+#include "sherpa-onnx/csrc/offline-fire-red-asr-model-config.h"
 #include "sherpa-onnx/csrc/offline-moonshine-model-config.h"
 #include "sherpa-onnx/csrc/offline-nemo-enc-dec-ctc-model-config.h"
 #include "sherpa-onnx/csrc/offline-paraformer-model-config.h"
@@ -23,6 +24,7 @@ struct OfflineModelConfig {
   OfflineParaformerModelConfig paraformer;
   OfflineNemoEncDecCtcModelConfig nemo_ctc;
   OfflineWhisperModelConfig whisper;
+  OfflineFireRedAsrModelConfig fire_red_asr;
   OfflineTdnnModelConfig tdnn;
   OfflineZipformerCtcModelConfig zipformer_ctc;
   OfflineWenetCtcModelConfig wenet_ctc;
@@ -54,6 +56,7 @@ struct OfflineModelConfig {
                      const OfflineParaformerModelConfig &paraformer,
                      const OfflineNemoEncDecCtcModelConfig &nemo_ctc,
                      const OfflineWhisperModelConfig &whisper,
+                     const OfflineFireRedAsrModelConfig &fire_red_asr,
                      const OfflineTdnnModelConfig &tdnn,
                      const OfflineZipformerCtcModelConfig &zipformer_ctc,
                      const OfflineWenetCtcModelConfig &wenet_ctc,
@@ -68,6 +71,7 @@ struct OfflineModelConfig {
         paraformer(paraformer),
         nemo_ctc(nemo_ctc),
         whisper(whisper),
+        fire_red_asr(fire_red_asr),
         tdnn(tdnn),
         zipformer_ctc(zipformer_ctc),
         wenet_ctc(wenet_ctc),

+// sherpa-onnx/csrc/offline-recognizer-fire-red-asr-impl.h
+//
+// Copyright (c)  2022-2023  Xiaomi Corporation
+
+#ifndef SHERPA_ONNX_CSRC_OFFLINE_RECOGNIZER_FIRE_RED_ASR_IMPL_H_
+#define SHERPA_ONNX_CSRC_OFFLINE_RECOGNIZER_FIRE_RED_ASR_IMPL_H_
+
+#include <algorithm>
+#include <cmath>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "sherpa-onnx/csrc/offline-fire-red-asr-decoder.h"
+#include "sherpa-onnx/csrc/offline-fire-red-asr-greedy-search-decoder.h"
+#include "sherpa-onnx/csrc/offline-fire-red-asr-model.h"
+#include "sherpa-onnx/csrc/offline-model-config.h"
+#include "sherpa-onnx/csrc/offline-recognizer-impl.h"
+#include "sherpa-onnx/csrc/offline-recognizer.h"
+#include "sherpa-onnx/csrc/symbol-table.h"
+#include "sherpa-onnx/csrc/transpose.h"
+
+namespace sherpa_onnx {
+
+static OfflineRecognitionResult Convert(
+    const OfflineFireRedAsrDecoderResult &src, const SymbolTable &sym_table) {
+  OfflineRecognitionResult r;
+  r.tokens.reserve(src.tokens.size());
+
+  std::string text;
+  for (auto i : src.tokens) {
+    if (!sym_table.Contains(i)) {
+      continue;
+    }
+
+    const auto &s = sym_table[i];
+    text += s;
+    r.tokens.push_back(s);
+  }
+
+  r.text = text;
+
+  return r;
+}
+
+class OfflineRecognizerFireRedAsrImpl : public OfflineRecognizerImpl {
+ public:
+  explicit OfflineRecognizerFireRedAsrImpl(
+      const OfflineRecognizerConfig &config)
+      : OfflineRecognizerImpl(config),
+        config_(config),
+        symbol_table_(config_.model_config.tokens),
+        model_(std::make_unique<OfflineFireRedAsrModel>(config.model_config)) {
+    Init();
+  }
+
+  template <typename Manager>
+  OfflineRecognizerFireRedAsrImpl(Manager *mgr,
+                                  const OfflineRecognizerConfig &config)
+      : OfflineRecognizerImpl(mgr, config),
+        config_(config),
+        symbol_table_(mgr, config_.model_config.tokens),
+        model_(std::make_unique<OfflineFireRedAsrModel>(mgr,
+                                                        config.model_config)) {
+    Init();
+  }
+
+  void Init() {
+    if (config_.decoding_method == "greedy_search") {
+      decoder_ =
+          std::make_unique<OfflineFireRedAsrGreedySearchDecoder>(model_.get());
+    } else {
+      SHERPA_ONNX_LOGE(
+          "Only greedy_search is supported at present for FireRedAsr. Given %s",
+          config_.decoding_method.c_str());
+      SHERPA_ONNX_EXIT(-1);
+    }
+
+    const auto &meta_data = model_->GetModelMetadata();
+
+    config_.feat_config.normalize_samples = false;
+    config_.feat_config.high_freq = 0;
+    config_.feat_config.snip_edges = true;
+  }
+
+  std::unique_ptr<OfflineStream> CreateStream() const override {
+    return std::make_unique<OfflineStream>(config_.feat_config);
+  }
+
+  void DecodeStreams(OfflineStream **ss, int32_t n) const override {
+    // batch decoding is not implemented yet
+    for (int32_t i = 0; i != n; ++i) {
+      DecodeStream(ss[i]);
+    }
+  }
+
+  OfflineRecognizerConfig GetConfig() const override { return config_; }
+
+ private:
+  void DecodeStream(OfflineStream *s) const {
+    auto memory_info =
+        Ort::MemoryInfo::CreateCpu(OrtDeviceAllocator, OrtMemTypeDefault);
+
+    int32_t feat_dim = s->FeatureDim();
+    std::vector<float> f = s->GetFrames();
+    ApplyCMVN(&f);
+
+    int64_t num_frames = f.size() / feat_dim;
+
+    std::array<int64_t, 3> shape{1, num_frames, feat_dim};
+
+    Ort::Value x = Ort::Value::CreateTensor(memory_info, f.data(), f.size(),
+                                            shape.data(), shape.size());
+
+    int64_t len_shape = 1;
+    Ort::Value x_len =
+        Ort::Value::CreateTensor(memory_info, &num_frames, 1, &len_shape, 1);
+
+    auto cross_kv = model_->ForwardEncoder(std::move(x), std::move(x_len));
+
+    auto results =
+        decoder_->Decode(std::move(cross_kv.first), std::move(cross_kv.second));
+
+    auto r = Convert(results[0], symbol_table_);
+
+    r.text = ApplyInverseTextNormalization(std::move(r.text));
+    s->SetResult(r);
+  }
+
+  void ApplyCMVN(std::vector<float> *v) const {
+    const auto &meta_data = model_->GetModelMetadata();
+    const auto &mean = meta_data.mean;
+    const auto &inv_stddev = meta_data.inv_stddev;
+    int32_t feat_dim = static_cast<int32_t>(mean.size());
+    int32_t num_frames = static_cast<int32_t>(v->size()) / feat_dim;
+
+    float *p = v->data();
+
+    for (int32_t i = 0; i != num_frames; ++i) {
+      for (int32_t k = 0; k != feat_dim; ++k) {
+        p[k] = (p[k] - mean[k]) * inv_stddev[k];
+      }
+
+      p += feat_dim;
+    }
+  }
+
+ private:
+  OfflineRecognizerConfig config_;
+  SymbolTable symbol_table_;
+  std::unique_ptr<OfflineFireRedAsrModel> model_;
+  std::unique_ptr<OfflineFireRedAsrDecoder> decoder_;
+};
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_OFFLINE_RECOGNIZER_FIRE_RED_ASR_IMPL_H_

@@ -24,6 +24,7 @@
 #include "onnxruntime_cxx_api.h"  // NOLINT
 #include "sherpa-onnx/csrc/macros.h"
 #include "sherpa-onnx/csrc/offline-recognizer-ctc-impl.h"
+#include "sherpa-onnx/csrc/offline-recognizer-fire-red-asr-impl.h"
 #include "sherpa-onnx/csrc/offline-recognizer-moonshine-impl.h"
 #include "sherpa-onnx/csrc/offline-recognizer-paraformer-impl.h"
 #include "sherpa-onnx/csrc/offline-recognizer-sense-voice-impl.h"
@@ -56,6 +57,10 @@ std::unique_ptr<OfflineRecognizerImpl> OfflineRecognizerImpl::Create(
     return std::make_unique<OfflineRecognizerWhisperImpl>(config);
   }
 
+  if (!config.model_config.fire_red_asr.encoder.empty()) {
+    return std::make_unique<OfflineRecognizerFireRedAsrImpl>(config);
+  }
+
   if (!config.model_config.moonshine.preprocessor.empty()) {
     return std::make_unique<OfflineRecognizerMoonshineImpl>(config);
   }
@@ -237,6 +242,10 @@ std::unique_ptr<OfflineRecognizerImpl> OfflineRecognizerImpl::Create(
     return std::make_unique<OfflineRecognizerWhisperImpl>(mgr, config);
   }
 
+  if (!config.model_config.fire_red_asr.encoder.empty()) {
+    return std::make_unique<OfflineRecognizerFireRedAsrImpl>(mgr, config);
+  }
+
   if (!config.model_config.moonshine.preprocessor.empty()) {
     return std::make_unique<OfflineRecognizerMoonshineImpl>(mgr, config);
   }

@@ -9,6 +9,7 @@ set(srcs
   features.cc
   keyword-spotter.cc
   offline-ctc-fst-decoder-config.cc
+  offline-fire-red-asr-model-config.cc
   offline-lm-config.cc
   offline-model-config.cc
   offline-moonshine-model-config.cc

+// sherpa-onnx/python/csrc/offline-fire-red-asr-model-config.cc
+//
+// Copyright (c)  2025  Xiaomi Corporation
+
+#include "sherpa-onnx/csrc/offline-fire-red-asr-model-config.h"
+
+#include <string>
+#include <vector>
+
+#include "sherpa-onnx/python/csrc/offline-fire-red-asr-model-config.h"
+
+namespace sherpa_onnx {
+
+void PybindOfflineFireRedAsrModelConfig(py::module *m) {
+  using PyClass = OfflineFireRedAsrModelConfig;
+  py::class_<PyClass>(*m, "OfflineFireRedAsrModelConfig")
+      .def(py::init<const std::string &, const std::string &>(),
+           py::arg("encoder"), py::arg("decoder"))
+      .def_readwrite("encoder", &PyClass::encoder)
+      .def_readwrite("decoder", &PyClass::decoder)
+      .def("__str__", &PyClass::ToString);
+}
+
+}  // namespace sherpa_onnx

+// sherpa-onnx/python/csrc/offline-fire-red-asr-model-config.h
+//
+// Copyright (c)  2025  Xiaomi Corporation
+
+#ifndef SHERPA_ONNX_PYTHON_CSRC_OFFLINE_FIRE_RED_ASR_MODEL_CONFIG_H_
+#define SHERPA_ONNX_PYTHON_CSRC_OFFLINE_FIRE_RED_ASR_MODEL_CONFIG_H_
+
+#include "sherpa-onnx/python/csrc/sherpa-onnx.h"
+
+namespace sherpa_onnx {
+
+void PybindOfflineFireRedAsrModelConfig(py::module *m);
+
+}
+
+#endif  // SHERPA_ONNX_PYTHON_CSRC_OFFLINE_FIRE_RED_ASR_MODEL_CONFIG_H_

@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "sherpa-onnx/csrc/offline-model-config.h"
+#include "sherpa-onnx/python/csrc/offline-fire-red-asr-model-config.h"
 #include "sherpa-onnx/python/csrc/offline-moonshine-model-config.h"
 #include "sherpa-onnx/python/csrc/offline-nemo-enc-dec-ctc-model-config.h"
 #include "sherpa-onnx/python/csrc/offline-paraformer-model-config.h"
@@ -25,6 +26,7 @@ void PybindOfflineModelConfig(py::module *m) {
   PybindOfflineParaformerModelConfig(m);
   PybindOfflineNemoEncDecCtcModelConfig(m);
   PybindOfflineWhisperModelConfig(m);
+  PybindOfflineFireRedAsrModelConfig(m);
   PybindOfflineTdnnModelConfig(m);
   PybindOfflineZipformerCtcModelConfig(m);
   PybindOfflineWenetCtcModelConfig(m);
@@ -33,35 +35,38 @@ void PybindOfflineModelConfig(py::module *m) {
 
   using PyClass = OfflineModelConfig;
   py::class_<PyClass>(*m, "OfflineModelConfig")
-      .def(
-          py::init<
-              const OfflineTransducerModelConfig &,
-              const OfflineParaformerModelConfig &,
-              const OfflineNemoEncDecCtcModelConfig &,
-              const OfflineWhisperModelConfig &, const OfflineTdnnModelConfig &,
-              const OfflineZipformerCtcModelConfig &,
-              const OfflineWenetCtcModelConfig &,
-              const OfflineSenseVoiceModelConfig &,
-              const OfflineMoonshineModelConfig &, const std::string &,
-              const std::string &, int32_t, bool, const std::string &,
-              const std::string &, const std::string &, const std::string &>(),
-          py::arg("transducer") = OfflineTransducerModelConfig(),
-          py::arg("paraformer") = OfflineParaformerModelConfig(),
-          py::arg("nemo_ctc") = OfflineNemoEncDecCtcModelConfig(),
-          py::arg("whisper") = OfflineWhisperModelConfig(),
-          py::arg("tdnn") = OfflineTdnnModelConfig(),
-          py::arg("zipformer_ctc") = OfflineZipformerCtcModelConfig(),
-          py::arg("wenet_ctc") = OfflineWenetCtcModelConfig(),
-          py::arg("sense_voice") = OfflineSenseVoiceModelConfig(),
-          py::arg("moonshine") = OfflineMoonshineModelConfig(),
-          py::arg("telespeech_ctc") = "", py::arg("tokens"),
-          py::arg("num_threads"), py::arg("debug") = false,
-          py::arg("provider") = "cpu", py::arg("model_type") = "",
-          py::arg("modeling_unit") = "cjkchar", py::arg("bpe_vocab") = "")
+      .def(py::init<const OfflineTransducerModelConfig &,
+                    const OfflineParaformerModelConfig &,
+                    const OfflineNemoEncDecCtcModelConfig &,
+                    const OfflineWhisperModelConfig &,
+                    const OfflineFireRedAsrModelConfig &,
+                    const OfflineTdnnModelConfig &,
+                    const OfflineZipformerCtcModelConfig &,
+                    const OfflineWenetCtcModelConfig &,
+                    const OfflineSenseVoiceModelConfig &,
+                    const OfflineMoonshineModelConfig &, const std::string &,
+                    const std::string &, int32_t, bool, const std::string &,
+                    const std::string &, const std::string &,
+                    const std::string &>(),
+           py::arg("transducer") = OfflineTransducerModelConfig(),
+           py::arg("paraformer") = OfflineParaformerModelConfig(),
+           py::arg("nemo_ctc") = OfflineNemoEncDecCtcModelConfig(),
+           py::arg("whisper") = OfflineWhisperModelConfig(),
+           py::arg("fire_red_asr") = OfflineFireRedAsrModelConfig(),
+           py::arg("tdnn") = OfflineTdnnModelConfig(),
+           py::arg("zipformer_ctc") = OfflineZipformerCtcModelConfig(),
+           py::arg("wenet_ctc") = OfflineWenetCtcModelConfig(),
+           py::arg("sense_voice") = OfflineSenseVoiceModelConfig(),
+           py::arg("moonshine") = OfflineMoonshineModelConfig(),
+           py::arg("telespeech_ctc") = "", py::arg("tokens"),
+           py::arg("num_threads"), py::arg("debug") = false,
+           py::arg("provider") = "cpu", py::arg("model_type") = "",
+           py::arg("modeling_unit") = "cjkchar", py::arg("bpe_vocab") = "")
       .def_readwrite("transducer", &PyClass::transducer)
       .def_readwrite("paraformer", &PyClass::paraformer)
       .def_readwrite("nemo_ctc", &PyClass::nemo_ctc)
       .def_readwrite("whisper", &PyClass::whisper)
+      .def_readwrite("fire_red_asr", &PyClass::fire_red_asr)
       .def_readwrite("tdnn", &PyClass::tdnn)
       .def_readwrite("zipformer_ctc", &PyClass::zipformer_ctc)
       .def_readwrite("wenet_ctc", &PyClass::wenet_ctc)

@@ -6,6 +6,7 @@ from typing import List, Optional
 from _sherpa_onnx import (
     FeatureExtractorConfig,
     OfflineCtcFstDecoderConfig,
+    OfflineFireRedAsrModelConfig,
     OfflineLMConfig,
     OfflineModelConfig,
     OfflineMoonshineModelConfig,
@@ -572,6 +573,78 @@ class OfflineRecognizer(object):
         return self
 
     @classmethod
+    def from_fire_red_asr(
+        cls,
+        encoder: str,
+        decoder: str,
+        tokens: str,
+        num_threads: int = 1,
+        decoding_method: str = "greedy_search",
+        debug: bool = False,
+        provider: str = "cpu",
+        rule_fsts: str = "",
+        rule_fars: str = "",
+    ):
+        """
+        Please refer to
+        `<https://k2-fsa.github.io/sherpa/onnx/fire_red_asr/index.html>`_
+        to download pre-trained models for different kinds of FireRedAsr models,
+        e.g., xs, large, etc.
+
+        Args:
+          encoder:
+            Path to the encoder model.
+          decoder:
+            Path to the decoder model.
+          tokens:
+            Path to ``tokens.txt``. Each line in ``tokens.txt`` contains two
+            columns::
+
+                symbol integer_id
+          num_threads:
+            Number of threads for neural network computation.
+          decoding_method:
+            Valid values: greedy_search.
+          debug:
+            True to show debug messages.
+          provider:
+            onnxruntime execution providers. Valid values are: cpu, cuda, coreml.
+          rule_fsts:
+            If not empty, it specifies fsts for inverse text normalization.
+            If there are multiple fsts, they are separated by a comma.
+          rule_fars:
+            If not empty, it specifies fst archives for inverse text normalization.
+            If there are multiple archives, they are separated by a comma.
+        """
+        self = cls.__new__(cls)
+        model_config = OfflineModelConfig(
+            fire_red_asr=OfflineFireRedAsrModelConfig(
+                encoder=encoder,
+                decoder=decoder,
+            ),
+            tokens=tokens,
+            num_threads=num_threads,
+            debug=debug,
+            provider=provider,
+        )
+
+        feat_config = FeatureExtractorConfig(
+            sampling_rate=16000,
+            feature_dim=80,
+        )
+
+        recognizer_config = OfflineRecognizerConfig(
+            feat_config=feat_config,
+            model_config=model_config,
+            decoding_method=decoding_method,
+            rule_fsts=rule_fsts,
+            rule_fars=rule_fars,
+        )
+        self.recognizer = _Recognizer(recognizer_config)
+        self.config = recognizer_config
+        return self
+
+    @classmethod
     def from_moonshine(
         cls,
         preprocessor: str,