Add GigaAM NeMo transducer model for Russian ASR (#1467)

@@ -38,7 +38,7 @@ jobs:
           mkdir $d/test_wavs
           rm scripts/nemo/GigaAM/model.onnx
           mv -v scripts/nemo/GigaAM/*.int8.onnx $d/
-          mv -v scripts/nemo/GigaAM/*.md $d/
+          cp -v scripts/nemo/GigaAM/*.md $d/
           mv -v scripts/nemo/GigaAM/*.pdf $d/
           mv -v scripts/nemo/GigaAM/tokens.txt $d/
           mv -v scripts/nemo/GigaAM/*.wav $d/test_wavs/
@@ -51,6 +51,34 @@ jobs:
 
           tar cjvf ${d}.tar.bz2 $d
 
+      - name: Run Transducer
+        shell: bash
+        run: |
+          pushd scripts/nemo/GigaAM
+          ./run-rnnt.sh
+          popd
+
+          d=sherpa-onnx-nemo-transducer-giga-am-russian-2024-10-24
+          mkdir $d
+          mkdir $d/test_wavs
+
+          mv -v scripts/nemo/GigaAM/encoder.int8.onnx $d/
+          mv -v scripts/nemo/GigaAM/decoder.onnx $d/
+          mv -v scripts/nemo/GigaAM/joiner.onnx $d/
+
+          cp -v scripts/nemo/GigaAM/*.md $d/
+          mv -v scripts/nemo/GigaAM/*.pdf $d/
+          mv -v scripts/nemo/GigaAM/tokens.txt $d/
+          mv -v scripts/nemo/GigaAM/*.wav $d/test_wavs/
+          mv -v scripts/nemo/GigaAM/run-rnnt.sh $d/
+          mv -v scripts/nemo/GigaAM/*-rnnt.py $d/
+
+          ls -lh scripts/nemo/GigaAM/
+
+          ls -lh $d
+
+          tar cjvf ${d}.tar.bz2 $d
+
       - name: Release
         uses: svenstaro/upload-release-action@v2
         with:
@@ -61,7 +89,7 @@ jobs:
           repo_token: ${{ secrets.UPLOAD_GH_SHERPA_ONNX_TOKEN }}
           tag: asr-models
 
-      - name: Publish to huggingface (CTC)
+      - name: Publish to huggingface (Transducer)
         env:
           HF_TOKEN: ${{ secrets.HF_TOKEN }}
         uses: nick-fields/retry@v3
@@ -73,7 +101,7 @@ jobs:
             git config --global user.email "csukuangfj@gmail.com"
             git config --global user.name "Fangjun Kuang"
 
-            d=sherpa-onnx-nemo-ctc-giga-am-russian-2024-10-24
+            d=sherpa-onnx-nemo-transducer-giga-am-russian-2024-10-24/
             export GIT_LFS_SKIP_SMUDGE=1
             export GIT_CLONE_PROTECTION_ACTIVE=false
             git clone https://csukuangfj:$HF_TOKEN@huggingface.co/csukuangfj/$d huggingface

@@ -354,6 +354,24 @@ def get_models():
             popd
             """,
         ),
+        Model(
+            model_name="sherpa-onnx-nemo-transducer-giga-am-russian-2024-10-24",
+            idx=20,
+            lang="ru",
+            short_name="nemo_transducer_giga_am",
+            cmd="""
+            pushd $model_name
+
+            rm -rfv test_wavs
+
+            rm -fv *.sh
+            rm -fv *.py
+
+            ls -lh
+
+            popd
+            """,
+        ),
     ]
     return models
 

@@ -75,6 +75,7 @@ def add_meta_data(filename: str, meta_data: Dict[str, str]):
     onnx.save(model, filename)
 
 
+@torch.no_grad()
 def main():
     model = EncDecCTCModel.from_config_file("./ctc_model_config.yaml")
     ckpt = torch.load("./ctc_model_weights.ckpt", map_location="cpu")

+#!/usr/bin/env python3
+# Copyright      2024  Xiaomi Corp.        (authors: Fangjun Kuang)
+
+from typing import Dict
+
+import onnx
+import torch
+import torchaudio
+from nemo.collections.asr.models import EncDecRNNTBPEModel
+from nemo.collections.asr.modules.audio_preprocessing import (
+    AudioToMelSpectrogramPreprocessor as NeMoAudioToMelSpectrogramPreprocessor,
+)
+from nemo.collections.asr.parts.preprocessing.features import (
+    FilterbankFeaturesTA as NeMoFilterbankFeaturesTA,
+)
+from onnxruntime.quantization import QuantType, quantize_dynamic
+
+
+def add_meta_data(filename: str, meta_data: Dict[str, str]):
+    """Add meta data to an ONNX model. It is changed in-place.
+
+    Args:
+      filename:
+        Filename of the ONNX model to be changed.
+      meta_data:
+        Key-value pairs.
+    """
+    model = onnx.load(filename)
+    while len(model.metadata_props):
+        model.metadata_props.pop()
+
+    for key, value in meta_data.items():
+        meta = model.metadata_props.add()
+        meta.key = key
+        meta.value = str(value)
+
+    onnx.save(model, filename)
+
+
+class FilterbankFeaturesTA(NeMoFilterbankFeaturesTA):
+    def __init__(self, mel_scale: str = "htk", wkwargs=None, **kwargs):
+        if "window_size" in kwargs:
+            del kwargs["window_size"]
+        if "window_stride" in kwargs:
+            del kwargs["window_stride"]
+
+        super().__init__(**kwargs)
+
+        self._mel_spec_extractor: torchaudio.transforms.MelSpectrogram = (
+            torchaudio.transforms.MelSpectrogram(
+                sample_rate=self._sample_rate,
+                win_length=self.win_length,
+                hop_length=self.hop_length,
+                n_mels=kwargs["nfilt"],
+                window_fn=self.torch_windows[kwargs["window"]],
+                mel_scale=mel_scale,
+                norm=kwargs["mel_norm"],
+                n_fft=kwargs["n_fft"],
+                f_max=kwargs.get("highfreq", None),
+                f_min=kwargs.get("lowfreq", 0),
+                wkwargs=wkwargs,
+            )
+        )
+
+
+class AudioToMelSpectrogramPreprocessor(NeMoAudioToMelSpectrogramPreprocessor):
+    def __init__(self, mel_scale: str = "htk", **kwargs):
+        super().__init__(**kwargs)
+        kwargs["nfilt"] = kwargs["features"]
+        del kwargs["features"]
+        self.featurizer = (
+            FilterbankFeaturesTA(  # Deprecated arguments; kept for config compatibility
+                mel_scale=mel_scale,
+                **kwargs,
+            )
+        )
+
+
+@torch.no_grad()
+def main():
+    model = EncDecRNNTBPEModel.from_config_file("./rnnt_model_config.yaml")
+    ckpt = torch.load("./rnnt_model_weights.ckpt", map_location="cpu")
+    model.load_state_dict(ckpt, strict=False)
+    model.eval()
+
+    with open("./tokens.txt", "w", encoding="utf-8") as f:
+        for i, s in enumerate(model.joint.vocabulary):
+            f.write(f"{s} {i}\n")
+        f.write(f"<blk> {i+1}\n")
+        print("Saved to tokens.txt")
+
+    model.encoder.export("encoder.onnx")
+    model.decoder.export("decoder.onnx")
+    model.joint.export("joiner.onnx")
+
+    meta_data = {
+        "vocab_size": model.decoder.vocab_size,  # not including the blank
+        "pred_rnn_layers": model.decoder.pred_rnn_layers,
+        "pred_hidden": model.decoder.pred_hidden,
+        "normalize_type": "",
+        "subsampling_factor": 4,
+        "model_type": "EncDecRNNTBPEModel",
+        "version": "1",
+        "model_author": "https://github.com/salute-developers/GigaAM",
+        "license": "https://github.com/salute-developers/GigaAM/blob/main/GigaAM%20License_NC.pdf",
+        "language": "Russian",
+        "is_giga_am": 1,
+    }
+    add_meta_data("encoder.onnx", meta_data)
+
+    quantize_dynamic(
+        model_input="encoder.onnx",
+        model_output="encoder.int8.onnx",
+        weight_type=QuantType.QUInt8,
+    )
+
+
+if __name__ == "__main__":
+    main()

@@ -21,11 +21,15 @@ function install_nemo() {
 }
 
 function download_files() {
-  curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/ctc_model_weights.ckpt
-  curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/ctc_model_config.yaml
-  curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/example.wav
-  curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/long_example.wav
-  curl -SL -O https://huggingface.co/csukuangfj/tmp-files/resolve/main/GigaAM%20License_NC.pdf
+  # curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/ctc_model_weights.ckpt
+  # curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/ctc_model_config.yaml
+  # curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/example.wav
+  # curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/long_example.wav
+  curl -SL -O https://huggingface.co/csukuangfj/tmp-files/resolve/main/GigaAM/ctc/ctc_model_weights.ckpt
+  curl -SL -O https://huggingface.co/csukuangfj/tmp-files/resolve/main/GigaAM/ctc/ctc_model_config.yaml
+  curl -SL -O https://huggingface.co/csukuangfj/tmp-files/resolve/main/GigaAM/example.wav
+  curl -SL -O https://huggingface.co/csukuangfj/tmp-files/resolve/main/GigaAM/long_example.wav
+  curl -SL -O https://huggingface.co/csukuangfj/tmp-files/resolve/main/GigaAM/GigaAM%20License_NC.pdf
 }
 
 install_nemo

+#!/usr/bin/env bash
+# Copyright    2024  Xiaomi Corp.        (authors: Fangjun Kuang)
+
+set -ex
+
+function install_nemo() {
+  curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
+  python3 get-pip.py
+
+  pip install torch==2.4.0 torchaudio==2.4.0 -f https://download.pytorch.org/whl/torch_stable.html
+
+  pip install -qq wget text-unidecode matplotlib>=3.3.2 onnx onnxruntime pybind11 Cython einops kaldi-native-fbank soundfile librosa
+  pip install -qq ipython
+
+  # sudo apt-get install -q -y sox libsndfile1 ffmpeg python3-pip ipython
+
+  BRANCH='main'
+  python3 -m pip install git+https://github.com/NVIDIA/NeMo.git@$BRANCH#egg=nemo_toolkit[asr]
+
+  pip install numpy==1.26.4
+}
+
+function download_files() {
+  # curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/rnnt_model_weights.ckpt
+  # curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/rnnt_model_config.yaml
+  # curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/example.wav
+  # curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/long_example.wav
+  # curl -SL -O https://n-ws-q0bez.s3pd12.sbercloud.ru/b-ws-q0bez-jpv/GigaAM/tokenizer_all_sets.tar
+
+  curl -SL -O https://huggingface.co/csukuangfj/tmp-files/resolve/main/GigaAM/rnnt/rnnt_model_weights.ckpt
+  curl -SL -O https://huggingface.co/csukuangfj/tmp-files/resolve/main/GigaAM/rnnt/rnnt_model_config.yaml
+  curl -SL -O https://huggingface.co/csukuangfj/tmp-files/resolve/main/GigaAM/example.wav
+  curl -SL -O https://huggingface.co/csukuangfj/tmp-files/resolve/main/GigaAM/long_example.wav
+  curl -SL -O https://huggingface.co/csukuangfj/tmp-files/resolve/main/GigaAM/GigaAM%20License_NC.pdf
+  curl -SL -O https://huggingface.co/csukuangfj/tmp-files/resolve/main/GigaAM/rnnt/tokenizer_all_sets.tar
+  tar -xf tokenizer_all_sets.tar && rm tokenizer_all_sets.tar
+  ls -lh
+  echo "---"
+  ls -lh tokenizer_all_sets
+  echo "---"
+}
+
+install_nemo
+download_files
+
+python3 ./export-onnx-rnnt.py
+ls -lh
+python3 ./test-onnx-rnnt.py
+rm -v encoder.onnx
+ls -lh

+#!/usr/bin/env python3
+# Copyright      2024  Xiaomi Corp.        (authors: Fangjun Kuang)
+
+import argparse
+from pathlib import Path
+
+import kaldi_native_fbank as knf
+import librosa
+import numpy as np
+import onnxruntime as ort
+import soundfile as sf
+import torch
+
+
+def create_fbank():
+    opts = knf.FbankOptions()
+    opts.frame_opts.dither = 0
+    opts.frame_opts.remove_dc_offset = False
+    opts.frame_opts.preemph_coeff = 0
+    opts.frame_opts.window_type = "hann"
+
+    # Even though GigaAM uses 400 for fft, here we use 512
+    # since kaldi-native-fbank only support fft for power of 2.
+    opts.frame_opts.round_to_power_of_two = True
+
+    opts.mel_opts.low_freq = 0
+    opts.mel_opts.high_freq = 8000
+    opts.mel_opts.num_bins = 64
+
+    fbank = knf.OnlineFbank(opts)
+    return fbank
+
+
+def compute_features(audio, fbank):
+    assert len(audio.shape) == 1, audio.shape
+    fbank.accept_waveform(16000, audio)
+    ans = []
+    processed = 0
+    while processed < fbank.num_frames_ready:
+        ans.append(np.array(fbank.get_frame(processed)))
+        processed += 1
+    ans = np.stack(ans)
+    return ans
+
+
+def display(sess):
+    print("==========Input==========")
+    for i in sess.get_inputs():
+        print(i)
+    print("==========Output==========")
+    for i in sess.get_outputs():
+        print(i)
+
+
+"""
+==========Input==========
+NodeArg(name='audio_signal', type='tensor(float)', shape=['audio_signal_dynamic_axes_1', 64, 'audio_signal_dynamic_axes_2'])
+NodeArg(name='length', type='tensor(int64)', shape=['length_dynamic_axes_1'])
+==========Output==========
+NodeArg(name='outputs', type='tensor(float)', shape=['outputs_dynamic_axes_1', 768, 'outputs_dynamic_axes_2'])
+NodeArg(name='encoded_lengths', type='tensor(int64)', shape=['encoded_lengths_dynamic_axes_1'])
+==========Input==========
+NodeArg(name='targets', type='tensor(int32)', shape=['targets_dynamic_axes_1', 'targets_dynamic_axes_2'])
+NodeArg(name='target_length', type='tensor(int32)', shape=['target_length_dynamic_axes_1'])
+NodeArg(name='states.1', type='tensor(float)', shape=[1, 'states.1_dim_1', 320])
+NodeArg(name='onnx::LSTM_3', type='tensor(float)', shape=[1, 1, 320])
+==========Output==========
+NodeArg(name='outputs', type='tensor(float)', shape=['outputs_dynamic_axes_1', 320, 'outputs_dynamic_axes_2'])
+NodeArg(name='prednet_lengths', type='tensor(int32)', shape=['prednet_lengths_dynamic_axes_1'])
+NodeArg(name='states', type='tensor(float)', shape=[1, 'states_dynamic_axes_1', 320])
+NodeArg(name='74', type='tensor(float)', shape=[1, 'states_dynamic_axes_1', 320])
+==========Input==========
+NodeArg(name='encoder_outputs', type='tensor(float)', shape=['encoder_outputs_dynamic_axes_1', 768, 'encoder_outputs_dynamic_axes_2'])
+NodeArg(name='decoder_outputs', type='tensor(float)', shape=['decoder_outputs_dynamic_axes_1', 320, 'decoder_outputs_dynamic_axes_2'])
+==========Output==========
+NodeArg(name='outputs', type='tensor(float)', shape=['outputs_dynamic_axes_1', 'outputs_dynamic_axes_2', 'outputs_dynamic_axes_3', 513])
+"""
+
+
+class OnnxModel:
+    def __init__(
+        self,
+        encoder: str,
+        decoder: str,
+        joiner: str,
+    ):
+        self.init_encoder(encoder)
+        display(self.encoder)
+        self.init_decoder(decoder)
+        display(self.decoder)
+        self.init_joiner(joiner)
+        display(self.joiner)
+
+    def init_encoder(self, encoder):
+        session_opts = ort.SessionOptions()
+        session_opts.inter_op_num_threads = 1
+        session_opts.intra_op_num_threads = 1
+
+        self.encoder = ort.InferenceSession(
+            encoder,
+            sess_options=session_opts,
+            providers=["CPUExecutionProvider"],
+        )
+
+        meta = self.encoder.get_modelmeta().custom_metadata_map
+        self.normalize_type = meta["normalize_type"]
+        print(meta)
+
+        self.pred_rnn_layers = int(meta["pred_rnn_layers"])
+        self.pred_hidden = int(meta["pred_hidden"])
+
+    def init_decoder(self, decoder):
+        session_opts = ort.SessionOptions()
+        session_opts.inter_op_num_threads = 1
+        session_opts.intra_op_num_threads = 1
+
+        self.decoder = ort.InferenceSession(
+            decoder,
+            sess_options=session_opts,
+            providers=["CPUExecutionProvider"],
+        )
+
+    def init_joiner(self, joiner):
+        session_opts = ort.SessionOptions()
+        session_opts.inter_op_num_threads = 1
+        session_opts.intra_op_num_threads = 1
+
+        self.joiner = ort.InferenceSession(
+            joiner,
+            sess_options=session_opts,
+            providers=["CPUExecutionProvider"],
+        )
+
+    def get_decoder_state(self):
+        batch_size = 1
+        state0 = torch.zeros(self.pred_rnn_layers, batch_size, self.pred_hidden).numpy()
+        state1 = torch.zeros(self.pred_rnn_layers, batch_size, self.pred_hidden).numpy()
+        return state0, state1
+
+    def run_encoder(self, x: np.ndarray):
+        # x: (T, C)
+        x = torch.from_numpy(x)
+        x = x.t().unsqueeze(0)
+        # x: [1, C, T]
+        x_lens = torch.tensor([x.shape[-1]], dtype=torch.int64)
+
+        (encoder_out, out_len) = self.encoder.run(
+            [
+                self.encoder.get_outputs()[0].name,
+                self.encoder.get_outputs()[1].name,
+            ],
+            {
+                self.encoder.get_inputs()[0].name: x.numpy(),
+                self.encoder.get_inputs()[1].name: x_lens.numpy(),
+            },
+        )
+        # [batch_size, dim, T]
+        return encoder_out
+
+    def run_decoder(
+        self,
+        token: int,
+        state0: np.ndarray,
+        state1: np.ndarray,
+    ):
+        target = torch.tensor([[token]], dtype=torch.int32).numpy()
+        target_len = torch.tensor([1], dtype=torch.int32).numpy()
+
+        (
+            decoder_out,
+            decoder_out_length,
+            state0_next,
+            state1_next,
+        ) = self.decoder.run(
+            [
+                self.decoder.get_outputs()[0].name,
+                self.decoder.get_outputs()[1].name,
+                self.decoder.get_outputs()[2].name,
+                self.decoder.get_outputs()[3].name,
+            ],
+            {
+                self.decoder.get_inputs()[0].name: target,
+                self.decoder.get_inputs()[1].name: target_len,
+                self.decoder.get_inputs()[2].name: state0,
+                self.decoder.get_inputs()[3].name: state1,
+            },
+        )
+        return decoder_out, state0_next, state1_next
+
+    def run_joiner(
+        self,
+        encoder_out: np.ndarray,
+        decoder_out: np.ndarray,
+    ):
+        # encoder_out: [batch_size,  dim, 1]
+        # decoder_out: [batch_size,  dim, 1]
+        logit = self.joiner.run(
+            [
+                self.joiner.get_outputs()[0].name,
+            ],
+            {
+                self.joiner.get_inputs()[0].name: encoder_out,
+                self.joiner.get_inputs()[1].name: decoder_out,
+            },
+        )[0]
+        # logit: [batch_size, 1, 1, vocab_size]
+        return logit
+
+
+def main():
+    model = OnnxModel("encoder.int8.onnx", "decoder.onnx", "joiner.onnx")
+
+    id2token = dict()
+    with open("./tokens.txt", encoding="utf-8") as f:
+        for line in f:
+            t, idx = line.split()
+            id2token[int(idx)] = t
+
+    fbank = create_fbank()
+    audio, sample_rate = sf.read("./example.wav", dtype="float32", always_2d=True)
+    audio = audio[:, 0]  # only use the first channel
+    if sample_rate != 16000:
+        audio = librosa.resample(
+            audio,
+            orig_sr=sample_rate,
+            target_sr=16000,
+        )
+        sample_rate = 16000
+
+    tail_padding = np.zeros(sample_rate * 2)
+
+    audio = np.concatenate([audio, tail_padding])
+
+    blank = len(id2token) - 1
+    ans = [blank]
+    state0, state1 = model.get_decoder_state()
+    decoder_out, state0_next, state1_next = model.run_decoder(ans[-1], state0, state1)
+
+    features = compute_features(audio, fbank)
+    print("audio.shape", audio.shape)
+    print("features.shape", features.shape)
+
+    encoder_out = model.run_encoder(features)
+    # encoder_out:[batch_size, dim, T)
+    for t in range(encoder_out.shape[2]):
+        encoder_out_t = encoder_out[:, :, t : t + 1]
+        logits = model.run_joiner(encoder_out_t, decoder_out)
+        logits = torch.from_numpy(logits)
+        logits = logits.squeeze()
+        idx = torch.argmax(logits, dim=-1).item()
+        if idx != blank:
+            ans.append(idx)
+            state0 = state0_next
+            state1 = state1_next
+            decoder_out, state0_next, state1_next = model.run_decoder(
+                ans[-1], state0, state1
+            )
+
+    ans = ans[1:]  # remove the first blank
+    print(ans)
+    tokens = [id2token[i] for i in ans]
+    underline = "▁"
+    #  underline = b"\xe2\x96\x81".decode()
+    text = "".join(tokens).replace(underline, " ").strip()
+    print("./example.wav")
+    print(text)
+
+
+if __name__ == "__main__":
+    main()

@@ -166,7 +166,8 @@ std::unique_ptr<OfflineRecognizerImpl> OfflineRecognizerImpl::Create(
     return std::make_unique<OfflineRecognizerParaformerImpl>(config);
   }
 
-  if (model_type == "EncDecHybridRNNTCTCBPEModel" &&
+  if ((model_type == "EncDecHybridRNNTCTCBPEModel" ||
+       model_type == "EncDecRNNTBPEModel") &&
       !config.model_config.transducer.decoder_filename.empty() &&
       !config.model_config.transducer.joiner_filename.empty()) {
     return std::make_unique<OfflineRecognizerTransducerNeMoImpl>(config);
@@ -191,6 +192,7 @@ std::unique_ptr<OfflineRecognizerImpl> OfflineRecognizerImpl::Create(
       " - EncDecCTCModelBPE models from NeMo\n"
       " - EncDecCTCModel models from NeMo\n"
       " - EncDecHybridRNNTCTCBPEModel models from NeMo\n"
+      " - EncDecRNNTBPEModel models from NeMO"
       " - Whisper models\n"
       " - Tdnn models\n"
       " - Zipformer CTC models\n"
@@ -338,7 +340,8 @@ std::unique_ptr<OfflineRecognizerImpl> OfflineRecognizerImpl::Create(
     return std::make_unique<OfflineRecognizerParaformerImpl>(mgr, config);
   }
 
-  if (model_type == "EncDecHybridRNNTCTCBPEModel" &&
+  if ((model_type == "EncDecHybridRNNTCTCBPEModel" ||
+       model_type == "EncDecRNNTBPEModel") &&
       !config.model_config.transducer.decoder_filename.empty() &&
       !config.model_config.transducer.joiner_filename.empty()) {
     return std::make_unique<OfflineRecognizerTransducerNeMoImpl>(mgr, config);
@@ -363,6 +366,7 @@ std::unique_ptr<OfflineRecognizerImpl> OfflineRecognizerImpl::Create(
       " - EncDecCTCModelBPE models from NeMo\n"
       " - EncDecCTCModel models from NeMo\n"
       " - EncDecHybridRNNTCTCBPEModel models from NeMo\n"
+      " - EncDecRNNTBPEModel models from NeMo\n"
       " - Whisper models\n"
       " - Tdnn models\n"
       " - Zipformer CTC models\n"

@@ -139,23 +139,29 @@ class OfflineRecognizerTransducerNeMoImpl : public OfflineRecognizerImpl {
     }
   }
 
-  OfflineRecognizerConfig GetConfig() const override {
-    return config_;
-  }
+  OfflineRecognizerConfig GetConfig() const override { return config_; }
 
  private:
   void PostInit() {
     config_.feat_config.nemo_normalize_type =
         model_->FeatureNormalizationMethod();
 
-    config_.feat_config.low_freq = 0;
-    // config_.feat_config.high_freq = 8000;
-    config_.feat_config.is_librosa = true;
-    config_.feat_config.remove_dc_offset = false;
-    // config_.feat_config.window_type = "hann";
     config_.feat_config.dither = 0;
-    config_.feat_config.nemo_normalize_type =
-        model_->FeatureNormalizationMethod();
+
+    if (model_->IsGigaAM()) {
+      config_.feat_config.low_freq = 0;
+      config_.feat_config.high_freq = 8000;
+      config_.feat_config.remove_dc_offset = false;
+      config_.feat_config.preemph_coeff = 0;
+      config_.feat_config.window_type = "hann";
+      config_.feat_config.feature_dim = 64;
+    } else {
+      config_.feat_config.low_freq = 0;
+      // config_.feat_config.high_freq = 8000;
+      config_.feat_config.is_librosa = true;
+      config_.feat_config.remove_dc_offset = false;
+      // config_.feat_config.window_type = "hann";
+    }
 
     int32_t vocab_size = model_->VocabSize();
 

@@ -153,6 +153,8 @@ class OfflineTransducerNeMoModel::Impl {
 
   std::string FeatureNormalizationMethod() const { return normalize_type_; }
 
+  bool IsGigaAM() const { return is_giga_am_; }
+
  private:
   void InitEncoder(void *model_data, size_t model_data_length) {
     encoder_sess_ = std::make_unique<Ort::Session>(
@@ -181,9 +183,11 @@ class OfflineTransducerNeMoModel::Impl {
     vocab_size_ += 1;
 
     SHERPA_ONNX_READ_META_DATA(subsampling_factor_, "subsampling_factor");
-    SHERPA_ONNX_READ_META_DATA_STR(normalize_type_, "normalize_type");
+    SHERPA_ONNX_READ_META_DATA_STR_ALLOW_EMPTY(normalize_type_,
+                                               "normalize_type");
     SHERPA_ONNX_READ_META_DATA(pred_rnn_layers_, "pred_rnn_layers");
     SHERPA_ONNX_READ_META_DATA(pred_hidden_, "pred_hidden");
+    SHERPA_ONNX_READ_META_DATA_WITH_DEFAULT(is_giga_am_, "is_giga_am", 0);
 
     if (normalize_type_ == "NA") {
       normalize_type_ = "";
@@ -245,6 +249,7 @@ class OfflineTransducerNeMoModel::Impl {
   std::string normalize_type_;
   int32_t pred_rnn_layers_ = -1;
   int32_t pred_hidden_ = -1;
+  int32_t is_giga_am_ = 0;
 };
 
 OfflineTransducerNeMoModel::OfflineTransducerNeMoModel(
@@ -298,4 +303,6 @@ std::string OfflineTransducerNeMoModel::FeatureNormalizationMethod() const {
   return impl_->FeatureNormalizationMethod();
 }
 
+bool OfflineTransducerNeMoModel::IsGigaAM() const { return impl_->IsGigaAM(); }
+
 }  // namespace sherpa_onnx

@@ -93,6 +93,8 @@ class OfflineTransducerNeMoModel {
   // for details
   std::string FeatureNormalizationMethod() const;
 
+  bool IsGigaAM() const;
+
  private:
   class Impl;
   std::unique_ptr<Impl> impl_;

@@ -404,6 +404,19 @@ fun getOfflineModelConfig(type: Int): OfflineModelConfig? {
                 tokens = "$modelDir/tokens.txt",
             )
         }
+
+        20 -> {
+            val modelDir = "sherpa-onnx-nemo-transducer-giga-am-russian-2024-10-24"
+            return OfflineModelConfig(
+                transducer = OfflineTransducerModelConfig(
+                    encoder = "$modelDir/encoder.int8.onnx",
+                    decoder = "$modelDir/decoder.onnx",
+                    joiner = "$modelDir/joiner.onnx",
+                ),
+                tokens = "$modelDir/tokens.txt",
+                modelType = "nemo_transducer",
+            )
+        }
     }
     return null
 }