diff --git a/sherpa-onnx/csrc/CMakeLists.txt b/sherpa-onnx/csrc/CMakeLists.txt
index b9bac58c4..ed2713453 100644
--- a/sherpa-onnx/csrc/CMakeLists.txt
+++ b/sherpa-onnx/csrc/CMakeLists.txt
@@ -78,9 +78,12 @@ set(sources
 if(SHERPA_ONNX_ENABLE_CHECK)
   list(APPEND sources log.cc)
 endif()
-
 add_library(sherpa-onnx-core ${sources})
 
+if(NOT WIN32)
+  target_link_libraries(sherpa-onnx-core -pthread)
+endif()
+
 if(ANDROID_NDK)
   target_link_libraries(sherpa-onnx-core android log)
 endif()
@@ -114,19 +117,23 @@ endif()
 
 add_executable(sherpa-onnx sherpa-onnx.cc)
 add_executable(sherpa-onnx-offline sherpa-onnx-offline.cc)
+add_executable(sherpa-onnx-offline-parallel sherpa-onnx-offline-parallel.cc)
 
 target_link_libraries(sherpa-onnx sherpa-onnx-core)
 target_link_libraries(sherpa-onnx-offline sherpa-onnx-core)
+target_link_libraries(sherpa-onnx-offline-parallel sherpa-onnx-core)
 if(NOT WIN32)
   target_link_libraries(sherpa-onnx "-Wl,-rpath,${SHERPA_ONNX_RPATH_ORIGIN}/../lib")
   target_link_libraries(sherpa-onnx "-Wl,-rpath,${SHERPA_ONNX_RPATH_ORIGIN}/../../../sherpa_onnx/lib")
 
   target_link_libraries(sherpa-onnx-offline "-Wl,-rpath,${SHERPA_ONNX_RPATH_ORIGIN}/../lib")
   target_link_libraries(sherpa-onnx-offline "-Wl,-rpath,${SHERPA_ONNX_RPATH_ORIGIN}/../../../sherpa_onnx/lib")
+  target_link_libraries(sherpa-onnx-offline-parallel "-Wl,-rpath,${SHERPA_ONNX_RPATH_ORIGIN}/../../../sherpa_onnx/lib")
 
   if(SHERPA_ONNX_ENABLE_PYTHON)
     target_link_libraries(sherpa-onnx "-Wl,-rpath,${SHERPA_ONNX_RPATH_ORIGIN}/../lib/python${PYTHON_VERSION}/site-packages/sherpa_onnx/lib")
     target_link_libraries(sherpa-onnx-offline "-Wl,-rpath,${SHERPA_ONNX_RPATH_ORIGIN}/../lib/python${PYTHON_VERSION}/site-packages/sherpa_onnx/lib")
+    target_link_libraries(sherpa-onnx-offline-parallel "-Wl,-rpath,${SHERPA_ONNX_RPATH_ORIGIN}/../lib/python${PYTHON_VERSION}/site-packages/sherpa_onnx/lib")
   endif()
 endif()
 
@@ -144,6 +151,7 @@ install(
   TARGETS
     sherpa-onnx
     sherpa-onnx-offline
+    sherpa-onnx-offline-parallel
   DESTINATION
     bin
 )
diff --git a/sherpa-onnx/csrc/offline-whisper-model.cc b/sherpa-onnx/csrc/offline-whisper-model.cc
index 57cc55e96..e0e7c97dc 100644
--- a/sherpa-onnx/csrc/offline-whisper-model.cc
+++ b/sherpa-onnx/csrc/offline-whisper-model.cc
@@ -60,9 +60,11 @@ class OfflineWhisperModel::Impl {
         decoder_input.size(), decoder_output_names_ptr_.data(),
         decoder_output_names_ptr_.size());
 
-    return {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])};
+    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() {
diff --git a/sherpa-onnx/csrc/sherpa-onnx-offline-parallel.cc b/sherpa-onnx/csrc/sherpa-onnx-offline-parallel.cc
new file mode 100644
index 000000000..faadb09cc
--- /dev/null
+++ b/sherpa-onnx/csrc/sherpa-onnx-offline-parallel.cc
@@ -0,0 +1,305 @@
+// sherpa-onnx/csrc/sherpa-onnx-offline-parallel.cc
+//
+// Copyright (c)  2022-2023  cuidc
+
+#include <stdio.h>
+
+#include <atomic>
+#include <chrono>  // NOLINT
+#include <fstream>
+#include <mutex>  // NOLINT
+#include <string>
+#include <thread>  // NOLINT
+#include <vector>
+
+#include "sherpa-onnx/csrc/offline-recognizer.h"
+#include "sherpa-onnx/csrc/parse-options.h"
+#include "sherpa-onnx/csrc/wave-reader.h"
+
+std::atomic<int> wav_index(0);
+std::mutex mtx;
+
+std::vector<std::vector<std::string>> SplitToBatches(
+    const std::vector<std::string> &input, int32_t batch_size) {
+  std::vector<std::vector<std::string>> outputs;
+  auto itr = input.cbegin();
+  int32_t process_num = 0;
+
+  while (process_num + batch_size <= static_cast<int32_t>(input.size())) {
+    auto chunk_end = itr + batch_size;
+    outputs.emplace_back(itr, chunk_end);
+    itr = chunk_end;
+    process_num += batch_size;
+  }
+  if (itr != input.cend()) {
+     outputs.emplace_back(itr, input.cend());
+  }
+  return outputs;
+}
+
+std::vector<std::string> LoadScpFile(const std::string &wav_scp_path) {
+  std::vector<std::string> wav_paths;
+  std::ifstream in(wav_scp_path);
+  if (!in.is_open()) {
+      fprintf(stderr, "Failed to open file: %s.\n", wav_scp_path.c_str());
+      return wav_paths;
+  }
+  std::string line, column1, column2;
+  while (std::getline(in, line)) {
+    std::istringstream iss(line);
+    iss >> column1 >> column2;
+    wav_paths.emplace_back(std::move(column2));
+  }
+
+  return wav_paths;
+}
+
+void AsrInference(const std::vector<std::vector<std::string>> &chunk_wav_paths,
+                   sherpa_onnx::OfflineRecognizer* recognizer,
+                   float* total_length, float* total_time) {
+  std::vector<std::unique_ptr<sherpa_onnx::OfflineStream>> ss;
+  std::vector<sherpa_onnx::OfflineStream *> ss_pointers;
+  float duration = 0.0f;
+  float elapsed_seconds_batch = 0.0f;
+
+  // warm up
+  for (const auto &wav_filename : chunk_wav_paths[0]) {
+    int32_t sampling_rate = -1;
+    bool is_ok = false;
+    const std::vector<float> samples =
+        sherpa_onnx::ReadWave(wav_filename, &sampling_rate, &is_ok);
+    if (!is_ok) {
+      fprintf(stderr, "Failed to read %s\n", wav_filename.c_str());
+       continue;
+    }
+    duration += samples.size() / static_cast<float>(sampling_rate);
+    auto s = recognizer->CreateStream();
+    s->AcceptWaveform(sampling_rate, samples.data(), samples.size());
+
+    ss.push_back(std::move(s));
+    ss_pointers.push_back(ss.back().get());
+  }
+  recognizer->DecodeStreams(ss_pointers.data(), ss_pointers.size());
+  ss_pointers.clear();
+  ss.clear();
+
+  while (true) {
+    int chunk = wav_index.fetch_add(1);
+    if (chunk >= chunk_wav_paths.size()) {
+      break;
+    }
+    const auto &wav_paths = chunk_wav_paths[chunk];
+    const auto begin = std::chrono::steady_clock::now();
+    for (const auto &wav_filename : wav_paths) {
+      int32_t sampling_rate = -1;
+      bool is_ok = false;
+      const std::vector<float> samples =
+          sherpa_onnx::ReadWave(wav_filename, &sampling_rate, &is_ok);
+      if (!is_ok) {
+        fprintf(stderr, "Failed to read %s\n", wav_filename.c_str());
+         continue;
+      }
+      duration += samples.size() / static_cast<float>(sampling_rate);
+      auto s = recognizer->CreateStream();
+      s->AcceptWaveform(sampling_rate, samples.data(), samples.size());
+
+      ss.push_back(std::move(s));
+      ss_pointers.push_back(ss.back().get());
+    }
+    recognizer->DecodeStreams(ss_pointers.data(), ss_pointers.size());
+    const auto end = std::chrono::steady_clock::now();
+    float elapsed_seconds =
+      std::chrono::duration_cast<std::chrono::milliseconds>(end - begin)
+          .count() /
+      1000.;
+    elapsed_seconds_batch += elapsed_seconds;
+    int i = 0;
+    for (const auto &wav_filename : wav_paths) {
+      fprintf(stderr, "%s\n%s\n----\n", wav_filename.c_str(),
+              ss[i]->GetResult().AsJsonString().c_str());
+      i = i + 1;
+    }
+    ss_pointers.clear();
+    ss.clear();
+  }
+  fprintf(stderr, "thread %lu.\n", std::this_thread::get_id());
+  {
+    std::lock_guard<std::mutex> guard(mtx);
+    *total_length += duration;
+    if (*total_time < elapsed_seconds_batch) {
+      *total_time = elapsed_seconds_batch;
+    }
+  }
+}
+
+
+int main(int32_t argc, char *argv[]) {
+  const char *kUsageMessage = R"usage(
+Speech recognition using non-streaming models with sherpa-onnx.
+
+Usage:
+
+(1) Transducer from icefall
+
+See https://k2-fsa.github.io/sherpa/onnx/pretrained_models/offline-transducer/index.html
+
+  ./bin/sherpa-onnx-offline-parallel \
+    --tokens=/path/to/tokens.txt \
+    --encoder=/path/to/encoder.onnx \
+    --decoder=/path/to/decoder.onnx \
+    --joiner=/path/to/joiner.onnx \
+    --num-threads=1 \
+    --decoding-method=greedy_search \
+    --batch-size=8 \
+    --nj=1 \
+    --wav-scp=wav.scp
+
+  ./bin/sherpa-onnx-offline-parallel \
+    --tokens=/path/to/tokens.txt \
+    --encoder=/path/to/encoder.onnx \
+    --decoder=/path/to/decoder.onnx \
+    --joiner=/path/to/joiner.onnx \
+    --num-threads=1 \
+    --decoding-method=greedy_search \
+    --batch-size=1 \
+    --nj=8 \
+    /path/to/foo.wav [bar.wav foobar.wav ...]
+
+(2) Paraformer from FunASR
+
+See https://k2-fsa.github.io/sherpa/onnx/pretrained_models/offline-paraformer/index.html
+
+  ./bin/sherpa-onnx-offline-parallel \
+    --tokens=/path/to/tokens.txt \
+    --paraformer=/path/to/model.onnx \
+    --num-threads=1 \
+    --decoding-method=greedy_search \
+    /path/to/foo.wav [bar.wav foobar.wav ...]
+
+(3) Whisper models
+
+See https://k2-fsa.github.io/sherpa/onnx/pretrained_models/whisper/tiny.en.html
+
+  ./bin/sherpa-onnx-offline-parallel \
+    --whisper-encoder=./sherpa-onnx-whisper-base.en/base.en-encoder.int8.onnx \
+    --whisper-decoder=./sherpa-onnx-whisper-base.en/base.en-decoder.int8.onnx \
+    --tokens=./sherpa-onnx-whisper-base.en/base.en-tokens.txt \
+    --num-threads=1 \
+    /path/to/foo.wav [bar.wav foobar.wav ...]
+
+(4) NeMo CTC models
+
+See https://k2-fsa.github.io/sherpa/onnx/pretrained_models/offline-ctc/index.html
+
+  ./bin/sherpa-onnx-offline-parallel \
+    --tokens=./sherpa-onnx-nemo-ctc-en-conformer-medium/tokens.txt \
+    --nemo-ctc-model=./sherpa-onnx-nemo-ctc-en-conformer-medium/model.onnx \
+    --num-threads=2 \
+    --decoding-method=greedy_search \
+    --debug=false \
+    ./sherpa-onnx-nemo-ctc-en-conformer-medium/test_wavs/0.wav \
+    ./sherpa-onnx-nemo-ctc-en-conformer-medium/test_wavs/1.wav \
+    ./sherpa-onnx-nemo-ctc-en-conformer-medium/test_wavs/8k.wav
+
+(5) TDNN CTC model for the yesno recipe from icefall
+
+See https://k2-fsa.github.io/sherpa/onnx/pretrained_models/offline-ctc/yesno/index.html
+      //
+  ./bin/sherpa-onnx-offline-parallel \
+    --sample-rate=8000 \
+    --feat-dim=23 \
+    --tokens=./sherpa-onnx-tdnn-yesno/tokens.txt \
+    --tdnn-model=./sherpa-onnx-tdnn-yesno/model-epoch-14-avg-2.onnx \
+    ./sherpa-onnx-tdnn-yesno/test_wavs/0_0_0_1_0_0_0_1.wav \
+    ./sherpa-onnx-tdnn-yesno/test_wavs/0_0_1_0_0_0_1_0.wav
+
+Note: It supports decoding multiple files in batches
+
+foo.wav should be of single channel, 16-bit PCM encoded wave file; its
+sampling rate can be arbitrary and does not need to be 16kHz.
+
+Please refer to
+https://k2-fsa.github.io/sherpa/onnx/pretrained_models/index.html
+for a list of pre-trained models to download.
+)usage";
+  std::string wav_scp = "";  // file path, kaldi style wav list.
+  int32_t nj = 1;  // thread number
+  int32_t batch_size = 1; // number of wav files processed at once.
+  sherpa_onnx::ParseOptions po(kUsageMessage);
+  sherpa_onnx::OfflineRecognizerConfig config;
+  config.Register(&po);
+  po.Register("wav-scp", &wav_scp,
+              "a file including wav-id and wav-path, kaldi style wav list."
+              "default="". when it is not empty, wav files which positional "
+              "parameters provide are invalid.");
+  po.Register("nj", &nj,
+              "multi-thread num for decoding, default=1");
+  po.Register("batch-size", &batch_size,
+              "number of wav files processed at once during the decoding"
+              "process. default=1");
+
+  po.Read(argc, argv);
+  if (po.NumArgs() < 1 && wav_scp.empty()) {
+    fprintf(stderr, "Error: Please provide at least 1 wave file.\n\n");
+    po.PrintUsage();
+    exit(EXIT_FAILURE);
+  }
+
+  fprintf(stderr, "%s\n", config.ToString().c_str());
+
+  if (!config.Validate()) {
+    fprintf(stderr, "Errors in config!\n");
+    return -1;
+  }
+  std::this_thread::sleep_for(std::chrono::seconds(10));  // sleep 10s
+  fprintf(stderr, "Creating recognizer ...\n");
+  const auto begin = std::chrono::steady_clock::now();
+  sherpa_onnx::OfflineRecognizer recognizer(config);
+  const auto end = std::chrono::steady_clock::now();
+  float elapsed_seconds =
+      std::chrono::duration_cast<std::chrono::milliseconds>(end - begin)
+          .count() /
+      1000.;
+  fprintf(stderr,
+          "Started nj: %d, batch_size: %d, wav_path: %s. recognizer init time: "
+          "%.6f\n", nj, batch_size, wav_scp.c_str(), elapsed_seconds);
+  std::this_thread::sleep_for(std::chrono::seconds(10));  // sleep 10s
+  std::vector<std::string> wav_paths;
+  if (!wav_scp.empty()) {
+    wav_paths = LoadScpFile(wav_scp);
+  } else {
+    for (int32_t i = 1; i <= po.NumArgs(); ++i) {
+      wav_paths.emplace_back(po.GetArg(i));
+    }
+  }
+  if (wav_paths.empty()) {
+    fprintf(stderr, "wav files is empty.\n");
+    return -1;
+  }
+  std::vector<std::thread> threads;
+  std::vector<std::vector<std::string>> batch_wav_paths =
+      SplitToBatches(wav_paths, batch_size);
+  float total_length = 0.0f;
+  float total_time = 0.0f;
+  for (int i = 0; i < nj; i++) {
+    threads.emplace_back(std::thread(AsrInference, batch_wav_paths,
+                         &recognizer, &total_length, &total_time));
+  }
+
+  for (auto& thread : threads) {
+      thread.join();
+  }
+
+  fprintf(stderr, "num threads: %d\n", config.model_config.num_threads);
+  fprintf(stderr, "decoding method: %s\n", config.decoding_method.c_str());
+  if (config.decoding_method == "modified_beam_search") {
+    fprintf(stderr, "max active paths: %d\n", config.max_active_paths);
+  }
+  fprintf(stderr, "Elapsed seconds: %.3f s\n", total_time);
+  float rtf = total_time / total_length;
+  fprintf(stderr, "Real time factor (RTF): %.6f / %.6f = %.4f\n",
+          total_time, total_length, rtf);
+  fprintf(stderr, "SPEEDUP: %.4f\n", 1.0 / rtf);
+
+  return 0;
+}