[binding] refactor wenet_decode api, remove wenet_get_result

runtime/binding/python/cpp/binding.cc

@@ -25,9 +25,8 @@ PYBIND11_MODULE(_wenet, m) {
         "wenet init");
   m.def("wenet_free", &wenet_free, "wenet free");
   m.def("wenet_reset", &wenet_reset, "wenet reset");
-  m.def("wenet_decode", &wenet_decode, "wenet decode");
-  m.def("wenet_get_result", &wenet_get_result, py::return_value_policy::copy,
-        "wenet get result");
+  m.def("wenet_decode", &wenet_decode, py::return_value_policy::copy,
+        "wenet decode");
   m.def("wenet_set_log_level", &wenet_set_log_level, "set log level");
   m.def("wenet_set_nbest", &wenet_set_nbest, "set nbest");
   m.def("wenet_set_timestamp", &wenet_set_timestamp, "set timestamp flag");

runtime/binding/python/py/decoder.py

@@ -96,8 +96,7 @@ def decode(self, pcm: bytes, last: bool = True) -> str:
         """
         assert isinstance(pcm, bytes)
         finish = 1 if last else 0
-        _wenet.wenet_decode(self.d, pcm, len(pcm), finish)
-        result = _wenet.wenet_get_result(self.d)
+        result = _wenet.wenet_decode(self.d, pcm, len(pcm), finish)
         if last:  # Reset status for next decoding automatically
             self.reset()
         return result

runtime/binding/python/setup.py

@@ -79,7 +79,7 @@ def read_long_description():
     cmdclass={"build_ext": BuildExtension},
     zip_safe=False,
     setup_requires=["tqdm"],
-    install_requires=["torch", "tqdm"] if "ONNX=ON" not in
+    install_requires=["torch>=1.10.0", "tqdm"] if "ONNX=ON" not in
         os.environ.get("WENET_CMAKE_ARGS", "") else ["tqdm"],
     classifiers=[
         "Programming Language :: C++",

runtime/core/api/wenet_api.cc

@@ -89,7 +89,6 @@ class Recognizer {
     if (decoder_ != nullptr) {
       decoder_->Reset();
     }
-    result_.clear();
   }
 
   void InitDecoder() {
@@ -115,7 +114,7 @@ class Recognizer {
                                                    *decode_options_);
   }
 
-  void Decode(const char* data, int len, int last) {
+  std::string Decode(const char* data, int len, int last) {
     using wenet::DecodeState;
     // Init decoder when it is called first time
     if (decoder_ == nullptr) {
@@ -129,25 +128,29 @@ class Recognizer {
       feature_pipeline_->set_input_finished();
     }
 
+    std::string result = "{}";  // empty json
     while (true) {
       DecodeState state = decoder_->Decode(false);
       if (state == DecodeState::kWaitFeats) {
+        result = UpdateResult(false);
         break;
       } else if (state == DecodeState::kEndFeats) {
         decoder_->Rescoring();
-        UpdateResult(true);
+        result = UpdateResult(true);
         break;
       } else if (state == DecodeState::kEndpoint && continuous_decoding_) {
         decoder_->Rescoring();
-        UpdateResult(true);
+        result = UpdateResult(true);
         decoder_->ResetContinuousDecoding();
+        break;
       } else {  // kEndBatch
-        UpdateResult(false);
+        result = UpdateResult(false);
       }
     }
+    return result;
   }
 
-  void UpdateResult(bool final_result) {
+  std::string UpdateResult(bool final_result) {
     json::JSON obj;
     obj["type"] = final_result ? "final_result" : "partial_result";
     int nbest = final_result ? nbest_ : 1;
@@ -168,11 +171,9 @@ class Recognizer {
       one["sentence"] = decoder_->result()[i].sentence;
       obj["nbest"].append(one);
     }
-    result_ = obj.dump();
+    return obj.dump();
   }
 
-  const char* GetResult() { return result_.c_str(); }
-
   void set_nbest(int n) { nbest_ = n; }
   void set_enable_timestamp(bool flag) { enable_timestamp_ = flag; }
   void AddContext(const char* word) { context_.emplace_back(word); }
@@ -191,7 +192,6 @@ class Recognizer {
   std::shared_ptr<wenet::PostProcessOptions> post_process_opts_ = nullptr;
 
   int nbest_ = 1;
-  std::string result_;
   bool enable_timestamp_ = false;
   std::vector<std::string> context_;
   float context_score_;
@@ -213,14 +213,11 @@ void wenet_reset(void* decoder) {
   recognizer->Reset();
 }
 
-void wenet_decode(void* decoder, const char* data, int len, int last) {
-  Recognizer* recognizer = reinterpret_cast<Recognizer*>(decoder);
-  recognizer->Decode(data, len, last);
-}
-
-const char* wenet_get_result(void* decoder) {
+const char* wenet_decode(void* decoder, const char* data, int len, int last) {
+  static std::string result;
   Recognizer* recognizer = reinterpret_cast<Recognizer*>(decoder);
-  return recognizer->GetResult();
+  result = recognizer->Decode(data, len, last);
+  return result.c_str();
 }
 
 void wenet_set_log_level(int level) {

runtime/core/api/wenet_api.h

@@ -34,14 +34,7 @@ void wenet_free(void* decoder);
  */
 void wenet_reset(void* decoder);
 
-/** Decode the input wav data
- * @param data: pcm data, encoded as int16_t(16 bits)
- * @param len: data length
- * @param last: if it is the last package
- */
-void wenet_decode(void* decoder, const char* data, int len, int last);
-
-/** Get decode result in json format
+/** Decode the input wav data and get decode result in json format
  *  It returns partial result when last is 0
  *  It returns final result when last is 1
 
@@ -68,7 +61,13 @@ void wenet_decode(void* decoder, const char* data, int len, int last);
     "nbest": nbest is enabled when n > 1 in final_result
         "sentence": the ASR result
         "word_pieces": optional, output timestamp when enabled
+
+ * @param data: pcm data, encoded as int16_t(16 bits)
+ * @param len: data length
+ * @param last: if it is the last package
  */
+const char* wenet_decode(void* decoder, const char* data, int len, int last);
+
 const char* wenet_get_result(void* decoder);
 
 /** Set n-best, range 1~10

runtime/core/bin/api_main.cc

@@ -36,9 +36,9 @@ int main(int argc, char* argv[]) {
 
   for (int i = 0; i < 10; i++) {
     // Return the final result when last is 1
-    wenet_decode(decoder, reinterpret_cast<const char*>(data.data()),
-                 data.size() * 2, 1);
-    const char* result = wenet_get_result(decoder);
+    const char* result =
+        wenet_decode(decoder, reinterpret_cast<const char*>(data.data()),
+                     data.size() * 2, 1);
     LOG(INFO) << i << " " << result;
     wenet_reset(decoder);
   }