refactoring JSON export of OnlineRecognitionResult, extending pybind11 API of OnlineRecognitionResult

Author: KarelVesely84

sherpa-onnx/csrc/online-recognizer.cc

@@ -18,56 +18,48 @@
 
 namespace sherpa_onnx {
 
-std::string OnlineRecognizerResult::AsJsonString() const {
-  std::ostringstream os;
-  os << "{";
-  os << "\"is_final\":" << (is_final ? "true" : "false") << ", ";
-  os << "\"segment\":" << segment << ", ";
-  os << "\"start_time\":" << std::fixed << std::setprecision(2) << start_time
-     << ", ";
-
-  os << "\"text\""
-     << ": ";
-  os << "\"" << text << "\""
-     << ", ";
-
-  os << "\""
-     << "timestamps"
-     << "\""
-     << ": ";
-  os << "[";
-
+/// Helper for `OnlineRecognizerResult::AsJsonString()`
+template<typename T>
+const std::string& VecToString(const std::vector<T>& vec, int32_t precision = 6) {
+  std::ostringstrean oss;
+  oss << std::fixed << std::setprecision(precision);
+  oss << "[ " <<
   std::string sep = "";
-  for (auto t : timestamps) {
-    os << sep << std::fixed << std::setprecision(2) << t;
+  for (auto item : vec) {
+    oss << sep << item;
     sep = ", ";
   }
-  os << "], ";
-
-  os << "\""
-     << "tokens"
-     << "\""
-     << ":";
-  os << "[";
-
-  sep = "";
-  auto oldFlags = os.flags();
-  for (const auto &t : tokens) {
-    if (t.size() == 1 && static_cast<uint8_t>(t[0]) > 0x7f) {
-      const uint8_t *p = reinterpret_cast<const uint8_t *>(t.c_str());
-      os << sep << "\""
-         << "<0x" << std::hex << std::uppercase << static_cast<uint32_t>(p[0])
-         << ">"
-         << "\"";
-      os.flags(oldFlags);
-    } else {
-      os << sep << "\"" << t << "\"";
-    }
+  oss << " ]";
+  return oss.str();
+}
+
+/// Helper for `OnlineRecognizerResult::AsJsonString()`
+template<>  // explicit specialization for T = std::string
+const std::string& VecToString<std::string>(const std::vector<T>& vec, int32_t) { // ignore 2nd arg
+  std::ostringstrean oss;
+  oss << "[ " <<
+  std::string sep = "";
+  for (auto item : vec) {
+    oss << sep << "\"" << item << "\"";
     sep = ", ";
   }
-  os << "]";
-  os << "}";
+  oss << " ]";
+  return oss.str();
+}
 
+std::string OnlineRecognizerResult::AsJsonString() const {
+  std::ostringstream os;
+  os << "{ ";
+  os << "\"text\": " << "\"" << text << "\"" << ", ";
+  os << "\"tokens\": " << VecToString(tokens) << ", ";
+  os << "\"timestamps\": " << VecToString(timestamps, 2) << ", ";
+  os << "\"ys_probs\": " << VecToString(ys_probs, 6) << ", ";
+  os << "\"lm_probs\": " << VecToString(lm_probs, 6) << ", ";
+  os << "\"constext_scores\": " << VecToString(context_scores, 6) << ", ";
+  os << "\"segment\": " << segment << ", ";
+  os << "\"start_time\": " << std::fixed << std::setprecision(2) << start_time  << ", ";
+  os << "\"is_final\": " << (is_final ? "true" : "false");
+  os << "}";
   return os.str();
 }
 

sherpa-onnx/csrc/online-recognizer.h

@@ -40,9 +40,9 @@ struct OnlineRecognizerResult {
   /// timestamps[i] records the time in seconds when tokens[i] is decoded.
   std::vector<float> timestamps;
 
-  std::vector<float> ys_probs;
-  std::vector<float> lm_probs;
-  std::vector<float> context_scores;
+  std::vector<float> ys_probs;  //< log-prob scores from ASR model
+  std::vector<float> lm_probs;  //< log-prob scores from language model
+  std::vector<float> context_scores;  //< log-domain scores from "hot-phrase" contextual boosting
 
   /// ID of this segment
   /// When an endpoint is detected, it is incremented
@@ -62,6 +62,9 @@ struct OnlineRecognizerResult {
    *     "text": "The recognition result",
    *     "tokens": [x, x, x],
    *     "timestamps": [x, x, x],
+   *     "ys_probs": [x, x, x],
+   *     "lm_probs": [x, x, x],
+   *     "context_scores": [x, x, x],
    *     "segment": x,
    *     "start_time": x,
    *     "is_final": true|false

sherpa-onnx/csrc/online-transducer-modified-beam-search-decoder.cc

@@ -198,7 +198,7 @@ void OnlineTransducerModifiedBeamSearchDecoder::Decode(
           new_hyp.ys_probs.push_back(y_prob);
 
           float lm_prob = new_hyp.lm_log_prob - prev_lm_log_prob;
-          new_hyp.lm_probs.push_back(lm_probs);
+          new_hyp.lm_probs.push_back(lm_prob);
 
           new_hyp.context_scores.push_back(context_score);
         }

sherpa-onnx/python/csrc/online-recognizer.cc

@@ -34,7 +34,18 @@ static void PybindOnlineRecognizerResult(py::module *m) {
           [](PyClass &self) -> std::vector<float> { return self.lm_probs; })
       .def_property_readonly(
           "context_scores",
-          [](PyClass &self) -> std::vector<float> { return self.context_scores; });
+          [](PyClass &self) -> std::vector<float> { return self.context_scores; })
+       .def_property_readonly(
+          "segment",
+          [](PyClass &self) -> int32_t { return self.segment; })
+       .def_property_readonly(
+          "start_time",
+          [](PyClass &self) -> float { return self.start_time; })
+       .def_property_readonly(
+          "is_final",
+          [](PyClass &self) -> bool { return self.is_final; })
+       .def("as_json_string", &PyClass::AsJsonString,
+            py::call_guard<py::gil_scoped_release>());
 }
 
 static void PybindOnlineRecognizerConfig(py::module *m) {