Add endpointing (#54)

sherpa-onnx/csrc/endpoint.cc

@@ -0,0 +1,91 @@
+// sherpa-onnx/csrc/endpoint.cc
+//
+// Copyright (c)  2022  (authors: Pingfeng Luo)
+//                2022-2023  Xiaomi Corporation
+
+#include "sherpa-onnx/csrc/endpoint.h"
+
+#include <string>
+
+#include "sherpa-onnx/csrc/log.h"
+#include "sherpa-onnx/csrc/parse-options.h"
+
+namespace sherpa_onnx {
+
+static bool RuleActivated(const EndpointRule &rule,
+                          const std::string &rule_name, float trailing_silence,
+                          float utterance_length) {
+  bool contain_nonsilence = utterance_length > trailing_silence;
+  bool ans = (contain_nonsilence || !rule.must_contain_nonsilence) &&
+             trailing_silence >= rule.min_trailing_silence &&
+             utterance_length >= rule.min_utterance_length;
+  if (ans) {
+    SHERPA_ONNX_LOG(DEBUG) << "Endpointing rule " << rule_name << " activated: "
+                           << (contain_nonsilence ? "true" : "false") << ','
+                           << trailing_silence << ',' << utterance_length;
+  }
+  return ans;
+}
+
+static void RegisterEndpointRule(ParseOptions *po, EndpointRule *rule,
+                                 const std::string &rule_name) {
+  po->Register(
+      rule_name + "-must-contain-nonsilence", &rule->must_contain_nonsilence,
+      "If True, for this endpointing " + rule_name +
+          " to apply there must be nonsilence in the best-path traceback. "
+          "For decoding, a non-blank token is considered as non-silence");
+  po->Register(rule_name + "-min-trailing-silence", &rule->min_trailing_silence,
+               "This endpointing " + rule_name +
+                   " requires duration of trailing silence in seconds) to "
+                   "be >= this value.");
+  po->Register(rule_name + "-min-utterance-length", &rule->min_utterance_length,
+               "This endpointing " + rule_name +
+                   " requires utterance-length (in seconds) to be >= this "
+                   "value.");
+}
+
+std::string EndpointRule::ToString() const {
+  std::ostringstream os;
+
+  os << "EndpointRule(";
+  os << "must_contain_nonsilence="
+     << (must_contain_nonsilence ? "True" : "False") << ", ";
+  os << "min_trailing_silence=" << min_trailing_silence << ", ";
+  os << "min_utterance_length=" << min_utterance_length << ")";
+
+  return os.str();
+}
+
+void EndpointConfig::Register(ParseOptions *po) {
+  RegisterEndpointRule(po, &rule1, "rule1");
+  RegisterEndpointRule(po, &rule2, "rule2");
+  RegisterEndpointRule(po, &rule3, "rule3");
+}
+
+std::string EndpointConfig::ToString() const {
+  std::ostringstream os;
+
+  os << "EndpointConfig(";
+  os << "rule1=" << rule1.ToString() << ", ";
+  os << "rule2=" << rule2.ToString() << ", ";
+  os << "rule3=" << rule3.ToString() << ")";
+
+  return os.str();
+}
+
+bool Endpoint::IsEndpoint(int num_frames_decoded, int trailing_silence_frames,
+                          float frame_shift_in_seconds) const {
+  float utterance_length = num_frames_decoded * frame_shift_in_seconds;
+  float trailing_silence = trailing_silence_frames * frame_shift_in_seconds;
+  if (RuleActivated(config_.rule1, "rule1", trailing_silence,
+                    utterance_length) ||
+      RuleActivated(config_.rule2, "rule2", trailing_silence,
+                    utterance_length) ||
+      RuleActivated(config_.rule3, "rule3", trailing_silence,
+                    utterance_length)) {
+    return true;
+  }
+  return false;
+}
+
+}  // namespace sherpa_onnx