saving adaptation state between utterances of a single session

src/Makefile

 all:
 
-KALDI_ROOT?=/home/tanel/tools/kaldi-online
+KALDI_ROOT?=/home/tanel/tools/kaldi-trunk
 
 ifeq ("$(wildcard $(KALDI_ROOT)/src/kaldi.mk)","")
 $(error Cannot find Kaldi's makefile $(KALDI_ROOT)/src/kaldi.mk. \

src/gstkaldinnet2onlinedecoder.cc

@@ -462,7 +462,7 @@ static void gst_kaldinnet2onlinedecoder_get_property(GObject * object,
 
 static void gst_kaldinnet2onlinedecoder_final_result(
     Gstkaldinnet2onlinedecoder * filter, const CompactLattice &clat,
-    int64 *tot_num_frames, double *tot_like) {
+    int64 *tot_num_frames, double *tot_like, guint *num_words) {
   if (clat.NumStates() == 0) {
     KALDI_WARN<< "Empty lattice.";
     return;
@@ -499,6 +499,7 @@ static void gst_kaldinnet2onlinedecoder_final_result(
   GST_DEBUG_OBJECT(filter, "Final: %s", sentence.str().c_str());
 
   guint hyp_length = sentence.str().length();
+  *num_words = hyp_length;
   if (hyp_length > 0) {
     GstBuffer *buffer = gst_buffer_new_and_alloc(hyp_length + 1);
     gst_buffer_fill(buffer, 0, sentence.str().c_str(), hyp_length);
@@ -545,10 +546,11 @@ static void gst_kaldinnet2onlinedecoder_loop(
 
   int32 chunk_length = int32(filter->sample_rate * chunk_length_secs);
 
+  OnlineIvectorExtractorAdaptationState adaptation_state(
+      filter->feature_info->ivector_extractor_info);
+
   bool more_data = true;
   while (more_data) {
-    OnlineIvectorExtractorAdaptationState adaptation_state(
-        filter->feature_info->ivector_extractor_info);
 
     OnlineNnet2FeaturePipeline feature_pipeline(*(filter->feature_info));
     feature_pipeline.SetAdaptationState(adaptation_state);
@@ -593,9 +595,25 @@ static void gst_kaldinnet2onlinedecoder_loop(
     GST_DEBUG_OBJECT(filter, "Lattice done");
     double tot_like = 0.0;
     int64 num_frames = 0;
+
+    guint num_words = 0;
     gst_kaldinnet2onlinedecoder_final_result(filter, clat, &num_frames,
-                                             &tot_like);
+                                             &tot_like, &num_words);
+    if (num_words > 0) {
+      // Only update adaptation state if the utterance was not empty
+      // We might avoid updating the adaptation state if
+      // we felt the utterance had low confidence.
+      feature_pipeline.GetAdaptationState(&adaptation_state);
+    }
   }
+
+  // We should also push out adaptation state now, something like this
+//  bool binary = false;
+//  Output ko("adaptation_state.txt", binary);
+//  adaptation_state.Write(ko.Stream(), binary);
+//  ko.Close();
+
+
   GST_DEBUG_OBJECT(filter, "Finished decoding loop");
   GST_DEBUG_OBJECT(filter, "Pushing EOS event");
   gst_pad_push_event(filter->srcpad, gst_event_new_eos());
@@ -699,6 +717,7 @@ static GstFlowReturn gst_kaldinnet2onlinedecoder_chain(GstPad * pad,
   if (G_UNLIKELY(!filter->audio_source))
     goto not_negotiated;
   if (!filter->silent) {
+    GST_DEBUG_OBJECT(filter, "Pushing buffer of length %zu", gst_buffer_get_size(buf));
     filter->audio_source->PushBuffer(buf);
   }
   gst_buffer_unref(buf);