1 files changed, 7 insertions, 2 deletions
diff --git a/kaldi_io/src/cwrapper_kaldi.cpp b/kaldi_io/src/cwrapper_kaldi.cpp
index e8b11a1..788128b 100644
--- a/kaldi_io/src/cwrapper_kaldi.cpp
+++ b/kaldi_io/src/cwrapper_kaldi.cpp
@@ -159,8 +159,13 @@ extern "C" {
     Matrix *kaldi_label_repo_read_utterance(KaldiLabelRepo *repo, KaldiFeatureRepo *frepo, int nframes,
                                             lua_State *L,
                                             int debug, MContext *context) {
-        Matrix *mat;
-        kaldi::Posterior targets = repo->targets_reader->Value(frepo->utt);
+        Matrix *mat = NULL;
+        /* check if the alignment of the utterance exists, otherwise return NULL */
+        kaldi::Posterior targets;
+        if (repo->targets_reader->HasKey(frepo->utt))
+            targets = repo->targets_reader->Value(frepo->utt);
+        else
+            return mat;
 
         int n = targets.size() < nframes ? targets.size() : nframes;
         int m = (int)targets[0].size();