Wrap transcription attempt in a try/except

If the audio file is empty or has no discernable human voices, the
transcription may fail with an exception.  Record that when it happens
and move continue to the next file, rather than failing.

tcd.py

@@ -188,11 +188,23 @@ def main():
         print("NOTICE: No new entries found to transcribe.")
         sys.exit(0)
 
-    eprint("Transcribing: {}".format(", ".join(files_to_transcribe)))
+    eprint(
+        "Transcribing {} files: {}".format(
+            str(len(files_to_transcribe)), ", ".join(files_to_transcribe)
+        )
+    )
     for index, f in enumerate(files_to_transcribe):
+        eprint(
+            "Transcribing file {}: {} ({})".format(
+                index + 1, f, converttcdfilename(f)
+            )
+        )
+        try:
             transcribe_with_timestamp(os.path.join(tcd_path, f))
             if index != len(files):
                 print("\n\n")
+        except:
+            eprint("Transcription failed!")
 
     writelast(files_to_transcribe[-1])
     sys.exit(0)