Fix gaps in phonetic recognition

Randomly, entire utterances yielded no phones with the phonetic recognizer.
The cause was a check for empty utterances that made sense for word
recognition, but not for phonetic recognition.

rhubarb/src/recognition/pocketSphinxTools.cpp

@@ -219,10 +219,19 @@ BoundedTimeline<string> recognizeWords(const vector<int16_t>& audioBuffer, ps_de
 	BoundedTimeline<string> result(
 		TimeRange(0_cs, centiseconds(100 * audioBuffer.size() / sphinxSampleRate))
 	);
+	const bool phonetic = cmd_ln_boolean_r(decoder.config, "-allphone_ci");
+	if (!phonetic) {
+		// If the decoder is in word mode (as opposed to phonetic recognition), it expects each
+		// utterance to contain speech. If it doesn't, ps_seg_word() logs the annoying error
+		// "Couldn't find <s> in first frame".
+		// Not every utterance does contain speech, however. In this case, we exit early to prevent
+		// the log output.
+		// We *don't* to that in phonetic mode because here, the same code would omit valid phones.
 		const bool noWordsRecognized = reinterpret_cast<ngram_search_t*>(decoder.search)->bpidx == 0;
 		if (noWordsRecognized) {
 			return result;
 		}
+	}
 
 	// Collect words
 	for (ps_seg_t* it = ps_seg_iter(&decoder); it; it = ps_seg_next(it)) {