Expose measured Opus codec delay for capture clock mapping

lib/opus_codec.c

@@ -151,6 +151,18 @@ int opus_codec_encoder_application_set(opus_codec_encoder_t* enc, int applicatio
     return opus_encoder_ctl(enc->opus_enc, OPUS_SET_APPLICATION(application));
 }
 
+int opus_codec_encoder_delay(opus_codec_encoder_t* enc, int* samples) {
+    if (!enc || !samples) { DEBUG_ERROR(DEBUG_CATEGORY_CALL, "Opus delay invalid arguments"); return -1; }
+    opus_int32 delay = 0;
+    int result = opus_encoder_ctl(enc->opus_enc, OPUS_GET_LOOKAHEAD(&delay));
+    if (result != OPUS_OK || delay < 0 || delay > enc->sample_rate) {
+        DEBUG_ERROR(DEBUG_CATEGORY_CALL, "Opus delay query failed result=%d samples=%d", result, (int)delay); return -1;
+    }
+    *samples = delay;
+    DEBUG_DEBUG(DEBUG_CATEGORY_CALL, "Opus capture delay samples=%d rate=%d", (int)delay, enc->sample_rate);
+    return 0;
+}
+
 const char* opus_codec_strerror(int err) {
     switch (err) {
     case OPUS_OK: return "OK";