fix recording mix sample rate mismatch

if a mix output is present already, use the mix output as format (sample
rate) specifier. otherwise there can be a mismatch between A, B and mix
sample rates in case of transcoding

Change-Id: I60fd2c249129baa470c1e257d5c127ed84922020

recording-daemon/packet.c

@@ -88,10 +88,10 @@ static void packet_decode(ssrc_t *ssrc, packet_t *packet) {
 		dbg("payload type for %u is %s", payload_type, payload_str);
 
 		output_t *outp = NULL;
-		if (ssrc->output)
-			outp = ssrc->output;
-		else if (mf->mix_out)
+		if (mf->mix_out)
 			outp = mf->mix_out;
+		else if (ssrc->output)
+			outp = ssrc->output;
 		ssrc->decoders[payload_type] = decoder_new(payload_str, outp);
 		if (!ssrc->decoders[payload_type]) {
 			ilog(LOG_WARN, "Cannot decode RTP payload type %u (%s)",