From d4fbec39d1bc2144150c6233f51c88cb40453559 Mon Sep 17 00:00:00 2001
From: Richard Fuchs <rfuchs@sipwise.com>
Date: Wed, 19 May 2021 13:22:42 -0400
Subject: [PATCH] TT#122401 return ptime from decoded packets for DTX

Change-Id: I382b842406fbee73ec752f6f4f0832736222ef52
---
 daemon/codec.c         | 24 ++++++++++++++++++++----
 include/media_socket.h |  1 +
 lib/codeclib.c         | 22 +++++++++++++++++-----
 lib/codeclib.h         |  2 ++
 4 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/daemon/codec.c b/daemon/codec.c
index 984c53ff6..752f48c49 100644
--- a/daemon/codec.c
+++ b/daemon/codec.c
@@ -2558,6 +2558,9 @@ static void __dtx_send_later(struct timerthread_queue *ttq, void *p) {
 
 	timerthread_queue_push(&dtxb->ttq, &dtxb->ttq_entry);
 
+	int ptime = dtxb->ptime;
+	int dtx_ptime = ptime;
+
 	mutex_unlock(&dtxb->lock);
 
 	rwlock_lock_r(&call->master_lock);
@@ -2568,8 +2571,13 @@ static void __dtx_send_later(struct timerthread_queue *ttq, void *p) {
 			ilogs(dtx, LOG_DEBUG, "Decoding DTX-buffered RTP packet (TS %lu) now; "
 					"%i packets left in queue", ts, p_left);
 
+			mp_copy.ptime = -1;
 			ret = dtxp->func(ch, dtxp->packet, &mp_copy);
-			if (ret)
+			if (!ret) {
+				if (mp_copy.ptime > 0)
+					ptime = mp_copy.ptime;
+			}
+			else
 				ilogs(dtx, LOG_WARN | LOG_FLAG_LIMIT,
 						"Decoder error while processing buffered RTP packet");
 		}
@@ -2583,7 +2591,7 @@ static void __dtx_send_later(struct timerthread_queue *ttq, void *p) {
 			// synthetic packet
 			mp_copy.rtp->seq_num += htons(1);
 
-			ret = decoder_dtx(ch->decoder, ts, dtxb->ptime,
+			ret = decoder_dtx(ch->decoder, ts, ptime,
 					ch->handler->packet_decoded, ch, &mp_copy);
 			if (ret)
 				ilogs(dtx, LOG_WARN | LOG_FLAG_LIMIT,
@@ -2598,6 +2606,13 @@ static void __dtx_send_later(struct timerthread_queue *ttq, void *p) {
 		}
 	}
 
+	if (ptime != dtx_ptime) {
+		mutex_lock(&dtxb->lock);
+		dtxb->ptime = ptime;
+		dtxb->tspp = ptime * dtxb->clockrate / 1000;
+		mutex_unlock(&dtxb->lock);
+	}
+
 	__ssrc_unlock_both(&mp_copy);
 
 	if (mp_copy.packets_out.length && ret == 0) {
@@ -2664,8 +2679,8 @@ static void __dtx_setup(struct codec_ssrc_handler *ch) {
 		dtx->ptime = 20;
 	ilogs(dtx, LOG_DEBUG, "Using DTX ptime %i based on handler=%i codec=%i", dtx->ptime,
 			ch->ptime, ch->handler->source_pt.codec_def->default_ptime);
-	dtx->tspp = dtx->ptime * ch->handler->source_pt.clock_rate / 1000;
 	dtx->clockrate = ch->handler->source_pt.clock_rate;
+	dtx->tspp = dtx->ptime * dtx->clockrate / 1000;
 }
 static void __ssrc_handler_stop(void *p) {
 	struct codec_ssrc_handler *ch = p;
@@ -3094,7 +3109,8 @@ static int packet_decoded_direct(decoder_t *decoder, AVFrame *frame, void *u1, v
 
 static int __rtp_decode(struct codec_ssrc_handler *ch, struct transcode_packet *packet, struct media_packet *mp)
 {
-	int ret = decoder_input_data(ch->decoder, packet->payload, packet->ts, ch->handler->packet_decoded,
+	int ret = decoder_input_data_ptime(ch->decoder, packet->payload, packet->ts, &mp->ptime,
+			ch->handler->packet_decoded,
 			ch, mp);
 	mp->ssrc_out->parent->seq_diff--;
 	return ret;
diff --git a/include/media_socket.h b/include/media_socket.h
index f39559c5c..de2933769 100644
--- a/include/media_socket.h
+++ b/include/media_socket.h
@@ -139,6 +139,7 @@ struct media_packet {
 	str payload;
 
 	GQueue packets_out;
+	int ptime; // returned from decoding
 };
 
 
diff --git a/lib/codeclib.c b/lib/codeclib.c
index c45c9829a..43bf402b0 100644
--- a/lib/codeclib.c
+++ b/lib/codeclib.c
@@ -842,7 +842,7 @@ err:
 	return -1;
 }
 
-static int __decoder_input_data(decoder_t *dec, const str *data, unsigned long ts, int ptime,
+static int __decoder_input_data(decoder_t *dec, const str *data, unsigned long ts, int *ptime,
 		int (*callback)(decoder_t *, AVFrame *, void *u1, void *u2), void *u1, void *u2)
 {
 	GQueue frames = G_QUEUE_INIT;
@@ -850,7 +850,7 @@ static int __decoder_input_data(decoder_t *dec, const str *data, unsigned long t
 	if (G_UNLIKELY(!dec))
 		return -1;
 
-	if (!data && !dec->dtx.do_dtx)
+	if (!data && (!dec->dtx.do_dtx || !ptime))
 		return 0;
 
 	ts *= dec->def->clockrate_mult;
@@ -879,11 +879,13 @@ static int __decoder_input_data(decoder_t *dec, const str *data, unsigned long t
 	if (data)
 		dec->def->codec_type->decoder_input(dec, data, &frames);
 	else
-		dec->dtx.do_dtx(dec, &frames, ptime);
+		dec->dtx.do_dtx(dec, &frames, *ptime);
 
 	AVFrame *frame;
 	int ret = 0;
+	unsigned long samples = 0;
 	while ((frame = g_queue_pop_head(&frames))) {
+		samples += frame->nb_samples;
 		dec->dec_out_format.format = frame->format;
 		AVFrame *rsmp_frame = resample_frame(&dec->resampler, frame, &dec->dest_format);
 		if (!rsmp_frame) {
@@ -897,6 +899,9 @@ static int __decoder_input_data(decoder_t *dec, const str *data, unsigned long t
 		av_frame_free(&frame);
 	}
 
+	if (ptime)
+		*ptime = samples * 1000L / dec->in_format.clockrate;
+
 	return ret;
 }
 int decoder_input_data(decoder_t *dec, const str *data, unsigned long ts,
@@ -904,12 +909,19 @@ int decoder_input_data(decoder_t *dec, const str *data, unsigned long ts,
 {
 	if (!data || !data->s || !data->len)
 		return 0;
-	return __decoder_input_data(dec, data, ts, 0, callback, u1, u2);
+	return __decoder_input_data(dec, data, ts, NULL, callback, u1, u2);
+}
+int decoder_input_data_ptime(decoder_t *dec, const str *data, unsigned long ts, int *ptime,
+		int (*callback)(decoder_t *, AVFrame *, void *u1, void *u2), void *u1, void *u2)
+{
+	if (!data || !data->s || !data->len)
+		return 0;
+	return __decoder_input_data(dec, data, ts, ptime, callback, u1, u2);
 }
 int decoder_dtx(decoder_t *dec, unsigned long ts, int ptime,
 		int (*callback)(decoder_t *, AVFrame *, void *u1, void *u2), void *u1, void *u2)
 {
-	return __decoder_input_data(dec, NULL, ts, ptime, callback, u1, u2);
+	return __decoder_input_data(dec, NULL, ts, &ptime, callback, u1, u2);
 }
 
 
diff --git a/lib/codeclib.h b/lib/codeclib.h
index b6b87bb36..e8a294a3f 100644
--- a/lib/codeclib.h
+++ b/lib/codeclib.h
@@ -307,6 +307,8 @@ decoder_t *decoder_new_fmtp(const codec_def_t *def, int clockrate, int channels,
 void decoder_close(decoder_t *dec);
 int decoder_input_data(decoder_t *dec, const str *data, unsigned long ts,
 		int (*callback)(decoder_t *, AVFrame *, void *u1, void *u2), void *u1, void *u2);
+int decoder_input_data_ptime(decoder_t *dec, const str *data, unsigned long ts, int *ptime,
+		int (*callback)(decoder_t *, AVFrame *, void *u1, void *u2), void *u1, void *u2);
 gboolean decoder_has_dtx(decoder_t *);
 int decoder_switch_dtx(decoder_t *dec, enum dtx_method);
 int decoder_set_cn_dtx(decoder_t *dec, const str *);