diff --git a/janus/src/client.c b/janus/src/client.c
index 3b3b6e5..14f62ed 100644
--- a/janus/src/client.c
+++ b/janus/src/client.c
@@ -193,20 +193,24 @@ static void *_video_or_acap_thread(void *v_client, bool video) {
 			};
 			janus_plugin_rtp_extensions_reset(&packet.extensions);
 
-			if (rtp.zero_playout_delay) {
-				// https://github.com/pikvm/pikvm/issues/784
-				packet.extensions.min_delay = 0;
-				packet.extensions.max_delay = 0;
-			} else {
-				// Эти дефолты используются в Chrome/Safari/Firefox.
-				// Работает всё одинаково, потому что у них общая кодовая база WebRTC.
-				packet.extensions.min_delay = 0;
-				packet.extensions.max_delay = 1000; // == 10s, i.e. 10ms granularity
+			if (rtp.first_of_frame) {
+				if (rtp.zero_playout_delay) {
+					// https://github.com/pikvm/pikvm/issues/784
+					packet.extensions.min_delay = 0;
+					packet.extensions.max_delay = 0;
+				} else {
+					// Эти дефолты используются в Chrome/Safari/Firefox.
+					// Работает всё одинаково, потому что у них общая кодовая база WebRTC.
+					packet.extensions.min_delay = 0;
+					packet.extensions.max_delay = 1000; // == 10s, i.e. 10ms granularity
+				}
 			}
 
-			if (rtp.video) {
+			if (rtp.video && rtp.first_of_frame) {
 				packet.extensions.abs_capture_ts = rtp.grab_ntp_ts;
+			}
 
+			if (rtp.video && rtp.last_of_frame) {
 				uint video_orient = atomic_load(&client->video_orient);
 				if (video_orient != 0) {
 					// The extension rotates the video clockwise, but want it counterclockwise.
diff --git a/janus/src/rtp.h b/janus/src/rtp.h
index 7d0b103..8f79c8e 100644
--- a/janus/src/rtp.h
+++ b/janus/src/rtp.h
@@ -45,6 +45,9 @@ typedef struct {
 	u16		seq;
 	u8		datagram[US_RTP_DATAGRAM_SIZE];
 	uz		used;
+
+	bool	first_of_frame;
+	bool	last_of_frame;
 	bool	zero_playout_delay;
 	u64		grab_ntp_ts;
 } us_rtp_s;
diff --git a/janus/src/rtpv.c b/janus/src/rtpv.c
index a5b6fa5..7db99e9 100644
--- a/janus/src/rtpv.c
+++ b/janus/src/rtpv.c
@@ -89,6 +89,8 @@ void us_rtpv_wrap(us_rtpv_s *rtpv, const us_frame_s *frame, bool zero_playout_de
 
 	assert(frame->format == V4L2_PIX_FMT_H264);
 
+	rtpv->rtp->first_of_frame = true;
+	rtpv->rtp->last_of_frame = false;
 	rtpv->rtp->zero_playout_delay = zero_playout_delay;
 	rtpv->rtp->grab_ntp_ts = us_get_now_ntp() - us_ld_to_ntp(us_get_now_monotonic() - frame->grab_begin_ts);
 
@@ -131,7 +133,9 @@ void _rtpv_process_nalu(us_rtpv_s *rtpv, const u8 *data, uz size, u32 pts, bool
 		us_rtp_write_header(rtpv->rtp, pts, marked);
 		memcpy(dg + US_RTP_HEADER_SIZE, data, size);
 		rtpv->rtp->used = size + US_RTP_HEADER_SIZE;
+		rtpv->rtp->last_of_frame = true;
 		rtpv->callback(rtpv->rtp);
+		rtpv->rtp->first_of_frame = false;
 		return;
 	}
 
@@ -163,7 +167,9 @@ void _rtpv_process_nalu(us_rtpv_s *rtpv, const u8 *data, uz size, u32 pts, bool
 
 		memcpy(dg + fu_overhead, src, frag_size);
 		rtpv->rtp->used = fu_overhead + frag_size;
+		rtpv->rtp->last_of_frame = last;
 		rtpv->callback(rtpv->rtp);
+		rtpv->rtp->first_of_frame = false;
 
 		src += frag_size;
 		remaining -= frag_size;