diff --git a/janus/src/memsinkfd.c b/janus/src/memsinkfd.c
index fc4d042..d2f1f96 100644
--- a/janus/src/memsinkfd.c
+++ b/janus/src/memsinkfd.c
@@ -46,12 +46,15 @@ int us_memsink_fd_wait_frame(int fd, us_memsink_shared_s* mem, uint64_t last_id)
 	return -2;
 }
 
-us_frame_s *us_memsink_fd_get_frame(int fd, us_memsink_shared_s *mem, uint64_t *frame_id) {
+us_frame_s *us_memsink_fd_get_frame(int fd, us_memsink_shared_s *mem, uint64_t *frame_id, bool key_required) {
 	us_frame_s *frame = us_frame_init();
 	us_frame_set_data(frame, mem->data, mem->used);
 	US_FRAME_COPY_META(mem, frame);
 	*frame_id = mem->id;
 	mem->last_client_ts = us_get_now_monotonic();
+	if (key_required) {
+		mem->key_requested = true;
+	}
 
 	bool ok = true;
 	if (frame->format != V4L2_PIX_FMT_H264) {
diff --git a/janus/src/memsinkfd.h b/janus/src/memsinkfd.h
index 0414abc..29d9e5e 100644
--- a/janus/src/memsinkfd.h
+++ b/janus/src/memsinkfd.h
@@ -22,6 +22,7 @@
 
 #pragma once
 
+#include <stdbool.h>
 #include <stdint.h>
 #include <unistd.h>
 
@@ -35,4 +36,4 @@
 
 
 int us_memsink_fd_wait_frame(int fd, us_memsink_shared_s* mem, uint64_t last_id);
-us_frame_s *us_memsink_fd_get_frame(int fd, us_memsink_shared_s *mem, uint64_t *frame_id);
+us_frame_s *us_memsink_fd_get_frame(int fd, us_memsink_shared_s *mem, uint64_t *frame_id, bool key_required);
diff --git a/janus/src/plugin.c b/janus/src/plugin.c
index 9468929..d4e467e 100644
--- a/janus/src/plugin.c
+++ b/janus/src/plugin.c
@@ -76,6 +76,7 @@ static pthread_mutex_t	_g_audio_lock = PTHREAD_MUTEX_INITIALIZER;
 static atomic_bool		_g_ready = false;
 static atomic_bool		_g_stop = false;
 static atomic_bool		_g_has_watchers = false;
+static atomic_bool		_g_key_required = false;
 
 
 #define _LOCK_VIDEO		US_MUTEX_LOCK(_g_video_lock)
@@ -149,10 +150,13 @@ static void *_video_sink_thread(UNUSED void *arg) {
 		while (!_STOP && _HAS_WATCHERS) {
 			const int result = us_memsink_fd_wait_frame(fd, mem, frame_id);
 			if (result == 0) {
-				us_frame_s *const frame = us_memsink_fd_get_frame(fd, mem, &frame_id);
+				us_frame_s *const frame = us_memsink_fd_get_frame(fd, mem, &frame_id, atomic_load(&_g_key_required));
 				if (frame == NULL) {
 					goto close_memsink;
 				}
+//				if (frame->key) {
+//					atomic_store(&_g_key_required, false);
+//				}
 				if (us_queue_put(_g_video_queue, frame, 0) != 0) {
 					_IF_NOT_REPORTED({ US_JLOG_PERROR("video", "Video queue is full"); });
 					us_frame_destroy(frame);
@@ -423,6 +427,7 @@ static struct janus_plugin_result *_plugin_handle_message(
 	} else if (!strcmp(request_str, "watch")) {
 		char *sdp;
 		{
+//			atomic_store(&_g_key_required, true);
 			char *const video_sdp = us_rtpv_make_sdp(_g_rtpv);
 			if (video_sdp == NULL) {
 				PUSH_ERROR(503, "Haven't received SPS/PPS from memsink yet");
diff --git a/man/ustreamer-dump.1 b/man/ustreamer-dump.1
index a15a8e0..c4a66b8 100644
--- a/man/ustreamer-dump.1
+++ b/man/ustreamer-dump.1
@@ -44,6 +44,9 @@ Limit the number of frames. Default: 0 (infinite).
 .TP
 .BR \-i ", "\-\-interval\ \fIsec
 Delay between reading frames (float). Default: 0.
+.TP
+.BR \-k ", " \-\-key
+Request keyframe from the sink. Default: disabled.
 
 .SS "Logging options"
 .TP
diff --git a/python/src/ustreamer.c b/python/src/ustreamer.c
index ee312bb..f2d9caf 100644
--- a/python/src/ustreamer.c
+++ b/python/src/ustreamer.c
@@ -181,12 +181,18 @@ static int _wait_frame(_MemsinkObject *self) {
 	return -2;
 }
 
-static PyObject *_MemsinkObject_wait_frame(_MemsinkObject *self, PyObject *Py_UNUSED(ignored)) {
+static PyObject *_MemsinkObject_wait_frame(_MemsinkObject *self, PyObject *args, PyObject *kwargs) {
 	if (self->mem == NULL || self->fd <= 0) {
 		PyErr_SetString(PyExc_RuntimeError, "Closed");
 		return NULL;
 	}
 
+	bool key_required = false;
+	static char *kws[] = {"key_required", NULL};
+	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|p", kws, &key_required)) {
+		return NULL;
+	}
+
 	switch (_wait_frame(self)) {
 		case 0: break;
 		case -2: Py_RETURN_NONE;
@@ -198,6 +204,9 @@ static PyObject *_MemsinkObject_wait_frame(_MemsinkObject *self, PyObject *Py_UN
 	self->frame_id = _MEM(id);
 	self->frame_ts = us_get_now_monotonic();
 	_MEM(last_client_ts) = self->frame_ts;
+	if (key_required) {
+		_MEM(key_requested) = true;
+	}
 
 	if (flock(self->fd, LOCK_UN) < 0) {
 		return PyErr_SetFromErrno(PyExc_OSError);
@@ -260,7 +269,7 @@ static PyMethodDef _MemsinkObject_methods[] = {
 	ADD_METHOD("close", close, METH_NOARGS),
 	ADD_METHOD("__enter__", enter, METH_NOARGS),
 	ADD_METHOD("__exit__", exit, METH_VARARGS),
-	ADD_METHOD("wait_frame", wait_frame, METH_NOARGS),
+	ADD_METHOD("wait_frame", wait_frame, METH_VARARGS | METH_KEYWORDS),
 	ADD_METHOD("is_opened", is_opened, METH_NOARGS),
 	{},
 #	undef ADD_METHOD
diff --git a/src/dump/main.c b/src/dump/main.c
index 4b790b8..c59f689 100644
--- a/src/dump/main.c
+++ b/src/dump/main.c
@@ -48,6 +48,7 @@ enum _OPT_VALUES {
 	_O_OUTPUT_JSON = 'j',
 	_O_COUNT = 'c',
 	_O_INTERVAL = 'i',
+	_O_KEY = 'k',
 
 	_O_HELP = 'h',
 	_O_VERSION = 'v',
@@ -67,6 +68,7 @@ static const struct option _LONG_OPTS[] = {
 	{"output-json",			no_argument,		NULL,	_O_OUTPUT_JSON},
 	{"count",				required_argument,	NULL,	_O_COUNT},
 	{"interval",			required_argument,	NULL,	_O_INTERVAL},
+	{"key",					no_argument,		NULL,	_O_KEY},
 
 	{"log-level",			required_argument,	NULL,	_O_LOG_LEVEL},
 	{"perf",				no_argument,		NULL,	_O_PERF},
@@ -98,6 +100,7 @@ static void _install_signal_handlers(void);
 static int _dump_sink(
 	const char *sink_name, unsigned sink_timeout,
 	long long count, long double interval,
+	bool key_required,
 	_output_context_s *ctx);
 
 static void _help(FILE *fp);
@@ -113,6 +116,7 @@ int main(int argc, char *argv[]) {
 	bool output_json = false;
 	long long count = 0;
 	long double interval = 0;
+	bool key_required = false;
 
 #	define OPT_SET(_dest, _value) { \
 			_dest = _value; \
@@ -150,6 +154,7 @@ int main(int argc, char *argv[]) {
 			case _O_OUTPUT_JSON:	OPT_SET(output_json, true);
 			case _O_COUNT:			OPT_NUMBER("--count", count, 0, LLONG_MAX, 0);
 			case _O_INTERVAL:		OPT_LDOUBLE("--interval", interval, 0, 60);
+			case _O_KEY:			OPT_SET(key_required, true);
 
 			case _O_LOG_LEVEL:			OPT_NUMBER("--log-level", us_g_log_level, US_LOG_LEVEL_INFO, US_LOG_LEVEL_DEBUG, 0);
 			case _O_PERF:				OPT_SET(us_g_log_level, US_LOG_LEVEL_PERF);
@@ -186,7 +191,7 @@ int main(int argc, char *argv[]) {
 	}
 
 	_install_signal_handlers();
-	const int retval = abs(_dump_sink(sink_name, sink_timeout, count, interval, &ctx));
+	const int retval = abs(_dump_sink(sink_name, sink_timeout, count, interval, key_required, &ctx));
 	if (ctx.v_output && ctx.destroy) {
 		ctx.destroy(ctx.v_output);
 	}
@@ -223,6 +228,7 @@ static void _install_signal_handlers(void) {
 static int _dump_sink(
 	const char *sink_name, unsigned sink_timeout,
 	long long count, long double interval,
+	bool key_required,
 	_output_context_s *ctx) {
 
 	if (count == 0) {
@@ -245,8 +251,10 @@ static int _dump_sink(
 	long double last_ts = 0;
 
 	while (!_g_stop) {
-		int error = us_memsink_client_get(sink, frame);
+		const int error = us_memsink_client_get(sink, frame, key_required);
 		if (error == 0) {
+			key_required = false;
+
 			const long double now = us_get_now_monotonic();
 			const long long now_second = us_floor_ms(now);
 
@@ -322,6 +330,7 @@ static void _help(FILE *fp) {
 	SAY("    -j|--output-json  ──────── Format output as JSON. Required option --output. Default: disabled.\n");
 	SAY("    -c|--count  <N>  ───────── Limit the number of frames. Default: 0 (infinite).\n");
 	SAY("    -i|--interval <sec>  ───── Delay between reading frames (float). Default: 0.\n");
+	SAY("    -k|--key  ──────────────── Request keyframe from the sink. Default: disabled.\n");
 	SAY("Logging options:");
 	SAY("════════════════");
 	SAY("    --log-level <N>  ──── Verbosity level of messages from 0 (info) to 3 (debug).");
diff --git a/src/libs/memsink.c b/src/libs/memsink.c
index c22f3d3..739412f 100644
--- a/src/libs/memsink.c
+++ b/src/libs/memsink.c
@@ -117,7 +117,7 @@ bool us_memsink_server_check(us_memsink_s *sink, const us_frame_s *frame) {
 	return (has_clients || !US_FRAME_COMPARE_META_USED_NOTS(sink->mem, frame));;
 }
 
-int us_memsink_server_put(us_memsink_s *sink, const us_frame_s *frame) {
+int us_memsink_server_put(us_memsink_s *sink, const us_frame_s *frame, bool *const key_requested) {
 	assert(sink->server);
 
 	const long double now = us_get_now_monotonic();
@@ -133,6 +133,12 @@ int us_memsink_server_put(us_memsink_s *sink, const us_frame_s *frame) {
 
 		sink->last_id = us_get_now_id();
 		sink->mem->id = sink->last_id;
+		if (sink->mem->key_requested && frame->key) {
+			sink->mem->key_requested = false;
+		}
+		if (key_requested != NULL) {
+			*key_requested = sink->mem->key_requested;
+		}
 
 		memcpy(sink->mem->data, frame->data, frame->used);
 		sink->mem->used = frame->used;
@@ -140,6 +146,7 @@ int us_memsink_server_put(us_memsink_s *sink, const us_frame_s *frame) {
 
 		sink->mem->magic = US_MEMSINK_MAGIC;
 		sink->mem->version = US_MEMSINK_VERSION;
+
 		atomic_store(&sink->has_clients, (sink->mem->last_client_ts + sink->client_ttl > us_get_now_monotonic()));
 
 		if (flock(sink->fd, LOCK_UN) < 0) {
@@ -159,7 +166,7 @@ int us_memsink_server_put(us_memsink_s *sink, const us_frame_s *frame) {
 	return 0;
 }
 
-int us_memsink_client_get(us_memsink_s *sink, us_frame_s *frame) { // cppcheck-suppress unusedFunction
+int us_memsink_client_get(us_memsink_s *sink, us_frame_s *frame, bool key_required) { // cppcheck-suppress unusedFunction
 	assert(!sink->server); // Client only
 
 	if (us_flock_timedwait_monotonic(sink->fd, sink->timeout) < 0) {
@@ -185,6 +192,9 @@ int us_memsink_client_get(us_memsink_s *sink, us_frame_s *frame) { // cppcheck-s
 			retval = 0;
 		}
 		sink->mem->last_client_ts = us_get_now_monotonic();
+		if (key_required) {
+			sink->mem->key_requested = true;
+		}
 	}
 
 	done:
diff --git a/src/libs/memsink.h b/src/libs/memsink.h
index d38d45d..79cf3c8 100644
--- a/src/libs/memsink.h
+++ b/src/libs/memsink.h
@@ -63,6 +63,6 @@ us_memsink_s *us_memsink_init(
 void us_memsink_destroy(us_memsink_s *sink);
 
 bool us_memsink_server_check(us_memsink_s *sink, const us_frame_s *frame);
-int us_memsink_server_put(us_memsink_s *sink, const us_frame_s *frame);
+int us_memsink_server_put(us_memsink_s *sink, const us_frame_s *frame, bool *const key_requested);
 
-int us_memsink_client_get(us_memsink_s *sink, us_frame_s *frame);
+int us_memsink_client_get(us_memsink_s *sink, us_frame_s *frame, bool key_required);
diff --git a/src/libs/memsinksh.h b/src/libs/memsinksh.h
index 583f2b7..6a90424 100644
--- a/src/libs/memsinksh.h
+++ b/src/libs/memsinksh.h
@@ -30,7 +30,7 @@
 
 
 #define US_MEMSINK_MAGIC	((uint64_t)0xCAFEBABECAFEBABE)
-#define US_MEMSINK_VERSION	((uint32_t)2)
+#define US_MEMSINK_VERSION	((uint32_t)3)
 
 #ifndef US_CFG_MEMSINK_MAX_DATA
 #	define US_CFG_MEMSINK_MAX_DATA 33554432
@@ -57,6 +57,7 @@ typedef struct {
 	long double	encode_end_ts;
 
 	long double	last_client_ts;
+	bool		key_requested;
 
 	uint8_t		data[US_MEMSINK_MAX_DATA];
 } us_memsink_shared_s;
diff --git a/src/ustreamer/h264/stream.c b/src/ustreamer/h264/stream.c
index d395e2c..2b6bf9a 100644
--- a/src/ustreamer/h264/stream.c
+++ b/src/ustreamer/h264/stream.c
@@ -56,9 +56,15 @@ void us_h264_stream_process(us_h264_stream_s *h264, const us_frame_s *frame, boo
 		US_LOG_VERBOSE("H264: JPEG decoded; time=%.3Lf", us_get_now_monotonic() - now);
 	}
 
+	if (h264->key_requested) {
+		US_LOG_INFO("H264: Requested keyframe by a sink client");
+		h264->key_requested = false;
+		force_key = true;
+	}
+
 	bool online = false;
 	if (!us_m2m_encoder_compress(h264->enc, frame, h264->dest, force_key)) {
-		online = !us_memsink_server_put(h264->sink, h264->dest);
+		online = !us_memsink_server_put(h264->sink, h264->dest, &h264->key_requested);
 	}
 	atomic_store(&h264->online, online);
 }
diff --git a/src/ustreamer/h264/stream.h b/src/ustreamer/h264/stream.h
index 416b740..c68a642 100644
--- a/src/ustreamer/h264/stream.h
+++ b/src/ustreamer/h264/stream.h
@@ -36,6 +36,7 @@
 
 typedef struct {
 	us_memsink_s		*sink;
+	bool				key_requested;
 	us_frame_s			*tmp_src;
 	us_frame_s			*dest;
 	us_m2m_encoder_s	*enc;
diff --git a/src/ustreamer/stream.c b/src/ustreamer/stream.c
index 4b4749e..fdf31dd 100644
--- a/src/ustreamer/stream.c
+++ b/src/ustreamer/stream.c
@@ -32,7 +32,7 @@ static void _stream_expose_frame(us_stream_s *stream, us_frame_s *frame, unsigne
 
 #define _SINK_PUT(x_sink, x_frame) { \
 		if (stream->x_sink && us_memsink_server_check(stream->x_sink, x_frame)) {\
-			us_memsink_server_put(stream->x_sink, x_frame); \
+			us_memsink_server_put(stream->x_sink, x_frame, NULL); \
 		} \
 	}