diff --git a/plugins/obs-outputs/flv-mux.c b/plugins/obs-outputs/flv-mux.c
index 9e18d5ef7..2b323e684 100644
--- a/plugins/obs-outputs/flv-mux.c
+++ b/plugins/obs-outputs/flv-mux.c
@@ -674,251 +674,3 @@ void flv_packet_metadata(enum video_id_t codec_id, uint8_t **output,
 	*output = data.bytes.array;
 	*size = data.bytes.num;
 }
-
-/* ------------------------------------------------------------------------- */
-/* stuff for additional media streams                                        */
-
-#define s_amf_conststring(s, str)                   \
-	do {                                        \
-		const size_t len = sizeof(str) - 1; \
-		s_wb16(s, (uint16_t)len);           \
-		serialize(s, str, len);             \
-	} while (false)
-
-#define s_amf_double(s, d)                            \
-	do {                                          \
-		double d_val = d;                     \
-		uint64_t u_val = *(uint64_t *)&d_val; \
-		s_wb64(s, u_val);                     \
-	} while (false)
-
-static void flv_build_additional_meta_data(uint8_t **data, size_t *size)
-{
-	struct array_output_data out;
-	struct serializer s;
-
-	array_output_serializer_init(&s, &out);
-
-	s_w8(&s, AMF_STRING);
-	s_amf_conststring(&s, "@setDataFrame");
-
-	s_w8(&s, AMF_STRING);
-	s_amf_conststring(&s, "onExpectAdditionalMedia");
-
-	s_w8(&s, AMF_OBJECT);
-	{
-		s_amf_conststring(&s, "processingIntents");
-
-		s_w8(&s, AMF_STRICT_ARRAY);
-		s_wb32(&s, 1);
-		{
-			s_w8(&s, AMF_STRING);
-			s_amf_conststring(&s, "ArchiveProgramNarrationAudio");
-		}
-
-		/* ---- */
-
-		s_amf_conststring(&s, "additionalMedia");
-
-		s_w8(&s, AMF_OBJECT);
-		{
-			s_amf_conststring(&s, "stream0");
-
-			s_w8(&s, AMF_OBJECT);
-			{
-				s_amf_conststring(&s, "type");
-
-				s_w8(&s, AMF_NUMBER);
-				s_amf_double(&s, RTMP_PACKET_TYPE_AUDIO);
-
-				/* ---- */
-
-				s_amf_conststring(&s, "mediaLabels");
-
-				s_w8(&s, AMF_OBJECT);
-				{
-					s_amf_conststring(&s, "contentType");
-
-					s_w8(&s, AMF_STRING);
-					s_amf_conststring(&s, "PNAR");
-				}
-				s_wb24(&s, AMF_OBJECT_END);
-			}
-			s_wb24(&s, AMF_OBJECT_END);
-		}
-		s_wb24(&s, AMF_OBJECT_END);
-
-		/* ---- */
-
-		s_amf_conststring(&s, "defaultMedia");
-
-		s_w8(&s, AMF_OBJECT);
-		{
-			s_amf_conststring(&s, "audio");
-
-			s_w8(&s, AMF_OBJECT);
-			{
-				s_amf_conststring(&s, "mediaLabels");
-
-				s_w8(&s, AMF_OBJECT);
-				{
-					s_amf_conststring(&s, "contentType");
-
-					s_w8(&s, AMF_STRING);
-					s_amf_conststring(&s, "PRM");
-				}
-				s_wb24(&s, AMF_OBJECT_END);
-			}
-			s_wb24(&s, AMF_OBJECT_END);
-		}
-		s_wb24(&s, AMF_OBJECT_END);
-	}
-	s_wb24(&s, AMF_OBJECT_END);
-
-	*data = out.bytes.array;
-	*size = out.bytes.num;
-}
-
-void flv_additional_meta_data(obs_output_t *context, uint8_t **data,
-			      size_t *size)
-{
-	UNUSED_PARAMETER(context);
-	struct array_output_data out;
-	struct serializer s;
-	uint8_t *meta_data = NULL;
-	size_t meta_data_size;
-
-	flv_build_additional_meta_data(&meta_data, &meta_data_size);
-
-	array_output_serializer_init(&s, &out);
-
-	s_w8(&s, RTMP_PACKET_TYPE_INFO); //18
-
-	s_wb24(&s, (uint32_t)meta_data_size);
-	s_wb32(&s, 0);
-	s_wb24(&s, 0);
-
-	s_write(&s, meta_data, meta_data_size);
-	bfree(meta_data);
-
-	write_previous_tag_size(&s);
-
-	*data = out.bytes.array;
-	*size = out.bytes.num;
-}
-
-static inline void s_u29(struct serializer *s, uint32_t val)
-{
-	if (val <= 0x7F) {
-		s_w8(s, val);
-	} else if (val <= 0x3FFF) {
-		s_w8(s, 0x80 | (val >> 7));
-		s_w8(s, val & 0x7F);
-	} else if (val <= 0x1FFFFF) {
-		s_w8(s, 0x80 | (val >> 14));
-		s_w8(s, 0x80 | ((val >> 7) & 0x7F));
-		s_w8(s, val & 0x7F);
-	} else {
-		s_w8(s, 0x80 | (val >> 22));
-		s_w8(s, 0x80 | ((val >> 15) & 0x7F));
-		s_w8(s, 0x80 | ((val >> 8) & 0x7F));
-		s_w8(s, val & 0xFF);
-	}
-}
-
-static inline void s_u29b_value(struct serializer *s, uint32_t val)
-{
-	s_u29(s, 1 | ((val & 0xFFFFFFF) << 1));
-}
-
-static void flv_build_additional_audio(uint8_t **data, size_t *size,
-				       struct encoder_packet *packet,
-				       bool is_header, size_t index)
-{
-	UNUSED_PARAMETER(index);
-	struct array_output_data out;
-	struct serializer s;
-
-	array_output_serializer_init(&s, &out);
-
-	s_w8(&s, AMF_STRING);
-	s_amf_conststring(&s, "additionalMedia");
-
-	s_w8(&s, AMF_OBJECT);
-	{
-		s_amf_conststring(&s, "id");
-
-		s_w8(&s, AMF_STRING);
-		s_amf_conststring(&s, "stream0");
-
-		/* ----- */
-
-		s_amf_conststring(&s, "media");
-
-		s_w8(&s, AMF_AVMPLUS);
-		s_w8(&s, AMF3_BYTE_ARRAY);
-		s_u29b_value(&s, (uint32_t)packet->size + 2);
-		s_w8(&s, 0xaf);
-		s_w8(&s, is_header ? 0 : 1);
-		s_write(&s, packet->data, packet->size);
-	}
-	s_wb24(&s, AMF_OBJECT_END);
-
-	*data = out.bytes.array;
-	*size = out.bytes.num;
-}
-
-static void flv_additional_audio(struct serializer *s, int32_t dts_offset,
-				 struct encoder_packet *packet, bool is_header,
-				 size_t index)
-{
-	int32_t time_ms = get_ms_time(packet, packet->dts) - dts_offset;
-	uint8_t *data;
-	size_t size;
-
-	if (!packet->data || !packet->size)
-		return;
-
-	flv_build_additional_audio(&data, &size, packet, is_header, index);
-
-	s_w8(s, RTMP_PACKET_TYPE_INFO); //18
-
-#ifdef DEBUG_TIMESTAMPS
-	blog(LOG_DEBUG, "Audio2: %lu", time_ms);
-
-	if (last_time > time_ms)
-		blog(LOG_DEBUG, "Non-monotonic");
-
-	last_time = time_ms;
-#endif
-
-	s_wb24(s, (uint32_t)size);
-	s_wb24(s, (uint32_t)time_ms);
-	s_w8(s, (time_ms >> 24) & 0x7F);
-	s_wb24(s, 0);
-
-	serialize(s, data, size);
-	bfree(data);
-
-	write_previous_tag_size(s);
-}
-
-void flv_additional_packet_mux(struct encoder_packet *packet,
-			       int32_t dts_offset, uint8_t **data, size_t *size,
-			       bool is_header, size_t index)
-{
-	struct array_output_data out;
-	struct serializer s;
-
-	array_output_serializer_init(&s, &out);
-
-	if (packet->type == OBS_ENCODER_VIDEO) {
-		//currently unsupported
-		bcrash("who said you could output an additional video packet?");
-	} else {
-		flv_additional_audio(&s, dts_offset, packet, is_header, index);
-	}
-
-	*data = out.bytes.array;
-	*size = out.bytes.num;
-}
diff --git a/plugins/obs-outputs/flv-mux.h b/plugins/obs-outputs/flv-mux.h
index 94c830ebf..e5cab0ddf 100644
--- a/plugins/obs-outputs/flv-mux.h
+++ b/plugins/obs-outputs/flv-mux.h
@@ -62,14 +62,8 @@ extern void write_file_info(FILE *file, int64_t duration_ms, int64_t size);
 
 extern void flv_meta_data(obs_output_t *context, uint8_t **output, size_t *size,
 			  bool write_header);
-extern void flv_additional_meta_data(obs_output_t *context, uint8_t **output,
-				     size_t *size);
 extern void flv_packet_mux(struct encoder_packet *packet, int32_t dts_offset,
 			   uint8_t **output, size_t *size, bool is_header);
-extern void flv_additional_packet_mux(struct encoder_packet *packet,
-				      int32_t dts_offset, uint8_t **output,
-				      size_t *size, bool is_header,
-				      size_t index);
 // Y2023 spec
 extern void flv_packet_start(struct encoder_packet *packet,
 			     enum video_id_t codec, uint8_t **output,
diff --git a/plugins/obs-outputs/rtmp-stream.c b/plugins/obs-outputs/rtmp-stream.c
index 3fdcedf2b..aa4f84de6 100644
--- a/plugins/obs-outputs/rtmp-stream.c
+++ b/plugins/obs-outputs/rtmp-stream.c
@@ -406,25 +406,17 @@ static int handle_socket_read(struct rtmp_stream *stream)
 }
 
 static int send_packet(struct rtmp_stream *stream,
-		       struct encoder_packet *packet, bool is_header,
-		       size_t idx)
+		       struct encoder_packet *packet, bool is_header)
 {
 	uint8_t *data;
 	size_t size;
 	int ret = 0;
 
-	assert(idx < RTMP_MAX_STREAMS);
 	if (handle_socket_read(stream))
 		return -1;
 
-	if (idx > 0) {
-		flv_additional_packet_mux(
-			packet, is_header ? 0 : stream->start_dts_offset, &data,
-			&size, is_header, idx);
-	} else {
-		flv_packet_mux(packet, is_header ? 0 : stream->start_dts_offset,
-			       &data, &size, is_header);
-	}
+	flv_packet_mux(packet, is_header ? 0 : stream->start_dts_offset, &data,
+		       &size, is_header);
 
 #ifdef TEST_FRAMEDROPS
 	droptest_cap_data_rate(stream, size);
@@ -712,8 +704,7 @@ static void *send_thread(void *data)
 			sent = send_audio_packet_ex(stream, &packet, false,
 						    packet.track_idx);
 		} else {
-			sent = send_packet(stream, &packet, false,
-					   packet.track_idx);
+			sent = send_packet(stream, &packet, false);
 		}
 
 		if (sent < 0) {
@@ -783,20 +774,6 @@ static void *send_thread(void *data)
 	return NULL;
 }
 
-static bool send_additional_meta_data(struct rtmp_stream *stream)
-{
-	uint8_t *meta_data;
-	size_t meta_data_size;
-	bool success = true;
-
-	flv_additional_meta_data(stream->output, &meta_data, &meta_data_size);
-	success = RTMP_Write(&stream->rtmp, (char *)meta_data,
-			     (int)meta_data_size, 0) >= 0;
-	bfree(meta_data);
-
-	return success;
-}
-
 static bool send_meta_data(struct rtmp_stream *stream)
 {
 	uint8_t *meta_data;
@@ -829,7 +806,7 @@ static bool send_audio_header(struct rtmp_stream *stream, size_t idx,
 	if (obs_encoder_get_extra_data(aencoder, &header, &packet.size)) {
 		packet.data = bmemdup(header, packet.size);
 		if (idx == 0) {
-			return send_packet(stream, &packet, true, idx) >= 0;
+			return send_packet(stream, &packet, true) >= 0;
 		} else {
 			return send_audio_packet_ex(stream, &packet, true,
 						    idx) >= 0;
@@ -866,7 +843,7 @@ static bool send_video_header(struct rtmp_stream *stream, size_t idx)
 		packet.size = obs_parse_avc_header(&packet.data, header, size);
 		// Always send H.264 on track 0 as old style for compatibility.
 		if (idx == 0) {
-			return send_packet(stream, &packet, true, idx) >= 0;
+			return send_packet(stream, &packet, true) >= 0;
 		} else {
 			return send_packet_ex(stream, &packet, true, false,
 					      idx) >= 0;