fix(stream): preserve live outputs and disable idle exit by default

Preserve RTP/RTMP session continuity across upstream stream_reset events by
forcing a keyframe on restart, remapping live timestamps, and keeping live
outputs open when the runtime requests reset continuity.

Disable idle auto-exit by default by changing ingest_idle_timeout_ms to 0,
removing validation that rejected 0, and only enforcing idle shutdown when a
positive timeout is configured in pipeline and ingest loops.

Also suppress libavformat FLV trailer header backfill attempts on RTMP sockets
and update the RTP output tester for the newer publisher create signature.

Docs are updated to state that 0 disables the idle timeout.

README.md

@@ -512,7 +512,7 @@ Run the fault injection and latency validation suite.
 | Flag | Description | Default |
 |------|-------------|---------|
 | `--ingest-max-frames N` | Process at most N frames then exit | 0 (unlimited) |
-| `--ingest-idle-timeout-ms MS` | Exit if idle for MS milliseconds | 0 (disabled) |
+| `--ingest-idle-timeout-ms MS` | Exit if idle for MS milliseconds; 0 disables the timeout | 0 (disabled) |
 
 ## Architecture
 

include/cvmmap_streamer/config/runtime_config.hpp

@@ -108,8 +108,9 @@ struct LatencyConfig {
 	std::size_t queue_size{1};
 	bool realtime_sync{true};
 	bool force_idr_on_reset{true};
+	bool keep_stream_on_reset{false};
 	std::uint32_t ingest_max_frames{0};
-	std::uint32_t ingest_idle_timeout_ms{1000};
+	std::uint32_t ingest_idle_timeout_ms{0};
 	std::uint32_t ingest_consumer_delay_ms{0};
 	std::uint32_t snapshot_copy_delay_us{0};
 	std::uint32_t emit_stall_ms{0};

include/cvmmap_streamer/encode/encoder_backend.hpp

@@ -18,6 +18,7 @@ struct RawVideoFrame {
 	ipc::FrameInfo info{};
 	std::uint64_t source_timestamp_ns{0};
 	std::size_t row_stride_bytes{0};
+	bool force_keyframe{false};
 	std::span<const std::uint8_t> bytes{};
 };
 

src/config/runtime_config.cpp

@@ -968,9 +968,6 @@ std::expected<void, std::string> validate_runtime_config(const RuntimeConfig &co
 	if (config.encoder.b_frames > config.encoder.gop) {
 		return std::unexpected("invalid encoder config: b_frames must be <= gop");
 	}
-	if (config.latency.ingest_idle_timeout_ms == 0) {
-		return std::unexpected("invalid ingest config: ingest_idle_timeout_ms must be >= 1");
-	}
 
 	return {};
 }

src/core/ingest_runtime.cpp

@@ -275,6 +275,7 @@ int run_ingest_loop(const RuntimeConfig &config) {
 		}
 	});
 
+	const auto idle_timeout_enabled = config.latency.ingest_idle_timeout_ms > 0;
 	const auto idle_timeout = std::chrono::milliseconds(config.latency.ingest_idle_timeout_ms);
 	auto last_event         = std::chrono::steady_clock::now();
 
@@ -283,7 +284,7 @@ int run_ingest_loop(const RuntimeConfig &config) {
 		const auto recv_result = subscriber.recv(message, zmq::recv_flags::none);
 		if (!recv_result) {
 			const auto now = std::chrono::steady_clock::now();
-			if (now - last_event >= idle_timeout) {
+			if (idle_timeout_enabled && now - last_event >= idle_timeout) {
 				spdlog::info(
 					"ingest idle timeout reached ({} ms), stopping",
 					config.latency.ingest_idle_timeout_ms);

src/encode/ffmpeg_encoder_backend.cpp

@@ -217,6 +217,12 @@ public:
 			first_source_timestamp_ns_ = frame.source_timestamp_ns;
 		}
 
+		frame_->pict_type = frame.force_keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_NONE;
+		if (frame.force_keyframe) {
+			frame_->flags |= AV_FRAME_FLAG_KEY;
+		} else {
+			frame_->flags &= ~AV_FRAME_FLAG_KEY;
+		}
 		frame_->pts = static_cast<std::int64_t>(frame.source_timestamp_ns - *first_source_timestamp_ns_);
 		const auto send_result = avcodec_send_frame(context_, frame_);
 		if (send_result < 0) {

src/pipeline/pipeline_runtime.cpp

@@ -62,6 +62,10 @@ constexpr int exit_code(PipelineExitCode code) {
 }
 
 struct ResolvedInputEndpoints {
+	std::string instance_name;
+	std::string namespace_name;
+	std::string ipc_prefix;
+	std::string base_name;
 	std::string shm_name;
 	std::string zmq_endpoint;
 	std::string nats_target_key;
@@ -78,6 +82,10 @@ std::expected<ResolvedInputEndpoints, std::string> resolve_input_endpoints(const
 			target.zmq_addr,
 			target.nats_target_key);
 		return ResolvedInputEndpoints{
+			.instance_name = target.instance,
+			.namespace_name = target.namespace_name,
+			.ipc_prefix = target.prefix,
+			.base_name = target.base_name,
 			.shm_name = target.shm_name,
 			.zmq_endpoint = target.zmq_addr,
 			.nats_target_key = target.nats_target_key,
@@ -327,6 +335,81 @@ bool stream_info_equal(
 		   lhs.bitstream_format == rhs.bitstream_format;
 }
 
+struct LiveOutputContinuityState {
+	bool boundary_pending{false};
+	bool encoded_keyframe_required{false};
+	std::optional<std::uint64_t> last_output_pts_ns{};
+	std::optional<std::uint64_t> segment_input_start_pts_ns{};
+	std::uint64_t segment_output_start_pts_ns{0};
+	std::uint64_t nominal_frame_interval_ns{33'333'333ull};
+
+	void reset() {
+		boundary_pending = false;
+		encoded_keyframe_required = false;
+		last_output_pts_ns.reset();
+		segment_input_start_pts_ns.reset();
+		segment_output_start_pts_ns = 0;
+		nominal_frame_interval_ns = 33'333'333ull;
+	}
+
+	void note_reset_boundary() {
+		boundary_pending = true;
+		encoded_keyframe_required = true;
+		segment_input_start_pts_ns.reset();
+	}
+
+	void note_new_session(const encode::EncodedStreamInfo &stream_info) {
+		reset();
+		update_nominal_frame_interval(stream_info);
+	}
+
+	void update_nominal_frame_interval(const encode::EncodedStreamInfo &stream_info) {
+		if (stream_info.frame_rate_num == 0 || stream_info.frame_rate_den == 0) {
+			nominal_frame_interval_ns = 33'333'333ull;
+			return;
+		}
+
+		const auto numerator = static_cast<std::uint64_t>(stream_info.frame_rate_den) * 1'000'000'000ull;
+		const auto denominator = static_cast<std::uint64_t>(stream_info.frame_rate_num);
+		if (denominator == 0) {
+			nominal_frame_interval_ns = 33'333'333ull;
+			return;
+		}
+
+		const auto interval = numerator / denominator;
+		nominal_frame_interval_ns = interval == 0 ? 1ull : interval;
+	}
+
+	[[nodiscard]]
+	std::uint64_t remap_pts(const std::uint64_t input_pts_ns) {
+		if (!last_output_pts_ns) {
+			last_output_pts_ns = input_pts_ns;
+			segment_input_start_pts_ns = input_pts_ns;
+			segment_output_start_pts_ns = input_pts_ns;
+			boundary_pending = false;
+			return input_pts_ns;
+		}
+
+		if (boundary_pending || !segment_input_start_pts_ns) {
+			segment_input_start_pts_ns = input_pts_ns;
+			segment_output_start_pts_ns = *last_output_pts_ns + nominal_frame_interval_ns;
+			boundary_pending = false;
+		}
+
+		const auto input_delta =
+			input_pts_ns >= *segment_input_start_pts_ns
+				? input_pts_ns - *segment_input_start_pts_ns
+				: 0ull;
+		auto remapped_pts = segment_output_start_pts_ns + input_delta;
+		if (remapped_pts <= *last_output_pts_ns) {
+			remapped_pts = *last_output_pts_ns + nominal_frame_interval_ns;
+		}
+
+		last_output_pts_ns = remapped_pts;
+		return remapped_pts;
+	}
+};
+
 [[nodiscard]]
 std::uint64_t body_tracking_timestamp_ns(const cvmmap::body_tracking_frame_t &frame) {
 	if (frame.header.timestamp_ns != 0) {
@@ -556,6 +639,7 @@ Status publish_access_units(
 	protocol::UdpRtpPublisher *rtp_publisher,
 	protocol::RtmpOutput *rtmp_output,
 	McapRecorderState *mcap_recorder,
+	LiveOutputContinuityState *live_output_continuity,
 	metrics::IngestEmitLatencyTracker &latency_tracker) {
 	for (auto &access_unit : access_units) {
 		if (access_unit.annexb_bytes.empty()) {
@@ -567,11 +651,29 @@ Status publish_access_units(
 			latency_tracker.note_emit_stall();
 		}
 
+		const auto should_rewrite_live_timestamps =
+			live_output_continuity != nullptr &&
+			(rtp_publisher != nullptr || rtmp_output != nullptr);
+		auto live_access_unit = access_unit;
+		const bool live_boundary_packet =
+			should_rewrite_live_timestamps &&
+			live_output_continuity->boundary_pending;
+		if (should_rewrite_live_timestamps) {
+			live_access_unit.stream_pts_ns = live_output_continuity->remap_pts(access_unit.stream_pts_ns);
+		}
+		if (live_boundary_packet) {
+			spdlog::info(
+				"PIPELINE_RESET_CONTINUITY first live packet keyframe={} source_pts_ns={} remapped_pts_ns={}",
+				access_unit.keyframe ? "true" : "false",
+				access_unit.stream_pts_ns,
+				live_access_unit.stream_pts_ns);
+		}
+
 		if (rtp_publisher != nullptr) {
-			rtp_publisher->publish_access_unit(access_unit.annexb_bytes, access_unit.stream_pts_ns);
+			rtp_publisher->publish_access_unit(live_access_unit.annexb_bytes, live_access_unit.stream_pts_ns);
 		}
 		if (rtmp_output != nullptr) {
-			auto publish = (*rtmp_output)->publish_access_unit(access_unit);
+			auto publish = (*rtmp_output)->publish_access_unit(live_access_unit);
 			if (!publish) {
 				return std::unexpected(publish.error());
 			}
@@ -607,6 +709,7 @@ Status drain_encoder(
 	protocol::UdpRtpPublisher *rtp_publisher,
 	protocol::RtmpOutput *rtmp_output,
 	McapRecorderState *mcap_recorder,
+	LiveOutputContinuityState *live_output_continuity,
 	metrics::IngestEmitLatencyTracker &latency_tracker) {
 	auto drained = flushing ? backend->flush() : backend->drain();
 	if (!drained) {
@@ -619,6 +722,7 @@ Status drain_encoder(
 		rtp_publisher,
 		rtmp_output,
 		mcap_recorder,
+		live_output_continuity,
 		latency_tracker);
 }
 
@@ -678,9 +782,17 @@ int run_pipeline(const RuntimeConfig &config) {
 		input_endpoints->nats_target_key,
 		config.input.nats_url);
 	cvmmap::NatsControlService recorder_service(
-		config.input.uri,
-		input_endpoints->nats_target_key,
-		config.input.nats_url);
+		cvmmap::NatsControlServiceOptions{
+			.instance_name = input_endpoints->instance_name,
+			.namespace_name = input_endpoints->namespace_name,
+			.ipc_prefix = input_endpoints->ipc_prefix,
+			.base_name = input_endpoints->base_name,
+			.target_key = input_endpoints->nats_target_key,
+			.shm_name = input_endpoints->shm_name,
+			.zmq_addr = input_endpoints->zmq_endpoint,
+			.backend = std::string((*source)->backend_name()),
+			.nats_url = config.input.nats_url,
+		});
 	std::mutex nats_event_mutex{};
 	std::deque<std::vector<std::uint8_t>> pending_body_packets{};
 	std::deque<int32_t> pending_status_codes{};
@@ -737,6 +849,10 @@ int run_pipeline(const RuntimeConfig &config) {
 
 	PipelineStats stats{};
 	metrics::IngestEmitLatencyTracker latency_tracker{};
+	LiveOutputContinuityState live_output_continuity{};
+	const bool keep_live_outputs_on_reset =
+		config.latency.keep_stream_on_reset &&
+		(config.outputs.rtp.enabled || config.outputs.rtmp.enabled);
 	bool producer_offline{false};
 	bool started{false};
 	bool using_encoded_input{false};
@@ -766,6 +882,7 @@ int run_pipeline(const RuntimeConfig &config) {
 		warned_unknown_depth_unit = false;
 		using_encoded_input = false;
 		active_stream_info.reset();
+		live_output_continuity.reset();
 		rtp_publisher.reset();
 		rtmp_output.reset();
 	};
@@ -784,6 +901,32 @@ int run_pipeline(const RuntimeConfig &config) {
 
 	const auto start_outputs_from_stream_info =
 		[&](const encode::EncodedStreamInfo &stream_info, const ipc::FrameInfo &target_info) -> Status {
+		const bool preserving_live_outputs =
+			keep_live_outputs_on_reset &&
+			live_output_continuity.boundary_pending &&
+			active_stream_info.has_value() &&
+			stream_info_equal(*active_stream_info, stream_info) &&
+			((config.outputs.rtp.enabled && rtp_publisher.has_value()) ||
+			 (config.outputs.rtmp.enabled && rtmp_output.has_value()));
+		if (preserving_live_outputs) {
+			spdlog::info(
+				"PIPELINE_RESET_CONTINUITY preserving live outputs codec={} width={} height={}",
+				to_string(stream_info.codec),
+				stream_info.width,
+				stream_info.height);
+			live_output_continuity.update_nominal_frame_interval(stream_info);
+		} else {
+			if (keep_live_outputs_on_reset && live_output_continuity.boundary_pending && active_stream_info.has_value() &&
+				!stream_info_equal(*active_stream_info, stream_info)) {
+				spdlog::warn(
+					"PIPELINE_RESET_CONTINUITY fallback to output rebuild reason='stream_info_change' old_codec={} new_codec={} old={}x{} new={}x{}",
+					to_string(active_stream_info->codec),
+					to_string(stream_info.codec),
+					active_stream_info->width,
+					active_stream_info->height,
+					stream_info.width,
+					stream_info.height);
+			}
 			rtp_publisher.reset();
 			rtmp_output.reset();
 			if (config.outputs.rtp.enabled) {
@@ -804,6 +947,9 @@ int run_pipeline(const RuntimeConfig &config) {
 				}
 				rtmp_output.emplace(std::move(*created));
 			}
+			live_output_continuity.note_new_session(stream_info);
+		}
+
 		update_mcap_stream_info(mcap_recorder, stream_info);
 		if (config.record.mcap.enabled) {
 			std::lock_guard lock(mcap_recorder.mutex);
@@ -865,6 +1011,7 @@ int run_pipeline(const RuntimeConfig &config) {
 		return start_outputs_from_stream_info(*stream_info, snapshot.metadata.info);
 	};
 
+	const auto idle_timeout_enabled = config.latency.ingest_idle_timeout_ms > 0;
 	const auto idle_timeout = std::chrono::milliseconds(config.latency.ingest_idle_timeout_ms);
 	auto last_event         = std::chrono::steady_clock::now();
 
@@ -894,6 +1041,19 @@ int run_pipeline(const RuntimeConfig &config) {
 			case cvmmap::ModuleStatus::StreamReset:
 				spdlog::info("pipeline status event status=stream_reset");
 				stats.resets += 1;
+				if (keep_live_outputs_on_reset) {
+					live_output_continuity.note_reset_boundary();
+					if (!using_encoded_input && backend) {
+						(*backend)->shutdown();
+						started = false;
+					}
+					restart_pending = false;
+					restart_target_info.reset();
+					spdlog::info(
+						"PIPELINE_RESET_CONTINUITY armed outputs_active={} encoded_input={}",
+						(rtp_publisher.has_value() || rtmp_output.has_value()) ? "true" : "false",
+						using_encoded_input ? "true" : "false");
+				} else {
 					if (backend) {
 						(*backend)->shutdown();
 					}
@@ -905,6 +1065,7 @@ int run_pipeline(const RuntimeConfig &config) {
 					active_info.reset();
 					rtp_publisher.reset();
 					rtmp_output.reset();
+				}
 				break;
 			}
 		}
@@ -961,7 +1122,7 @@ int run_pipeline(const RuntimeConfig &config) {
 					return exit_code(PipelineExitCode::RuntimeError);
 				}
 			}
-				if (now - last_event >= idle_timeout) {
+			if (idle_timeout_enabled && now - last_event >= idle_timeout) {
 				spdlog::info("pipeline idle timeout reached ({} ms), stopping", config.latency.ingest_idle_timeout_ms);
 				break;
 			}
@@ -974,6 +1135,7 @@ int run_pipeline(const RuntimeConfig &config) {
 					rtp_publisher ? &*rtp_publisher : nullptr,
 					rtmp_output ? &*rtmp_output : nullptr,
 					&mcap_recorder,
+					keep_live_outputs_on_reset ? &live_output_continuity : nullptr,
 					latency_tracker);
 				if (!drain) {
 					const auto reason = format_error(drain.error());
@@ -1075,6 +1237,14 @@ int run_pipeline(const RuntimeConfig &config) {
 					restart_backend(reason, snapshot->metadata.info);
 					continue;
 				}
+				if (keep_live_outputs_on_reset && live_output_continuity.encoded_keyframe_required && !access_unit->keyframe) {
+					spdlog::info(
+						"PIPELINE_RESET_CONTINUITY dropping encoded access unit until keyframe pts_ns={} source_timestamp_ns={}",
+						access_unit->stream_pts_ns,
+						access_unit->source_timestamp_ns);
+					continue;
+				}
+				live_output_continuity.encoded_keyframe_required = false;
 				std::vector<encode::EncodedAccessUnit> access_units{};
 				access_units.push_back(std::move(*access_unit));
 				auto publish = publish_access_units(
@@ -1084,6 +1254,7 @@ int run_pipeline(const RuntimeConfig &config) {
 					rtp_publisher ? &*rtp_publisher : nullptr,
 					rtmp_output ? &*rtmp_output : nullptr,
 					&mcap_recorder,
+					keep_live_outputs_on_reset ? &live_output_continuity : nullptr,
 					latency_tracker);
 				if (!publish) {
 					const auto reason = format_error(publish.error());
@@ -1094,6 +1265,7 @@ int run_pipeline(const RuntimeConfig &config) {
 				auto push = (*backend)->push_frame(encode::RawVideoFrame{
 					.info = snapshot->metadata.info,
 					.source_timestamp_ns = snapshot->metadata.timestamp_ns,
+					.force_keyframe = keep_live_outputs_on_reset && live_output_continuity.boundary_pending,
 					.bytes = std::span<const std::uint8_t>(snapshot_buffer.data(), snapshot->bytes_copied),
 				});
 				if (!push) {
@@ -1137,6 +1309,7 @@ int run_pipeline(const RuntimeConfig &config) {
 					rtp_publisher ? &*rtp_publisher : nullptr,
 					rtmp_output ? &*rtmp_output : nullptr,
 					&mcap_recorder,
+					keep_live_outputs_on_reset ? &live_output_continuity : nullptr,
 					latency_tracker);
 				if (!drain) {
 					const auto reason = format_error(drain.error());
@@ -1166,6 +1339,7 @@ int run_pipeline(const RuntimeConfig &config) {
 			rtp_publisher ? &*rtp_publisher : nullptr,
 			rtmp_output ? &*rtmp_output : nullptr,
 			&mcap_recorder,
+			keep_live_outputs_on_reset ? &live_output_continuity : nullptr,
 			latency_tracker);
 		if (!drain) {
 			spdlog::error("pipeline publish failed during flush: {}", format_error(drain.error()));

src/protocol/rtmp_output.cpp

@@ -325,6 +325,7 @@ private:
 		const encode::EncodedStreamInfo &stream_info) {
 		Session session{};
 		session.url = url;
+		AVDictionary *muxer_options{nullptr};
 
 		const auto alloc_result = avformat_alloc_output_context2(&session.format_context, nullptr, "flv", url.c_str());
 		if (alloc_result < 0 || session.format_context == nullptr) {
@@ -369,7 +370,18 @@ private:
 			}
 		}
 
-		const auto header_result = avformat_write_header(session.format_context, nullptr);
+		// RTMP sockets are non-seekable, so the FLV muxer must not try to backfill
+		// duration/filesize metadata during trailer write.
+		const auto options_result = av_dict_set(&muxer_options, "flvflags", "no_duration_filesize", 0);
+		if (options_result < 0) {
+			av_dict_free(&muxer_options);
+			close_session(session);
+			return unexpected_error(
+				ERR_ALLOCATION_FAILED,
+				"failed to configure FLV muxer flags for '" + url + "': " + av_error_string(options_result));
+		}
+		const auto header_result = avformat_write_header(session.format_context, &muxer_options);
+		av_dict_free(&muxer_options);
 		if (header_result < 0) {
 			close_session(session);
 			return unexpected_error(

src/testers/rtp_output_tester.cpp

@@ -163,7 +163,7 @@ int main(int argc, char **argv) {
 		return exit_code(TesterExitCode::BackendInitError);
 	}
 
-	auto publisher = cvmmap_streamer::protocol::UdpRtpPublisher::create(config);
+	auto publisher = cvmmap_streamer::protocol::UdpRtpPublisher::create(config, *codec);
 	if (!publisher) {
 		spdlog::error("failed to initialize RTP publisher: {}", publisher.error());
 		return exit_code(TesterExitCode::PublisherInitError);