I’m using VST version 1.3.0-24.08.1 on a Jetson Orin device.
I noticed a consistent 3–5 second delay between the live stream and the recorded stream, even though the system time appears correct and synchronized.
- Source stream: FFmpeg with RTSP output
- Overlay: Real-time clock using
drawtext='%{localtime}' - Livestream: Viewed through VST WebUI
- Recording: Done by VST (
always_recording: true) - Issue: Recorded stream timestamps (visually confirmed via overlay) are delayed by ~5 seconds vs real-time
I’ll attach two frame captures:
-
Live stream screenshot (with timestamp overlay)
-
Recorded stream frame (same frame delayed ~5s)
The stream type doesn’t matter - it can be ffmpeg, rtsp live camera, above are only examples
Here is my config
{
"network":
{
"http_port": 30080,
"server_domain_name":"",
"stunurl_list": ["stun.l.google.com:19302","stun1.l.google.com:19302"],
"static_turnurl_list": [],
"use_coturn_auth_secret": false,
"coturn_turnurl_list_with_secret": [],
"use_twilio_stun_turn": false,
"twilio_account_sid": "",
"twilio_auth_token": "",
"use_reverse_proxy": false,
"use_sensor_ntp_time": true,
"reverse_proxy_server_address": "REVERSE_PROXY_SERVER_ADDRESS:100",
"ntp_servers": [],
"max_webrtc_out_connections": 3,
"max_webrtc_in_connections": 1,
"webservice_access_control_list":"",
"rtsp_server_port": 8070,
"rtsp_preferred_network_iface": "eth0",
"rtsp_in_base_udp_port_num": -1,
"rtsp_out_base_udp_port_num": -1,
"rtsp_streaming_over_tcp": false,
"rtsp_server_reclamation_client_timeout_sec": 10,
"socket_buffer_size":2000000,
"stream_monitor_interval_secs": 2,
"rtp_udp_port_range" : "31000-31200",
"udp_latency_ms": 200,
"udp_drop_on_latency": false,
"webrtc_latency_ms": 20,
"enable_frame_drop": true,
"webrtc_max_birate": 10000,
"webrtc_min_birate": 2000,
"webrtc_start_birate": 4000,
"webrtc_peer_conn_timeout_sec": 10,
"enable_grpc": true,
"grpc_server_port": "50051",
"webrtc_in_audio_sender_max_bitrate": 128000,
"webrtc_in_video_degradation_preference": "resolution",
"webrtc_in_video_sender_max_framerate": 30,
"remote_vst_address": "",
"webrtc_port_range": {"min":0, "max":0},
"enable_websocket_pingpong": false,
"websocket_keep_alive_ms": 5000
},
"onvif":
{
"device_discovery_timeout_secs":10,
"onvif_request_timeout_secs":20,
"device_discovery_freq_secs":15,
"device_discovery_interfaces": [],
"max_devices_supported": 8,
"default_bitrate_kbps": 8000,
"default_framerate": 30,
"default_resolution": "1920x1080",
"default_gov_length": 60
},
"data":
{
"storage_config_file": "/root/vst_release/configs/vst_storage.json",
"storage_threshold_percentage": 95,
"storage_monitoring_frequency_secs": 2,
"enable_avsync_udp_input": true,
"nv_streamer_directory_path": "/home/vst/vst_release/streamer_videos/",
"nv_streamer_loop_playback":true,
"nv_streamer_seekable":false,
"nv_streamer_max_upload_file_size_MB": 10000,
"nv_streamer_media_container_supported": ["mp4","mkv"],
"nv_streamer_metadata_container_supported": ["json"],
"nv_streamer_rtsp_server_output_buffer_size_kb": 1000,
"supported_video_codecs": ["h264","h265"],
"supported_audio_codecs": ["pcmu","pcma","mpeg4-generic"],
"enable_aging_policy": false,
"max_video_download_size_MB":1000,
"always_recording": true,
"event_recording": true,
"event_record_length_secs": 10,
"record_buffer_length_secs": 0,
"use_software_path": false,
"webrtc_in_fixed_resolution": "1280x720",
"webrtc_in_max_framerate": 30,
"webrtc_in_video_bitrate_thresold_percentage": 50,
"webrtc_in_passthrough": false,
"webrtc_sender_quality": "pass_through",
"enable_rtsp_server_frameid_support": true,
"gpu_indices": [],
"webrtc_out_enable_insert_sps_pps" : true,
"webrtc_out_set_iframe_interval" : 30,
"webrtc_out_set_idr_interval" : 256,
"webrtc_out_min_drc_interval" : 5,
"device_name" : "VST",
"device_location" : "",
"enable_dec_low_latency_mode": false
},
"notifications":
{
"enable_notification": false,
"use_message_broker": "None",
"message_broker_topic": "vst.event",
"message_broker_payload_key": "sensor.id",
"message_broker_metadata_topic": "test",
"redis_server_env_var":"localhost:6379",
"kafka_server_address": "localhost:9092"
},
"debug":
{
"enable_perf_logging":true,
"enable_qos_monitoring":true,
"qos_logfile_path":"/root/vst_release/webroot/log/",
"qos_data_capture_interval_sec":1,
"qos_data_publish_interval_sec":5,
"enable_gst_debug_probes":true,
"enable_prometheus":false,
"prometheus_port": "8080",
"enable_highlighting_logs":false,
"enable_debug_apis": false,
"dump_webrtc_input_stats": false,
"enable_frameid_in_webrtc_stream": false,
"enable_network_bandwidth_notification" : false
},
"overlay":
{
"video_metadata_server": "",
"video_metadata_query_batch_size_num_frames": 300,
"use_video_metadata_protobuf": false,
"enable_gem_drawing": false,
"analytic_server_address": "http://10.24.216.236:30080/emdx"
},
"security":
{
"use_https": true,
"use_rtsp_authentication": false,
"use_http_digest_authentication": false,
"use_multi_user": false,
"enable_user_cleanup": false,
"session_max_age_sec": 2592000,
"multi_user_extra_options": ["Secure", "SameSite=none"],
"nv_org_id": "",
"nv_ngc_key": ""
}
}
Questions
- Is this delay expected under default recording setup?
- Can VST record frames with the exact same timing as the live stream feed?
- Any recommended config or flags to reduce or eliminate this offset?
