Real-Time Target Tracking (traject)

When subscribed to traject via httpPostV2, the camera sends continuous HTTP Posts for the entire duration a target is being tracked. This is fundamentally different from alarm-based approaches.

Tested: IPC v1.9 (firmware 5.1.4.0), March 27-29, 2026

Comparison vs Polling and Alarm Methods

Method	Signal	Gaps While Present	Gap Duration
GetAlarmStatus polling	perimeterAlarm=true	Yes (frequent)	5-20 seconds
Alarm server push (legacy)	One POST per event	Yes (large)	20-60 seconds
httpPostV2 traject	Continuous POSTs	None	N/A

Key characteristics:

• 6-12 posts per second for the entire tracking duration
• Zero gaps while target is in zone
• Posts stop within ~1 second of target leaving
• Each post includes target ID, type, bounding box, velocity, direction
• Multiple targets tracked simultaneously

traject Post Format

<?xml version="1.0" encoding="UTF-8" ?>
<config version="1.7" xmlns="http://www.ipc.com/ver10">
  <types>
    <openAlramObj>
      <enum>MOTION</enum><enum>SENSOR</enum><enum>PEA</enum>
      <!-- ... all alarm types ... -->
    </openAlramObj>
    <subscribeRelation>
      <enum>ALARM</enum>
      <enum>FEATURE_RESULT</enum>
      <enum>ALARM_FEATURE</enum>
    </subscribeRelation>
    <perStatus>
      <enum>SMART_NONE</enum>
      <enum>SMART_START</enum>
      <enum>SMART_STOP</enum>
      <enum>SMART_PROCEDURE</enum>
    </perStatus>
    <targetType>
      <enum>person</enum>
      <enum>car</enum>
      <enum>motor</enum>
    </targetType>
  </types>
  <subscribeOption type="subscribeRelation">FEATURE_RESULT</subscribeOption>
  <currentTime type="tint64">1774646121524166</currentTime>
  <mac type="string"><![CDATA[58:5b:69:5f:42:1b]]></mac>
  <sn type="string"><![CDATA[I421B0Z1173Q]]></sn>
  <deviceName type="string"><![CDATA[FaceCam]]></deviceName>
  <traject type="list" count="1">
    <item>
      <targetId type="uint32">434</targetId>
      <point>
        <x type="uint32">0</x>
        <y type="uint32">0</y>
      </point>
      <rect>
        <x1 type="uint32">6534</x1>
        <y1 type="uint32">2708</y1>
        <x2 type="uint32">7585</x2>
        <y2 type="uint32">6388</y2>
      </rect>
      <velocity type="uint32">0</velocity>
      <direction type="uint32">0</direction>
      <targetType type="targetType">person</targetType>
      <trajectlength type="list" count="0"/>
    </item>
  </traject>
</config>

traject Fields

Field	Type	Description
targetId	uint32	Unique ID for the tracked target. New ID per entry.
point	x, y	Target point (observed as 0,0 -- possibly unused)
rect	x1, y1, x2, y2	Bounding box (normalized 0-10000 coordinates)
velocity	uint32	Target velocity (observed as 0)
direction	uint32	Target direction (observed as 0)
targetType	string	person, car, or motor
trajectlength	list	Trajectory path points (observed as empty)

Test Results

Test: Person standing in zone for 60 seconds (IPC standalone)

• 6-8 posts per second, zero gaps
• Posts stopped within ~1 second of leaving

Test: Two entries with gap (IPC standalone)

• 104 traject posts total (50 + 54)
• Clean start/stop, new targetId per entry

Test: IPC connected to NVR PoE (March 29, 2026)

• 72 traject posts (39 + 33), post rate 9-12/sec
• XML format identical to standalone
• Source IP was the NVR's PoE interface

Post Sizes by Data Type

Data Type	Size	Frequency
traject	~1.7 KB	~7/sec continuous
alarmStatus	~660 bytes	1 per alarm cycle
smartData + images	~510-530 KB	1-2 per entry
keepalive	0 bytes (empty body)	every ~90 sec

Configuration

Enable traject on an IPC via SetHttpPostConfig:

<?xml version="1.0" encoding="UTF-8"?>
<config version="1.0" xmlns="http://www.ipc.com/ver10">
<httpPostV2><postUrlConf>
  <urlList type="list" count="1"><item>
    <urlId>1</urlId>
    <switch>true</switch>
    <url>
      <protocol>http</protocol>
      <domain><![CDATA[192.168.0.53]]></domain>
      <port>80</port>
      <path><![CDATA[/API]]></path>
      <authentication>none</authentication>
    </url>
    <heatBeatSwitch>true</heatBeatSwitch>
    <keepaliveTimeval>90</keepaliveTimeval>
    <subscribeDateType type="list" count="1">
      <item>traject</item>
    </subscribeDateType>
    <subscriptionEvents type="list" count="1">
      <item>PERIMETER</item>
    </subscriptionEvents>
  </item></urlList>
</postUrlConf></httpPostV2>
</config>

Important Notes

• traject is IPC-only. NVRs do not forward traject data and do not expose the smart track data subscription.
• The "Smart track data" checkbox must be enabled in the camera's HTTP Post V2 web interface (Edit HTTP POST dialog). The camera will not send traject even if configured via API unless this checkbox is also checked.
• Works through NVR PoE. The camera sends traject directly to your server, independent of the NVR. Format is identical.
• Recommended dual setup: NVR HTTP Post for alarm events + IPC httpPostV2 for traject tracking.

Use Cases

• Real-time presence detection (relay control, lighting automation)
• People/vehicle counting with continuous position tracking
• Dwell time analysis
• Custom alarm logic based on target position and movement
• Occupancy monitoring

Example implementation: See the Raspberry Pi Human Detection Relay Controller for a working implementation using traject data.

Application Guides

For a complete traject-based automation project, see Real-Time Object Tracking and Relay Control & IoT Automation.