IPC Event Format (v1.x)

IP cameras send alarm data directly to your HTTP server using config version 1.0 or 1.7 with Content-Type: application/xml; charset=utf-8 and Connection: keep-alive.

The IPC sends three types of messages: keepalive heartbeats, alarm status changes, and full alarm data with detection details and images.

Several details depend on camera firmware. See Firmware Differences before you hard-code a field name or value.

Keepalive

Periodic heartbeat. The interval is configurable in the camera's HTTP POST settings (keepaliveTimeval, 30-120 seconds; see Webhook Configuration). Base any "connection lost" timeout on the value you configured, not on a fixed number. For example, an LPR-IP4 on firmware 5.3.1 with the setting at 90 seconds sent a keepalive every 90 seconds over one persistent connection. 90 seconds is an example setting, not a fixed value.

The body depends on firmware, so accept every form below.

Firmware 5.3.1

Observed on LPR-IP4 firmware 5.3.1. A <config> document (version 1.7) with messageType keepalive and a deviceInfo block. There is no XML declaration.

<config version="1.7" xmlns="http://www.ipc.com/ver10">
<messageType>keepalive</messageType>
<deviceInfo>
<deviceName><![CDATA[LPR Camera]]></deviceName>
<ip><![CDATA[192.0.2.100]]></ip>
<mac><![CDATA[00:00:00:00:00:00]]></mac>
</deviceInfo>
</config>

Older firmware

Older firmware uses a <DeviceInfo> root element (not <config>) and includes the serial number.

<?xml version="1.0" encoding="UTF-8"?>
<DeviceInfo>
    <DeviceName>Device Name</DeviceName>
    <DeviceNo.>1</DeviceNo.>
    <SN><![CDATA[SERIALNUMBER]]></SN>
    <ipAddress>192.0.2.100</ipAddress>
    <macAddress>00:00:00:00:00:00</macAddress>
</DeviceInfo>

Some cameras send keepalive posts with an empty body (see the httpPostV2 Data Types timeline).

Alarm Status (alarmStatusInfo)

Sent when an alarm state changes. Small post (~660 bytes), no images.

<?xml version="1.0" encoding="UTF-8" ?>
<config version="1.7" xmlns="http://www.ipc.com/ver10">
<alarmStatusInfo>
<perimeterAlarm type="boolean" id="1">true</perimeterAlarm>
</alarmStatusInfo>
<dataTime><![CDATA[2026-03-29 09:58:21]]></dataTime>
<deviceInfo>
<deviceName><![CDATA[FaceCam]]></deviceName>
<deviceNo.><![CDATA[1]]></deviceNo.>
<sn><![CDATA[I421B0Z1173Q]]></sn>
<ipAddress><![CDATA[192.168.0.52]]></ipAddress>
<macAddress><![CDATA[58:5b:69:5f:42:1b]]></macAddress>
</deviceInfo>
</config>

dataTime follows the camera's date and time display format. The sample above uses YYYY-MM-DD HH:MM:SS. LPR-IP4 firmware 5.3.1 sent MM-DD-YYYY hh:mm:ss AM/PM (for example 09-21-2026 02:15:30 PM). Parse both, or use currentTime on alarm data posts. License plate alarms use vehiceAlarm (firmware spelling).

Key behavior:

true arrives shortly after first detection
false arrives after alarmHoldTime expires -- NOT when the person leaves
Only one true/false cycle per alarm period

Alarm Data (smartData with images)

Full detection event with coordinates, zone boundary, and optionally images.

PEA -- Perimeter Intrusion

<?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>
  <smartType type="openAlramObj">PEA</smartType>
  <subscribeOption type="subscribeRelation">FEATURE_RESULT</subscribeOption>
  <currentTime type="tint64">1774792701902505</currentTime>
  <mac type="string"><![CDATA[58:5b:69:5f:42:1b]]></mac>
  <sn type="string"><![CDATA[I421B0Z1173Q]]></sn>
  <deviceName type="string"><![CDATA[FaceCam]]></deviceName>
  <perimeter>
    <perInfo type="list" count="1">
      <item>
        <eventId type="uint32">2357</eventId>
        <targetId type="uint32">2157</targetId>
        <status type="perStatus">SMART_START</status>
        <boundary type="list" count="5">
          <item><point><x type="uint32">450</x><y type="uint32">466</y></point></item>
          <item><point><x type="uint32">9775</x><y type="uint32">400</y></point></item>
          <item><point><x type="uint32">9675</x><y type="uint32">9466</y></point></item>
          <item><point><x type="uint32">425</x><y type="uint32">9700</y></point></item>
          <item><point><x type="uint32">400</x><y type="uint32">500</y></point></item>
        </boundary>
        <rect>
          <x1 type="uint32">4403</x1><y1 type="uint32">694</y1>
          <x2 type="uint32">5909</x2><y2 type="uint32">8125</y2>
        </rect>
      </item>
    </perInfo>
  </perimeter>
  <relativeTime type="tint64">167998902412</relativeTime>
  <sourceDataInfo>
    <dataType type="uint32">0</dataType>
    <width type="uint32">1280</width>
    <height type="uint32">720</height>
    <sourceBase64Length type="uint32">474378</sourceBase64Length>
    <sourceBase64Data type="string"><![CDATA[... (base64 JPEG) ...]]></sourceBase64Data>
  </sourceDataInfo>
</config>

PEA with Target Crop

When both source and target images are subscribed, the post includes a <listInfo> block with cropped target image data:

<config version="1.7" xmlns="http://www.ipc.com/ver10">
    <smartType type="openAlramObj">PEA</smartType>
    <subscribeOption type="subscribeRelation">FEATURE_RESULT</subscribeOption>
    <currentTime type="tint64">1563528106584193</currentTime>
    <perimeter>
        <perInfo type="list" count="1">
            <item>
                <eventId type="uint32">220</eventId>
                <targetId type="uint32">20</targetId>
                <status type="smartStatus">SMART_START</status>
                <boundary type="list" count="4">
                    <item><point><x type="uint32">1625</x><y type="uint32">2133</y></point></item>
                    <item><point><x type="uint32">1725</x><y type="uint32">8800</y></point></item>
                    <!-- ... additional points ... -->
                </boundary>
                <rect>
                    <x1 type="uint32">113</x1><y1 type="uint32">0</y1>
                    <x2 type="uint32">5511</x2><y2 type="uint32">8472</y2>
                </rect>
            </item>
        </perInfo>
    </perimeter>
    <sourceDataInfo>
        <dataType type="uint32">0</dataType>
        <width type="uint32">1920</width>
        <height type="uint32">1080</height>
        <sourceBase64Length type="uint32">161438</sourceBase64Length>
        <sourceBase64Data type="string"><![CDATA[... (base64 JPEG) ...]]></sourceBase64Data>
    </sourceDataInfo>
    <listInfo type="list" count="1">
        <item>
            <targetId type="tuint32">20</targetId>
            <rect>...</rect>
            <targetImageData>
                <dataType type="uint32">0</dataType>
                <targetType type="uint32">1</targetType>
                <Width type="tuint32">1276</Width>
                <Height type="tuint32">1080</Height>
                <targetBase64Length type="uint32">100774</targetBase64Length>
                <targetBase64Data type="string"><![CDATA[... (base64 JPEG) ...]]></targetBase64Data>
            </targetImageData>
        </item>
    </listInfo>
</config>

IPC smartData Fields

Field	Description
`smartType`	Detection type: `PEA`, `VEHICE`/`VEHICLE`, `VFD`, `VSD`, etc.
`perimeter/perInfo`	Perimeter data (for PEA intrusion). Line crossing uses `tripwire/tripInfo`.
`eventId`	Unique event ID
`targetId`	Target ID (matches `targetId` in concurrent traject posts)
`status`	`SMART_START`, `SMART_STOP`, or `SMART_PROCEDURE`
`boundary`	Zone polygon coordinates (normalized 0-10000)
`rect`	Target bounding box (normalized 0-10000)
`sourceDataInfo`	Full frame JPEG (when `sourceImage` subscribed)
`listInfo/targetImageData`	Cropped target JPEG. `targetType` is numeric (1=person, 2=car, 4=bike) in the samples above. LPR-IP4 firmware 5.3.1 sends a string (`car`) on plate posts, so accept both.

The type attributes are type names, and their spelling varies by firmware. The samples above show openAlramObj and subscribeRelation. LPR-IP4 firmware 5.3.1 sends openAlarmObj and subscribeRelationV1. Match on element names (smartType, subscribeOption), not on type attribute values.

IPC smartType Codes (Complete)

smartType	Description	AlarmData Field	AlarmStatus Field	Images
`MOTION`	Motion detection	`motion` (grid)	`motionAlarm`	Yes
`SENSOR`	Sensor alarm	None	`sensorAlarm`	No
`PEA` (intrusion)	Perimeter intrusion	`perimeter/perInfo`	`perimeterAlarm`	Yes
`PEA` (line cross)	Line crossing	`tripwire/tripInfo`	`tripwireAlarm`	Yes
`AVD` (blur)	Video blur	None	`clarityAbnormal`	No
`AVD` (cast)	Video cast	None	`colorAbnormal`	No
`AVD` (scene)	Scene change	None	`sceneChange`	No
`OSC`	Object removal	`smartType: OSC`	`oscAlarm`	Yes
`CPC`	People counting	`CPC`	`CPCAlarm`	Yes
`CDD`	Crowd density	`CDD`	`CDDAlarm`	Yes
`IPD`	People intrusion	`IPD`	`IPDAlarm`	Yes
`VFD`	Face detection	`VFD`	`VFDAlarm`	Yes
`VFD_MATCH`	Face recognition	`VFD_MATCH`	`VFDAlarm`	Yes
`VEHICE` / `VEHICLE`	License plate (spelling depends on firmware, see Firmware Differences)	`listInfo`	`vehiceAlarm`	Yes
`AOIENTRY`	Region entry	`AOIENTRY`	(undocumented)	Yes
`AOILEAVE`	Region exit	`AOILEAVE`	(undocumented)	Yes
`PASSLINECOUNT`	Line counting	`PASSLINECOUNT`	(undocumented)	Yes
`TRAFFIC`	Area counting	`TRAFFIC`	(undocumented)	Yes

LPR Event (VEHICE / VEHICLE)

A plate read arrives as one FEATURE_RESULT post. There is no sourceDataInfo block. listInfo has two items:

Item 0 is the overview image (image 0, empty plateNumber, width/height 0, empty targetType).
Item 1 is the plate read and the plate crop (image 1, targetType car).

Shape observed on LPR-IP4 firmware 5.3.1 (HTTP POST V1 layout). Device identity, the timestamp, image data, and vehicle attribute values are placeholders. IB36NL is a test plate. The full file is examples/ipc-v1x/lpr.xml.

<?xml version="1.0" encoding="UTF-8" ?>
<config version="1.7" xmlns="http://www.ipc.com/ver10">
<types><!-- ... enum lists ... --></types>
<smartType type="openAlarmObj">VEHICE</smartType>
<subscribeOption type="subscribeRelationV1">FEATURE_RESULT</subscribeOption>
<currentTime type="tint64">1785000000123456</currentTime>
<mac type="string"><![CDATA[00:00:00:00:00:00]]></mac>
<sn type="string"><![CDATA[SERIALNUMBER]]></sn>
<deviceName type="string"><![CDATA[LPR Camera]]></deviceName>
<channelId type="uint32">1</channelId>
<plateCount type="uint32">1</plateCount>
<listInfo type="list" count="2">
    <item>
        <image type="uint32">0</image>
        <plateNumber type="string"><![CDATA[]]></plateNumber>
        <!-- ... same fields as item 1, all zero ... -->
        <targetImageData>
            <dataType type="uint32">0</dataType>
            <targetType type="targetType"></targetType>
            <width type="uint32">0</width>
            <height type="uint32">0</height>
            <targetBase64Length type="uint32">770384</targetBase64Length>
            <targetBase64Data type="string"><![CDATA[... (base64 JPEG overview) ...]]></targetBase64Data>
        </targetImageData>
    </item>
    <item>
        <image type="uint32">1</image>
        <vehiceId type="uint32">1</vehiceId>
        <plateNumber type="string"><![CDATA[IB36NL]]></plateNumber>
        <plateCharCount type="uint32">6</plateCharCount>
        <vehicleDirect type="vehicleDirectType">approach</vehicleDirect>
        <vehicleListType type="vehileMatchAlarmList">whiteList</vehicleListType>
        <PlateWidth type="uint32">176</PlateWidth>
        <PlateHeight type="uint32">100</PlateHeight>
        <SourceImageWidth type="uint32">2688</SourceImageWidth>
        <SourceImageHeight type="uint32">1776</SourceImageHeight>
        <leftTop><x type="uint32">7559</x><y type="uint32">2072</y></leftTop>
        <rightTop><x type="uint32">8214</x><y type="uint32">2072</y></rightTop>
        <leftBottom><x type="uint32">7559</x><y type="uint32">2635</y></leftBottom>
        <rightBottom><x type="uint32">8214</x><y type="uint32">2635</y></rightBottom>
        <PlateConfidence type="uint32" count="9900"/>
        <plateColor type="uint32" count="3"/>
        <plateColorRate type="uint32" count="0"/>
        <plateStyle type="uint32" count="1"/>
        <vehiceColor type="uint32" count="0"/>
        <plateAngleH type="uint32" count="0"/>
        <plateAngleV type="uint32" count="0"/>
        <province type="string"></province>
        <carAttr>
            <color type="vsdCarAttrColorType">white</color>
            <type type="vsdCarAttrTypeType">saloon car</type>
            <brand type="vsdCarAttrBrandType">Toyota</brand>
            <model type="vsdCarAttrModelType">Toyota_Camry</model>
        </carAttr>
        <carRect>
            <x type="uint32">1242</x><y type="uint32"/>
            <width type="uint32">586</width><height type="uint32">446</height>
        </carRect>
        <targetImageData>
            <dataType type="uint32">0</dataType>
            <targetType type="targetType">car</targetType>
            <width type="uint32">176</width>
            <height type="uint32">100</height>
            <targetBase64Length type="uint32">19520</targetBase64Length>
            <targetBase64Data type="string"><![CDATA[... (base64 JPEG plate crop) ...]]></targetBase64Data>
        </targetImageData>
    </item>
</listInfo>
</config>

LPR Fields

"Confirmed on" names the firmware where the field was seen in a captured post.

Field	Description	Confirmed on
`smartType`	`VEHICE` or `VEHICLE`, depending on firmware	5.1.1, 5.3.1
`currentTime`	Event time from the camera clock, Unix microseconds (16 digits). Check the camera clock before comparing it with arrival time.	5.3.1
`plateCount`	Number of plates in the post	5.3.1
`listInfo/item[0]/targetImageData`	Overview JPEG (base64). About 760 KB of base64 text in an LPR-IP4 post.	5.1.1, 5.3.1
`plateNumber`	Plate text (CDATA). Empty on item 0.	5.1.1, 5.3.1
`plateCharCount`	Number of characters in the plate text	5.3.1
`vehicleDirect`	`approach` or `away`. Earlier versions of this page listed `leave`, which has not been seen in a captured post. Treat `leave` like `away` if it appears.	5.1.1 (`approach`), 5.3.1 (both)
`vehicleListType`	Plate list the plate matched (table below). Not sent at all on 5.1.x.	5.3.1
`PlateConfidence`	Value is in the `count` attribute, on a 0-10000 scale (`count="9900"` = 99%). The element has no text.	5.3.1
`plateColor`	Numeric code in the `count` attribute (for example `count="3"`), not a color name. The code-to-color mapping is not documented.	5.3.1
`plateColorRate`, `plateStyle`, `vehiceColor`, `plateAngleH`, `plateAngleV`	Numeric values in the `count` attribute. Meaning not documented.	5.3.1
`leftTop`, `rightTop`, `leftBottom`, `rightBottom`	Plate corner points, normalized 0-10000. There is no `rect` on IPC plate posts.	5.3.1
`PlateWidth`, `PlateHeight`	Plate crop size in pixels	5.3.1
`SourceImageWidth`, `SourceImageHeight`	Full-frame size in pixels	5.3.1
`province`	Plate region text. Empty in U.S. reads.	5.3.1
`carAttr/color`, `carAttr/type`, `carAttr/brand`, `carAttr/model`	Vehicle color, type (for example `saloon car`), brand, and model (`Brand_Model` form)	5.3.1
`carRect`	Vehicle box: `x`, `y`, `width`, `height`. `y` was an empty element. Units not confirmed.	5.3.1
`listInfo/item[1]/targetImageData`	Plate crop JPEG (base64), `targetType` `car`. About 19 KB of base64 text.	5.1.1, 5.3.1

The post carries no plate group number. Map list names yourself.

Plate database status (vehicleListType):

Value	Meaning	Confirmed on
`whiteList`	Plate is on the allow list	5.3.1
`blackList`	Plate is on the block list	5.3.1
`temporaryList`	Plate is on the temporary list	Not yet confirmed in a captured post
(field absent)	Plate is on no list. On 5.1.x the field is always absent, even for listed plates.	5.1.1, 5.3.1

Not yet confirmed: plates whose valid date range has expired (allow, block, or temporary) are expected to have vehicleListType omitted, so the camera checks date ranges for every list type. Test this on your firmware before you rely on it.

Image data

Decode the actual base64 text, and don't size buffers from targetBase64Length. On LPR-IP4 firmware 5.3.1 the declared length didn't match the text: the overview declared 770,384 characters and carried about 760,500, and the plate crop declared 19,520 and carried 19,270.

Firmware Differences

Observed on LPR-IP4 cameras. Behaviour on other models may differ.

Behaviour	5.1.1.0 (build 52592)	5.1.1.0 (build 66800)	5.3.1
Public API version (`GetDeviceInfo`)	1.7	1.7	2.1.0
Plate post layout	V1, config `1.7`	V1, config `1.7`	V1, config `1.7` (also when a V2 row is saved; see IPC Format (v2.1))
`smartType`	`VEHICE`	`VEHICLE`	`VEHICE`
`vehicleListType`	Never sent	Never sent	Sent for listed plates (`whiteList`, `blackList`); absent for unlisted plates
`vehicleDirect`	`approach` seen on 5.1.1 (build not recorded)	`approach` seen on 5.1.1 (build not recorded)	`approach` and `away` seen
`carAttr` vehicle attributes	Not confirmed	Not confirmed	Sent
Keepalive body	Not confirmed	Not confirmed	`config` 1.7 + `messageType` `keepalive` + `deviceInfo`
`type` attribute names	Not confirmed	Not confirmed	`openAlarmObj`, `subscribeRelationV1`

Accept both VEHICE and VEHICLE. The spelling doesn't follow firmware age: 5.3.1 is newer than build 66800 and still sends VEHICE.

Application Guides

For step-by-step setup of IPC webhook events, see Webhook Event Notification API. For traject-based real-time tracking from IPC, see Real-Time Object Tracking. For LPR plate database management, see LPR Configuration.

Keepalive​

Firmware 5.3.1​

Older firmware​

Alarm Status (alarmStatusInfo)​

Alarm Data (smartData with images)​

PEA -- Perimeter Intrusion​

PEA with Target Crop​

IPC smartData Fields​

IPC smartType Codes (Complete)​

LPR Event (VEHICE / VEHICLE)​

LPR Fields​

Image data​

Firmware Differences​