Integrate Dashcam

The Dashcam app is designed to integrate with AAOS, providing drivers with video recording capabilities for enhanced safety and security. This guide outlines the technical requirements, integration steps, and best practices to ensure a successful implementation.

Prerequisites

Before you continue, ensure these preconditions are fulfilled:

SDK:

  • SDK 31 or higher is required.

Hardware:

  • EVS or Camera2 cameras available to AAOS.
  • Sufficient internal storage space or support for removable external storage
    must be available for video recordings.

Software requirements:

  • Unbundled support. To learn more, see Unbundled Apps.
  • Permissions. Dashcam requires system permissions.

Get the source code

Find the source code in Android Code Search at:

https://cs.android.com/android/platform/superproject/+/ub-automotive-master-20250219:packages/apps/Car/Dashcam/

Source code is provided in these three modules:

  • Dashcam Service. Streaming, recording, and triggering logic.
  • Dashcam Manager. Connects to the Dashcam Service and exposes a stable API to clients
  • Dashcam App. Reference Dashcam application using the Dashcam Manager API

Architecture diagram

Build Dashcam

Use Soong or Gradle to build Dashcam.

Soong

Before building from Soong, be sure to clean the .cxx directories.

On Soong:

mma DashcamService DashcamManager-lib DashcamApp

The APKs are located in out/target/product/[lunch-target]/system/priv-app/

Gradle

On Gradle:

./gradlew :dashcam-app:assemble
./gradlew :dashcam-manager:assemble
./gradlew :dashcam-service:assemble

The APKs are located in out/aaos-apps-gradle-build/

Detailed instructions for building Dashcam with Gradle are provided in the README file.

Permissions

Several system permissions are required for the Dashcam Service and the Dashcam App.

The most staight-forward way to grant these permissions is to include them in a prebuilt setup using either Blueprint or Make.

In Blueprint:

Android.bp
android_app_import {
    name: "DashcamApp-prebuilt",
    apk: "DashcamApp.apk",
    privileged: true,
    certificate: "platform",
    required: ["allowed_privapp_com.android.car.dashcam"],
}

In Make:

dashcam.mk
PRODUCT_PACKAGES += \
    DashcamApp
PRODUCT_COPY_FILES :=\
vendor/[path-to-vendor-prebuilts]/apps/CarCatApp/allowed_privapp_com.android.car.dashcam:$(TARGET_COPY_OUT_PRODUCT)/etc/permissions/com.android.car.dashcam.xml \

Create a permissions file named allowed_privapp_com.android.car.dashcam.xml:

<permissions>
  <privapp-permissions package="com.android.car.dashcam.service">
      <permission name="" />
  </privapp-permissions>
  <privapp-permissions package="com.android.car.dashcam.app">
      <permission name="" />
  </privapp-permissions>
</permissions>

Add permissions from Manifest to the permissions file.

To learn more, see Prebuilt into a system image.

Sideload

The permissions file can also be sideloaded. Use this method when the prebuilt Dashcam is not configured.

Using the permissions file created in the prebuilts section previously, run:

adb root
adb remount
adb push allowed_privapp_com.android.car.dashcam.xml /etc/permissions/allowed_privapp_com.android.car.dashcam.xml
adb shell chmod 644 /etc/permissions/allowed_privapp_com.android.car.dashcam.xml

Configure overlays

Dashcam service has overlayable configurations.

Service configuration

dashcam-service/res/values/config.xml

This file contains configurations for the service:

  • allow_internal_storage Allow recordings to internal storage
  • save_location The directory name to save recordings. Defaults to dashcam
  • max_storage_mb How much storage to allow dashcam to use
  • max_age_days How long to hold onto a file before pruning
  • boot_startup_enabled Dashcam service start on device boot up
  • notifications_on Show notifications when recording starts
  • native_recorder Use NDK APIs, defaults to Java APIs
  • native_renderer Use NDK APIs, defaults to Java APIs
  • default_app_component The default dashcam application, this application has global recordings access and global trigger access
  • recording_module ComponentName of IRecordingModule implementation
  • streaming_module ComponentName of IRecordingModule implementation
  • trigger_module ComponentName of IRecordingModule implementation

Configure a trigger

To trigger the configuration, run:

dashcam-service/src/assets/config.xml

This file contains configurations for recording triggers. The trigger configuration consists of two parts:

  • Pre roll ID. The ID of the camera either EVS or Camera2 depending on what is supported.

  • prerollLengthMs Length of the pre roll to stored with each event.

<Preroll>
  <Camera
      ID="0"
      prerollLengthMs="10000" />
</Preroll>

This example shows camera Id 0 with a 10 second pre roll.

  • name The unique trigger name

  • camera Id of the camera either EVS or Camera2 depending on what is supported

  • sensorPropertyID Id of the sensor

  • description Description of the trigger that is displayed in the UI

  • recordingLengthMs Duration after the event to record in milliseconds.

  • sensorType Which type of sensor. Options are VHAL or SENSOR_MANAGER

  • sensorValueType Type of data produced by the sensor. Options are INT, INT_ARRAY, FLOAT, FLOAT_ARRAY, and BOOLEAN, STRING

  • thresholdType How to evaluate the sensor value. Options are AVERAGE, BOOLEAN, EQUALS, LEAP, LEAP_AVERAGE, LEAP_OVER, PEAK, and PEAK_HOLD

  • thresholdValue The value to compare the sensor value to with the threshold type

  • thresholdExtra Extra value needed for some threshold types such as range for AVERAGE

  • triggerCooldown Cool-down before firing another event of this type in millseconds.

<EventTriggers>
  <EventTrigger
      name="AEB"
      camera="1 2"
      sensorPropertyID="289411073"
      description="Automatic Emergency Braking"
      recordingLengthMs="20000"
      sensorType="VHAL"
      sensorValueType="INT"
      thresholdType="EQUALS"
      thresholdValue="2"
      triggerCooldown="5000"/>
</EventTriggers>

This example shows a VHAL sensor producing integer values where we compare an equality to the threshold value. When the equality condition is met, a trigger records on cameras 1 and 2.

<EventTrigger
            name="SPEED"
            camera="1 2 3 4"
            sensorPropertyID="291504648"
            description="Over speed"
            recordingLengthMs="10000"
            sensorType="VHAL"
            sensorValueType="FLOAT"
            thresholdType="AVERAGE"
            thresholdValue="20.0"
            thresholdExtra="1000"
            triggerCooldown="2000"/>

This example shows a VHAL sensor producing float values where we evaluate the average over a range of samples against the threshold value. The sample range is set in thresholdExtra

Modules

The Dashcam Service consists of three modules:

  • Stream contains the logic for handling streams from cameras.

  • Recording contains the logic for handling recordings.

  • Trigger contains the logic for triggering a recording from sensor data. The module APIs are defined in their corresponding interfaces, IStreamModule, IRecorderModule, and ITriggerModule and exposed to the DashcamManager through DashcamServiceAPI

Overlay modules

Dashcam Service uses dashcam-service/res/values/config.xml to determine where to find the module implementations. We provide default implementations for each module. However, each module can be overlaid by setting its component in the corresponding config value.

  • Set OEM implementation component name of IRecorderModule to recording_module

  • Set OEM implementation component name of IStreamModule to the streaming module.

  • Set OEM implementation component name of ITriggerModule to trigger_module

    At runtime, the Dashcam service instantiates the component name set in config.xml for each module.

App developer's guide

Dashcam is a production ready and customizable dashcam solution. Dashcam uses Dashcam Manager APIs to communicate with Dashcam service. The Dashcam Manager API can be found at IDashcamManager. Any app with the required permissions can use Dashcam Manager.

Permissions

Camera2 and EVS are supported.

Prebuilt

The easiest way to grant these permissions is to include them in the prebuilt setup using either Blueprint or Make.

OverlayUI

The app can be customized with Runtime Resource Overlays. To learn more, see Runtime Resource Overlays. To see the list of overlayable elements, see overlayable.xml.

Extend triggers

Triggers can be extended for the current session with a call to DashcamManager.addTrigger(). Added triggers persist for the current session only.

Autostart

Autostart recording is not supported. However, a manual trigger can be started onBoot with a call to DashcamManager.startRecording()

Best practices

  • Storage. External removable storage is highly recommended.

  • User experience. Design the Dashcam app's UI to be intuitive and user-friendly, adhering to AAOS design guidelines.

  • Performance optimization. Optimize the app's performance to minimize resource usage and ensure smooth operation in AAOS.

Troubleshooting

  • Camera Connectivity Issues. EVS or Camera2 must be supported and available in AAOS IVI.

  • Storage errors. Verify available storage space and manage recordings. External storage is highly recommended since using internal storage can prematurely cause storage to wear out.