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camm.md

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CAMM (Camera Motion Metadata Spec)

Google has created a comprehensive page detailing the CAMM data format you will find useful in understanding the decoded structure and content.

In short there should be only one CAMM track per MP4 video file.

Within the CAMM track there are 7 cases (think of them as layers).

The video does not write to all layers (because some cases have duplicate fields (e.g. camm5 and camm6 both have latitude and longitude fields).

Deconstructing the CAMM Spec

camm

Description:

The video file should contain the following sample entry box to indicate the custom metadata track, and the subComponentType of the track should be set to meta.

Structure:

Camera Motion Metadata Sample Entry (camm)

Definition
Box Type: camm
Container: stsd
A sample entry indicating the data track that saves the camera motion.

Syntax
aligned(8) class CameraMotionMetadataSampleEntry extends SampleEntry('camm') {
}

Example:

  "Main:HandlerDescription": {
    "id": 24,
    "table": "QuickTime::Handler",
    "val": "CameraMetadataMotionHandler"
  },
  "Main:OtherFormat": {
    "id": 4,
    "table": "QuickTime::OtherSampleDesc",
    "val": "camm"
  }

Taken from: Insta360 Pro2

camm0

Description:

Angle axis orientation in radians representing the rotation from local camera coordinates to a world coordinate system. The world coordinate system is defined by applications.

Structure:

  case 0:
    float angle_axis[3];
  break;

Example:

camm1

Description:

Structure:

  case 1:
    int32 pixel_exposure_time;
    int32 rolling_shutter_skew_time;
  break;

Example:

camm2

Description:

Structure:

  case 2:
    float gyro[3];
  break;

Example:

  "Doc1:AngularVelocity": {
    "id": 4,
    "table": "QuickTime::camm2",
    "val": "0.0462660863995552 0.139929175376892 -0.204053655266762"
  }

Taken from: Insta360 Pro2

camm3

Structure:

  case 3:
    float acceleration[3];
  break;

Example:

  "Doc2:Acceleration": {
    "id": 4,
    "table": "QuickTime::camm3",
    "val": "1.1484375 -0.0741699188947678 15.0469236373901"
  }

Taken from: Insta360 Pro2

camm4

Structure:

  case 4:
    float position[3];
  break;

Example:

camm5

Structure:

  case 5:
    double latitude;
    double longitude;
    double altitude;
  break;

Example:

camm6

Structure:

  case 6:
    double time_gps_epoch;
    int gps_fix_type;
    double latitude;
    double longitude;
    float altitude;
    float horizontal_accuracy;
    float vertical_accuracy;
    float velocity_east;
    float velocity_north;
    float velocity_up;
    float speed_accuracy;
  break;

Example:

  "Doc25:GPSDateTime": {
    "id": 4,
    "table": "QuickTime::camm6",
    "val": "2020:04:02 09:43:22.2Z"
  },
  "Doc25:GPSMeasureMode": {
    "id": 12,
    "table": "QuickTime::camm6",
    "val": "3-Dimensional Measurement"
  },
  "Doc25:GPSLatitude": {
    "id": 16,
    "table": "QuickTime::camm6",
    "val": "50.456102 N"
  },
  "Doc25:GPSLongitude": {
    "id": 24,
    "table": "QuickTime::camm6",
    "val": "30.479831 E"
  },
  "Doc25:GPSAltitude": {
    "id": 32,
    "table": "QuickTime::camm6",
    "val": "146.8 m"
  },
  "Doc25:GPSHorizontalAccuracy": {
    "id": 36,
    "table": "QuickTime::camm6",
    "val": 1.02999997138977
  },
  "Doc25:GPSVerticalAccuracy": {
    "id": 40,
    "table": "QuickTime::camm6",
    "val": 1.02999997138977
  },
  "Doc25:GPSVelocityEast": {
    "id": 44,
    "table": "QuickTime::camm6",
    "val": 0.699336230754852
  },
  "Doc25:GPSVelocityNorth": {
    "id": 48,
    "table": "QuickTime::camm6",
    "val": 1.19965398311615
  },
  "Doc25:GPSVelocityUp": {
    "id": 52,
    "table": "QuickTime::camm6",
    "val": 0
  },
  "Doc25:GPSSpeedAccuracy": {
    "id": 56,
    "table": "QuickTime::camm6",
    "val": 0
  },

Taken from: Insta360 Pro2

camm7

Structure:

  case 7:
    float magnetic_field[3];
  break;

Example: