Adjust to latest gyroflow file format

[AdrianEddy]

Hi,

In latest dev build, and soon to be v1.5.1, I've changed the format of the extended data a bit. Instead of using bincode I now use standard CBOR, which should be easier to parse

If version == 3, then gyro_data = cbor2.decoder.loads(raw)

This was needed because we now have additional data from certain files, like per-frame offset, per-frame exposure time and hopefully soon per-frame lens profile information. Adding all these additional information using bincode would be pretty hard to parse in external tools, so I decided to switch to CBOR, which has parsers in all languages

raw_imu and quaternions fields were removed from gyro_source. Instead, there's now file_metadata there which contains:

pub struct FileMetadata {
    pub imu_orientation:     Option<String>,
    pub raw_imu:             Vec<telemetry_parser::util::IMUData>, 
    pub quaternions:         BTreeMap<i64, Quaternion<f64>>,
    pub gravity_vectors:     Option<BTreeMap<i64, Vector3<f64>>>,
    pub image_orientations:  Option<BTreeMap<i64, Quaternion<f64>>>,
    pub detected_source:     Option<String>,
    pub frame_readout_time:  Option<f64>,
    pub frame_rate:          Option<f64>,
    pub camera_identifier:   Option<CameraIdentifier>,
    pub lens_profile:        Option<serde_json::Value>,
    pub lens_positions:      Option<BTreeMap<i64, f64>>,
    pub has_accurate_timestamps: bool,
    pub additional_data:     serde_json::Value,
    pub per_frame_time_offsets: Vec<f64>,
    pub per_frame_data:      Vec<serde_json::Value>,
}

// definition of telemetry_parser::util::IMUData
pub struct IMUData {
    pub timestamp_ms: f64,
    pub gyro: Option<[f64; 3]>,
    pub accl: Option<[f64; 3]>,
    pub magn: Option<[f64; 3]>
}

// definition of CameraIdentifier
pub struct CameraIdentifier {
    pub brand: String,
    pub model: String,
    pub lens_model: String,
    pub lens_info: String,
    pub focal_length: Option<f64>,
    pub camera_setting: String,
    pub fps: usize,
    pub video_width: usize,
    pub video_height: usize,
    pub additional: String,
    pub identifier: String
}

Additionally, I added:

• synced_imu_timestamps - array of timestamps for every IMU sample, with added interpolated offsets
• synced_imu_timestamps_with_per_frame_offset - same as above + per frame time offset, which involves exposure time and custom VSYNC offset from the file metadata - this is the final offset. The timestamps represent middle of the frame, ie. in case of 59.94 video, 0 is the middle row of first frame, 16.68 middle row of the second frame etc.
• adaptive_zoom_fovs - per frame smoothed FOV for adaptive zoom

So instead of interpolating the offsets on your side in python, you can just use imu.timestamp = synced_imu_timestamps_with_per_frame_offset[imu_index]

file_metadata = cbor2.decoder.loads(zlib.decompress(decode(data['gyro_source']['file_metadata'])))
synced_imu_timestamps_with_per_frame_offset = cbor2.decoder.loads(zlib.decompress(decode(data['gyro_source']['synced_imu_timestamps_with_per_frame_offset'])))

[AdrianEddy]

samples.zip

[AdrianEddy]

GyroFlowToCSV.zip

updated, but not tested and only works with the new version, will need to be updated with ifs that check version to work with both new and old

[AndrewHazelden]

Hi @AdrianEddy,

updated, but not tested and only works with the new version, will need to be updated with ifs that check version to work with both new and old

I finally tested out the revised GyroflowToCSV script you posted. To get the script to work successfully with Python v3.10.9 on my laptop I had to adjust the cbor2 function to use the cbor2._decoder.loads() instead of cbor2.decoder.loads().

Here is the modified python script should anyone else want to explore it:

GyroFlowToCSV.zip

[AdrianEddy]

In latest dev build I added an option to export camera data directly to CSV, JSON, USD or JSX (for AE) from Gyroflow. Please test if it works as expected for you.

I also have a question - what's the use case for this data? Since this only exports camera rotations, and not translations, it doesn't replace 3D camera tracker. Is there a way to use rotations and then track translations only?

https://gyroflow.xyz/devbuild/ Motion Data -> Export -> Export camera data

[AndrewHazelden]

Thanks for adding the native data export options to GyroFlow. This will make things far more accessible for end users!

[AndrewHazelden]

My primary interest in the GyroFlow CSV/JSON/USD data export options is to use the motion data to help with spherical video rotational stabilization for 180VR/360VR post-production workflows.