MotionCam MCRAW decoder

A simple library for decoding files recorded by MotionCam Pro.

Usage

Look in example.cpp for a simple example on how to extract the RAW frames into DNGs and the audio into a WAV file.

To build the example:

mkdir build

cd build

cmake ..

make

To extract the first frame and audio from a .mcraw file run:

./example <path to mcraw file> -n 1

Embedded gyro data

Recent .mcraw files can contain raw gyroscope samples. The timestamps use the same nanosecond timeline as frame timestamps, and the axis values are radians per second:

motioncam::Decoder decoder("input.mcraw");
std::vector<motioncam::MotionSample> gyroSamples;

if(decoder.hasGyroData())
    decoder.loadGyroData(gyroSamples);

Embedded accelerometer data

New .mcraw files can also contain accelerometer samples. They use the same nanosecond timeline as frames and gyro samples. Values are m/s² including gravity, retaining the source platform's sensor axes and sign convention. MotionCam already converts iOS values from g when recording; do not convert them again when decoding. The decoder preserves sample timestamps and values without resampling or rotating them into image coordinates.

motioncam::Decoder decoder("input.mcraw");
std::vector<motioncam::MotionSample> accelerometerSamples;

if(decoder.hasAccelerometerData())
    decoder.loadAccelerometerData(accelerometerSamples);

Like loadGyroData, loadAccelerometerData appends to the supplied vector. Files without accelerometer data leave the vector unchanged. OIS chunks are safely skipped so they do not prevent discovery of the accelerometer index; OIS samples are not exposed by this API.

The stream uses item IDs 12 (index) and 13 (data), with version-1 headers and the existing 24-byte MotionSample layout. The container version remains 3.

To run the decoder regression tests:

cmake -S . -B build -DBUILD_TESTING=ON
cmake --build build
ctest --test-dir build --output-on-failure

Sample Files

You can download a sample file from here.

MotionCam Pro

MotionCam Pro is an app for Android that provides the ability to record RAW videos. Get it from the Play Store.