Mi Sphere 360, where is stored the gyro data?
The data are stored within the file disregarding of the .mp4 file standard.

the chunk containing those per frame data starts with: #¿Ttlyd or 23C05474 6C7964in hex


Each frame has 36 bytes of data, those seem to be 9 floats of normalized (from -1 to 1) numbers

Those numbers seem to be a 3x3 matrix representing the current coordinate system for this frame.