The heart of this issue is Premiere's lack of support for variable frame rate. Our downloadable mp4s use the original frame timing that the BoxCaster receives when encoding. So video frames are timestamped with actual timing. Under ideal situations, these timestamps will be approximately (if not exactly) coincide with the camera's frame rate (e.g. 30fps or 29.97fps) or a fraction thereof (e.g. 30fps for a 60fps source). However, any perturbation, like the camera dropping a frame, or a network disruption significant enough to incur packet loss, means that the video frame will not be received by the cloud, and will not make it into the resulting mp4 file.