During NASA's Deep Space Optical Comms demo (https://www.nasa.gov/mission/deep-space-optical-communicatio...), they transmitted video at 267 Mbps from 16 million kilometers away. That's 1.78 GiB stored in space while in transit (assuming 53.3 seconds light-speed delay).

The furthest they did was 8.3 Mbps at 400 million km which is around ~1.38 GiB in transit.