It depends on the duration of the actual recording.
We have prepared a new setting for adjusting the quality within the project settings. Adjusting the quality can increase/decrease the size of the video.
The video size is determined by the bitrate with the default bitrate for both the iOS and Android SDKs set at 80 000 b/s. That should generate data of an approximate size of 0.5 MB per minute. The video quality depends on the resolution used with a certain bitrate setting.