06-12-2015 11:05 AM
There is a time and/or file size limit on video recording. You probably are just hitting that limit, so the camera stops recording.
I think that limit is to prevent the imaging sensor from overheating. But I don't shoot video with my DSLRs, so am not certain of this.
Check your particular camera manual. There may be some difference in file size/time limit, depending upon caeram model.