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Can you describe these ring patterns in a little more detail? There is a ring or spiral pattern that appears if you hold any BD-R in a bright light, but when tilting it away from the light source the surface coloration becomes uniform. One of our members has mentioned that Aone discs were rather low quality, I would not recommend burning them faster than their rated speed. Do you know what the media code of these discs is?
Disc manufacturers list capacities in decimal format, operating systems list capacity in binary format. 25GB decimal = 23.3GB binary.