I have downloaded the following standard.
80 mm (1,23 Gbytes per side) and 120 mm (3,95 Gbytes per side) DVD-Recordable Disk (DVD-R)
I do not know about the 80mm disk but I do know present day 120mm DVD-R disks are labeled "4.7 GB" by the manufacturer. Assume the 3.95 GB of the standard are really 3.95 GiB and that 4.7 GB are expressed in true GBytes (GB). Then, doing some arithmetics, we get 3.95 GiB = 4.24... GB, which falls short of 4.7 GB. Of course if DVD-R disks were labeled in GiB, then the difference would be greater.
This brings me to suspect the ECMA-279 standard is at present obsolete. Can this be so? Any hint would be greatly appreciated.