why it is 29 gegabytes

@Kurdistan0001 it's possible that the reason why is because Blu-ray discs are 25 GB because they were designed to provide a high-capacity storage medium for high-definition video and other data. The format was developed by the Blu-ray Disc Association (BDA) and was introduced in 2006 as a successor to DVDs, which had a maximum storage capacity of 4.7 GB for a single-layer disc and 8.5 GB for a dual-layer disc. The increased capacity of Blu-ray discs is made possible by the use of a blue laser instead of the red laser used in DVDs. The shorter wavelength of the blue laser allows more data to be packed into the same amount of space, which results in higher storage capacities. Blu-ray discs are available in both single-layer and dual-layer versions. The single-layer discs have a capacity of 25 GB, while the dual-layer discs can hold up to 50 GB.