Following Playboy's decision to release downloadable content for the PSP, Japanese adult entertainment producer Glay'z has announced plans to release at least eight video titles on the UMD (Universal Media Disk) format starting in early July 2005. Adult content played a major role in boosting sales of video players in the 70s and 80s. However, Sony has officially dismissed the notion of adult content driving PSP sales. The company has made an effort to publicly distance itself from the issue, noting that video content is not subject to Sony's approval, unlike PSP games. Sony has also emphasized that PSPs contain a locking function for parental control.