Sony and Panasonic have announced plans for a successor to Blu-ray discs.
The firms say they want to develop an optical disc capable of holding at least 300 gigabytes of data by the end of 2015.
By contrast, normal dual-layer Blu-rays can only hold up to 50GB.
Sony has previously said that 4K ultra-high-definition movies - which offer four times the resolution of 1080p video - were likely to take up more than 100GB of space.
It recently launched a device that allows 4K films to be streamed over the internet, but that will be impractical for people with slow internet access or accounts with data-use limits.