What does it mean that there is an "efficient video format" in Huawei's mobile phone camera settings?

Turn on the camera and select the recording mode.

Choose a space-saving video format: Click Settings to turn on the Efficient Video Format switch.

Turn on this switch, and the mobile phone will adopt a more efficient video format to help you save storage space. However, other devices may not be able to play videos in this format. Please choose according to actual needs.