The request refers to specific technical documents related to digital video standards, specifically .

: For Scalable Video Coding (SVC), the VUI extension must include information for all present combinations of dependency IDs to ensure compatibility across different viewing devices.

: Ensuring that compressed video maintains its visual integrity and correct "aspect ratio" when played back on different screen sizes. ETSI TS 101 154 V2.1.1 (2015-03)