Problem · storage
Why Is My DVD Rip 5 GB — and Should You Compress It?
A five-gigabyte DVD rip can be completely normal. DVD-Video stores standard-definition MPEG-2 at relatively high bitrates by modern standards. If you copy the main movie without re-encoding, keep several audio streams or create an ISO, the result can remain several gigabytes.
If you need hundreds of movies on a NAS, the storage equation changes. Re-encoding to H.264 or HEVC can shrink the library significantly, but there is no honest universal “80% smaller with zero quality loss” rule that applies to every disc. Animation, grain, runtime, interlacing, bitrate, audio and quality settings all affect the result.
Structural backupLargest, preserves the most disc structure
Direct MPEG-2Large, avoids a new video encode
H.264Strong compatibility and efficient storage
HEVCCan save more space, but needs broader decode support
For a large collection, make one short test encode and watch motion, dark scenes, subtitles and audio before committing. Quality mistakes multiplied across 600 discs are expensive to redo.