A 300MB movie is only suitable for watching on a phone or laptop with a small window, or for archival purposes on a device with limited storage.

Typically, these movies are rendered at 480p or 720p . While not "True 4K," they are optimized for viewing on smartphone screens where the pixel density makes the compression less noticeable.

If you own the DVD or Blu-ray legally and want to create a for your phone, you don't need to hunt for illegal downloads. Use HandBrake (free, open source).