Film grain and digital noise are the enemies of compression. x265 sees noise as "important detail" and wastes gigabytes trying to preserve random dots.
| Source Type | Original Size | Shrunk Size (High Quality) | Shrunk Size (Archival) | Notes | | :--- | :--- | :--- | :--- | :--- | | | 25-35 GB | 4-6 GB (CRF 20) | 2-3 GB (CRF 24) | Use 10-bit. Avoid cartoon animation (which can go smaller). | | 4K Blu-ray (HDR) | 50-90 GB | 12-18 GB (CRF 22) | 6-10 GB (CRF 24) | Must use 10-bit. Keep HDR metadata. | | Web-DL | 5-10 GB | 2-3 GB | 1-1.5 GB | Web streams are already compressed; shrinking further is risky. | | Anime (1080p) | 10 GB | 1-2 GB | 500 MB | Anime has flat colors; x265 excels here. | shrinking x265
This article is your deep dive into the science, art, and syntax of shrinking x265. Before we look at the "how," we need to look at the "why." Film grain and digital noise are the enemies of compression