If a file has x264 in the title, it loses 10000 points. If it has x265 , it gains 10000. The x265 file wins by 20,000 points. Sonarr will literally download a lower quality x265 file (like a WEB-DL) before downloading a remux x264.
To truly prefer x265, you need a that punishes x264. The "Anti-Anime" Block Anime encoders love 10-bit x265. TV scene groups love x264. Use this regex in Preferred Terms with a high negative score:
Check the raw release name. Is x265 actually in the title? Some indexers hide the codec in the description. Sonarr only sees the release name. Fix: Add HEVC and H.265 to your preferred terms.
This article will guide you through everything you need to know about forcing Sonarr to prefer x265, the pitfalls of transcoding, and the hardware required to actually play these files back. The Efficiency Argument HEVC (High Efficiency Video Coding) is roughly 50% more efficient than H.264. A 45-minute TV episode in high-bitrate 1080p x264 might be 2.5GB . The same quality in x265? 1.2GB .
In the world of digital hoarding and home media servers, space is the final frontier. As 4K becomes standard and TV series box sets stretch into hundreds of gigabytes, the question is no longer "Can I store it?" but "How long can I afford to store it?"
