While we don’t have access to Sirius Pixels, or whatever the most expensive solution currently is, isn’t it fair to say that that, regardless of who has licensed the x264 codec and built a shiny wrapper around it with some custom presets designed for maximum quality, the codec at the heart of the application is probably exactly the same as the free version it was built on?
No, it’s a different codec entirely. X264 is the best free AVC codec available, and it’s better than Mainconcept - a commonly used “entry level” commercial AVC codec. Try it yourself, grab yourself a bluray encoded using the Sirus codec, rip it and re-encode it to the same size using x264. Preferentially try it with a BD25 as the difference in quality will be more obvious. Doesn’t matter what settings you use, x264 can’t achieve the same quality at the same size.
You can run the same test on MPEG2 encoders as well. In this case the free encoders are TMPGEnc, QuEnc, and HC Encoder. As a general rule the slower the encoder the better the quality, but even the best quality of the three - HC Encoder - is both slower and lower quality than comparable commercial encoders like Mainconcept and Procoder. I think this is why there are so many SL discs out there - Mainconcept will produce with 4.3GB quality that back in the early days of DVD was impossible even with two discs, and that advancement has allowed DVD publishers to press high quality SL discs. If they were using HC Encoder they wouldn’t be the same quality. And the free MPEG2 encoders, as you’ve no doubt noticed, have not advanced at all in the last 10 years in terms of the quality they produce.
In any case, unless somebody wants to buy us a $100,000 license for the Sirius Pixels encoder, it’s a moot point. Tweaking the settings is all we can do…
My point is that what Sirius Pixels can do in 22GB, x264 needs more like 30GB to achieve. My advice is to stick the CRF down to 16, use the Slower pre-set, and don’t worry about the size. It’ll get down-converted and transcoded by others anyway.