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Post #898545

Author
Jan
Parent topic
team negative1 - star wars 1977 - 35mm theatrical version (Released)
Link to post in topic
https://originaltrilogy.com/post/id/898545/action/topic#898545
Date created
18-Jan-2016, 5:08 PM

RU.08 said:

Jan said:

  1. In my opinion, a total size of about 25GB is sufficient for a 1080p encode at a very good quality (just compare it to encodes of other movies available on various file sharing sites), if the encoding settings were to be somewhat enhanced compared to your V1.0. As you’re aiming for a final file size, 2pass encoding fits the purpose much better than CRF. Additionally, some other settings might need adjustments. Overall, the settings suggested at the official x264 website (see link below) are quite a good starting point. The one thing I would change though is --tune grain instead of --tune film for obvious reasons. Any other possible, manual change of the encoding settings is just fine-tuning in my point of view. With these settings, the encoding quality will be quite a bit better and fine details as well as grain will be be preserved much better! BTW, I helped Harmy with his encodes of the Despecialized Edition😃

Hi Jan, sorry to say you’re wrong on this one. The best h264 commercially available encoders are about 40% more efficient than x264. And I’m not talking about Mainconcept which is the encoder everyone compares x264 to, I’m talking about Sirius Pixels which is much better than x264, hence the reason that top authoring houses prefer it. So if you have a Bluray that’s already encoded using the Sirius Pixels encoder then no matter what you do, the x264 encode will be significantly lower quality at the same size (beyond just the generational loss). A single-layer movie encoded using the Sirius Pixels encoder can match the quality of a double-layer movie encoded using Mainconcept or x264. Also, the 2pass option does not produce better quality at the same size as CRF.

Additionally, movies are made more compressible before encoding as well. Such as removing film grain - especially in the effects shots.

With this release we have neither option - the -1 team don’t have access to the best encoders (and if they do they don’t want us to know), and they want to release the film as it is, and not cleaned up to a point that makes it much more compressible. So in my view it’s not the x264 settings that are an issue, rather it’s the CRF value itself. In this case, CRF = 19, which is just not quite good enough, and leads to visible compression artefacts, at least in some parts of the movie. If it were up to me, which it isn’t as I’m not a part of their team, I’d suggest a CRF value of 16. This might result in a 34-50GB file size, but I’d personally rather see that.

Yes it is much larger, but we have a v1.0 now so I say go all out for v1.5 and so I say: let the material truly shine!

Also: many thanks to the Team -1 - what a terrific effort with this release!!

V

Hi Ru.08, I’ll just use your post as a reference to the discussion about encoders and encoding settings that has been going on on the last two pages.

First of all, I have never heard of that Sirius Pixels encoder and a quick Google search did not bring up any comparision to x264, so do you have any source proofing that it’s really 40% better? That would be an extremly high margin among two encoders using the same codec. Actually, the first thought that came to my mind is that you’re comparing an HEVC (H265) encoder to an AVC (H264) encoder. Then the significant difference in quality at the same file size would make sense.

Here are some basic rules about quality vs. file size vs. encoding settings (subme, reference frames etc.):

  • Yes, CRF and 2pass result in the same quality at a given file size. However, the two encoding modes are tailored for completely different purposes. When using CRF, the goal really is to achieve a certain quality (represented by the CRF value) irregardless of the file size! With 2pass the filesize/bitrate is given and the encoder tries to distribute the bits in an optimal way to achieve the best possible quality at that very filesize. Here the encoding settings are crutial. I hope it’s clear now why it’s reasonable to use 2pass for a Bluray encode.
  • A given CRF will always result in the same quality. If you use better encoding settings though, the encoder distributes the bits more efficiently (so to say), resulting in a smaller file size. The enconding time however increases.
  • When using 2pass, the filesize is fixed, hence better encoding settings lead to a better overall quality. The enconding time however increases.

This is why I think it would make sense to use more optimised encoding settings for the upcoming BD release of Star Wars and ESB.