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  1. Originally Posted by PatrickBatman View Post
    So does this mean CRF is still better quality (than ABR) even though it's final output size is nearly one gigabyte smaller (than ABR)?
    I'd take the CRF encode if it's only about 3% smaller than the ABR encode. However, when using true CRF the eventual file size is completely unpredictable and my guess is that setting a file size is ignored for a CRF encode (he says, never having used BD-Rebuilder). Maybe you used a slightly lower number from an earlier CRF encode that came out too small for your tastes? Or does BD-Rebuilder make a quick partial encode to try and determine an optimal CRF number to reach close to the desired size? I'll bet others here know better than I how it does its CRF encodes, if at the same time you can pick an putput size.
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    Jdobbs has said that using CRF mode in BD Rebuilder, the program samples sections in order to hit an approximate overall size. So it isn't quite like using X264 CRF in another program like VidCoder or Megui. Changing the CRF value throws this sampling process off kilter, and file size becomes really unpredictable.

    And yes, gonca is right (below) about this applying to blu ray encodes. When making mkv or mp4 files, size constraints don't apply.
    Last edited by Kerry56; 16th Dec 2013 at 16:47.
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    For BDs it does a predictive pass to see what CRF value can fit on the target size.
    For alternate outputs , like MKV, it is a true CRF pass with no size control.
    Is he gone?
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  4. Originally Posted by gonca View Post
    For BDs it does a predictive pass to see what CRF value can fit on the target size.
    Right, then once you find a filesize that results in getting close to what you really want, for slightly better quality I think I'd go with its CRF mode. Others might disagree but, since you don't want to take the time to do full 2-pass encodes, that's how I'd do it if I were you.

    It seems to be very similar to, if not exactly like, the old OPV mode for DVD-Rebuilder, and that worked pretty well to give good results close to the desired final file size while saving time.
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    For BD's I do 2 pass, since the size is fixed, and for MKV I go with CRF=18 since there are no size constraints
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  6. Gonca, how accurate is 2 pass really? exact? (and i do mean exact) or a few MB's off or few hundred MB off? I've never finished one because how long it takes on my computer.
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    Accurate enough. Considering there is some overhead involved, audio type -- converted or not, the fact that you should not burn right to the edge of the disc. Off the top of my head I would say roughly 97 to 98 percent of the target size.
    Please note that there are exceptions to every rule and that I use DGDecNV which seems to be a little more accurate than ffdshow for sizing
    Is he gone?
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  8. And I just realized no one answered my question directly, "So does this mean CRF is still better quality (than ABR) even though it's final output size is nearly one gigabyte smaller (than ABR)?"

    Will this question garner a subjective and aesthetic answer only or can someone give me a solid mathematical answer proving the quality should be better at least in theory. If they're both using the same encoder then which ever has the bigger bitrate/file size would have better quality. Does ABR and CRF use the same encoder? I just dont see how CRF would be better using the same encoder if the file size is smaller. If it's using a different encoder then I get it.


    EDIT
    (Quality in the above scenario, not file size I know CRF file size isn't static)
    Last edited by PatrickBatman; 16th Dec 2013 at 21:47.
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  9. If you think of ABR as being in between CBR and real VBR, then when doing ABR encodes the complex scenes won't get as many bits as they need and the slower and more static scenes will get more than they need as compared to a true VBR encode for the same quality. That is, an ABR encode will have more swings in quality as compared to a CRF encode or a 2-pass VBR encode. It's not as bad as a CBR encode, but it still has the same problems.

    But I don't think you'll find any objective evidence that a CRF encode resulting in a size 3% less than an ABR encode of the same film is any better. Me, I like my encodes to have the same quality as much as possible, throughout the entire movie, and always prefer a true VBR encode (whether CRF or 2-pass in the BD-Rebuilder you use, or 5-pass for a DVD in CCE). And I also like to fill the disc, if burning to disc. And I do fill the disc, but that's for DVD. And, like gonca, when filesize isn't a consideration (like for YouTube uploads) I also use CRF 18.
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  10. I went ahead and put another movie through the same regimen (CRF 24400 MB) and it went over 23.7 GB (25,489,923,516 bytes) to be exact. Just barely went over, like I had previously predicted. So I'll just have to stick to my ABR method for now. Sometimes though I use DVDFab does anybody know what method that uses and if the quality is better? It seems to be good with final size output, however since it's a paid software I only have used it in demo mode.

    BTW Thanks guys for all the advice.
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    ragazzi scusatemi ma ultimamente sto avendo un problema col bd e sarebbe questo dopo avermi portato il blu ray a 25 giga se faccio per masterizzarlo mi esce dopo masterizzato col film sopra la dicitura


    carico cpu
    ora dei sistema
    informazioni codifica unknow
    durata filmato ecc


    e mi rimane fisso quando vado a vederlo sul masterizzatore non mi mai successo prima eppure ne avro fatto a centinaia chi saprebbe darmi una risposta grazie
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  12. Member leghorn's Avatar
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    I don't think so. Please rephrase your post and use English!
    Das Leben ist eine Nebelwand voller Rasierklingen. (C. Bukowski)
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  13. Originally Posted by PatrickBatman View Post
    Sometimes though I use DVDFab does anybody know what method that uses and if the quality is better?
    It only transcodes and I know the quality is much worse. Most around here might use it for decrypting but keep away from its conversion functions. BD-Rebuilder is the way to go.
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    CRF over ABR
    DVDFAB compression quality --- ughh!
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  15. Member louv68's Avatar
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    Originally Posted by PatrickBatman View Post
    I went ahead and put another movie through the same regimen (CRF 24400 MB) and it went over 23.7 GB (25,489,923,516 bytes) to be exact. Just barely went over, like I had previously predicted. So I'll just have to stick to my ABR method for now. Sometimes though I use DVDFab does anybody know what method that uses and if the quality is better? It seems to be good with final size output, however since it's a paid software I only have used it in demo mode.

    BTW Thanks guys for all the advice.
    Since you appear to do movie only, have you considered trying BDtoAVCHD to see how it compares in terms of speed on your laptop? It's super easy to setup and use. Just a thought.
    -The Mang
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