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Difference between DVD Shrink 'Quality Enhancement' Settings

Discussion in 'DVD Shrink forum' started by MrMingus, Dec 1, 2004.

  1. MrMingus

    MrMingus Member

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    Hello.

    I was wondering which were the differences between the 'Quality Enhancements' options on DVD Shrink. The program gives you only minor info.

    What factors should I consider when choosing an option? Which factors favor a 'smooth' enhancement? Which favor a 'sharp'?

    thx
     
  2. flip218

    flip218 Moderator Staff Member

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    *moved from Ripping*
     
  3. MrMingus

    MrMingus Member

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    woops
     
  4. zippyd

    zippyd Regular member

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    Ever hear the phrase "beauty is in the eye of the beholder"? Well, in the world of DVD backup, quality is in the eye of the beholder. It's really up to you to decide what you think is best.
    I know that isn't the answer you were looking for, but it's 100% truth.
     
  5. Juhnny

    Juhnny Member

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    I just recently asked this same question. I was burning at 8x using just "deep analysis" and movies played fine on my portable. They looked great too. However they did not play that great in my stand alone. I was getting hesistations and choppyness. So I dropped down to 4x and used "deep analysis" and "smooth" enhancement. The movies now play flawless on my stand alone. The extra enhancements will double if not triple the time it takes to burn if you don't use them. On avg about 1 hr with both enhancements for me at 4x. It was only about 20 minutes before with out. Let me put it this way. If the movies play fine-no hesistations or choppyness then you probably don't need the enhancements. If you do see these flaws then you should try them to see if it fixes them. Best advice I can share with you that I have recieved here on the forums and have worked for me is this...use good media and burn slow.
     
  6. bigorange

    bigorange Active member

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    was wondering which were the differences between the 'Quality Enhancements' options on DVD Shrink. The program gives you only minor info

    Deep analysis means it does an extra pass, two instead of one.

    "Maximum Sharpness" will try and reach DVD Shrink target size by compressing B-frames almost to their maximum compressability (as measured by DVD Shrink analysis).
    If the target size cannot be reached, it will then start compressing P-frames, followed by I-frames.

    "Maximum Smoothness" will try and reach the target size by spreading compression more evenly between frame types.

    "Sharp" and "Smooth" are gradual variations ("in-betweens"), lowering the threshold at which I-frames and P-frames start to be compressed.

    In all settings, an error-correction algorithm is used, so as to minimize the propagation of errors between frames.

    Hope this helps :>)
     
  7. zippyd

    zippyd Regular member

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    Thanks bigorange! I never knew the technical details of the individual settings. Looks like a new bookmark for my AD help links folder. :)
     
  8. bigorange

    bigorange Active member

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    LOL, you are most welcome :>)
     
  9. MrMingus

    MrMingus Member

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    wtf?
     
  10. zippyd

    zippyd Regular member

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    I'm guessing you don't get it. well I don't fully understand it either, so don't feel bad. I pretty much just use max smoothness.
     
  11. Grampaw

    Grampaw Regular member

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    This MPEG encoding stuff is not a simple subject and my following description is a way over-simplification. None-the-less, I'll try to explain a little about I, P, and B frames so you can maybe understand what Bigorange meant about sharpness and smoothing.

    At a basic level you have a "Group of Pictures" (GOP) which is typically composed of 12 picture frames in the order IBBPBBPBBPBB. The "I" (Intra) frames contain still pictures, which are not dependent on any other frame types. The "P" (Perdictive) frames depend on the preceding I frame and only contain the differences from that reference. The "B" (Bi-directional) frames contain differences, both forward and backward, from the adjacent I and P frames.

    I frames take about 150 kbits/sec bandwidth (most space), while P frames take maybe 50 kbits/sec (less space) and B frames 20 kbits/sec (least space) - this is where the compression comes from by using P and B frames with the I frame as a reference.

    So, if you are "shrinking", you've got to get that GOP smaller somehow. One approach is to treat the I frames as the most important, since they are absolute reference points for P and B frames. So you compress the I frames last after compressing the B and then P frames - the max sharpness approach. At the other extreme, you treat the frames types as all pretty much equal in importance, and try not to compress the P and B frames too much so your transitions between I frames looks good - the max smoothness approach.

    I have no clue if sharpness or smoothness is the better approach since I don't use quality enhancements. I just use the deep analysis which is good enough for me.

     
  12. bigorange

    bigorange Active member

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    That's a very good explanation grampaw. (for some reason I didn't get a post reply to zippyd's post).

    I would suggest you try the max smoothness setting. You will see a decidedly improved difference and since you're using deep analysis anyway it will not add much to your time.

    I think you'll be pleasantly surprised. :>)
     
    Last edited: Dec 27, 2004
  13. zippyd

    zippyd Regular member

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    Thanks for the details. This page would make a good sticky.
     
  14. Grampaw

    Grampaw Regular member

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    Bigorange,

    If I were to use Quality Enhancements, I would look at two things - the running time of the movie relative to the GBs used on the original DVD, and the type of movie.

    A 90 min movie taking 7+ GBs on a DVD-9 has a whole lot more resolution to play with in transcoding to a DVD-5 than the 180 min move taking the same 7+ GBs of space. So I'd be inclined to use the "sharpness" settings for the 90 min movie (since the P and B frames have room to be compressed) and the "smoothness" settings for the longer movie (so you maintain reasonable P and B frame compression thresholds).

    A theatrical-drama type movie has a whole lot less motion than a big-buck-action type movie. I'd use the "sharpness" settings for the drama type movie (since P and B frames are similar to the I frames). I'd use the "smoothness" settings for the big-buck action (since there are big differences between P or B and I frames).

    And when in doubt, I'd just use the "smoothness" settings, since most movies on DVD-9s are long-running and/or have lots of motion.

    Like Mr. Shrink (whoever he is) says though, you should "please take the time to try one or the other and determine which is best for your backup." Some day I'll get around to experimenting...

     
  15. bigorange

    bigorange Active member

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    Actually I did quite a bit of the beta testing for shrink 3.2 before the final release and it turned out that max smoothness seemed to provide the best results the majority of the time. This was generally true with most of the other beta testers also.

    But as a rule of thumb so to speak, if someone asks I usually recommend the max smoothness, because most people don't want to experiment or even care about the reasoning behind it like you do.

    I salute you :>)
     

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