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(AutoGK) Motion problem on some titles

Discussion in 'DivX / XviD' started by samsayit, Feb 15, 2010.

  1. samsayit

    samsayit Member

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    I'm using AutoGK to convert my entire DVD collection to XviD.
    I use all default settings and Target Quality 75%. By far most of the movies come out great and I am really happy with AGK and would not consider changing.

    However, I have a few titles which come out with some problems with motion such as a car passing through the picture it will not be a smooth motion. Other than that the picture quality looks OK.

    The titles in question were oddly enough all TV movies in 4:3.
    I used GSpot to see the framerate of the original DVD (VOB) files and it is 29.970 and so is the output XviD file.
    The only thing I can see is different is the frame resolution where the original is 720x480 and the output XviD is 720x544 (this I have seen on other 4:3 conversions and has always been beyond my understanding but never complained because it usually looks OK anyway).

    Any ideas would be appreciated!
     
  2. davexnet

    davexnet Active member

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    Regarding the resolution, in general, it's OK. AutoGK is preserving
    the proper 4:3 ratio of the original.

    As far as the juddery movement, it's difficult to say with out
    looking at it. For example, overall bitrate too low, or artifacts to
    do with interlaced material.

    Perhaps post a small section of the troubled area and let us
    look at it.
     
  3. seagrave

    seagrave Regular member

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    That AGK is going to 544 pixels is odd. Given that 4:3 DVDs are usually 720x480, there seems to be no need to create extra pixels.

    I've usually thought anamorphic video was only for widescreen. But in another forum I was told it also was used to squeeze a 720 pixel wide source onto a 4:3 screen. If so... the encode should remain the same as the original. That's what I get.

    I sometimes use Handbrake and in dealing with such videos, I set the anamorphic setting to "strict". This maintains the 4:3 ratio at 720x480. Of course another way is to go with square pixels and reduce the resolution to 640x480. I don't know if every encoder has this option. TMPGEnc does.
     
    Last edited: Feb 20, 2010
  4. seagrave

    seagrave Regular member

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    Will a 720x544 video even play on a standalone DVD player?

    My concern is that in creating all those unnecessary extra pixels, it reduces the overall quality for any particular bitrate or increases the file size without any increase in quality.

    I'd recode the affected files to bring them in line with the original source.
     
  5. seagrave

    seagrave Regular member

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    Given how much more efficient mpeg4 is, isn't 75% of an mpeg2 source excessive? I often have to encode to mpeg2 at 75% with good results.

    What's your end game? To put them all on DVD? Blu-Ray? Hard drive?
     
  6. davexnet

    davexnet Active member

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    I must admit, whenever I've encoded anything myself with the intent
    of playing back on the standalone, I've limited the vertical
    resolution to 480. The DVD player will resize it on the fly
    anyway if it's bigger - I've had no problems playing 720*576 @25
    FPS converted to NTSC in the player.
     
  7. seagrave

    seagrave Regular member

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    Good to know... since I have 2 AVI capable DVD players.

    But the bigger question remains.... in creating all those unnecessary pixels, does it reduce the overall quality for any particular bitrate or increase the file size without any increase in quality? After all, no matter how much you increase the resolution... there's no more data than in the original 720x480 source.

     
    Last edited: Feb 21, 2010
  8. davexnet

    davexnet Active member

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    In general, you're right. Nothing is really achieved by
    increasing the vertical resolution.

    However, if the source is PAL DVD (720*576) 720*544 is perfectly
    valid.
     
    Last edited: Feb 21, 2010
  9. seagrave

    seagrave Regular member

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    True, but samsayit said the original was 480 so it had to be NTSC.
     
  10. samsayit

    samsayit Member

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    Guys, thanks for posting.
    I'm a bit confused. if you do a calculation, 720x480 is not anywhere near 4:3 (it's a 1.5 ratio - 4:3 is 1.33).

    The source is NTSC.

    The goal is not to play these on DVD players, but to stream them from a media server to my PS3.

    Frankly, I am by no means an expert in this field (although I'm not that green). The reason I chose AutoGK is that it's so easy to use and default settings produce decent quality (in most cases).
    I might try out Handbrake - any recommended setup?
     
  11. davexnet

    davexnet Active member

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    It's because the DVD has a display aspect ratio of 4:3 (or 16:9)
    regardless of the SAR (720/480). The pixels are non-square.

    Usually, AVI files are created 1:1 pixels so we have to compensate.
    See this for details:
    http://forum.videohelp.com/threads/314105-Aspect-ratio-problem?p=1942276&viewfull=1#post1942276
     
  12. seagrave

    seagrave Regular member

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    Handbrake did a wonderful job encoding some grainy video to H264.
    But I would not recommend it for XVID. In fact they were going to take XVID out to concentrate on H264.

    You might want to checkout StaxRip.
     
  13. samsayit

    samsayit Member

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    Just a followup.
    I tried in AutoGK forcing width to 640 and it produced 640x480 output (no extra lines).
    Still had the problem of jitterish motion though, don't know why.

    I used StaxRip on your suggestion - used default settings XviD conversion only resizing to 640x480 (to keep a clean 4:3 ratio), and the outout came out just nice, motion too!

    Thanks for all your input guys, appreciate it!
     
  14. ute4after

    ute4after Member

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    I use AutoGK, the same version. I always use 2-Pass, encoding as Xvid. I set the
    output size to just under 698Mb. I don't change anything, just letting AGK do the work and I never have any problems the OP writes about.
     
  15. samsayit

    samsayit Member

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    @ute4after:
    That was my case too. I have converted hundred of titles, all came out great. But I got the problem on a few titles - some TV shows...

    Whether you do 2-pass or not should have nothing to say in this at all. 2-pass is used when you set a target size. I don't use target size but target quality instead (75%) which generally produces much nicer quality (but also generally bigger size).
     
  16. creaky

    creaky Moderator Staff Member

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    I've also converted many hundred of movies, all came out great too, I only use 2-Pass, encoding as XviD.
     
  17. cyprusrom

    cyprusrom Active member

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    It is possible Staxrip has some filters enabled by default, which you maybe did not enable in AutoGK(to deal with Telecine or Interlace).
     
    Last edited: Apr 23, 2010

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