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Thread: Interlacing and resolution issues!

  1. #1

    Default Interlacing and resolution issues!

    Hi!

    Iīve been (and sort of am) suffering from the good olīinterlacing issue where lines appear when things move. When i set up the project properties to Field order: "none (progressive scan)" the lines are removed but things still appear thorny while moving. Although i understand that the problem has to do with the interlacingprocess i havent really been able to comprehend what i should be doing with my project to make this thing go away. Is it a correct assumption that the settings in project properties should be equal to the type of capturing my camera has made? Would this then be PAl DV if my camera is a Panasonic NV-GS27 with PAL?
    If not iīm practically clueless as to how to determine what settings are appropriate in Project properties.

    However, i have been tampering so many times with the interlacing methods (or lack there of) in both project properties and render as that iīm starting to wonder if something is just fundamentally wrong with the way the project has been captured. Actually, the interlacing isnt the only problem. Both the rendered product (iīve tried mpeg2 and AVI) and the preview is in a state of unrealistically bad quality. No matter how much i try to spice up the quality it always turns out equally bad.
    Itīs especially apparent in one scene where there are a lot of lights on the ceiling and the camera moves alot. This causes the lights to splash out making the scenario look like something experienced while on drugs. The bad focus doesnt exactly help either but is completely unexplainable since it canīt be
    spotted on the tapes.

    Basically i would really appreciate a step to step approach to determining what settings are wrong (or if it actually is the footage thatīs really bad for some reason, god forbid) and what i should do to salvage my project. Since this is a 2 hour project iīve been working on for the last 6 months i would really hate to not be able to finish it. Iīm new to Sony Vegas and really need to be treated accordingly. I wont understand complex technical information regarding the function of interlacing . However a "to-do-list" would be just the thing to steer me right.

    I would be extremely thankful for any help. If theres some further information you need please be so kind as to simply ask me for it. Iīm not even entirely sure what information counts as relevant in this case.

  2. #2
    Join Date
    Mar 2008
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    Well, your camera is a MiniDV one (apparently) and if you're in "PAL" land then PAL DV would be a good starting point for your project settings - assuming you did a standard firewire capture into your PC that is. PAL DV is lower field first and that is what the default project settings within Vegas use.

    You should be able to determine whether your source footage is "good" by playing back some of problem areas from your original camcorder tapes onto your TV.

    It would be useful to know what you've been doing to "spice" up the quality. A few straight cuts and dissolves and rendering back out to DV-AVI again shouldn't give any problems. Rendering out to MPEG2 for DVD creation is a different matter - you may have up bitrate settings to reduce the artifacts you say you're seeing.

    But first things first. Determine whether your original footage is ok, set the project settings back to their defaults for PAL DV and render out a "problematic" region of your project to DV-AVI and check the playback of that.

  3. #3

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    Quote Originally Posted by Andy E View Post
    Well, your camera is a MiniDV one (apparently) and if you're in "PAL" land then PAL DV would be a good starting point for your project settings - assuming you did a standard firewire capture into your PC that is. PAL DV is lower field first and that is what the default project settings within Vegas use.

    You should be able to determine whether your source footage is "good" by playing back some of problem areas from your original camcorder tapes onto your TV.

    It would be useful to know what you've been doing to "spice" up the quality. A few straight cuts and dissolves and rendering back out to DV-AVI again shouldn't give any problems. Rendering out to MPEG2 for DVD creation is a different matter - you may have up bitrate settings to reduce the artifacts you say you're seeing.

    But first things first. Determine whether your original footage is ok, set the project settings back to their defaults for PAL DV and render out a "problematic" region of your project to DV-AVI and check the playback of that.
    Ok, well my project settings are now set to:

    PAL DV (720x576; 25,000 fps)

    Field order: Lower field first
    Pixelformat: 32 bit floating point
    composition gamma: 1.000 (linear)
    Full resolution rendering quality: Best
    Motion blur type: Gaussian
    Deinterlace method: Interpolate

    After viewing problem areas on the TV iīve discovered that the thorny edges of the lights (in the scene with all the lights i mentioned) are there even in the original material. Generally things have much better sharpness though. Could this perhaps have to do with the difference between TV-screens and computer-screens? The way itīs being seen on the computerscreen isnt equivalent to the way it looks on TV?

    i`ve been experimenting with different templates in "render as" and with such options as "pixel format", "deinterlace method", "frame rate" and "field order". All these options has been restored to original shape afterwards though with the exception of pixel format which i switched from "8-bit" to "32-bit floating point" without noticing any difference in render output.

    Unexperienced as i am with rendering and quality-issues iīm not sure what you mean by "A few straight cuts and dissolves". I made two DV AVI-render samples however. One (set in custom settings for rendering) with Field order: Lower field first and one with Field order: none (progressive)
    Lower field first causes the lines to appear while progressive removes them. Itīs safe to say that Field order: none (progressive) makes it a whole lot easier to watch it seems more grainy however then a rendered Mpeg2-version with Field order: none (progressive). The Mpeg2 version on the other hand looks less sharp and more colorfaded not to mention stretched horizontally. This does not cause it to look much worse than the AVI-version though. But it doesnt look better either. The difference seems pretty marginal and since iīm making a DVD i figure MPEG 2 is the way to go!?

    I use variable bitrate with maximum 9 500 000 and minimum 192 000. As iīm planning on fitting it on DVD i canīt really turn the bitrate up that much. Should i perhaps switch to a constant bitrate of say 6 000 000? Iīve read somewhere that something around 5,50 mbps is appropriate for fitting in 2 hours on DVD but maybe thatīs not correct!?

    Perhaps i can back my story up (so to speak) with some screencaps of the different results of rendering!? Iīm not familiar with uploading images just to be linked to and i donīt really know where i could upload them to. At first i thought facebook would work but then i realized i have a limited access account so that wont work. If you wish perhaps you could guide me towards some easy wbesite i can upload to without to much trouble.

    Thank you for taking the time to help me out! I really appreciate it!

  4. #4
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    Quote Originally Posted by Kronblom View Post
    Could this perhaps have to do with the difference between TV-screens and computer-screens? The way itīs being seen on the computerscreen isnt equivalent to the way it looks on TV?
    Oh yes Have you actually looked at your rendered MPEG2 on a TV. I strongly suspect all your interlace problems will disappear (unless you've zoomed in). I suspect your "blurriness" compared with the original MiniDV footage is due to you having set De-interlace to interpolate. Try setting it to none.

    I also spent hours worrying about similar problems - all because I didn't have a preview TV monitor and didn't actually play back on a TV.

    I may be wrong, but I hope not.
    Tim

  5. #5

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    I have now watched several rendered Mpeg2 and AVI-clips on tv and come to the conclusion that Avi with options:

    Project settings:
    field order: none (progressive)
    Deinterlace method: None

    Frame rate: 50 000

    Render settings:
    Field order none (progressive)

    ...Looks best on TV. Mpeg2 with equal options seem to be the best of the mpegversions but doesnt look quite as good as the AVI-version. In other words you were absolutely right. The lines disappear when the rendered product is viewed on tv so basically i didnīt have to tamper with the settings much at all.

    The quality isnt exactly hollywood material but i guess thats what you get when you film with mini DV. And the quality is much better than it was viewed on the computer so itīs completely acceptable.

    Question though: can i use AVI for DVD if it fits on disc or is there some specific reason for using mpeg2 for DVDs? I figure since it looks better and is smaller than mpeg2 when rendered it would be the more appropriate choice!?

    Thanks for the help so far!

  6. #6

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    oh i almost forgot...When i watch AVI on TV i get two relatively thin curved black bars on both sides of the screen. On mpeg2 these bars disappear but as i said before the quality isnt equally good. Itīs like mpeg2 stretches the image in a way that covers these bars but causes a more blurry quality. Is there some way to solve this so i can go with avi on the DVD or can it perhaps simply be caused by the displaysettings used when plugging in the computer to the TV? Perhaps making it into a DVD turns it into a certain format compatible with televisonscreens!?

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