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I've learned an important lesson today

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  • User profile image
    Sven Groot

    And it is this: never trust your DVD software.

    I am a very satisfied PowerDVD user, ever since version 3. Ever since version 3, I've known that PowerDVD's method of detecting whether content is interlaced isn't entirely trustworthy; there are cases on NTSC DVDs where it will decide not to de-interlace even though the content is, infact, interlaced. Even today, with PowerDVD 6, which has added a new 'bitstream analysis' method for detecting this (to root out incorrectly flagged DVDs), this still sometimes happens.

    Never once though has it occurred to me to question its judgement the other way around. Today I was watching the R1 Star Trek Generations (which I imported because Paramount Benelux decided the people of the Netherlands speak French and denied us the English DTS track), and it once again decided the content was progressive. Which, for the first time in my life, I noticed it was.

    This got me thinking. Why would PAL movies be interlaced? I know for a fact that PowerDVD says they are and performs de-interlacing on them. So I started doing some Google searches on PAL progressive scan. But nowhere could I find a reason for this. Then I decided to check it. So I popped in the Return of the King Extended Edition DVD (R2), and played it. Sure enough, PowerDVD said it was interlaced and was using pixel adaptive deinterlacing to reconstruct the image. So I unchecked 'Perform interlacing'. And lo and behold, no horizontal striping occurs, and the image is significantly sharper! The DVD is friggin' progressive! PowerDVD now also says the content is progressive. So I re-enable interlacing, and now suddenly it thinks it's interlaced again.

    So I tried a few other PAL DVDs. Star Trek First Contact? Progressive. Cowboy Bebop The Movie? Progressive. Star Wars? Progressive. (on a side note, the people at 20th Century Home Entertainment decided that anyone who's DVD player language is not set to English (but, for instance, to Dutch) should get French menus...)

    You know what this means? This means I'm going to have to rewatch my entire DVD movie collection! Ah well, to keep the French subtheme of this post alive, c'est la vie! Wink

    (Thank you for listening to me rant about me being stupid)

  • User profile image
    Rossj

    Sven Groot wrote:
    This means I'm going to have to rewatch my entire DVD movie collection!


    No small feat if it includes LOTR Smiley I bought the LOTR extended edition two weeks ago and I am still only on TT. Sad

  • User profile image
    ZippyV

    Isn't progressive able to brake your monitor/tv?

  • User profile image
    Sven Groot

    I think if you hook up a progressive standalone DVD player to a non-progressive TV (99.9% of TVs are interlaced) and set the player to progressive it wouldn't be good. I don't know it it'd damage your TV or just look bad, but it wouldn't be good.

    Computer monitors are not interlaced anyway, hence the need for de-interlacing on non-progressive DVDs.

  • User profile image
    Sven Groot

    Rossj wrote:
    Sven Groot wrote: This means I'm going to have to rewatch my entire DVD movie collection!


    No small feat if it includes LOTR Smiley I bought the LOTR extended edition two weeks ago and I am still only on TT. Sad

    Luckily movies take up only a small part of my complete DVD collection. As you can see, most of it is anime, and since that's made for TV it's naturally interlaced. Rewatching my entire collection would take more than a week... a week of non-stop back-to-back viewing, that is. Wink

  • User profile image
    ZippyV

    So there is a 99% chance that my monitor is progressive?

  • User profile image
    Manip

    I'm a little concerned now .. before reading the above post I thought I understood most of what I need to about todays DVD tech but now I'm not so sure.. What the hell are you talking about? Progressive DVD?

  • User profile image
    Sven Groot

    You mean your computer monitor? Then there's a 100% chance. Interlacing doesn't happen with computers. Not ever. It never has, and never will.

    TVs are traditionally interlaced. Nowadays there may be a few high-end models that are capable of progressive scan, but 99% of TVs are interlaced.

    For those of you reading this thread who have no idea what I'm talking about:
    Interlacing means that the an image is transmitted in two parts, first the even lines, then the odd lines. Your TV actually displays 50 fields per second (60 for NTSC). The 25fps (or 30fps for NTSC) video is spread out by every frame taking 2 fields, one for the even lines, one for the odd lines. If a video that is interlaced is played back on a computer monitor, the odd and even lines don't always line up perfectly, which causes horizontal striping. Therefore DVD playback software must perform deinterlacing to compensate for that. Deinterlacing does decrease the quality of the picture, but interlaced content is unwatchable on a progressive display otherwise.
    Progressive scan simply means that the lines in an image are sent in order. This means that on a progressive display (such as a computer monitor) no deinterlacing needs to be done, with much better quality as a result.

    EDIT: This is what an interlaced picture looks like on a progressive scan display if no deinterlacing is performed:
    interlacing

  • User profile image
    Minh

    I must have an older version of PowerDVD, I can't even see that interlace option. I can't even see how to get version # from PowerDVD.

  • User profile image
    Sven Groot

    Older versions of PowerDVD do have the option, they just name it differently. If you go to the advanced video options, on PowerDVD version <6 you should be able to choose between three deinterlacing settings: Auto-Select, Weave, and Bob. Weave actually means no real deinterlacing is done. Bob is the only deinterlacing mode supported by pre-6 PowerDVD. PowerDVD 6 supports pixel adaptive, median and bob.

    To check the version of PowerDVD, click the Cyberlink logo on the controls, it should pop up the about dialog.

    http://www.100fps.com/ is the site I got that image from btw, it offers a pretty good explanation of what interlacing is, why it occurs, and how deinterlacing works, and what kind of quality loss occurs when doing it.

  • User profile image
    Manip

    Thanks for that explanation. Smiley

  • User profile image
    Minh

    Sven Groot wrote:
    Older versions of PowerDVD do have the option, they just name it differently. If you go to the advanced video options, on PowerDVD version <6 you should be able to choose between three deinterlacing settings: Auto-Select, Weave, and Bob. Weave actually means no real deinterlacing is done. Bob is the only deinterlacing mode supported by pre-6 PowerDVD. PowerDVD 6 supports pixel adaptive, median and bob.

    To check the version of PowerDVD, click the Cyberlink logo on the controls, it should pop up the about dialog.


    Aahh, bob & weave, cute. To complicate things, My PC is routed to the living room TV, which can do progressive. Of the 2 DVDs I tried so far, Finding Nemo & Pirates of Carebean, I can see the horz lines in fast scenes. Maybe DVD Shrink did something to them. Oh well.

  • User profile image
    Maurits

    I've been thinking about burning my VHS collection to DVD.  What's a good way to do this?  Any particular hardware recommendations?

  • User profile image
    Minh

    Maurits wrote:
    I've been thinking about burning my VHS collection to DVD.  What's a good way to do this?  Any particular hardware recommendations?

    No, but I WOULDN'T recommend the Hauppague PVR PCI-II. It does have video-in, but for some reason, video & audio de-synchronize over time, as quickly as about 10 minutes.

  • User profile image
    rhm

    Minh wrote:

    No, but I WOULDN'T recommend the Hauppague PVR PCI-II. It does have video-in, but for some reason, video & audio de-synchronize over time, as quickly as about 10 minutes.


    I wouldn't recommend anything made by Hauppague. I had one of the original PVR PCI cards which did the same thing. The audio quality was pretty awful as well. And the mpeg2 encoding on the video wasn't the best even at the maximum bitrate. Got rid of it on ebay without losing too much money.

    I always recommend using an external convertor box for digitizing analog video as I've had trouble with a Matrox video digitizer before as well and no longer trust PCI solutions at all. (If I was setting up a proper video editing lab and needed a PCI card based solution I'd buy a whole PC with everything already configured by a specialist cos then it would all be their problem).  I've got a Canopus box that takes s-video and audio and plugs into the firewire port on my PC and appears to software as if it was a MiniDV camcorder. Quality is good (though not excellent it's a helluva lot better than that Hauppague card) and AV sync is perfect even on hour-long captures.

    That's perhaps not ideal for everyone though as DV files are huge because they don't use inter-frame compression and don't compress the audio at all. It makes them easy to edit, but you then have to use something like virtualdub to get them down to a realistic size. There are boxes about now that compress to mpeg2 and plug into the more common usb2 port. Don't know what the quality is like though.

  • User profile image
    Gandalf

    Rossj wrote:

    No small feat if it includes LOTR Smiley I bought the LOTR extended edition two weeks ago and I am still only on TT. Sad


    Spoiler : I return from the dead. Or did you get to that part already? Smiley


  • User profile image
    Rossj

    Gandalf wrote:
    Rossj wrote:
    No small feat if it includes LOTR Smiley I bought the LOTR extended edition two weeks ago and I am still only on TT. Sad


    Spoiler : I return from the dead. Or did you get to that part already? Smiley




    Seen 'em all before. Twice. And I read the book as a child.

  • User profile image
    Sven Groot

    Minh wrote:
    Aahh, bob & weave, cute. To complicate things, My PC is routed to the living room TV, which can do progressive. Of the 2 DVDs I tried so far, Finding Nemo & Pirates of Carebean, I can see the horz lines in fast scenes. Maybe DVD Shrink did something to them. Oh well.

    It's entirely possible that your TV out is interlacing the picture because it assumes your TV can't do progessive. Maybe it has a setting for it somewhere? If it doesn't you'll need a stand-alone DVD player that's capable of progressive scan to take advantage of your TVs ability.

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