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#273431 - 04/01/2006 05:08 Video annoyances
Dignan carpal tunnel Registered: 08/03/2000 Posts: 12338 Loc: Sterling, VA	I've been messing around with video again. One of the things I'm doing is backing up the family's home videos. This is being done from a DV Digital8 camcorder. I'm using a program called Editstudio (because I can't afford Premiere and Elements will still have that horrible Adobe UI). The problem I'm experiencing, I'm not sure if it's the program or the process, but the picture has this artifact that I've seen in a lot of video I've been working on recently. When there's motion or edges, there are extremely apparent horizontal...jaggies? I've attached an image to show what I mean. You can see it around the people with the white wall behind them. That's a minor example, and it's far more noticeable when there's motion. That is before any compression or transcoding. It's from the very large AVI file right after the capture. Does anyone know what causes this? Attachments 273472-example.jpg (130 downloads)
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#273432 - 04/01/2006 05:09 Re: Video annoyances [Re: Dignan]
tman carpal tunnel Registered: 24/12/2001 Posts: 5528	Can't see any attachment but DV camera video is already compressed. You got it set to LP or anything similar?
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#273433 - 04/01/2006 05:11 Re: Video annoyances [Re: tman]
Dignan carpal tunnel Registered: 08/03/2000 Posts: 12338 Loc: Sterling, VA	Wow! You're quick! I forgot and edited a second later to add the attachment, but you'd already posted! As for your question, I don't think I am, but I'll check. _________________________ Matt
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#273434 - 04/01/2006 05:17 Re: Video annoyances [Re: Dignan]
tman carpal tunnel Registered: 24/12/2001 Posts: 5528	Yup. Just happened to be browsing before heading off to work. I see what you mean about the lines tho. Doesn't look like a MPEG compression artifact. It looks interlaced?
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#273435 - 04/01/2006 05:46 Re: Video annoyances [Re: Dignan]
tfabris carpal tunnel Registered: 20/12/1999 Posts: 31596 Loc: Seattle, WA	The effect you are describing is called COMBING and it is an artifact caused when you try to convert an interlaced video picture into a progressive-scan video picture. More details to follow. _________________________ Tony Fabris
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#273436 - 04/01/2006 05:52 Re: Video annoyances [Re: tfabris]
tfabris carpal tunnel Registered: 20/12/1999 Posts: 31596 Loc: Seattle, WA	Okay, here is a link to an article that describes and illustrates combing in great detail: http://206.225.87.49/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html However, that article is mostly talking about playback on progressive-scan DVD players, not editing video clips yourself. But it will give you an understanding of the basic concept. First thing to do is figure out where the combing is happening: - Is it happening at the stage where you import the video from your DV camera to the PC? - Is it happening at the stage where you convert the DV into something editable on your PC? - Is it happening during the editing stage? - Is it happening when you perform the data compression? - Is it happening only on final playback? Somewhere in the various bits of software will be a setting to deal with it. But you need to know which stage it's happening at before you start twiddling settings. Just so you know, even professional video can be affected by combing. I'm watching the Season 1 Buffy DVDs and they all comb really badly on my progressive-scan DVD player because the frame tags are wrong and my player doesn't know it should be going into interlaced video mode when it plays them. _________________________ Tony Fabris
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#273437 - 04/01/2006 06:00 Re: Video annoyances [Re: tfabris]
tfabris carpal tunnel Registered: 20/12/1999 Posts: 31596 Loc: Seattle, WA	Oh, and a couple things I wanted to make clear... Just because you see it on your computer's screen doesn't mean it's actually a problem in the video file itself. It might be only happening at playback time. If the video files you're working with are interlaced, and they're staying interlaced as you capture, edit, compress, and play them, then maybe it's only the actual process of playing back the interlaced video to your computer's progressive-scan screen that's causing the combing. If the first capture file off of the camcorder is genuinely combed, then your capture process needs to do something about deinterlacing the video better. Or, possibly, you might need to simply tell all the bits of software (from capture all the way through to final edit) that you want them to stay interlaced the whole time and don't even TRY deinterlacing. That way the final playback (let's assume it's a DVD-R) will look right on your parents' interlaced television set. _________________________ Tony Fabris
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#273438 - 04/01/2006 16:11 Re: Video annoyances [Re: tfabris]
Dignan carpal tunnel Registered: 08/03/2000 Posts: 12338 Loc: Sterling, VA	Quote: First thing to do is figure out where the combing is happening: - Is it happening at the stage where you import the video from your DV camera to the PC? yes - Is it happening at the stage where you convert the DV into something editable on your PC? - Is it happening during the editing stage? - Is it happening when you perform the data compression? - Is it happening only on final playback? Somewhere in the various bits of software will be a setting to deal with it. But you need to know which stage it's happening at before you start twiddling settings. You know, I suspected it would have something to do with interlacing, but couldn't find any setting to address this. Quote: If the first capture file off of the camcorder is genuinely combed, then your capture process needs to do something about deinterlacing the video better. Or, possibly, you might need to simply tell all the bits of software (from capture all the way through to final edit) that you want them to stay interlaced the whole time and don't even TRY deinterlacing. That way the final playback (let's assume it's a DVD-R) will look right on your parents' interlaced television set. That's what I looked for, but unfortunately the program I was using had almost no settings in regards to the actual capture of the video. It had all sorts of settings for previewing, length of capture, etc, but nothing that dealt with the video and audio. I assumed it grabbed it just like it saw it, so that made me wonder why it was doing this to the video. Basically, when I'm in the capture screen of my video editor, I can play back the video in preview mode (just like most of these types of programs), and I can even see a little of the combing there. Is there a setting on the camcorder I should use? _________________________ Matt
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#273439 - 04/01/2006 16:18 Re: Video annoyances [Re: Dignan]
tfabris carpal tunnel Registered: 20/12/1999 Posts: 31596 Loc: Seattle, WA	Quote: Is there a setting on the camcorder I should use? Dunno. But at least you've got the basic idea of what's going on and what to look for. Quote: unfortunately the program I was using had almost no settings in regards to the actual capture of the video. Perhaps that's where the limitation lies. Maybe you just need better software. _________________________ Tony Fabris
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#273440 - 04/01/2006 16:37 Re: Video annoyances [Re: Dignan]
CrackersMcCheese pooh-bah Registered: 14/01/2002 Posts: 2489	Have you tried writing a 2 minute clip to dvd and seeing if the prpblem still exits when played back?
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#273441 - 04/01/2006 18:32 Re: Video annoyances [Re: CrackersMcCheese]
Dignan carpal tunnel Registered: 08/03/2000 Posts: 12338 Loc: Sterling, VA	Quote: Have you tried writing a 2 minute clip to dvd and seeing if the prpblem still exits when played back? That's an excellent idea. I'll give that a shot. And you may be right, Tony. Does anyone have a good suggestion for software to use for DV capture? Maybe something other than Adobe? Something freeware would be excellent. _________________________ Matt
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#273442 - 04/01/2006 18:34 Re: Video annoyances [Re: Dignan]
CrackersMcCheese pooh-bah Registered: 14/01/2002 Posts: 2489	I captured stuff from video using a PVR-250 card. I saw what you were seeing when I used Long Play and it wasn't there on standard play. In both cases I saw the artifacts on the PC but not on a standalone DVD player. Maybe you'll be the same.
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#273443 - 05/01/2006 01:23 Re: Video annoyances [Re: Dignan]
adavidw addict Registered: 10/11/2000 Posts: 497 Loc: Utah, USA	Quote: Does anyone have a good suggestion for software to use for DV capture? Maybe something other than Adobe? Something freeware would be excellent. iMovie works great for me, and it's free. (insert obligatory crack about how it's only free with the overpriced hardware you have to buy to run it on, blah, blah, blah). _________________________ -Aaron
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