PC DVD Resolution?
May 28, 2005 11:36 AM   Subscribe

So, are PC DVD drives progressive scan?

I know most PC monitors can display 720 x 1280 (480p), but if you play a DVD on your PC, can you assume that it is EDTV quality? Is there extra software (beyond something like WinDVD) or hardware required to get the best quality image while watching a DVD on your PC?
posted by Hackworth to Technology (10 answers total)
PC DVD drives don't output video, so asking whether they are progressive scan or not is immaterial. The decoding is done by the software, often with help from your video card, and most DVD player software (again, often with help from your video card) will do deinterlacing, which is what you want when playing interlaced video on a progressive device like your computer's monitor. Watching a DVD on your computer represents just about the best picture quality you can get out of the medium.
posted by kindall at 11:43 AM on May 28, 2005

For film-based material, there is a "correct" solution to deinterlacing, and it is fairly trivial to implement. However, for video-based material, deinterlacers can vary wildly in quality.
posted by trevyn at 1:31 PM on May 28, 2005

All PC monitors are progressive scan, so the answer is technically yes, but as others have said, whether the output to your monitor is generated the same way as a hardware progressive player is up to the software.
posted by cillit bang at 2:11 PM on May 28, 2005

All PC monitors are progressive scan

Unless you run them in interlaced mode. I don't know why you'd be doing that in 2005 though.
posted by grouse at 2:47 PM on May 28, 2005

My first computer's monitor did 1024x768 in interlaced mode.

Just sharing.
posted by delmoi at 3:31 PM on May 28, 2005

I don't know why you'd be doing that in 2005 though.

So you can get a better picture from an interlaced source?

I just wish I could actually get a dvd/monitor softs to set my monitor up properly to watch DVDs (in the case of a computer monitor and an NTSC disc, double scanned at just under 120 fields/sec interlaced would work well).

If you display an interlaced source on a CRT monitor locked to the same interlace speed you should be able to get a better picture since no deinterlacing magic needs to be performed (de-interlacing, by definition, must distort the picture from the original). If only I could cite a source. Oh well.

Besides, converting an interlaced program to progressive halfs the field rate, meaning smooth looking motion goes from being smooth to either a bit more jerky or motion blurred.
posted by shepd at 3:49 PM on May 28, 2005

converting an interlaced program to progressive halfs the field rate

No it doesn't, since normally one field is interpolated to become one frame, unless 3:2 pulldown reversal ("weaving") is used, which it shouldn't be on natively interlaced sources.
posted by cillit bang at 5:16 PM on May 28, 2005

cillit bang, I'll admit you can use "Bob" to remove artifacts (what you're mentioning) but it still doesn't look like the original. Close and not bad, but since computer monitors support interlacing, why go through the effort to do it the almost-right way, when you can just not bother and do it perfectly? Oh well.
posted by shepd at 8:18 PM on May 28, 2005

Interlacing is a 1950s hack, and converting interlaced video to progressive is the most polite thing you can do to it. Let's put interlacing in the dustbin of history where it belongs.
posted by kindall at 12:28 AM on May 29, 2005

It's impossible to display video natively at anything other than its native resolution and frame/field rate. When you blow that up to a big screen, flicker is going to be a big problem, since flicker is more obvious in peripheral vision (in a previous life I had a natively-interlaced CRT video projector). Jitter (flicker introduced by the picture moving up and down one line between each field) is also going to be magnified.

I can't think of a sensible way to "double scan" interlacing without distorting motion, and it won't help jitter one bit. The only sane way to increase the frame rate of an interlaced source is to convert to progressive. It is just about possible to scale interlaced video natively, however.

1920s hack, at the very least, Mr Kindall.
posted by cillit bang at 7:58 AM on May 29, 2005

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