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Does DVD has progressive scan signal (line doubled signal?)?What is the difference between the two in watching DVD movie?
1. DVD player has no progressive scan function (but has composit, S-video, and component output anyway). TV has progressive scan (line doubling) function.
2. DVD player has progressive scan function. TV accepts progressive signal.
I also heard something like "2/3". What is it? What is its relation to line doubler (progressive scan)?
Follow Ups:
DVDs are encoded in the interlaced format. There are a few discs that contain some progressive fields, but they are far from the norm. About 99.99% of all DVDs are encoded as interlaced.At the bottom of the linked page is a sectioned called DVD Benchmark -- Article Index . All of the answers to your questions are there (especially Part 1 and Part 5 ).
- http://www.hometheaterhifi.com/volume_7_3/dvd-benchmark-introduction-9-2000.html (Open in New Window)
DVDs can be encoded with either a progressive or interlaced signal. The difference between the two is that interlaced splits each frame into two fields. These fields represent either all of the odd lines or all of the even lines horizontally. This is what gives the flicker on TV. Progressive scan provides a more film-like image in that every frame is presented in full; however, you will need a progressive scan monitor or TV to be able to take advatange of this.For info on 2-3 pulldown, check out http://www.zerocut.com/tech/pulldown.html . Basically it's a means of converting 24fps to 30fps and is not related to line doubling. Line doubling is more a means of converting lower quality signals to fill out higher quality displays.
"DVDs can be encoded with either a progressive or interlaced signal. "Then which is true?
1. If we decode the disc into interlaced signal, we are throwing away half of the information on the disc.
2. When we decode the disc into progressive scan signal, we are creating additional information (not originally on the disc) by the player's processor's interpolation calculation.
Does it depend on the disc? Then is it written on the disc cover which is the case?
> > DVDs can be encoded with either a progressive or interlaced signal.> Then which is true
> 1. If we decode the disc into interlaced signal, we are throwing
> away half of the information on the disc.If you're using a regular TV (non-progressive) then your DVD player is just converting the progressive signal into an interlaced signal... about 30 full frames per second into 60 fields (or half-frames split every other line) per second.
> 2. When we decode the disc into progressive scan signal, we are
> creating additional information (not originally on the disc) by
> the player's processor's interpolation calculation.It's not really creating additional information, but rather combining the fields together into one frame and presenting it that way. You can generally see the effects of this in motion shots... they appear more choppy.
The key to understanding the difference between interlaced and progressive is the understanding the difference between fields and frames. One frame is made up of two fields. The term "interlaced" comes from the fact that each field is presented one after the other, first the odd rows, then the even rows, which is then referred to as one frame. Progressive simply pops up the full frame (or both the odd and even fields at the same time... sort of.) Progressive is the same principle as film, although film only moves at 24 fps against NTSC videos rate of 29.97 fps and PAL at 25 fps.
The actuality is that we only refer to frames per second with NTSC as a reference... frames don't really exist. It's all fields. There is no pause between each set of fields, so it's odd/even/odd/even and so forth... Feel free to read up on it some more.
http://graphics.lcs.mit.edu/~tbuehler/video/ntsc.html
It's the PLAYER. A progressive scan player requires a digital television and will produce a higher resolution picture from any DVD.A progressive scan player hooked to an analog TV will show a picture but it won't be progressive scanned.2/3 (more accurately called 3/2) "pulldown" takes into account that film is shot at 24 frames per second and TV has 30 frames per second. To account for this discrepancy a device (sometimes in the TV, sometines in the DVD player) will adjust for this, resulting in a "smoother" picture.
Film is make at 24 frames per second?Then movies on DVD has lesser quality than progressive scan signal (in term of refresh rate)?
So do you mean that the progressive scan signal is made up by player and that it is not originally on the disc?
Then is there no difference between these two?
1. player makes progressive signal and digital TV accepts it.
2. player sends interlaced signal and digital TV makes progressive signeal internally (doubles the lines) and displays it.
> Film is make at 24 frames per second?Modern film is projected (and generally shot at) 24 frames per second. Most silent films were shot at 16fps, which is why they appear to be moving so fast in some transfers as they didn't show them at the right speed. This has been corrected in most archival sets and DVDs, but I remember in videos from the 70s and 80s almost all of them were shown at a faster speed.
One last digression... film is usually shot faster to show slo motion shots. You can easily tell when it isn't as the motion will be choppy... but yes, generally film is made at 24fps.
> Then movies on DVD has lesser quality than progressive scan signal
> (in term of refresh rate)?Don't get consfused by the terms... refresh rate is for displays, not for players. It refers to how quickly the monitor can rescan the lines. Movies on DVD are just that... movies on DVD. They are not the height of quality (720x480 is only barely higher than VGA and at the bottom of the HDTV standards) and pale in comparison to film (less color resolution and far less in terms of picture resolution); however, they still look pretty good.
> So do you mean that the progressive scan signal is made up by player
> and that it is not originally on the disc?Progressive scan can be on the disc. I'd thought most DVDs were encoded with progressive signals, but I could be wrong on that. It's true that pretty much anything shot with a video camera is an interlace source already, but I'd thought that movies were encoded as progressive signals considering that's how they started out (full frame as opposed to fields...)
I've ripped a few DVDs in my time and it appeared to me that the data being pulled off was being pulled off in frames rather than fields in most cases; but, this could also be that the fields are being recombined into fields. My thoughts against this are that I've never really seen any interlace artifacts on the stills, but rather full blur on motion shots... if you've seen still shots of motion on interlaced sources, you'll notice the individual lines of the fields can be clearly identified.
For some more in-depth info, read this VERY informative site:
http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html
This info appears to be from 2000, so I'm not sure if most DVDs are still interlaced or not. With anamorphic transfers now the norm, progressive scan players far more common (remember that they used to cost $700-1000 and regular DVD players in 2000 were at least $200), and HDTV being more than just a toy for the uber-rich, it's quite possible that films are being encoded as progressive on the DVD. I couldn't find anything to verify that, but that's just my deduction.
> Then is there no difference between these two?
> 1. player makes progressive signal and digital TV accepts it.
> 2. player sends interlaced signal and digital TV makes progressive
> signeal internally (doubles the lines) and displays it.Well, if an interlaced source, then the only real difference is in what is doing the deinterlacing. Progressive DVD players and digital TVs both have deinterlacers that will convert the signal, but there are always different levels of quality to the process. Just one more thing to consider in the purchase process.
The question then comes in with what happens with a progressive signal... It should logically pass right through to the TV and be broadcast as is, but who knows what really happens?
I thought the 3:2 pulldown was the ability of some tv's to compress the horizontal lines into a widescreen so the black bars aren't wasting potential resolution. Anamorphic DVD's only. Learn something new every day.
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