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Discussion Starter · #1 ·
This is maybe a stupid question, but I can't imagine why a DVD player would put out an interlaced signal? Aren't DVD's compressed MPEG2 images on a disc? These images aren't interlaced are they? Or am I wrong? What about HD DVD, why are there 1080i players out there? It seems to me that the player would need to "create" the interlaced signal, while the progressive scan (an entire image at a time) is native to the MPEG encodeing... no???


Can someone shed tome light on this
 

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Quote:
Originally Posted by DaveMoi /forum/post/0


This is maybe a stupid question, but I can't imagine why a DVD player would put out an interlaced signal? Aren't DVD's compressed MPEG2 images on a disc? These images aren't interlaced are they? Or am I wrong? What about HD DVD, why are there 1080i players out there? It seems to me that the player would need to "create" the interlaced signal, while the progressive scan (an entire image at a time) is native to the MPEG encodeing... no???


Can someone shed tome light on this

NTSC dvds are encoded at 480i; PAL at 576i.


HD-DVD and Blu-Ray are encoded at 1080p. Why 1080i players? Until recently 1080p signals were very rare and most displays would not accept 1080p. 1080i has been common for a long time.


I've also heard reports that HD players must produce an interlaced signal internally to merge HD and SD content, as in the picture-in-picture feature. This sounds crazy to a film buff who just wants to see the movie and figures 1080p disc to 1080p signal would be the best way to do that.


But I haven't kept up with the HD player issues.


-Bill
 

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SD DVDs are 480i, but you're only going to find old players that cannot do progressive output (480p). I assume most of the HD-DVD players don't do 1080p to cut costs, plus most displays don't accept 1080p anyway. Even most (if not all) BD players don't output 1080p correctly anyway (they convert it to 1080i, then back to 1080p, so PQ would look the same whether the player or the display does that last 1080i-to-1080p conversion).
 

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Quote:
Originally Posted by DaveMoi /forum/post/0


This is maybe a stupid question, but I can't imagine why a DVD player would put out an interlaced signal? Aren't DVD's compressed MPEG2 images on a disc? These images aren't interlaced are they? Or am I wrong? What about HD DVD, why are there 1080i players out there? It seems to me that the player would need to "create" the interlaced signal, while the progressive scan (an entire image at a time) is native to the MPEG encodeing... no???


Can someone shed tome light on this

the HD-DVD player is creating a 1080i/60 signal from a 1080p/24 signal.

There are at least a dozen articles on why and how this is done and how it doesn't affect Picture quality.
 

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It's a fair question Dave, but on the other hand look at how many posts there were recently when someone asked what DVD players would put out 480i from HDMI or DVI. For people with video processors or older TVs it's still a good thing. I spent the money to have my DVD player modified so that I could get a 480i signal over a digital cable, without having to use HDMI.
 

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Quote:
Originally Posted by mhsens /forum/post/0


It's a fair question Dave, but on the other hand look at how many posts there were recently when someone asked what DVD players would put out 480i from HDMI or DVI. For people with video processors or older TVs it's still a good thing. I spent the money to have my DVD player modified so that I could get a 480i signal over a digital cable, without having to use HDMI.

Although SDI mods and the like are often to bypass player processing and use outboard processing instead, so that's kind of a different thing, but is interesting to note.
 

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My DVD player is 6 years old and it's not a progressive scan unit. The last TV we had that recently died (set was just over 3 years old) had a DVD component connection. It would not accept a progressive scan signal.
 

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Discussion Starter · #10 ·
Thanks everyone for the great info
I really didn't know that a DVD is "coded" with interlaced images! Then again, I guess it would be logical, as the technology is old enough that there were very few display devices that would accept a progressive scan when DVD was being designed. What surprises me a *lot* more is that HDDVD players generate a 1080i signal to then change it to a 1080p signal, while the source is 1080p !


I guess the lesson to be learned here is that it's best to feed a good scaler 480i ntsc or 575i pal DVD or 1080i HDDVD signals, and let the scaler take care of the deinterlacing.... Right?
 

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DaveMoi, first, BD players do the same thing as the HD-DVD players (convert the 1080p signal to 1080i). Second, there are excellent upscaling DVD players that do a great job deinterlacing, a a fraction of the cost of an external scaler.
 
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