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On HD DVD film content resolution and scaling

882 Views 5 Replies 4 Participants Last post by  FGM
I have read in another forum that HD DVD film "content" is 1080p at 24fps. Therefore, since my HD-D3 player can't pass 1080p signals and since I have selected an output signal of 720p to match the native resolution of my pj, I presume that the D3 has the capability and smarts of just scaling the signal down to the selected 720p and converting it from 24fps to 60fps. Can someone confirm this?

In the negative, can anybody shed light on the way the D3 player converts the 1080p content of the HD DVD films to the selected output of 720p for my pj.

Could an A30/A35 player that can do 1080p/24 output a 720p/ at 48 or 72 fps? Would this solution theoretically yield a better PQ than the A3 because of less signal processing?

All comments appreciated.
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I have not seen any credible reports of how Toshiba HD players process the 1080p24 on the DVDs. There is a consensus (for what its worth) that the sequence is 1080p24 > 1080i60 > 1080p60. My guess is that 720p60 is scaled and deinterlaced from the 1080i60 format. There is also consensus that the 1080p24 format is taken directly from the DVD data because it in is better quality than 1080p60 on the A20, A30 and A35. The only 720p format available is the 720p60.
Yes, the D3 will convert the 1080P24 info on an HD DVD and output it as 720P.

Most users with most displays find that outputting 1080i looks better even on a display that is only capable of 720P. I know my Panasonic plasma looks best with 1080i. Some 720P PJs don't seem to do as good a job of down converting and may look best when the HD DVD player is set to output 720P max. It's all trial and error and you have to see what looks best with your combo. Something like a DVE test disc might help you out if you're not sure what looks best.
txrose and unclewebb thank you for your informative replies.

From reading in and around these forums I got the perception that it is difficult for players to do the deinterlacing part right and I find it is a step backwards to interlace a 1080p original content signal which comes straight to the player from the HD DVD, particularly, when the player is 1080p capable.

It would then theoretically appear that the best PQ would be obtained when the player sends a totally unadulterated 1080p/24 signal to a capable 1080p/24 display. Right?

Why would these 1080p capable players not do the 24 to 60 fps conversion (when required) while keeping the 1080p information whole?

Would it then be reasonable with a 1080p/24 display to expect an improved PQ out of a1080p/24 capable player such as the A30/35 as compared to the A3/D3?

TIA for your comments

Originally Posted by FGM /forum/post/12855721

Why would these 1080p capable players not do the 24 to 60 fps conversion (when required) while keeping the 1080p information whole?

Would it then be reasonable with a 1080p/24 display to expect an improved PQ out of a1080p/24 capable player such as the A30/35 as compared to the A3/D3?

TIA for your comments

Players are suppose to make accurate 1080i/60 or 1080p/60 frames from the 1080p/24 and 1080p/30 recorded on the disc. There is a wider range of performance within TVs, however. Its difficult to generalize when talking this kind of PQ detail, however, as each device has its own unique circuitry quirks (some brought on by cost considerations). Some devices attempt to “improve” the video instead of providing the most accurate translation. Also, the function of a chip is not always as advertised and each device may use a different chip set. Circuitry is typically proprietary, so we guess based on a trial and error process which also can be flawed. By the time one model is figured out, the next model is released

We know that a player that takes 1080p/24 right off the HD disc and sends it to a display at 1080p/24 that displays it at 72hz, 96hz, or more with an even pull down and 1080p native resolution has the least chance of PQ error. There are few TV devices that do this. I know it works perfectly with an XA2 and pio 6010. If you want to be assured the best possible video accuracy and PQ, you need to spend at least that kind of money (although it doesn't guarantee you will notice any PQ difference).

I also know that when an XA2 takes 1080p/24 (or 30fps) off a HD disc, makes it into 1080i/60 and sends it to a pio 6010 which then extracts the 1080p/24 video and displays it at 72 hz, the identical PQ results in spite of the oportunity for error (the 6010 will display the 30fps at 60hz of course). I also know that substituting an XA1 has the same performance. Because of pio circuit quirks, it doesn't work well for a 1080p/60 signal and sometimes the pio TVs are a bit slow to pick up video cadence, but otherwise it works fine. I'm sure there are others, I just can't vouch for them. I think all the tosh HD players make 1080i/60 correctly, 1080p/60 may be an issue (for film, 1080i/60 has just as much resolution and PQ content as 1080p/60). You can't make these kinds of generalizations with every device.

Its a similar story with SD DVDs but with additional inconsistency and flaws in SD DVD recording, so the mileage varies from disc to disc as well as device to device (and scalling issues adds another dimention).

Now there are a wide variety of video cadence and encoding details in use around the world. It may be possible to find performance inconsistency in any device for some esoteric combination, but for the typical 3:2 or 2:2 pull down and interlace/de-interlace process, the above should hold true. The DVE HD test disc can point out some of these esoteric problems for you.
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Thank you for a most informative answer and links.

I just could not intuitively figure (nor digest) the thought that having a wonderful 1080p start up PQ our HD HW could possibly shortchange us in the processing to a less than the "advertised" 1080p level of excellence.

So, if I've got the gist of it, the conversion of 1080p into 1080i it is not necessarily bad in terms of PQ or "content" information.

However, since my display is 48Hz and 72Hz capable (alas at only 720p) it would have been nice to have the D3 (or A30/A35) able of outputting these timings at 720p.

I guess I will have to wait to a next upgrade into a 1080p/24 display.

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