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View Full Version : Can someone explain in layman's terms how upconverting/upscaling works?


daveymark
01-29-2008, 12:34 AM
I've googled and can't find anything to help me with this.

How does upconverting work? if a DVD is 480, I don't understand how it can "convert" it to 720 or 1080. Even if it can, I don't understand how it will look better. a 480 signal is a 480 signal, so wouldn't the content need to be altered somehow to "upconvert"?

After that question is answered, please answer this: Will I notice a difference on a 50" from 10 feet away between a standard 480p signal and an upconverted signal?

krotchy
01-29-2008, 02:47 AM
So the big thing is theres alot of ways to interpolate (create the in between info) the information when you increase the number of lines. Some can be quite amazing, some terrible.

The most simple way is to obviously just double the size of the pixels to 2x2. This leaves really blocky looking images and is generally garbage.
The 2nd easiest way is to map the pixels to the bigger screen size at even spaces. Then simply average all the information between pixels to create a sort of smear effect as its blown up. It will be smoother than the doubling method, but quite blurry.

Now a good way to do it is it actually attempt edge detection. Since most objects tend to consist of a base color (or gradient) and an edge, you can attempt to keep the edges really sharp by drawing them precisely and not averaging the changes across the edges, then sort of smearing the flat color or gradient inside of the object. This is better than average because it reduces the blurring on edges, while still keeping the smoothness of surfaces.

On top of that theres many other methods to increase the number of lines, but basically the better the guessing algorithm the better the upconversion. One of the most well regarded upconverters is the HQV Reon chip, found in a few newer TV's and some newer Audio Receivers (Onkyo 875/905 for example).

So yeah, the reason an upconverting DVD player can improve the quality of a DVD is through the use of a high end upconverting chip running a more complex precise algorithm. The reason this is preferred, is depending on your brand of TV, the internal upconverting chip in the TV itself is often not as good as one found on the DVD player. Mostly because a TV has to play back the input in real time, but a DVD player can buffer (delay output) the audio and video and then send them simultaneously as the improved signal. Because a good upconversion algorithm can likely take longer than a simple one, the ability to buffer without hindering performance (games etc.) is pretty essential.


To answer your 2nd question. MAYBE... lol. It really depends on alot of factors including how good of a TV you have and how good of an upconverting DVD player you get.

PurdueRy
01-29-2008, 02:50 AM
Originally posted by: daveymark
I've googled and can't find anything to help me with this.

How does upconverting work? if a DVD is 480, I don't understand how it can "convert" it to 720 or 1080. Even if it can, I don't understand how it will look better. a 480 signal is a 480 signal, so wouldn't the content need to be altered somehow to "upconvert"?

After that question is answered, please answer this: Will I notice a difference on a 50" from 10 feet away between a standard 480p signal and an upconverted signal?



Alright here is my best "easy" explanation.

Go into paint and resize an image. Double or quadruple the overall size and then zoom in and take a look at the result. You will notice that diagonal lines turn out jagged....kind of similar to playing a game without AA on.

Now use a program like photoshop and turn bilinear smoothing on. Look at the result. You will notice this has much fewer jagged parts to the lines.

A fixed pixel display needs to display the image in its native resolution. The simplest way to do this is by doubling of lines. Simply take the line and copy it to the next, then do the next line of resolution the same way. This will make a 640 x 480 image become 1280 x 960 and effectively upscaled. This will probably not look the best however because there is no averaging applied.

Now a good upconverter will use complex algorithms to average between multiple lines of resolution. The simplest way to explain this would be to take two lines of resolution instead of one. Add their respective values together(grayscale 0-255 lets assume) and then divide by two. Now the result will be a line of resolution which is "halfway between" the two original lines of resolution. This will result in a smoother image than just doubling

There are obviously much more complex algorithms for this. You would not just handle horizontal lines of resolution in real life. You would handle blocks of pixels. For instance maybe your upscaler would process a 3 x 3 block of pixels at a time WITH overlap(first block processed would be pixels 1-3 horizontal x 1-3 vertical, then 2-4 horizontal x 2-4 vertical). This takes quite a bit of processing power to do on the fly but it will result in a much better image than the simple methods described earlier.

Hope this makes it clearer. Just remember, a upscaler does not add detail, it just attempts to remove the artifacts that become visible when an image is resized larger.

daveymark
01-29-2008, 12:12 PM
thanks guys! that really helps. Especially the following comment

" a upscaler does not add detail, it just attempts to remove the artifacts that become visible when an image is resized larger"

I was getting confused during my google searching as some people were stating they were content to hold on to their standard DVD collection and watch it on their upconverting player, rather than spend money replacing their collection with bluray.

I have a pioneer kuro 5080 hooked up to my xbox 360 via component. the kuro is 768p. does that mean the kuro is automatically upconverting the 480 signal from the xbox when playing movies?

Also, I've read that the xbox can upconvert movies as well, I just need a VGA cable to do it. So would it be better if I can get the xbox to upconvert the signal first, so the kuro has a closer match, or should the kuro do a good enough job as an upconverter?

PurdueRy
01-29-2008, 12:28 PM
Originally posted by: daveymark
thanks guys! that really helps. Especially the following comment

" a upscaler does not add detail, it just attempts to remove the artifacts that become visible when an image is resized larger"

I was getting confused during my google searching as some people were stating they were content to hold on to their standard DVD collection and watch it on their upconverting player, rather than spend money replacing their collection with bluray.

I have a pioneer kuro 5080 hooked up to my xbox 360 via component. the kuro is 768p. does that mean the kuro is automatically upconverting the 480 signal from the xbox when playing movies?

Also, I've read that the xbox can upconvert movies as well, I just need a VGA cable to do it. So would it be better if I can get the xbox to upconvert the signal first, so the kuro has a closer match, or should the kuro do a good enough job as an upconverter?



Correct, the Kuro is upconverting the picture before it is displayed.

Personally, if you really want a upconverter, research one and pay for it. There are many upconverters which do a fairly crappy job(hardly a difference from the TV). Then there are ones that are good. It's not worth your time and money if the end result is no different.

There has been a deal going on for a Pioneer upconverting DVD player that I guess is supposed to be good. Perhaps look into that as I am not sure that the 360 does that great of a job.

DaveSimmons
01-29-2008, 01:46 PM
FYI, the PS3 is highly rated for its DVD upscaling, besides being the most future-proof blu-ray player, so it's one option to consider. Netflix carries almost all new blu-ray releases.

You might wait a little to see if the 40 GB version gets a price drop or is upgraded to include the dual-shock 3 controller with rumble.

daveymark
01-29-2008, 02:09 PM
yep I've already done research on upconverting players, the only other option for me as i see it is to get a ps3. I can sell the 360 and upgrade to ps3 for around the cost of buying an oppo or other premium upconverter.

If the standard def movies will see an improvement with a $10 VGA cable, I was going to do that in the interim. just trying to figure out if that's even worth doing though.

DisgruntledVirus
01-29-2008, 02:24 PM
Originally posted by: daveymark
yep I've already done research on upconverting players, the only other option for me as i see it is to get a ps3. I can sell the 360 and upgrade to ps3 for around the cost of buying an oppo or other premium upconverter.

If the standard def movies will see an improvement with a $10 VGA cable, I was going to do that in the interim. just trying to figure out if that's even worth doing though.




I doubt with a VGA cable you will really notice the difference. HDMI sure you might, but a VGA is doubtful.

But if you want to try it go to Radioshack, buy a VGA cable and if it doesn't do anything then return it for a full refund. :)