DVD Upconversion:Noticeable difference in picture? or sellinggimmick?

"Jer" wrote in message
...


Would a 480 native image look the same as a 480 upconverted image on the
same TV?



by the time it was on your screen it wouldn't be 480 native anymore - the tv
would have altered it to the same resolution as the screen.


--
Gareth.

That fly... is your magic wand.

Jer wrote:

That's not how I understand it. Additional new pixels are inserted
into the bit stream for each frame, "interpolated" from the adjacent
pixels in the original bit stream. An upconverted 1080 signal
contains more data than an original 480 signal, so it sounds to me
like additional data is being added from somewhere.

Alan wrote:

It may be more data, but it is not more *information*.

The question was is it better to do this in the DVD player, or in the
TV set.

Alan


Would a 480 native image look the same as a 480 upconverted image on the
same TV?

If you have a HDTV panel in mind as the same TV testbed, how are you
going to get a true native 480 image (if I correctly understand what
you're getting at)? The TV will "expand" (interpolate) those 480i DVD
native pixels to it's own TV native resolution.

Aren't you back to racing interpolation between DVD player side and
television side, again?

If you use a CRT TV as the testbed reference, the results would be
meaningless in the flat-panel world.

winf

the dog from that film you saw wrote:
"Jer" wrote in message
...


Would a 480 native image look the same as a 480 upconverted image on the
same TV?



by the time it was on your screen it wouldn't be 480 native anymore - the tv
would have altered it to the same resolution as the screen.




Yeah, okay... so let's presume, for the sake of argument, you could turn
the upconversion feature on and off with a button. Would a 480 native
image look the same as a 480 upconverted image on the same TV?

--
jer
email reply - I am not a 'ten'

In article Jer writes:
the dog from that film you saw wrote:
"Jer" wrote in message
...

Would a 480 native image look the same as a 480 upconverted image on the
same TV?

by the time it was on your screen it wouldn't be 480 native anymore - the tv
would have altered it to the same resolution as the screen.

Yeah, okay... so let's presume, for the sake of argument, you could turn
the upconversion feature on and off with a button. Would a 480 native
image look the same as a 480 upconverted image on the same TV?

No, if it were not upconverted, it would be a teeny picture somewhere on
the big screen.

Alan

"Jer" wrote in message
...
the dog from that film you saw wrote:
"Jer" wrote in message
...


Would a 480 native image look the same as a 480 upconverted image on the
same TV?



by the time it was on your screen it wouldn't be 480 native anymore - the
tv would have altered it to the same resolution as the screen.




Yeah, okay... so let's presume, for the sake of argument, you could turn
the upconversion feature on and off with a button. Would a 480 native
image look the same as a 480 upconverted image on the same TV?



the 480 native picture would occupy a 640x480 pixel area in the middle of
the screen and be surrounded by black on all 4 sides.
you can experience this by connecting a pc to your tv via hdmi, turning off
scaling on your pc and switching to 640x480 resolution.


--
Gareth.

That fly... is your magic wand.

On Mar 3, 11:30*pm, Jer wrote:
the dog from that film you saw wrote:

"Jer" wrote in message
...

Would a 480 native image look the same as a 480 upconverted image on the
same TV?

by the time it was on your screen it wouldn't be 480 native anymore - the tv
would have altered it to the same resolution as the screen.

Yeah, okay... so let's presume, for the sake of argument, you could turn
the upconversion feature on and off with a button. *Would a 480 native
image look the same as a 480 upconverted image on the same TV?

--
jer
email reply - I am not a 'ten'

If you could turn off up-converting at both the TV and the source
(say, DVD), the 480i/p image would occupy only a small portion of the
screen: 640x480 (4:3) out of 1920x1080 for a 1080p screen. If either
unit performs the up-conversion, the 640x480 native content would be
converted up to 1440x1080. In the practical sense of watching an
HDTV, up-converting and scaling refer to the same act: expanding a
smaller pixel dimension image to fill a larger pixel dimention
display.

A really poor implementation would simply double every pixel (and
triple every 4th). Unless you moved far enough away that your eyes
could only distinguish every 4 pixels, the result would be larger but
blocky. A slightly better implementation would not just create
multiple identical pixels, but would smoothly interpolate intermediate
values for the extra pixels. Now the result wouldn't look blocky, but
it would look quite soft with blurry edges. A yet better up-
conversion algorithm would interpolate the extra pixels, but would
also perform edge detection and would leave edges single pixel to
increase sharpness. And a yet better algorithm would interpolate,
detect edges, and anti-alias edges to put intermediate value pixels
along non-horizontal or non-vertical edges to prevent visible "stair
stepping". And so on. (And by-the-way, as I've stated before, some
TVs have the option of 1:1 viewing - no up-conversion. If your TV has
the option, and you have an up-converting source, you can compare the
effectiveness of each device for yourself.)

As I hope you can see, there are many algorithms for up-converting,
and the perceived quality of the results can vary greatly. Generally,
better quality algorithms cost more (due to processing power and
memory/buffering costs), though there could be exceptions. So,
whether or not you will see a noticeable difference in picture from an
up-converting DVD player versus a standard DVD player depends on the
ability of both the DVD player and the TV to up-convert the video
material. If you are really tempted, buy an up-converting unit from a
store that takes returns and try it out. Ultimately, the best choice
is the one *you* like the best.

Dan (Woj...)