Dreamcast-Talk.com

Neohound wrote:Gary_b, are you sure you tried the right cable from your DC vga box to your tv ? I had a similar problem some time ago and I discovered I had the wrong type. There are three types of DVI cable: DVI.a DVI.d and DVI.i One takes an analogue signal, with one being digital and the other is interchangeable. I've got two cables which I hook up my computer with and they look identical, just that one works whereas the other doesn't.

yea i know, i do have a few of them, but no, i am not sure if the correct adapter will work or not. its possible that these are not the correct ones. i got them to convert VGA to DVI on a PC a while ago. there is at least one type of adapter i do not have to test. when i got my converter box i had a different TV. it only had component hook ups. then i got this Toshiba that has a DVI input and i also have Sony Wega with a DVI port. both TVs fail to load the VGA signal with just these adapters alone. i suspected that i could use a different adapter, but i dont see the need when i have the converter box to use with my TVs component inputs. this leaves the DVI port for my HD cable




i just looked at my adapters and DVI inputs on my TVs. its looking like both TVs use DVI-D and that means i wont be able to just use the adapter.

If one connection is analog and the other connection is digital, there is no way to connect them with a single cable. You'll have to use an electronic converter box, such as our analog VGA to digital DVI/HDMI converter.

http://www.datapro.net/techinfo/dvi_info.html#Page02

cabou wrote:hooking a converter to the TV input, chains actually TWO video upscalers:
[*]the up/downscaler that is in the converter
[*]the up/downscaler that is "built in" the TV (and which purpose is to make the image fulfill exactly the screen, whatever the resolution of the entering video signal is)

That results naturally in two consecutive degradations of the video signal.

Well that's really not different than what you would get from any current generation console. The image is scaled by the scaler in the console to the output resolution, then scaled by the TV.

For instance the Call of Duty series runs at 1024x600. The 360 or PS3 then scales the video to the output resolution. The TV then has to scale the video to match the actual pixel resolution of the TV (keep in mind most HDTVs have an odd resolution and only scale to 720p/1080i/1080p).

The difference is there is more data in 1024x600 than 640x480.

However, if your TV has as bad of a scaler as mine, it's better to get the image as close to the TVs actual resolution as possible. Like I mentioned before when scaling from 480p I get weird artifact lines on my HDTV that don't show up on other displays (my girlfriends HDTV or my 1080p monitor). I don't see any artifacting at 720p (that is noticeable anyway), which for me makes a converter box better quality. Remember if one conversion ruins the quality, taking most of the load off of it will improve the overall output.

haxfactory wrote:

cabou wrote:hooking a converter to the TV input, chains actually TWO video upscalers:
[*]the up/downscaler that is in the converter
[*]the up/downscaler that is "built in" the TV (and which purpose is to make the image fulfill exactly the screen, whatever the resolution of the entering video signal is)

That results naturally in two consecutive degradations of the video signal.

Well that's really not different than what you would get from any current generation console. The image is scaled by the scaler in the console to the output resolution, then scaled by the TV.

For instance the Call of Duty series runs at 1024x600. The 360 or PS3 then scales the video to the output resolution. The TV then has to scale the video to match the actual pixel resolution of the TV (keep in mind most HDTVs have an odd resolution and only scale to 720p/1080i/1080p).

The difference is there is more data in 1024x600 than 640x480.

However, if your TV has as bad of a scaler as mine, it's better to get the image as close to the TVs actual resolution as possible. Like I mentioned before when scaling from 480p I get weird artifact lines on my HDTV that don't show up on other displays (my girlfriends HDTV or my 1080p monitor). I don't see any artifacting at 720p (that is noticeable anyway), which for me makes a converter box better quality. Remember if one conversion ruins the quality, taking most of the load off of it will improve the overall output.

the dreamcast is also going to have to scale the image as well, pointing out that current gen consoles scale images is somewhat irreverent. also having more data in a higher resolution image seems moot to me. any and all of the the images will be degraded every time it passes through a scaler and a cable. the best you can do is reduce this as much as possible by limiting these contributing factors.

I totally agree with you Haxfactory, except one on little point:

the built-in TV scaler can NOT be disabled (I do not know TV which permits that)

so you have to deal with it anyway....
that's why -when this is possible- it is better to avoid another external scaler (mainly those with anlogue ports, because you have to add the loss of the A/D and or D/A conversions)

take the example of your DC + VGA cable + Component HD box.

you get:
1. the loss of the Dreamcast built-in RGB video Chip (video DAC)
2. the loss of the A/D conversion inside the HD box
3. the loss of the digital upscaling treatment inside the HD box
4. the loss of the D/A conversion inside the HD box (to get back to analog --component- signal)
5. the loss of the AD conversion inside the TV
6. the loss of the component to RGB conversion (displays "understand" only RGB)
7. the loss of the digital up/downscaling treatment inside the TV


you see that if you hook your DC directly in VGA, you avoid steps 2, 3 4, 6 losses...

It works with plenty of adapters.
http://dreamcast-talk.com/forum/viewtop ... 1&start=10

The one is use for instance is generic. And for this one, 720p is a lot clearer than 1080i. And thats fine by me because personally i prefer progressive over interlaced.

And as you can see by the date i posted this, this isnt news.