ATI Rage Theatre capture chip native capture resolution?

[shardison]

Does anyone know the All in Wonder 128 series capture chip's native capture resolution? Is it 640x480? I haven't been able to find any literature on the chip. I've used the "ATI AIW MMC Reg Tool" to set the capture size to 640 x 960, and it works and looks pretty good (other than being really tall). What's going on here? How many horizontal lines are really being encoded?

[Spicuzza]

shardison,

I have the All in Wonder 128 Pro.
The default capture codec is UYVY video format (native),
my understanding, this is uncompressed AVI.
The default capture "frame size" is 320 x 240.

I believe capturing at 640 x 960?, (odd size), is not getting you anymore video quality than 640 x 480, just a much larger file size.

There is great debate on this site regarding video quality. However, there is undoubtably a point of absolute diminshing returns.

Personally, if I'm wanting to make an XVCD with the end result being very near the quality of the source material I'll capture at 352 x 480 "frame size", uncompressed AVI, encode that to 352 x 240, "frame size" @ 2300 kbps, played on my Pioneer DV-343, burned with either Nero or Ulead VideoStudio 6.0.

Unfortunately, the terms "frame size" and "resolution" are used interchangeably. They are not one and the same thing.

For example, your computer monitor is a certain "frame size" this size never changes, however, if you set the screen "resolution" to 1024 x 768 you'll have a much sharper image than if the resolution was set at 640 x 480.

"Resolution" is determined by kbps for video and dpi for photos.

Sorry to ramble, hope this helps.

Gary Spicuzza
cic7@juno.com

[Nelson37]

On the MMC tool, the RtInterval is on the lower number, which "doubles" vertical resolution. Assuming this setting is the Vertical Retrace Interval, the slower setting was used 5 years ago for Interlaced monitors. Since all monitors today are Non-Interlaced, I don't think this is used anymore.

Since we are capturing an Interlaced image on a Non-Interlaced monitor and display system, I believe the lower (x960) setting is just doubling the image. Now I have seen some tricks for De-Interlacing using sort of a "unfold and refold" strategy, and I have not yet tried reducing a 960 capture to 480, or playing one on my TV, for that matter.

One thing you should try is using the horizontal and vertical cropping to take of 16 pixels on each side on capture, add the borders back on later.
This border is not seen on the TV, and is just wasted bitrate, both on the capture AND on the encode.

[shardison]

After much digging, I finally found an old spec on the ATI site: The chip captures (sees) 640 x 480.

I was interested in this because it's possible to make a anamorphic home video DVD, IF you have 480 resolution of the picture portion of a 16x9 widescreen picture (minus the mask bars.) Obviously, what you normally get is 480 resolution, including bars.

But since the chip only captures at 480, there's nothing to be gained by capturing at a higher software resolution, and cropping the 16x9 image to 480 lines.

The only way to make a home video anamorphic DVD is to film with an anamorphic lens on your camera. Rats.