ATI AIW cropping

[anitract]

I ran into this GUIDE recently (which actually refers to LS's site). I'm wondering about this quote:

"Now encoding interlaced is one way to keep the maximum video data - so is encoding the video uncropped. Basically - watch the captured footage on the PC and you'll see noise as the frame edge - watch it on a TV and that noise disappears into the overscan area of the TV. Crop it and you are essentially zooming in on the source, losing even more detail at the edges as a result."

See that last sentence about losing detail from cropping because it zooms in? Is that right? I thought cropping just masked over the overscan area with black...

[thecoalman]

No cropping removes that part of the video. Depending on your software you can then have it encode as is (which will result in a non compliant resolution for computer playback only), expand it to fit the original resolution or reduce it. All of which are not very good options if ou intend on creating a DVD with it.

When you add borders or frame it your replacing that part of the video. This will give you a nice clean edge for computer playback and maintain the best quality since the only part of the source that is being changed is the edges.

[anitract]

All right, but what about this...

From lordsmurf's site:

"The MPEG-2 DVD format (rather than plain MPEG-2 format) will allow proper cropping of the video, thus removing noise often found on VHS tapes in the overscan viewing area. If capturing VHS or other non-live sources, it is suggested to use the MPEG-2 DVD settings and to enable the RECORD CROPPED VIDEO SETTING. . This feature is only found on ATI MMC 8.x and 9.x."

So I should be ok if I pick MMC's MPEG-2 DVD format and cropping? Meaning, I will have no quality loss or zooming?

[lordsmurf]

You're confusing things.

ATI MMC uses the word "crop" twice. Neither are similar to what you're talking about. If you only use one of them, the video is cropped and

There are 3 terms here:
1. "Crop", which is really MASK.
2. Crop, and just cut it off. Weird size output.
3. Crop, and zoom back out to a preset size.

ATI MMC does #1 and/or #2
That other thing you read is a warning about #3.
ATI MMC does not do #3.

ATI MMC has two settings, in two places. Only selecting one of them will crop the video and give you a weird size output. It just chopped off the edges.

If you select BOTH of them , as you should, it crops off the out edge of the video, and then fills in the rest of the preset size in with black. It's final effect is that of a mask.

Now then, the warning you got is a good general rule, although not a 100% always correct one. In general, cropping loses picture, and that's bad. However, sometimes, when errors around the edges of video cannot be fixed (not overscan, but visible errors inside the overscan), this is a last-resort restoration technique.

This is why people that download tv shows and movies off the internet have garbage output. They do not account for the overscan, so you lose picture viewed on tv. This is one reason I think DVD burners ought to come with an IQ test or some sort of required primer reading.

Does that make more sense now?

[anitract]

lol Yeah, heh, makes sense. I knew something didn't seem quite right because I hadn't _noticed_ anything weird in my captures, but then I bumped into that page which seems to have bumped around a few of my brain cells.

So in a nutshell. I will continue to both select "MPEG-2 DVD Format" AND check "Record Cropped Video" when I want a crop that doesn't affect the video resoultion.

Now, I'm curious, in your guide you say "If capturing VHS or other non-live sources, it is suggested to use the MPEG-2 DVD settings and to enable the RECORD CROPPED VIDEO SETTING. . This feature is only found on ATI MMC 8.x and 9.x. " Is this still your recommendation for vhs-to-dvd captures?

[lordsmurf]

Yes, remove overscan noise when it exists. Not because it "looks pretty" on the computer or some other such non-sense, but simply because it saves bitrate for the actual image, not wasted on overscan noise.

[thecoalman]

You're confusing things.

ATI MMC uses the word "crop" twice.

I think it's ATI that is confusing things.

[Nelson37]

Here's another question along similar lines.

Is there any way to get MMC to record and mask a letterbox movie?

Display setting set to Letterbox 2:35 to 1 gives this effect but with a movie resolution of 640 x 480.

Probably have to edit the mask settings manually with display set to 4:3?