Upconverting vs. Downconverting AVI to DVD

[Bum_Rush]

As the topic implies, I can't figure out which resoluton I should use when encoding divx / xvid files to DVD.

Should I use Full D1 (720x480 NTSC) or Half D1 (352x480 NTSC)?

The reason I am confused is because the files I am converting have a resolution that is somewhere in the middle of these two standards.

Many of the files are captured TV shows that I want to burn and save to watch later. Here are two examples:

XVID PDTV Capture: 576x432 (4:3)
XVID PDTV Capture: 512x384 (4:3)

Basically, I need to know what you guys think would give the best quality, half or full D1? Let's say I was using an average bitrate of 5000? Of course, this is a great bitrate for half D1, but am I losing quality if I downconvert 576x432 to 352x480?

I read on other posts that upconverting can actually make the quality worse, but in this care, I am worried that downconverting would also be worse. This is a PDTV capture, so it really has a crisp digital resolution as listed above, not an analog cap from VCR. (I realize that in any case, the height of the video files will be upconverted).

Also, any comments on compatibility or sharpness on large TV screens when using Full/Half D1 are appreciated. Thanks in advance.

[FulciLives]

The width isn't that "low" and since the quality is so good (the quality of the encoding) you probably will get excellent quality by upconverting to 720 just make sure you use enough video bitrate when doing the MPEG-2 conversion.

Going to Half D1 352 width will result in a slightly softer image.

- John "FulciLives" Coleman

[monzie]

Whoever said upconverting can make quality worse is talking bull.

I always go UP when converting .avi to DVD with anything above 500 wide. The TRICK is NOT to use the full resolution but instead make a video size of around 1.2 to 1.3 times the source (of course you need to go to the nearest 'natural' size.....a res divisible by 16). Use either BICUBIC or LANCZOS for your resize filter.

Example: 512 (h) X 1.25 = 640... so the nearest 'natural' for a 4:3 will be 640 X 432 or (for x 1.3) 656 X 448. Remember that OVERSCAN will shrink those added borders.

[lordsmurf]

It can get worse, or better, depending on the show content, the ORIGINAL source resolution, the encoder, and any hardware that is involved.

Fun, huh?

I would tend to lower the smaller one, maybe go larger on the next one.

It also depends ENTIRELY on the original source's resolution and the quality of the original capture device. For most sources, 352x480 would be best option.

It just depends on many factors NOT covered in the original post.

[monzie]

How can coverting to 352 wide then playing back thru a DVD player at DOUBLE that width (at the TV end) make it better?

Also what height would you suggest?

Please explain.

[lordsmurf]

x480, period.

Too much for me to explain right now, far too busy for that dissertation.

Like I said, it depends on more factors that are known by the simple first post.

[jimmalenko]

I've always held the belief that resizing up should be avoided. This is only based on my own limited experiences with resizing video - who knows, maybe I need to RTFM

We get back to the old debate of creating new data is bad for quality Vs throwing away data is bad for quality though.

[vhelp]

First, (because these sources have odd resolutions) some questions should
be asked before an assumption of tips can be properly made

And, remember.. that you are subject to the person who *actually*
encoded these odd clips ..don't expect really good quality from these *unknown*
sources.. specially since you want to convert to DVD now. Anyways.

* Are these Wide Screen shows you are trying to convert ??
* Or, are they Full Screen.

-vhelp

[lenti_75]

why don't you convert it up and down, and see what you like most ???

if the size is that close to a full resolution, I don;t think you will loose the quality, but that depends on the encoder.