Best resolution for DVD made from 512x384 AVIs?

[PatrickBateman]

I'm making a DVD set for a friend. The source files are TV captures at 512x384. What resolution is best for the DVDs? 352x480 (which will be stretched to 640x480 as I understand it) or 352x240? Do DVD players use good stretching algorithms?

I wish to fit about 230 minutes per DVD, which means the average video bitrate would be 2375KBps. The show is a sitcom.

My friend's DVD player has progressive scanning, but I don't think her TV does.

[lordsmurf]

352x480
You're pushing it on the bitrate.
Use Procoder, not TMPGENC for something that low.

[CaseyComb]

Well if your friend doesn't own an HD TV then progressive scanning is fairly irrelevant. I would encode at 352X480 which is one of the proper resolutions for DVD. Her player should have no problem playing it.

As far as using either procoder or tmpgenc is concerned, it's really dependent on the quality of the .avi. No encoder will improve the quality of the source file.

Its also dependent on whether or not you have both encoders...if not... well use the one you have.

[PatrickBateman]

Thanks.

I'm planning on using Mainconcept 2-pass VBR with maximum motion searching. Also, I'm running the source files through several filters.

[monzie]

OK, i might go against the grain here, but in my experience the best size for a source of 512 X 384 is to encode at 720 X 480 (or 704 X 480) with a video size of 656 X 448 using BICUBIC.

If you go 352 X 480 you are stretching in the vertical yet shrinking in the horizontal...which I find a rather poor way of doing things and so will your resizing filter...if the .avi had an original height of 480 then it would be OK to go the CVD route.

You would be FAR better just using 2 DVDr's than trying to squeeze nearly 4 hours onto a single DVDr. If its a sicom you can go as low as around 3400/3500kbs and still get good results but I wouldn't go much lower.

Better still (my other method) buy an avi enabled DVD player and slap the avi's onto a DVD....job done.

Although no encoder will increase quality encoding at the wrong res and bitrate will destroy any quality you had to start with.

Why not just try a couple of minutes encoding to 352 X 480 and 656 X 448 (on 704 X 480) and pick the one you think is best...then you can make up your own mind.

[lordsmurf]

I almost said 720x480 myself.

Think back to what he said ...... "tv capture".

His source was never 720x480 to begin with. It was artificially upsized to 512x384. No reason to upsize it again. Just inflating filesize.

It should look equally as good at 352x480.

[PatrickBateman]

Aren't standard TV shows broadcast in something analogous to 512x384?

[PatrickBateman]

You would be FAR better just using 2 DVDr's than trying to squeeze nearly 4 hours onto a single DVDr. If its a sicom you can go as low as around 3400/3500kbs and still get good results but I wouldn't go much lower.

If that were the case, I would certainly do that. However, I have 42 hours of video to convert, not 4.

[lordsmurf]

Aren't standard TV shows broadcast in something analogous to 512x384?

Not even close.

[PatrickBateman]

What is it, then?

If that's the case, would it not be better to go down, closer to the original resolution?

[lordsmurf]

352x480 is optimal for this situation
http://www.digitalfaq.com/understandsource.htm

[Alan69]

I almost said 720x480 myself.

His source was never 720x480 to begin with. It was artificially upsized to 512x384. No reason to upsize it again. Just inflating filesize.

It should look equally as good at 352x480.

"Upsized"? There was no upsizing, it is analog, there aren't any pixels. Resolution in lines is video bandwidth to the next closest possible opposite edge, not pixels. The next edge may be 1.5 'pixels' over if you only use 352, since there is no place the edge is supposed to be in the first place in analog. 352 will 'blur' that over to 1 or 2 pixels instead of having the edge closer to where it should be. Lines of resolution only limits how close the next opposite edge can be, that simply does not mean that the next analog edge has to be only at the exact place the next 352 pixel edge would be. That necessitates a higher pixel resolution to capture where the analog edges really are in an accurate manner.

It's not imagination when you cap somthing at 720x480 off the TV instead of 352 and everything looks more clear. The clarity difference is easily seen, you guys must have terrible cable to say it's the same. Or just love the smaller file sizes, so don't really test so you don't have to upgrade.

Actually Farscape with it's excellent backgrounds is on tonight, I'll try and stay up to do a short cap of each with proportionate bitrates and post a couple pics. Won't be hard to tell which is which.

Alan

[sacajaweeda]

Or not.

[lordsmurf]

Pixel equivalency is closest to about 352x480 in the DVD spec, from tv sources.

Some cards look like crap at anything other than "max" resolutions (or even some oddball sizes). Those are cheap cards, upgrade.

512x384 was definite overcapture of horizontal resolution, plus it also dumped interlace (most likely, depends on the "AVI" that was used). The vertical should have stayed x480, that was slaughtered. Nothing to do about it now, damage is done.

It's not imagination when you cap somthing at 720x480 off the TV instead of 352 and everything looks more clear.

Usually, actually, it is 100% imagination. Or just sub-standard capture hardware/software. Either way.

[canadateck]

I always cap at 720x480 and it looks great.And i also have a bad imagination.

But never really did a test of the two.

[Wilbert]

Pixel equivalency is closest to about 352x480 in the DVD spec, from tv sources.

That's not relevant. It's way below the "ideal" size.

NTSC bandwidth is 4.2 MHz ~ 440 pixels and PAL bandwidth is 5 MHz ~ 520 pixels. Capping 352 pixels is far too low (it's even crap for bt8x8).

[ronnylov]

Given the average bitrate of 2375 kbit/s I would say it is better to not use any higher resolution than 352x480. The bitrate is like a normal SVCD but the lower resolution of 352x480 and variable bitrate on DVD would make the quality OK. The next higher DVD compatible resolution of 704x480 is too high with this bitrate.

Regarding "resolution" of live analogue broadcasts I agree with Wilbert that 352 pixels width may be too low to get all details but in this case the bitrate is too low anyway for anything above half D1 resolution.

Regarding the stretching algoritm of DVD players it depends on the player. Some are better and some are worse. My new Pioneer is much better than my old cheap Nintaus player.

[Wilbert]

Sorry, I missed the proposed average bitrate. In that case I agree, although personally I would resize to 352x480 during postprocessing (for doing noise removal).

[PatrickBateman]

I'm going to do some test runs on the bitrate.

I'm planning on resizing last. Does mainconcept use a good resizing algorithm, or should I frameserve from virtualdub?