Question about online distribution

[jediphoenix]

From what I've read, 640x480 and 23.976fps is what the AR and framerate should be at for putting the video online, but I've seen multiple people have their videos at 720x480 and 29.97fps, as well as at other AR and framerates. I'm just curious if it's necessary to keep the PAR at 1.00 and at 23.976fps for viewing on a computer screen.

[Mister Hatt]

Framerate and AR should be what is necessary for your source and NOTHING else. You can set the PAR or DAR to whatever you want as long as your actual displayed pixels are correct. The general use though is "if you resize, calculate the DAR and use that in the container; if you only crop or don't do either, use the PAR in the bitstream." That should clear it up. As for framerate, 24-1% is most common but some anime is 30-1% or significantly stranger combinations, but that isn't common.

[jediphoenix]

Most of my sources are at 720x480, so I was just planning on editing at that with the PAR at .9. So technically as long as I edit in that PAR and DAR in my software program, I can then export with those same settings and they'll be fine when viewed on the PC? I just find confusion given how the guide says that on a PC monitor, NTSC dvds need resizing to 640x480 to be 4:3.

[jediphoenix]

And also why those videos I've seen online are with the .9 PAR as well when it's said that it should be square pixels for online distribution?

[BasharOfTheAges]

Square pixels are what monitors have. Most people are going to watch what they download on a monitor... hence people use square pixels.

HD TVs use square pixels as well - its projectors and SD TVs that those guides were referencing (and how the DVDs were stamped).

It really doesn't matter how you edit the video; as long as your exported version for online distro ends up being 640x480 it's correct.

EDIT - I suppose that last statement isn't entirely correct. You could do a lot of things within your editing suite to really fuck up the AR by adding boarders or stretching the video or whatnot.

[Mister Hatt]

Those guides are kinda old. Normally I would say use the correct PAR as calculated and not some arbitrary number, but I think this might be a bit too complicated for you unless you know your way around your NLE quite well. Don't crop or resize, leave it all alone, and then once you export, then you can do so and set a container aspect flag. Most likely easier to do it that way.

[jediphoenix]

I'm fine with editing in Premiere Pro and making my settings match what my source is - I'm just confused as to why, if monitors are square pixels, people still put their videos up online with a different PAR.
Also, if HDTVs and monitors have square pixels, why do DVDs have .9 PAR if they're going to be viewed on those tvs/monitors?

[Cannonaire]

DVDs were made to conform to the NTSC spec. Older TVs do not have square pixels, they have rectangular pixels (well, it's a bit more complicated, but yeah). When shown on a standard definition TV, 720x480 DVDs have correct geometry.

One reason it's best to keep your video at the DVD resolution is to avoid quality/resolution loss. You do lose information when you resize to other resolutions, larger or smaller. You also have to take into account that most people will be viewing the video in full screen mode anyway, and not 640x480 windows. When the player resizes the video for viewing, it uses the correct ratio that was specified in the container, and since you didn't resize to begin with, it has more information to work with.

That said, I would personally crop an AMV before doing a final encode. Generally anime DVD sources could use about 8 pixels cropped off each side, and it's normally best to crop to a resolution evenly divisible by 16 (such as 704) for compression reasons, although this isn't entirely necessary with x264. Crop amount may vary depending on source as well.

Here's a handy calculator for figuring out what number to use when you specify the DAR:
http://ps-auxw.de/cgi-bin/ar-calc.pl

[BasharOfTheAges]

And as to you other question of why people put stuff up incorrectly, It's simply a case of them "doing it wrong." A lot of people fail at AR stuff. Hell, I know someone that's been editing for going on a decade and has made over 100 vids and they still can't get it right.

[jediphoenix]

So even if I have a video with .9 PAR, the video player will make the monitor think that it's square pixels? Thus, I don't necessarily need to have my video up for online distribution at 640x480 and 1.00 PAR, and can, say, keep it at 720x480 .9 PAR since the video player will compensate for that? Or am I way off base with that assumption?