[Marc Istook]

Thanks Ralph.

I think another responder thought I was talking about using still images as part of a video project — I was referring to picture compilations on a DVD. I would imagine that a resolution over 720 X 480 wouldn’t help you at all because that’s as high as the DVD would be able to display on a normal NTSC television. Do you use square pixels or .9?

Thanks again!

Marc

[Marc Istook]

I’ve done this before — MANY times — and never had a problem. You have a few options — either merge the layers you want as your lower 3rd, with the transparency (to whatever degree) in place, or you can import the photoshop file into AE as a composition and overlay that as a pre-composed graphic. I have not had the bad experiences that Myleneum has had with AE interacting with .psd layers.

[Marc Istook]

This all makes perfect sense. But it raises a new question… and I’m just kinda thinking out loud here…..

When I encode a 24p DVD Architect mpeg stream (with default settings), a post-render analysis shows the bitrate to be in the 7.4 range…. When I encode the same video as a 30i DVDA stream, the same analysis shows the video to be in the 5.9 range, roughly. This causes the 24p file to end up *slightly* larger than the 30i file. Of course, I’d assume the quality is vastly higher with the 24p file, based on the principles we’ve discussed. So I wonder if Vegas, as a default, knowingly encodes 24p at such a high bitrate to take advantage of the opportunity for a higher quality final product?

[Marc Istook]

Do you mind explaining a bit more?

Why would 24p video at the same bitrate as 30i video be of higher quality than the 30i video? Is it because of the 30i video has 25% more info than the 24p video, and therefore would require a bitrate 25% higher to achieve equal quality?

What my experience showed me was that a 24p piece of video encoded with a CBR of 6,000,000 was in fact *larger* in size than a 30i piece of the same video, same length, encoded with the same CBR. Later tests showed me that the rendered file, in fact, had a larger average bitrate than the encoder was set to — which makes me wonder how Vegas determines bitrates if they end up, in actuality, being different than the CBR…

This whole thing started after I completed a 24p project and rendered it as a DVD Architect mpeg, using default settings. For grins, I decided to render the project as a 30i DVD Architect mpeg (again, default settings) to see what size it would end up being. I expected it to be significantly larger in than the 24p mpeg because Sony’s help files say that “24p video uses less space on a DVD, allowing you to add more video or use higher-quality video than you could with 30i video”. I read this to mean that, all things being equal (default settings/bitrates vs. default settings/bitrates — the only standard for quality I could think of), a 24p video would be smaller than 30i.

But what I’m understanding from you now is that a 6,000,000 CBR 24p video is in fact of *higher* quality than 30i, because it contains 20% less data than a 30i file and therefore is using the same bitrate for *less* data, resulting in higher quality. Am I following you correctly?!

Thanks for your time……. This has been an education in bitrates, to say the least.. 😉

[Marc Istook]

I’m sorry you had to hear me *many times*… The reason I had to repeat myself *many times* was that despite the many posts, I didn’t receive an answer that reconciled my personal rendering experience with what Sony wrote. If it was simply an error in Sony’s help files, that was fine. Or if it was something I was doing wrong in my renders, that’s fine too. I was getting more than one answer from more than one source, which only complicated things and muddied the issue. I’m not a dense guy — but in this situation, 2 and 2 hasn’t seemed to add up to 4.

By the way — did anything come out of your test renders?

Best wishes…

Marc

[Marc Istook]

Fair enough…

But Sony writes: 24p video uses less space on a DVD… That’s pretty straightforward, right?? It doesn’t say “24p video uses less space on a DVD — if you use a lower bitrate”. If it said that, then this whole mess could’ve been cleared up in the first place!!

[Marc Istook]

Thanks Liam.

When you choose constant bitrate, it greys out the min, max and average settings. So unless the rendered factors in those numbers *before* they’re greyed out, I wouldn’t suspect they’d make a difference. Would be worth noting if they did.

I definitely respect your experience and the experience from all the other users on here. And if the end result is simply that a 24p file of similar bitrate and quality is no different in size than a 29.97 file, I’m fine with that. My goal has simply been to reconcile my experience with Sony’s own help files, which seem to clearly state the opposite. Perhaps if Sony’s help was more helpful, this all could have been cleared up in the first place. 😉

[Marc Istook]

Ok, that sounds fine. I’m just trying to reconcile that with what Sony has posted in their help files –which implies that video of similar quality (and similar bitrates), when in 24p form, takes up less space than the same video in 29.97 form.

[Marc Istook]

The way Sony’s post reads (24p video uses less space on a DVD, allowing you to add more video or use higher-quality video than you could with 30i video) makes it seem as though, all things being identical, 24p files would be smaller. It implies that you’d have to render 24p video at a higher bitrate or make it longer in duration to have it be equal in size to a 30i piece of video.

I ran two test renders, 11 seconds long, of some footage. Both were output as DVD Architect streams — one at 29.97, the other at 24p. Bitrate was set to a constant 6,000,000 bps for both. The resulting 29.97 interlaced mpeg file was 8.44 MB in size. The 24p file was 8.45 MB in size, larger than the 29.97 file, despite being the exact same video, rendered with the exact same bitrate as the 29.97 file.

So, if it is all about the bitrate, and 24p video should, at least, have 20% less information than 29.97 video (23.976 full frames versus 29.97 full frames), then why am I getting a larger file from the 24p video rendered with the exact same bitrate as the 29.97 video?

I’m not trying to be difficult here — this just doesn’t seem to add up.

[Marc Istook]

VERY helpful. Thanks for showing that program to me!

What I found was that Vegas, when encoding the same project, using the default settings, uses a higher bitrage for encoding 24p than it does when encoding 30i. The 30i file’s bitrate was even below the range Vegas uses in the default setting, which I found odd, but acceptable.