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Pixelation, 2-pass rendering in Vegas VS DVD author program
Hi Guys!
I ran into a snag rendering a DVD. I rendered my final project (made up of predominately mpeg-2 clips on the timeline) using the DVD ARchitect template and the Main Concept 2 mpeg-2. After the movie rendered everything seems okay except my opening credits sequence. It look very “blocky” or pixelated (sometimes showing video that is elsewhere on the timeline inside the “blocks.” Now I have done render tests on this project and this is the first time I’ve gotten the pixelation on the opening credits. The only thing I did different this time was changed the template as described above whereas before that it was just the regular NTSC DVD template (which also changed it to 2-pass encoding. Now my opening credits are very similar to the open credits to 1978’s Superman: The Movie (the animated flash letters) with video in the background. It seems since I changed my SOny Vegas render settings to 2-pass encoding that this problem started. So my question is, is my suspicion correct? That it must be the 2-pass encoding creating this since it doesn’t happen with the standrd 1-pass rendering using the standard NTSC DVD template as opposed to DVD Architect?
Of course this leads me to another question. If I render in Vegas using 2-pass…should I again use 2-pass when encoding that mpoeg2 to DVD in a separate DVD authoring program or leave that as 1-pass since Vegas itself already rendered that file in 2-pass.
Thanks guys, I’m just at a loss here as to what’s going on. I want the best quality obviously so I figured 2-pass rendring in Vegas was best, but obviously not at the cost of ruining my animated open credits.
Any hel would be appreciate guys! Thanks so much! -
19 Replies
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Hey Guys! Just a quick update here before someone wastes time answering me. I spent yesterday doing trial and error and is does indeed seem like the only time the open credits animation gets severely “blocky” is when I use 2-pass. This kind of stinks because my movie is 2.5 hours long and I am trying to squeeze it onto a standard blank Verbatim DVD-R. Now most of my 1-pass renders look pretty decent on TV, the only thing I see occasionally are vertical lines every now and again (in text and slightly in some scenes…but I am looking real close to find them so I don’t know that anyone else would notice.
What I am doing is rendering from Vegas using the following:
Rendering using Main Concept MPEG2
Using template DVD NTSC Video Stream
Bit rate settings are as follows:
High 9,500,000
Avg 6,000,000
Low 192,000I’m not sure which template to use as I don’t know the difference between template DVD NTSC and DVD NTSC Video Stream.
As I said, my renders to DVD look fairly nice on TV, I am just trying to see if it’s possible to clean it up a bit more because even though the picture looks pretty good on TV (smooth camera pans, smooth movement like a “soap opera” looks and like the raw footage looks)I do still see some lines and grain every now and again in the picture. Keep in mind this is not an HD project, just an old-fashioned SD film. Perhaps I am trying to fix something that can’t be improved upon. I haven’t been able to see what 2-pass would like because as I said above, every time I render this project using 2-pass, the opening credits animation gets all jumbled up. So I am very, very, curious what it would like with 2-pass but I can’t get around the darn open credits not getting jumbled. Do you guys think 2-pass is even worth working on at this point? I mean will it make THAT much of a difference in terms of what I’m trying to fix?
Also, I actually author the DVD with TMPGENC Authoring Works (TAW) and I would like to know if I need to set that to 2-pass too even if the master mpeg2 file was rendered in Vegas using 2-pass (if I am even able to get that far with the open credits problem.) That’s something that confuses me, how to set up the authoring program considering that 2-pass will have already been done in the Vegas rendering.
Thanks guys! -
Your bitrate is far too high for a 2.5 hr. video.
I used Mark’s Bitrate Calculator and got the following numbers:Low: 2,104,000
Avg: 3,512,000
High: 6,152,000This assumes AC-3 for your audio at the default of 192.
For this long of a program a 2-pass render is, IMO, a necessity.
Use the DVD Architect NTSC video stream template (24P and widescreen are options as well) and customize it.
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Thanks so much for the reply Mike! I did try rendering it with lower setting as you described, in fact the setting were close to yours listed I beleive. However it looked terrible on TV. I have rendered at this bitrate into mpeg2 and then imported that mpeg2 into TMPGENC Authoring Works and make the DVD. As far as 2-pass goes, do i do the 2-pass rendering from Vegas or from within the DVD authoring program which also allows for bitrate adjustments, 1 or 2 pass encoding, etc. In fact I always have to change my audio to Dolby Digital before the program will render the Vegas mpeg2 (which suggests to me that TMPGENC is making sure the content is proper for a standard DVD before it will even attempt to render it. I’m just not sure which render should be set to 2-pass…Vegas or TMPGENC. Also, as I mentioned earlier, whenever I render 2-pass, the opening credits get severely jumbled and pixelated.
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“the opening credits get severely jumbled and pixelated”
Only the credits?? I would like to see a screenshot.
Steve Mann
MannMade Digital Video
http://www.mmdv.com -
Sure Stephen, here’s a screencap. It’s supposed to be video in the backgrounds and the animated credits on top of that. However whenever I 2-pass encode this project with Vegas this happens. It doesn’t happen on 1-pass.
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Have you tried the lower bitrate as suggested? If your target bitrate is too high, the second pass will recompress the sections that need additional compression.
Have you tried without GPU support?
What bitrate was your CBR set to?
Steve Mann
MannMade Digital Video
http://www.mmdv.com -
Hi Stephen,
I am trying the lower bitrate settings now. The only reason I haven’t set them that low is because I am assuming that will make the final DVD’s quality much poorer than it is now. Even though I have higher bitrate settings, the picture on the DVD looks pretty good and the 2 1/2 hours fits on the DVD. I even tested the DVD in different players because I understand if the bitrate is too high, some players struggle to play the DVD. The DVD workes fine in different players. As it is now, I have a final DVD I am relatively happy with. I do still see one scene that appears nice and clear and then another that gets a tiny bit grainy which is strange as they are scenes shot with the same camera and in the same format. There also isn’t especially more motion in one or the other. It just seems like the film shifts from clear to a tiny a bit grainy at random times.
Again this is 1-pass encoding though. Perhaps the 2-pass will improve it further. I’m starting to think I am being too perfectionistic. After all I am taking 4:3 SD footage and playing it on a widescreen TV. However even when I set the TV display to 4:3 I still see the slight graininess every now and again.
So so you think if I lower the bitrate to those suggested above and do 2-pass I may fix these minor issues or am I just being picky? -
Yes, too picky. SD is SD and it sounds like you are doing the best possible. I always use one-pass with SD because two-pass really doesn’t add anything.
You have to remember that the encoder is considering changes it sees in EVERY PIXEL of the video frames. What appears to be little movement to you can be substantial to the encoder. For example, a wedding video on YouTube looked horrible and the videographer couldn’t figure out why when it looks great on the DVD. He had not considered that the wedding was outdoors in a gentle breeze. The encoder was expending a lot of bandwidth on the leaves on the trees behind the couple, leaving little for the couple themselves.
Steve Mann
MannMade Digital Video
http://www.mmdv.com -
I think you’re right Stephen. Also, the DVD authoring program is taking Vegas MPEG-2 and compressing it further to fit on a standard DVD…considering all that…it still looks pretty good. It’s just hard to see the beautiful raw footage and then see it compressed but alas, that’s all you can expect after editing it and compressing it twice. It was rendered once from Vegas to MPEG-2 and then imported to TAW where it is compressed further automatically by the DVD authoring program. I’ve adjusted to the lower bit rate settings in TAW for a render try I am doing now just to see if lowering the bitrate cuts down a bit on the already Vegas compressed compression in TAW. If this one looks worse…or the same…I think I need to stop being such a perfectionist. It really doesn’t look that bad on my big screen considering it’s SD on a widescreen TV on top of it all. Thinking of it that way, I’m actually surprised it looks as good as it does.
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“Also, the DVD authoring program is taking Vegas MPEG-2 and compressing it further to fit on a standard DVD”
This wouldn’t happen if you made DVD compliant video in Vegas. Are you using DVDA? Any recompression is bad, but letting the DVD authoring program do it is introducing an unknown codec and parameters into the process as well as an unnecessary encode.
Steve Mann
MannMade Digital Video
http://www.mmdv.com
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