Rendering quality.

[Ben Longden]

This is a question for the tech heads in the community.

I did an experiment last night. I rendered a project to a .avi file in Vegas 9, then placed that .avi file in DVDA 5 to burn to disc.

The project was set at 8mbps, in DVDA's properties.

Once the disc was burnt, I went back to the original timeline and used Vegas 9 to render it to MPEG2, again at 8mbps. Then used DVDA to burn that MPEG file to disc.

Checking both discs on a 42 inch plasma, the vision quality of the first disc was visibly superior to that of the second.

Any ideas why?

I was always under the impression that the Vegas MPEG engine was superior to that of the one in DVD Architect. Having seen the difference with identical vision on the same screen, I am swayed to change my workflow and let DVDA do the MPEG conversion.

Thoughts?
Arguments for and against?

Ben

[Chris Harding]

Hi Ben

Many moons ago I discovered that doing MPEG2 and then allowing DVDA to re-render gave me inferior DVD's. I may be wrong but it might be something to do with the GOP they use. Typically DVD video has a GOP only every couple of frames and even Vegas itself does a lousy job of re-rendering MPEG2 video unless it has a GOP of 1

I swapped over to using DVD Lab and the results were way better!!! Now I render in Vegas and author in DVD Lab.

Instead of getting technical why not try another DVD authoring package and compare the DVDA DVD and a DVD made from another package?? That way you can isolate whether the problem lies in DVDA's rendering of an MPEG2 file. Otherwise you just might have to render out AVI from Vegas.

Chris

[Ben Longden]

Thanks Chris...
I might do just that, but the vision off the DVDA encoded disc is almost as good as watching the vision out of the composite port on the camera..

It makes me want to further explore possibilities... What was astonishing was there was naff all motion artifacts on the DVDA version. certainly it took an hour and half for DVDA to burn a 26 min project (I only have an old 3.4Ghz chip), but the result is stunning..

Ben

[Perrone Ford]

Can you post a screen shot of your Mpeg2 settings that you used to make the second disk? This is quite curious and might cause me to change my workflow as well. Would save me a step in my DVD workflow.

[Brian Luce]

Okay I'm lost. I'd always heard you're supposed to render the video to mp2 and the audio to ac3 and import both clips to dvda. But you're feeding dvda a avi file and the results are superior? What kind of file is your camera recording natively and are you editing in that native format then rendering to avi?

[Seth Bloombaum]

People go wild for what someone else tells them about quality. Kudos to Ben for putting "what everybody knows" to the test.

The shocking truth is that the rendering engine in DVDA and Vegas are the same.

What is different is that DVDA will automatically choose settings that it thinks is best. With Vegas, you get to choose settings.

Something as simple as DVDA using Variable Bitrate encoding (VBR) but you choosing Constant Bitrate (CBR) in Vegas could account for the differences in picture quality, even at the same overall bitrate.

DVDA's defaults are OK, especially for up to 60 minutes of content.

THE WORST quality may be acheived by making a mistake in the Vegas MPEG2 encode sufficiently large that DVDA says "I can't put this on a standards-compliant DVD, must re-encode it to MPEG2". You'll know this has happened, because it will look horrible, it will take extra time to build the disk while the video is re-encoded, and DVDA will tell you it's going to re-encode if you read the messages closely.

[Brian Luce]

Okay so need to render separate mp2 and ac3 files, just render to avi and import to DVDA and make DVD?

[Tomasz Kalinowski]

Hi,

I tried many things to make a better quality. You can dump .avi or m2t file and DVDA will handle it, but it will take longer to re-render (if Im not mistaken DVDA is a single core app).

I took a different route. I use the best setting (in vegas) while rendering to DVDA (mp2 and aac). In DVDA i burn to .iso file. The Iso file size is about 6GB. Then I use DVD Shrink program which is free DVD Shrink v3.2.0.15 (freeware)
and hack my own DVD by compressing (automatic setting approx 10 to 15% compression) DVD. The compressing process takes approx 2 to 5 minutes and builds an another iso file (4.7gb) which i can burn to dvd disk.
This method will eliminate guesswork on final size of the file and it looks better (in my opinion)

[Don Bloom]

while I agree that DVDA may have a decent render quality when doing small projects, I prefer to do all rendering (mpg and ac3) in Vegas by setting the right bitrate for the size of the project. All are VRB and some are 2 pass depending on the job. I test run all my DVDs on at least a 42" screen and have never had a problem with quality. I've had them run on big screens (10' wide) and they look fine.
I have also put as much as 3 hours on a DVD and while I really had to crush it, it looked pretty good on the 42 to 52" screens.

I never go above 8,000,000 as a top BR and my lowest BR is set to 2,000,000. Its the average BR that gets changed unless I'm doing CBR.
I'ts been working for me since DVDA 1/Vegas 3

[Jim Snow]

When you are trying squeeze the maximum content onto a DVD, it really helps the encoder to have low noise video. Noise really increases the burden on an encoder. It has to use a great deal of the available bitrate to encode the noise which is high frequency and changes frame to frame. This leaves less available bitrate for the actual video content. It's worth it to use a product like Neat Video to remove the noise first. The resulting encoded video quality difference is surprisingly better when you have "bit rate starvation" on a 1+ hour DVD. The only problem is that Neat Video is processor intensive which results in a slow render.

[Eugene Kosarovich]

Another option to consider is using TMPGEnc via the Frameserver from Vegas. I've always been very happy with my results. It also includes a noise filter, if you need it, that can take advantage of CUDA processing on a modern nVidia graphics card for speed improvements in the heavy processing noise filtering.

Both the older TMPGEnc Plus 2.5 and the latest TMPGEnc 4.0 XPress work great with the debugmode frameserver out of Vegas Pro 8 or 9.

[Ben Longden]

Mmmm.. I wasnt aware the MPEG engine was the same in Vegas and DVDA..

But to help things;

Perrone, The vision is shot on a Sony DSR-570, http://img.photobucket.com/albums/v3...60/DSR-570.jpg
and ingest into the system is via a Sony DSR-11 VTR linked using firewire.
Ingest is done using Sony Video Capture 6e, which is a part of Vegas 9.

In the media manager, the files are listed as an .avi file, with the following attibutes
http://img.photobucket.com/albums/v3...eattribute.jpg
and are cut on the timeline as such. Rendering is done using the following:

Rendering to MPEG2 in Vegas is done using the following preset;
http://img.photobucket.com/albums/v3...PEGsetting.jpg
Which as you can see is a two pass render, VBR max of 8Mbps.

Rendering to .AVI in Vegas is done with the following preset;
http://img.photobucket.com/albums/v3...AVIsetting.jpg

Rendering to MPEG in DVDA is with the following;
http://img.photobucket.com/albums/v3...iscsetting.jpg
What is not specified is if this 8Mbps is a constant or variable bit rate.

Looking at the vision, on the same screen and same player is the areas where motion artifact is noted on the Vegas render is not apparent on the DVDA render.

No filtration, such as sharpening, NEAT or correction was carried out on the project. It was 'untouched by human hand'.


Brian; Screenshots are above as requested.
Yes. I just took the .avi and placed it directly into DVDA and went from there.

Don; I have noted a two pass VBR render gives better viaual quality than a CBR. Also I have noted that Vegas will do a 9.8Mbps render, the max readable with most players is 8.0Mbps, and so I have stuck with that as a maximum in VBR and CBR renders.

Seth; Ive never encountered a video recompression issue when placing an MPEG2 file into DVDA. I also never knew the two programs used the same MPEG engine. How can you tell in DVDA what 'fine tuning' its doing?

Ben

[Perrone Ford]

Originally Posted by Ben Longden

Looking at the vision, on the same screen and same player is the areas where motion artifact is noted on the Vegas render is not apparent on the DVDA render.

The Bitrate is higher in the DVDA version. I am certain that would make a difference.

[Jeff Kellam]

Originally Posted by Ben Longden

This is a question for the tech heads in the community.

I did an experiment last night. I rendered a project to a .avi file in Vegas 9, then placed that .avi file in DVDA 5 to burn to disc.

The project was set at 8mbps, in DVDA's properties.

Once the disc was burnt, I went back to the original timeline and used Vegas 9 to render it to MPEG2, again at 8mbps. Then used DVDA to burn that MPEG file to disc.

Checking both discs on a 42 inch plasma, the vision quality of the first disc was visibly superior to that of the second.

Any ideas why?

I was always under the impression that the Vegas MPEG engine was superior to that of the one in DVD Architect. Having seen the difference with identical vision on the same screen, I am swayed to change my workflow and let DVDA do the MPEG conversion.

Thoughts?
Arguments for and against?

Ben

Ben:

There is not enough information provided about your source material and Vegas settings to provide you any reccomendations.

There is no doubt that Vegas Professional will provide better or at least equal results to DVDA since they have the same basic rendering engine but the Vegas Pro version has far more tuning available.

[Seth Bloombaum]

Originally Posted by Ben Longden

...Ive never encountered a video recompression issue when placing an MPEG2 file into DVDA. I also never knew the two programs used the same MPEG engine. How can you tell in DVDA what 'fine tuning' its doing?

No recompression = good!

DVDA really doesn't tell you anything about the tuning it's doing, except the alerts it displays when you finally build the DVD.

Regarding the settings you've posted - what's the total length of all video segments you're putting on a DVD?

Regarding the Vegas MPEG2 render settings -
* Did you start with "Mainconcept MPEG2 | DVD Architect PAL Widescreen Video Stream" template, (which you then modified)?
* Your minimum and average bitrates are quite high. Usually, for content under an hour, I'd set 4Mb - min, 6Mb - avg, 8Mb - max. But it isn't clear to me that lower min and avg bitrates would make more bits available for bursting to cover short scenes that need it. Maybe so.

What kind of content are you working with - is it high-motion subjects (sports)? Static subjects? Shot handheld? Shot on a tripod? Well lit? Underlit? Is there video noise from camera gain?

In your first post, you referred to "vision quality" differences. Can you be any more specific about what you're seeing? Common playback errors include pixellation aka. macroblocking, banding, frame drops aka. freezes, mosquito noise (noise outside an object), video noise (in darker areas).