Loss of video quality when rendering

gplongworth wrote on 1/6/2009, 10:07 PM

I have a project shot on mini DV tape, edited with Vegas Pro 8 and authored with DVD Architect Pro 5. I’m loosing video quality in the rendering process. Subject matter is go karts so there is lots of motion and the camera was only consumer grade but the uploaded avi clips look very good when played on Windows Media Player even on full screen. When pausing the player a frame with motion still shows a fairly crisp outline of subjects. After rendering to MPG-2 and playing on the same player there is a very noticeable blurry aspect in moving subjects and even on fixed objects during a slow pan. Pause the player and the frame looks as if two frames have been overlapped and are not aligned correctly. Of course this follow through to the DVD.

The project is intended for viewing on TV and I want it to fill a wide screen. The project is set for 16:9 and the original clips are all cropped and stretched to fill the screen. The quality was much worse when I first started so I check the help files for suggestions and tried many combinations for rendering and settings in the project properties and even the clip properties. I mostly played with de-interlacing, resampling, field order and alpha channel values. There are so many possible combinations I’m sure I didn’t try them all. I don’t even know what the default project properties are any more. I also checked for previous posts and found several but I’m not technical enough to understand all the great explanations and determine the combination that solves my problem.

Below I’ve listed all the specs and settings for everything I can think of. I added a few remarks and questions in brackets. Can anyone tell me if I have some obvious blunders or suggest different settings that might improve the video quality? Thanks for any help at all!

PC SPECS:
Windows Vista Home Premium 32 bit
Service Pack 1
Intel Core2 Quad CPU Q9550 @2.83GHz
4GB RAM

CAMERA
Sony DCR-TRV38
Mini DV digital tape

SONY VEGAS PRO 8.0
Version 8.0c Build 260

SONY PROJECT PROPERITES SETTINGS
Video Settings:
Width = 720
Height = 480
Field Order = Upper field first
Pixel aspect ratio = 1.2121 (NTSC DV Widescreen)
Output rotation = 0 (original)
Frame rate = 29.970 (NTSC)
Pixel format = 32-bit floating point
Compositing gamma = 1.000 (Linear)
Full-resolution rendering quality = Best
Motion blur type = Gaussian
Deinterlace method = Interpolate fields

SONY INDIVIDUAL VIDEO CLIPS PROPERTIES
Video Event settings:
Mute = off
Lock = off
Loop = on
Maintain aspect ratio = on
Reduce interlace flicker = on [default was off]
Smart resample = on

Media settings:
Use timecode in file
Stream = video 1
Format: DV
Frame rate = 29.970 (NTSC)
Field order = Upper field first [default was Lower field first]
Pixel aspect ratio = 0.9091 (NTSC)
Alpha channel = Premultiplied [default was none]

SONY RENDERING SETTINGS
Type = MainConcept MPEG-2
Template = DVD Architect NTSC Widescreen video stream
[Used default template settings but just noticed that on the Customize/Video tab the Field order is Lower field first – could this be an issue for not matching the rendered file?]

SONY DVD Architect Pro 5.0
Version 5.0a Build 173

DVDA PROJECT PROPERTIES
Disc Properties:
Disc format = DVD
Target media size = 4.70
Video defaults:
Video format = MPEG-2
Bit rate (Mbps) = 9.800
Aspect ratio = 16:9
Resolution = 720x480 (NTSC)
Frame rate = 29.97
Progressive = No

DVDA MEDIA AND MENU PAGE PROPERTIES
Reduce interlace flicker = on

OPTIMIZE DISC RESULTS
Max bit rate is 10.080 but the file bit rate is 10.212 [how does this happen?]
[Note: the Default video bit rate slider is turned up all the way to 9.800]
Video file recompression is required due to “Reduced interlace flick” being turned on.
Recompress Settings:
Video format = MPEG-2
Use default bit rate = yes
Bit rate = 9.800
Aspect ratio = 16:9
Resolution = 720x480(NTSC)
Frame rate = 29.97
Progressive = Auto [What does this mean?]

Comments

farss wrote on 1/6/2009, 10:36 PM

"SONY RENDERING SETTINGS

The vital clue is missing, what bit rate?

On top of that which camera?

Were you shooting with a NTSC 16:9 camera?

The blended frame you are seeing also suggests to me that something funky is going on with the frame rate or it could just be the result of seeing the two fields of the interlaced frame in the preview monitor. A screen grab would help as descriptions are always vague and missleading.

Bob.

Coursedesign wrote on 1/6/2009, 11:02 PM

Turn off the deinterlace immediately. Just a world of trouble for what I think you are trying to do. For DVDs, just let the DVD player handle outputting your interlaced footage as interlaced or progressive.

And what's with "Alpha channel = Premultiplied?"?? What are you doing that would need this?

And while you're at it, drop the "Smart resample" unless you have something going on you're not telling us about.

And drop the 32-bit float also, that could also be a source of troubles (it shouldn't be, but reality may be different).

Finally, reduce the bit rate to 9 Mbps tops, as not all DVD player can handle 10 Mbps.

You'll rerender in a jiffy with the above changes, and I suspect the quality will be much better too.

fldave wrote on 1/7/2009, 5:03 AM

Project setting of deinterlace-Interpolate should be fine. I've heard that None messes things up. Interpolate works best for fast motion footage.

Render settings: go to Custom tabs and make sure "Best" is set on the first tab.

Try some short clips of several variations to see which one is best to your eyes.

gplongworth wrote on 1/7/2009, 7:18 AM

Thanks for the quick responses. Again, I'm not too technical but I'll try to answer the questions in your replies.

farss:
The vital clue is missing, what bit rate?
When I use the OPTIMIZE DISC option in DVDA it tells me that the Max bit rate is 10.080 but my file bit rate (in red type) is 10.212. I have the bit rate slider all the way to the right which says it will render at 9.800. I could not figure out where to look in Vegas for bit rate info so I'm not sure what the default settings are or if I did anything to cause the 10.212 bit rate.
Can you tell me how to find the answer to this question?

On top of that which camera?
Sony DCR-TRV38 (not a pro quality camera)
3.8mm (1/4.7 type) CCD
Tape speed Approx. 18.81 mm/s

Were you shooting with a NTSC 16:9 camera?
NTSC color, EIA standards
4:3

As near as I can tell the frame rate was 29.97 all through the process.

Coursedesign
Turn off the deinterlace immediately
I will try this and do a test.

what's with "Alpha channel = Premultiplied?
This is just one of the settings I played around with. It didn't seem to make much difference what it was set to and I forgot what the default was. Premultiplied was just the last setting I tried.
What should it be set at? (what is the default?)

drop the "Smart resample"
Again this was just trial and error.
Should it be set to force resample or No resample?

As you suggest, I will reduce the bit rate in DVDA although it seems that the problem is inherent in the rendered mpg file before DVD authoring takes place. Is it possible that correct settings in the authoring stage will clean thigs back up?

fldave
I'll check for a setting of BEST in the rendering settings and try a test with the Interpolate option.

To all
I will try these variations tonight when I get home as well as any other suggestions posted between now and then. If I still have problems I'll try to post some video samples or screen shots.

Q.Can anyone suggest the correct setting for Field Order? Based on something I read in the help files I changed the settings in the project properties and the clip properties to Upper field first. I now notice that the template for rendering with "DVD Architect NTSC Widescreen video stream" has the default set to Lower field first. Should I change it?

Q.Is it a mistake to change any of the properties of a clip (event) after placing it in the timeline? I changed "Reduce interlace flicker" from off to on, "Field order" to Upper first and "Alpha channel" to Premultiplied as I was experimenting. Could this be causing problems?

Thanks again.

farss wrote on 1/7/2009, 12:11 PM

"Can you tell me how to find the answer to this question?"

Best way to prepare your video is to encode to mpeg-2 out of Vegas. You need to consider how much video a DVD will hold at the bitrate you select however for less than 60mins you can use 8Mb/sec CBR without having to consider that

You need to stop fiddling with things!

You're just making a NTSC 4:3 video and DVD. The default field orders etc in Vegas and your video should NOT be changed.

Keep in mind that shooting hand held close ups of fast motion is always going to look like shite and it gets worse after encoding to mpeg-2.

Bob.

plasmavideo wrote on 1/7/2009, 12:57 PM

"Media settings:
Use timecode in file
Stream = video 1
Format: DV
Frame rate = 29.970 (NTSC)
Field order = Upper field first [default was Lower field first]
Pixel aspect ratio = 0.9091 (NTSC)
Alpha channel = Premultiplied [default was none]"

Question? Why did you change this to Upper Field first? This might be the source of the problem. DV NTSC footage is lower field first. Use the media defaults for this. Also use the default field dominance in the MPG rendering template.

Good luck!

Tom

Coursedesign wrote on 1/7/2009, 1:13 PM

Tom is right.

Btw, why did you shoot in 4:3 on this 16:9 capable camera and then try to make it 16:9 in post?

Or did I not understand your process?

plasmavideo wrote on 1/7/2009, 2:14 PM

Oh, i didn't catch that. Maybe the stretch is contributing to the loss. Any resizing like that will soften the look unless you use the proper software. I've never tried doing a stretch like that in Vegas. I'll have to see what it looks like..

kairosmatt wrote on 1/7/2009, 2:27 PM

Also, it sounds like you are using DVDA to re-encode the file. You shouldn't have to optimize the project or reduce the bit rate inside DVDA. Just let it make a disc for you.

Also, whatever you do, don't go messing with field orders! That is a world of pain, I can tell you from experience. Just leave the media how it is at let Vegas render it out to the DVD template and it will take care of everything for you.

gplongworth wrote on 1/8/2009, 8:16 AM

Thanks again for the responses. You are all really helping me out. I've been using Vegas since long before Sony bought it from Sonic Foundry. I had been using it for editing home videos and personal projects (nothing professional) with no problems. A few months ago the hard drive and mother board on my PC died. I used this opportunity to upgrade to a much better editing machine and the newest version of DVDA but I was not able to recover all files from my old system. Somewhere in the process of reloading all my software into a Vista PC (I hate it), and trying to load in some old Vegas projects something got corrupted. While "Fiddling" with all the settings trying to improve the output I checked the box for "start all new projects with these settings". This is why I no longer know the default settings for Vegas and DVDA.

Tom - The reason I tried changing to Lower field first was because one of the help files said it's better for projects that will be played on a TV.

Bob - I shot in 4:3 because I didn't know th camera could do 16:9. When I first got it years ago everything I produced was played on a regular TV. I had already shot much of the footage before being asked to use it to make a 30 minute promo video for a kart racing club last Summer. The video will most likely be played on newer wide screen TVs now that everyone is buying them so I thought I would "Fake it" in hopes that it would look better in that format.

Last night I started a new project with one short clip and made the following changes in my Vegas settings:

Alpha channel = none
Field order = Lower first
Pixel format = 8-bit
Rendering quality = BEST
Since the original video was 4:3 I kept the whole project in that format.

I rendered the first test to .avi as a control test. Then I went back to rendering to MPG-2 and changed only one of the following settings in each test:

deinterlace: changed from interpolate to None
Smart resample: changed from on to disable ('on' was the default)
Reduce interlace flicker: changed from off to on

I then put all files into one DVDA project and rendered at a bit rate of 8.000. The .avi test file and all the other test files but one had quality that was equal to the original footage. Yeah!!!!! The test that still had the original "blurring" problem was the one with "Reduce interlace flicker" set on. This was also the only file that DVDA forced a recompress.

I discovered that the "bad" condition was evident even before the authoring. I looked at each clip in the time line in DVDA and by looking at the individual frames I could see the blurring, or doubling, effect that I tried to explain in my original post. Here are links to screen shots of those frames:
www.gar.00me.com/images/GoodKarts.jpeg
www.gar.00me.com/images/BadKarts.jpeg

For one last test I went back and made the change to a widescreen template and stretched the media file to fill the screen as I did in my original project. This had no ill effect. The quality was not visibly affected.

Lessons learned:
I will reload Vegas and DVDA to try to get back all defaults.
I will change my camera to shoot at 16:9

The only thing left is to learn more about the bit rate. I understand about how it affects the size of the file when authoring but if size isn't a problem then what is the best setting so that it will produce best results. I don't how or if I can/should try to do something with bit rate during filming, editing or rendering. I will search this forum for these answers.

Thanks again.

johnmeyer wrote on 1/8/2009, 8:58 AM

This thread sure has gotten complicated. The problem is obvious (you changed to upper field first and this is just plain wrong) and the solution is easy: change back to the defaults. Here are the defaults. Follow these exactly and you will get good video. Render the results using the MPEG-2 "DVD Architect PAL Widescreen video stream" template.

Coursedesign wrote on 1/8/2009, 9:04 AM

PAL?

Christian de Godzinsky wrote on 1/8/2009, 2:21 PM

I have always had the feeling that the Vegas Mpeg2 codec (for DVD burning) is not up to par. I never got fully satisfactory results using it, albeit the source material is pristine. I am not asking for more than is possible, but commercial DVD's looks better. Therefore I'm totally puzzled that a "Pro" application comes with a Mpeg2 converter that is just good, not excellent... This topic has been discussed so many times before... What is the truth about it??? Why DO people use other codecs? Tell me.

Christian

johnmeyer wrote on 1/8/2009, 3:04 PM

PAL?Oh darn. I had another window open when I did that work snapshotting the Vegas UI and was answering someone else's question regarding PAL.

I apologize.

Hopefully gplongworth can translate what is shown in the snapshots in my earlier post from PAL back to NTSC. Everything that I want him to set is the same for both, except for the framerate, resolution, and PAR. Framerate obviously is 29.97; resolution is 720x480 for NTSC; and widescreen PAR is 1.2121.

Here are some updated images. The first is the project setting:

These next two are what you get when you right-click on an event, or a video in the mediapool. You normally should not change ANY of these settings and, indeed, none of what is shown has been changed from the default.

And, here's what you should have in the Render As dialog when you click on MPEG-2, select the DVD Architect Widescreen template, and then click on the Custom button. You can change the Average bitrate to as high as 8,000,000 if your project is under 80 minutes, or lower if your project is longer (use a bitrate calculator).

I have always had the feeling that the Vegas Mpeg2 codec (for DVD burning) is not up to par. Yes, this has been discussed a lot. There was one long thread just a few months ago specifically about why "Hollywood" movies look better:

Why do Studio DVD releases look so good?

I highly recommend you read all the posts. The Short Version is that the Mainconcept MPEG-2 plugin is extremely good, and any loss of quality you are seeing is probably due to something else, unless you are doing really high-end work with 32-bit color, extensive use of dissolves, smoke, etc., and unless you look at your video extremely critically. Most of the big-time quality problems that I have seen reported here were from cockpit errors and not from lack of quality in the encoding. Again, I'm talking about MPEG-2 for DVD, not m2t, not AVCHD, and not any other format like WMV.

Coursedesign wrote on 1/8/2009, 3:31 PM

John,

I take my hat off to you, that was beautiful.

The Vegas/MC MPEG-2 encoder really is very good.

The #1 reason I see for ugly video on DVD is that NTSC DV format's already meager 4:1:1 color sampling gets cut in half during encoding to 4:2:0 MPEG-2, leaving only 12.5% of the original color information.

The #2 reason is crappy lighting, but with standard DV ("DV25") even the best lighting can only do so much anyway.

gplongworth wrote on 1/8/2009, 3:55 PM

Thanks for resending the screen shots and especially for the location of the bit rate information.
Gar

johnmeyer wrote on 1/8/2009, 5:16 PM

The #1 reason I see for ugly video on DVD is that NTSC DV format's already meager 4:1:1 color sampling gets cut in half during encoding to 4:2:0 MPEG-2, leaving only 12.5% of the original color information.I'll bet you're right. This may be yet another reason why shooting in HDV and then going direct to DVD from that (i.e., no DV or other intermediate which uses a lesser colorspace) produces such vastly superior results. Spot and others pointed some of this out three years ago, but my recollection is that they were concentrating mostly on sharpness (although colorspace was definitely mentioned).

I'll tell you this: the difference in color between shooting DV and shooting HDV, and then creating an SD DVD is not subtle: the HDV sourced material looks significantly richer in color (probably not the right term, but it is a little like saturation when speaking of old-fashioned color film).

P.S. to the original poster: Make darn sure that the quality slider in the Render As dialog is set to 31. No other setting should ever be used. Unfortunately, in many versions of Vegas (not sure about 8.x), the "default" template set this to 15. I think this was done so that idiot reviewers would report a really fast MPEG-2 rendering speed. However, the quality stinks. Unless you want to get a "draft" render in the fastest possible time, I would never, ever change this setting.