Hit & Miss On Render Quality

BobWard wrote on 5/7/2011, 7:27 PM
I am using VMS 10. I am rendering avi files to DVD AS 5.0. Total movie length is 26 minutes.

Rendering settings are as follows:


Rendered at 720 x 480 as:

mpeg-2 / AC-3 (separate renders to each format)

Variable bit rate - 2 Pass
Max: 9,800,000 bps
Avg: 6,000.000 bps
Min: 192,000 bps

When the rendered project is opened in DVD AS 5.0, I sometimes get a pretty clean (but not 100%) render and other times I get several portions of scenes that are momemtarily pixelated, blurry, and shimmery looking. After a few seconds, the image problem clears up and I have a good picture again.

This is very hit and miss - sometimes it happens, other times it does not. When it does happen, it does not always occur at the same scene.

Some of the occurrences seem to happen where I have inserted key frames to do a zoom-in, i.e., I see some blurriness as the image is zooming-in. However, other occurrences are where there are no key frames present. None of these problems occur on the VMS timeline - they only happen in the rendered file when viewed in DVDAS 5.0.

This is starting to become very annoying, since once it happens, I have to go back into VMS10 and re-render the entire project which takes about 1.5-hours.

I have rendered the project 6 times now and have yet to get one complete render without the described problem occurring somewhere.

I am running WIN7, 64-bit, Intel i5 quad core, 4 megs RAM, NVIDIA 560Ti.

Any ideas on what could be done to get a 100% clean render?

Comments

Steve Grisetti wrote on 5/7/2011, 7:49 PM
What is your original video source?

These would be great settings if your video was captured from a miniDV camcorder connected to your computer via FireWire.

If you are rezzing down from a hi-def source (say, using AVCHD footage in a 720x480 project) that could account for some of your quality issues.
BobWard wrote on 5/7/2011, 8:12 PM
Steve,

The original video source was a series of flight simulation sequences captured on my computer by FRAPS. In between the FRAPS avi clips, I have some digitized 16mm gun camera film (avi format). Do not have any problems with the digitized 16 mm files. About 98% of the FRAPS files render fine, its just that other 2% that randomly act up somewhere during the movie.

I also just read in the Help menu that "Allow Field Based Motion Compensation" should be turned OFF in the "Custom, Advanced Video" rendering settings if you are preparing an MPEG file for NTSC. This was on by Default, so I turned it off. Have not re-rendered yet though with this new setting.
musicvid10 wrote on 5/7/2011, 8:40 PM
Set your minimum bitrate at 2,000,000 and try again.
BobWard wrote on 5/7/2011, 8:45 PM
Thanks musicvid, I will give that a shot right now. I'll report back tomorrow after I re-render the project.
BobWard wrote on 5/8/2011, 7:45 AM
Set the mimimum render bit rate to 2,000,000 bps and turned OFF the "Allow Field Based Motion Compensation" under the Custom render settings in Advanced Video.

Still get some minor "jaggies" while the key frame scenes are zooming in - but that is tolerable and probably unavoidable.

Everything was going pretty good until towards the end when one scene (no key frames) experienced a significant muddy-looking, blocky, pixelated mess for about 4 seconds before the picture cleared up - the problem on this particular scene was worse than what I had seen on any previous renders.

It is very odd how this render problem seems to be somewhat random in where it strikes.

I will be happy to try any other suggestions. Thanks
Steve Grisetti wrote on 5/8/2011, 12:13 PM
It still might help us to know what kind of camcorder your original video is coming from?

Remember, matching your project's settings to your source video is the key to getting the highest quality in your work.
Chienworks wrote on 5/8/2011, 4:10 PM
I'd also lower the max to 8,500,000 at most. Any more than that and you risk having some DVD players not be able to keep up with the data stream and skipping.
BobWard wrote on 5/8/2011, 6:17 PM
Just started a new render with:

max bit rate = 8,500,000
avg bit rate = 5,250,000
min bit rate = 2,000,000

I also turned back ON the "Allow Field Based Motion Compensation" under the Advanced Video tab in Custom Render settings. Not been able to find much info on this setting on the Internet. It is odd that Sony has it turned ON by default and then recommnends in the Help file that the box be "cleared" (I assume that means to turn it OFF) for MPEG renders to NTSC DVDs.

Steve, there was no camcorder involved. As I mentioned above, the avi files on the timeline were produced from digitized 16mm film and from FRAPs captures directly from my computer.

I will report back in a couple hours and let you know how this render works out.

Thanks for the suggestions.
BobWard wrote on 5/8/2011, 9:30 PM
No improvement with the above render settings. In fact, it may have been worse this time.

Since it only happens to the FRAPs avi files that are on the timeline, it may be due to some issue with FRAPs. The FRAPs avi files load instantaneously on the VMS10 timeline and they play flawlessly on the VMS10 timeline. The problems only arise during the render process, and even then, only very infrequently, and randomly.

Guess I will just have to keep rolling the dice until I get a render to come out with no pixelated and muddy images during some of the FRAPs frames.

BTW, is there any way to improve/remove the "jaggies" during the key frame zoom sequences? The jaggies only occur during the zooms as the interpolated frames are being generated.

If you have any additional ideas, please fell free to respond.

Thanks.
Chienworks wrote on 5/9/2011, 1:58 AM
What is the resolution of the FRAPs files? What's the resolution of the output file? If there's a lot of resizing going on this can cause odd results.

I assume the interpolated frames you refer to result from the .avi file having the slower frame rate of the film. Zooming wouldn't cause interpolated frames.
BobWard wrote on 5/9/2011, 9:03 AM
Chienworks - The FRAPs clips were originally recorded from my computer using a screen resolution of 1600x1200 at 29.97 fps.

This resolution was not an option on the VMS timeline - the closest matching resolution was 1600x1080 at 29,97 fps, so that is the resolution that the entire project is set at. Of course the rendered output file is a 720x480 mpeg2 for import to DVDAS 5.0..

Under Project Properties, the "Adjust Source Media To Better Match Project Or Render Settings" box is also checked. and the "Full Resolution Rendering Quality" is set at "BEST".

Regarding the interpolated frames comment, I had just assumed that some interpolation was being done during the key frame zoom sequences - however, that would just be ignorance on my part, since I do not know exactly what the program is doing to create the "zoomed" image. But whatever is gong on, the airplane images always get a slightly "jaggy-looking" outline during the zoom-ins. If there is someway to remove the "zoom" jaggies, I would be grateful to hear the solution.

Don't know if this is enough info to provide any clues to the randomly pixelated & muddy looking rendered images or not.
BobWard wrote on 5/10/2011, 9:59 AM
Well, I think I may have found the reason for the short-duration muddy, shimmerring, and pixelated scenes. Or, I may have just gotten lucky on my latest render.

I went back and reviewed all the FRAPs clips on my VMS timeline and found that several of them had duplicate video FX settings. For example, a given event on the timeline had 2 FX "Levels" effects boxes attached to the event, and, each "Levels" box had different settings. Found similar instances with duplicate Saturation, Color Corrector, etc. boxes on the same event.

These duplicate FX boxes were created when I copied Event properties from one event to another, thinking that the copy process would replace any video FX settings that I had previously applied to the event that was being copied to. Obviously, the copy process did not replace the previous settings - it just added to the FX settings that I had already asssigned to that event.

So I am guessing that the original video smearing issue that I compalined about was due to the fact the problem events had competing FX settings (e.g., 2 different "Levels" settings) that were fighting each other for a few seconds at the beginning of each clip. Once the fight was over, the clip settled down and displayed normally. The only aspect of this theory that I do not understand is why the clips played normally on the VMS timeline and only exhibited the muddy, smearing problem in the rendered file.

Anyway, once I deleted all the duplicate FX boxes, the movie rendered normally with no more muddy and shimmering images at the beginning of clips.

The only remaing issue I have is the "jaggies" that still occur during zoom sequences that use key frames. Some of the clips had 3 key frames to do incremental zooms. I eliminated the 3rd key frame so that no clip has more than 2 key frames now. This helped to reduce the duration of the jaggies.

Unless someone has any other ideas, I think the "jaggies" are unavoidable during key frame zoom sequences.