Pixelation in rendered version - but WHY?

Samuraiko wrote on 3/2/2012, 9:21 PM
Heya,

I'm using SVMS HD Plat 11.0 (v 295), and I am having an IRRITATING time trying to render my video. I have a bunch of footage shot at 1280x720 (29.97fps) from CITY OF HEROES, all saved via VirtualDub as AVIs (and codec'd as ffdshow). Individually, they play fine - no pixel problem whatsoever.

I imported them all into my SVMS project (which is also set to 1280x720, 29.97fps), and while I'm not surprised to see some pixelation in the previews (regardless of quality setting there), the final rendered video CONSTANTLY has some spot that's pixelated, and even worse, it keeps CHANGING.

Attempt one - it happened during a transition
Attempt two - transition now fine, happens later mid-clip
Attempt three - happens again during the transition, mid-clip pixelation gone, now shows up mid-clip ELSEWHERE
Attempt four - nearly perfect, then pixelation

ARGH!

Quick specs:
Windows 7 Pro / AMD FX-8150, 3.60GHz, 16GB RAM
Radeon 6950
Sony Vegas Movie Studio HD Plat 11.0 (build 295)

Preferred specs for finished product:
6MB, 1280x720, 29.97fps, 192k audio (basically the 6MB template)

Can ANYONE help me? Please?

Comments

musicvid10 wrote on 3/2/2012, 9:37 PM
Please provide your complete media, project, and render specs.
Samuraiko wrote on 3/2/2012, 10:36 PM
All video footage is AVI (ffdshow codec), 1280x720, 29.97 fps.

PROJECT PROPERTIES:
Template: HDV 720-30p (1280x720, 29.970 fps)
Width: 1280 Field order: None (progressive scan)
Height: 720 Pixel aspect ratio: 1.0000 (Square)
Frame rate: 29.970 (NTSC)
Stereoscopic 3D mode: off
Full-resolution rendering quality: Best
Deinterlace method: None
Adjust source media to better match project or render settings (unchecked)

RENDER SPECS:
6 Mbps HD 720-30p Video
Audio: 192 Kbps, 48,000 Hz, 16 Bit, Stereo, WMA
Video: 29.970 fps, 1280x720 Progressive, WMV, 6.3 Mbps
Pixel Aspect Ratio: 1.000
Mode: CBR
Format: Windows Media Video 9
Image size: High definition (1280x720)
Frame rate: 29.9720 (NTSC) Seconds per keyframe: 5
Override default compression buffer (seconds): 3 (checked)
Video smoothness: 90

Did I miss anything?
musicvid10 wrote on 3/3/2012, 9:52 AM
Your Media Properties can be found using MediaiInfo (freeware, Sourceforge).

AVI, ffdshow could mean any of a thousand things. Ffdshow is a library of codecs, not a codec.

Beyond that, I don't use WMV for my work, so I can't be of any help there.
big daddy wrote on 3/3/2012, 7:41 PM
Based on this:

"Video: 29.970 fps, 1280x720 Progressive, WMV, 6.3 Mbps"

I will hazard a guess you are seeing the effects of the wmv codec running at a relatively low rate. My guess is you see noticeable pixelization during times of camera motion and/or scene transitions. A 6Mb/s rate is difficult to get a clean 480p video stream on a DVD let alone a video sequence of 720p. Also wmv is an old codec technology in 2012. If you want the better quality at a lower bit rate try H.264 (aka AVC) and experiment with lowering the bit rate till the distortion becomes a problem. Or keep wmv and turn up the bit rate till the distortion is minimized to your taste.
Samuraiko wrote on 3/3/2012, 8:24 PM
You guessed correctly - that is where most of the pixelation occurs. Switching to AVC mostly worked - while it solved the pixelation problem (and thank God for that), it renders as much darker than I'd expected. But your advice on the WMV codec is appreciated - at least now I know it's not my footage just randomly corrupting.

Just as a matter of opinion, are there any other codecs you'd recommend for high-quality/high-motion footage?

Thanks again!