weird wmv renders... please help

brnijeff wrote on 12/28/2003, 8:59 PM
Hi All,
I've been diligently tweaking render settings for wmv renders from VV3. Tweaking things like widthxheight, bitrate, 2 pass encoding, and quality slider.

I find the single biggest impact on video quality and file size is bitrate. I was quite surpised to find that 320x240 vs 160x120 didn't change file size much. I thought it would have a huge effect. Isn't that why when you have a low and high speed version choice when visiting a website, the dial up choice is always a postage stamp?????

Thoughts?
THanks,
Jeff

Comments

Spot|DSE wrote on 12/28/2003, 9:32 PM
The biggest impact is the number of keyframes that the encoder has to insert. Working on making frames more redundant, less color information, and less motion information makes all the difference in the world. Controlling blacks, whites, saturation, contrast, fringing, cropping to subject will all make substantial differences in quality and filesize well before any of the adjustments you selected above will make.
The_Jeff wrote on 12/28/2003, 9:43 PM
This response may sound glib...But...Of course the single biggest impact on filesize is the bitrate. The bit rate says (roughly) how many bits will end up stored in the file per second of video. So a 1024x1024 at 128Mbps will end
up with roughly the same file size as a 128x128 at 128Mbps. (

The difference is that if these two files are encoded at the same bit rate then the picture 1024x1024 will have more compression artifacts.

So, use the bitrate to control the filesize
Then use the resolution and frame rate to control how the pictures look.
Adjusting things like keyframes can help allow you achieve acceptable quality at lower bit rates (longer intervals will work good
for very static images)

Now of course if you go too low on bit rate you may not find any frame rate and resolution that looks good...
Jessariah67 wrote on 12/28/2003, 9:57 PM
All dialup issues aside, I've had some good results with a bit of tweaking of Vegas' wmv8-256k preset. Change the quality from "good" to "best" and enable two-pass encoding on the video tab and you'll get a fairly decent result without increasing the kbps all that much.