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-   -   When rendering pictures, can I go for a lower VBR? (https://www.dvinfo.net/forum/what-happens-vegas/236914-when-rendering-pictures-can-i-go-lower-vbr.html)

David Delaney June 7th, 2009 03:14 PM

When rendering pictures, can I go for a lower VBR?
 
I have about 1100 pictures for a slideshow that I am rendering out in Vegas. I want to include them on a DVD using ARCH 5, but it will be quite long and almost take up the entire single DVD (I don't want to go dual layered). I have Mark's Bitrate Calc and it works great, but I was wondering IF I can I lower the variable bit rate (VBR) for pictures -still images- will this retain better quality then with moving video at the same VBR? (if that makes sense)

Harold Brown June 7th, 2009 06:25 PM

What rates are you using? How long is it running? You should be able to keep the average rate low. The transitions will need more.

David Delaney June 7th, 2009 07:31 PM

Are you saying that transition make a file size bigger or did I misunderstand? The project is huge, and I am in the middle of trying to pare things down to a smaller size so I can fit it all on one DVD. As I said, about 2000 stills images altogether as well as video. I have been putting transitions between the images, but if that is going to add to the render size (and probably time as well), I think I will take them out and just use dissolves instead...

Mike Kujbida June 7th, 2009 07:38 PM

The encoder in Vegas won't give you the kind of control you're looking for (i.e. different bitrates for different sections).

Transitions won't make a file bigger, only the overall length.

Stick with the numbers you get from Mark's Bitrate Calc.
I've been using it for a long time and it's never let me down.

edit: Harold is correct about how VBR works.
I was referring to (but forgot to mention) high-end encoders that have the ability to adjust these settings on a shot- by-shot basis.

Harold Brown June 7th, 2009 10:07 PM

David,
VBR gives different bitrates to different sections. It gives a higher bit rate to the areas that need it by taking away from other scenes that don't. A 2 pass render allows Vegas to do a better job of distributing the bits. Too bad it doesn't have a 3 pass render to squeeze more out of it. This is important if you have video and stills on the same time line.

You can control the final size by keeping the pictures on the time line small (720x480 for SD) and the bitrate as low as possible (since you have so much content). You can determine that from the calculator but you can always experiment with the bitrate to see what you can do.

Dan Bridges June 7th, 2009 11:46 PM

Use two-pass VBR.

low: 192 Kb/s
avg. as explained below.
max: 8000 kb/s should be ok.
Either 9-bit or 8-bit DC coefficient. (Probably 8-bit).

I think you should be able to get down to an avg. bitrate rate of about 1500 kb/s. Try a test render first of 20 pictures using some different 2-pass VBRs: 500, 750, 1000, 1500, 2000, 2500 kb/s and use these 6 tracks as 6 clips in a multi-clip DVD. Since most of the time, the image is static, the avg. bit rate can be quite low. So what you're really interested in is the quality of the transitions.

Other trick is to use the half-D1 format (352x480 NTSC, 352x576 PAL) rather than the standard D1. The DVD player automatically shows the right aspect ratio during playback. Halving the number of bits encoded makes lower bitrates possible. There is no preset in Vegas for this format, but you can change it in the MPEG-2 encoder settings (Custom | Video | Width). In the Architect 5 you can set it in File | Properties | Disk Properties | Resolution. You will find half-D1 values in the drop-down resolutions shown.

Dan.

Brian Berg June 8th, 2009 11:38 AM

Quote:

Originally Posted by Harold Brown (Post 1155427)
You can control the final size by keeping the pictures on the time line small (720x480 for SD) and the bitrate as low as possible (since you have so much content). You can determine that from the calculator but you can always experiment with the bitrate to see what you can do.

I agree. Higher resolution images just give you more flicker issues anyways.

Mike Kujbida June 8th, 2009 12:09 PM

Quote:

Originally Posted by Brian Berg (Post 1155621)
I agree. Higher resolution images just give you more flicker issues anyways.

That's why the recommendation is, unless you're doing really deep zooms, to keep the images to no more than 2X your project properties size.
This helps a lot in reducing flicker.

Harold Brown June 8th, 2009 03:53 PM

Yep, I had some flicker a couple of different times with my projects on just a couple of pictures and until I saw posts about it I could never figure out why it was doing it. It had never occurred to me that those pictures were much larger than the others.

Mike Kujbida June 8th, 2009 06:39 PM

And if you still get flicker, try the Gaussian Blur FX with Horizontal set to 0.0 and Vertical to between 0.001 to 0.003.
Make sure this FX is applied before scaling the image (in Pan/Crop, for example).


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