2 Hr Video = 6GB MPEG2 using VV5

cworld29 wrote on 5/31/2004, 2:08 PM
My first project after upgrading to 5.0. OK, I am rendering 2:00:02 of video using the DVD Architect NTSC Video Stream template. The first attempt I had used cookie cutter to take off some tracking jitter from the bottom edge of the video and also applied track motion to better center the video on screen. This render took 8 HOURS and I ended up with a 5.9GB file.

This morning I tried it again without the event FX or the track motion. This render was a much more reasonable 1.5 hours but the file size ended up being the same.

This video is simple childrens animation. I have rendered projects like this before and produced 4 and sometimes maybe 4.5GB files. Two hours should not take up this much space after compression right? I haven't even rendered the audio to AC3 yet so I am wondering what is wrong here.

Comments

johnmeyer wrote on 5/31/2004, 2:43 PM
The complexity of the project does not change the MPEG file size; only the bitrate changes that.

Download this bitrate calculator:

Bitrate Calculator

and then enter your project size. It will give you the bitrate you need to use to "just fit" the project onto your DVD. Click on the "Custom" button when rendering your MPEG file and then enter this bitrate figure into the Average bitrate setting.
cworld29 wrote on 5/31/2004, 4:27 PM
Right, I guess I didn't expect the size to change but the ammount of extra time required just adding those two effects seems off.

Thanks for the link. The calculator gives me a bit rate of about 4900Kbs. In the custom drop down box for setting constant bit rate there is 4200. What will this do to the quality of the video?

It still seems odd that the file is this large. I thought a DVD is supposed to be able to holdabout 2 hours of MPEG2 video.
johnmeyer wrote on 5/31/2004, 4:31 PM
A DVD-R or DVD+R recordable DVD holds about 60% of what a commercial DVD can hold. Therefore, if you want identical quality to what you get on a commercial 2 hour DVD, you can only put about 70 minutes on a DVD-R. Double layer DVD-R and DVD+R discs are starting to show up, but it will be awhile before they are cost effective. I don't know what the compatibility will be. Quality at 4,000 will be far less than at 8,000 (which is the nominal maximum).
farss wrote on 5/31/2004, 4:35 PM
IF it's only animation i.e. there's not much motion between frames then you should be able to set the bitrate quite low and still have excellent quality. I'd suspect setting the average bitrate low but keeping the maximum as high as possible would be the best way to achieve this.
Rather than using the cookie cutter I use the border fx to get rid of sloppy edges, don't know though if it renders any faster,
cworld29 wrote on 5/31/2004, 10:26 PM
At 4200 it came out to be about 3.6GB. It looks fine. I'll add the FX and let it render overnight. Thanks for your help guys. I'll give the border FX a try and see if it makes any difference on the render time.
johnmeyer wrote on 5/31/2004, 10:45 PM
For exactly 2:00 hours, you can go up to 4800, unless you plan to put lots of motion video on your DVD menus. The quality will be better at 4800 than it will at 4200.
thrillcat wrote on 6/1/2004, 10:33 AM
I would love to see an option in the render options like Sorenson Squeeze has, where you can "Constrain Output File Size To: ______" and it will run the bitrate calculator for you. I was doing the same thing this weekend, I had a file that was 2:02:00 and I rendered 3 times trying to get it under the limit.
jetdv wrote on 6/1/2004, 10:49 AM
If you let DVDA do the rendering, it WILL help you figure out the proper bitrate. Personally, I just use the chart in the newsletter at www.jetdv.com/tts
johnmeyer wrote on 6/1/2004, 1:00 PM
I was just trying to create a script that would do this, but apparently I cannot set the bitrate via script.

Sony, a LOT of people want to render in Vegas (which Sony and other people recommend as the preferred workflow, especially since there are more advanced MPEG-2 encoding settings only available in Vegas). The OBVIOUS script (which I was writing, but cannot be finished due to the inability to set bitrates via script control) is to get the project (or selected) length; calculate the bitrate, put in a fudge factor for the size of the DVDA menus (pretty small, unless lots of background video and sound is used), and then render.

Imagine, Vegas users of the world, a single button that would let you render for DVD Architect, and not have to mess with bitrate and all those other parameters, and know that your project will be at maximum quality without being too big to fit on one DVD?

Yes, I know the objections: You cannot estimate the DVDA menu sizes exactly, and for some people the current way is no bother, so why can't new users just learn how to use Vegas?

All I am saying is that I have read and "listened" to all the posts I have seen over the past fifteen months (perhaps several hundred) that have asked questions relating to encoding. A good script could surely answer many of these.