DVD & Number Crunching

Maverick wrote on 11/14/2003, 6:42 PM

Further to my earlier posts regarding trying to put 80+ minutes on to a 4.7 GB DVD at the default bit rate in V4 for PAL MPEG-2 the resultant files are reported in DVD-Optimize as taking upover 105% of the disc.

So, if the default max bit rate in V4 is for MPEG-2 PAL video stream 'Best' is 8MB and the min is 6MB what would I need to set them to (or is there another setting I can change) in order to maintain a high quality but reduce the resultant file sizes to just under the 100%.

Cheers

Comments

riredale wrote on 11/14/2003, 7:30 PM

Maverick:

(1) A DVD is 4,700,000,000 bytes, or 4.38GB.

(2) The question of bitrate has been discussed many times on the forum. Here's the short version: 600 / (minutes) = target average bitrate including audio.

So for 80 minutes of video, your average bitrate has to be at or under 600 / 80 = 7.5Mb/sec. Regular audio eats up 1.6Mb/sec, leaving a video bitrate of 5.9. If you instead compress the audio using AC-3, you only need 0.2Mb/sec for it, leaving you with a video bitrate of 7.3Mb/sec.

craftech wrote on 11/14/2003, 7:39 PM

I have found that the menu complexity can make a huge dent in the calculations. My last project had an average bitrate of 5000 and came out to 3.77GB in Vegas. After I added the AC3 audio and the menu it ended up at 4.65GB and just fit.

John

Rogueone wrote on 11/14/2003, 9:49 PM

Craftech, I don't know how you come up with those calculations! I hate math, so I wouldn't have considered that. :-) They're very accurate, though.

Rogue One

Maverick wrote on 11/15/2003, 6:09 AM

Thanks everyone - The info is now stored on HD for future reefrence.

Cheers

farss wrote on 11/15/2003, 7:06 AM

Be very careful with menus, a few times I've had DVDA decide to put mulitple instances of the same clip on the DVD even though it should hav eonly needed one. Seems to screw up mostly when you get very close to the max.