Need Concert files just a tad smaller!!!

[Chris Harding]

Hi Guys

I did a dance recital and the clips created of each session comes out at 1 hr 36 minutes and 4.71GB so after a basic DVD menu I'm not going to able to squeeze it onto 1 DVD disk!!

The 1920x1080 footage has been rendered down to PAL 720x576 Widescreen and I used my own default template with a VBR of 9500 max, 6000 average and 4200 minimum when rendered out to MPEG2
I need to shave off just a fraction from each of the 29 clips so I took Clip 1 (2mins 50 seconds) and instead of VBR I used a Constant BitRate of not 6000 but 5000 and the file size drops from 143mb down to 125mb which is more than adequate!!

Viewing the clips I cannot see any difference in the quality (which is SD anyway) but I just wanted to ask if it's better to use a CBR of 5000 or rather a VBR and drop the average to 5000 from 6000. Which is the better method to retain as much quality as possible but shave maybe 10 mb or less from each clip????

There are 29 clips (all MPEG2 ) ready for the DVD (NB: I use DVDLab NOT Architect) so I only need a minimal reduction in file size to enable me to get them all on one DVD

Any hints on the best method ?? I left the quality slider at FULL (31) and just went from VBR to CBR with a lower rate.....is there a preferred method here????

Chris

[Gerald Webb]

No firm opinion to offer, sorry, but have to say, you are so lucky with that length.
The 2 dance concerts I just did were marathons, one over 4 hrs long, the other about 3.5. I just went the way of 2 DVDs in a dual case.
FWIW, I would have dropped the high end to 8.5, then drop the average to 5850 on one dance to see the difference, then calculate for the full render.
Others prob have more accurate ways though.....
Good luck.

[Don Bloom]

Chris,
I routinely do 120 minute work and use VBR with the BR set to the average needed for the total lenght of time of the project. I've been down to an average BR of 4.2 and have not had any problems with either playability or quality. Of course all of my stuff is SD rendered in to MPEG/AC3 in Vegas then burned in DVDA but I don't think it would make much difference. Render in Vegas then burn in DVDlab. Should work.

I hope this all makes sense since it's 5AM and I've been up since 4AM. No reason just did. Hell to get old! ;-O

[Chris Harding]

Thanks Guys!!

Gerald, actually it WAS a 4 hour concert!! The juniors had an hour, intermission and another hour..then I had a one hour break and the seniors did the same format...started a 3pm and the first was 4pm to 6pm ..then hang around until the next began from 7pm to 9pm.

Some Mum's want the Juniors only and some want the Seniors only and some want both!!! I want to be able to supply either one or two DVD's NOT two or four!!! ..otherwise my burn times for orders so far of nearly 100 disks will be way too long!!

Cool Don, I really appreciate the input as well!! OK, you can get some sleep but when you used a average VBR of 4200, did you change the max (default is 9500K) and the min(default is 1920K)

These are dancers so I suspect that due to the movement involved very few frames would be at minimum, that's why I used a CBR so nothing would encode higher than 5000. I have yet to do the 2nd concert so it just might be safer to drop the 5000 to the 4200 preset to give me some extra space.

When you are sufficiently rested, can you cast your mind back and remember what the max VBR was set to???? Yeah us oldies can comfortably say that getting old is a bummer!!!

Thanks again guys

Chris

[Garrett Low]

Hi Chris,

I'm actually getting ready to go back into the dance recital season. First two are this weekend. I usually don't let the max bitrate go over 8000 some old set top boxes will choke on higher rates. I've gone as low as max 8000, ave 4750, min 3500. I try to keep the min as high as possible as Vegas' mpeg encoder tends to drop the min very aggressively so that it tends to yield a lot of ugly blocking in dark areas of the stage.

Unless you are going to have the max, ave, and min values equal you will always get a better overall result using multipass VBR allowing higher max bitrates than a CBR setting.

-Garrett

[Don Bloom]

Hi Chris,
Sleep? Ha! Anyway I always set the max to 8 and the min to 2 then adjust the average as needed andI always use VBR although I will vary from 1 pass to 2 pass depending on what the action is. For weddings and seminars I find 1 pass works just fine but for sports I generally use 2 pass.
HTHs
Have a good day!

[Mike Kujbida]

Chris, it's times like this that I dig out my tried and tested bitrate calculator and that is the one found at http://www.johncline.com/bitcalc110.zip
I make a few changes to the default settings and they are as follows.
Click the Settings button (lower left corner), set 1 kilobit=1000 bits, set Audio encoding type and Bitrate to 192 Kb/s - Dolby 1.0 (the AC-3 default in Vegas) and the Safety Margin to 5% (default is 1% and I like to have more margin than that).
When I do that, I come up with the following Custom VBR settings.
9,608,000 / 5,912,000 / 3,544,000
Do this as a 2-pass render, make sure to set the Video quality slider in the Custom Video tab at 31 (High), and you'll get the best quality you can out of Vegas.
BTW, the calculator only gives you the first 4 digits as it assumes that you know that you must add the 3 zeros at the end of each set.

[Chris Harding]

Thanks Guys

I use default with two pass for weddings but for this concert 4200K average and keeping the max at 6000 and the min at 2000 and just a single pass makes a good enough MPEG2 for me and the new 29 clips come out and just under 4GB as opposed to 4.71GB at default which wouldn't have fitted on a DVD!!

I know that's 2000 lower than what I use for weddings but it worked out nicely... I tried the same clips at both VBR 4200 and CBR 5000 and visually there is no resolution difference so the excited Mummies won't complain!!

Thanks again..that's the Junior Concert done ..now I still have to do the Seniors!!!

Chris