That seems more like one of 'those' VBR vs Constant discussions Steve. I'm keen to find info on 'VBR Constants Quality'. It seems a contradiction in terms.

Has anyone here used TMPGEnc Video mastering Works for rendering the files for DVDs or Bluray disks? I am drawn to the workflow of rendering out one high quality master and using a program like this to generate the different versions: Youtube, Vimeo, DVD, and Bluray rather than multiple renders from Vegas.

Constant quality (crf) average bitra4e can't be specified because it can't be calculated before the encode. There is no initial scan pass. That's why it is faster.

We seem to be still talking at cross purposes. I'll see if I can get a print-screen up of the option. Might be clearer then.

With Handbrake, constant quality, and bitrate curiosity, the only way I could figure it out was to look at a CC rendered file with MediaInfo. You could try the same thing with TMPenc. Just render out files with various CC settings, then look at them with MediaInfo to see what bitrates various CC settings seem to average around. It won't be exact since the more complex the material, the higher the bitrate you will get at a given CC setting, but at least you'll have a ballpark idea.

if i recall, VBR keep bitrate on average, and have a "bucket" to save and to spare depending on scene complexity/motion/etc.

VBR "quality-based", use quantizer setting to maintain constant "visual quality", using bitrate between set levels. depending on implementation, this setting may result in unpredictable final filesize. (but if offer 2 pass, most likely to be predictable)

Not a mystery or crossed purposes. I use Constant Quality (crf) every single day (x264).
Constant Quality is Variable Bitrate. All Variable Bitrate is not CQ. It uses a single pass The bitrate is not predictive, but adaptive. It uses a Quality metric (called a Rate Factor), not a bandwidth metric. The lower the RF, the higher the quality, up to a point. Lower RF means larger files (and higher average bitrate). It is possible to exceed the size of the source with RF settings lower than 18.

Therefore, each and every encode will have a different size and average bitrate depending on source complexity. That size and bitrate can NOT be predicted in advance.Commands called vbv-min and vbv-max can cap the upper and lower bitrates.
Plenty of places to read up about it.

Laurence,
I've been using TMPGEnc VMW for a couple of years to create DVD and Bluray files. I think it does a much better job than Vegas. I've been frame serving my Vegas projects to VMW but see no reason a high quality master wouldn't work. Render times are slightly longer than Vegas for DVD and Bluray.

DVDA woks just fine with the VMW files, which include audio so you save a bit of time by not rendering the audio separately. If you deliver DVD or Bluray I think the program is well worth the money.

I've not fully explored it for mp-4 files but think Handbrake or Vegas is superior for that chore.

Thanks guys...got my head around it now. Googling it just came up with the usual Constant Vs VBR stuff.