1 pass VBR: is CCE's bitrate "optimal"?

[DaWolf]

When converting DivX for my kids speed is of the essence. Many 1 CD DivX movies are encoded between 800-1200 kbits/sec so using 3 pass VBR to make a SVCD probably will not squeeze out much more quality then given anyway. (? assumption on my part).

Did a one-pass VBR on Pitch Black today. Minimum 300, Maximum 2400. The 675 MB DivX converted to a 574 MB mpv (no audio: 2 96 kbits language streams will be muxed later on, hopefully with subs) with as far as I could see when checking in on CCE a bitrate of around 800 kbits/sec most of the time.

Now I wonder.... I have no idea how the actual bitrate is chosen by CCE as in one-pass no average is given. 800 is also not the average between 300-2400. Which speculatively leads me to believe this "analysis bitrate" of CCE is actually the best/optimal for those scenes. (??)

On a side note... Are bitrates compared absolutely (divx 1000 kbits = SVCD 1000 kbits) or on a scale based on how much compression is achieved?

[Matthew]

Bitrates cannot be compared absolutely across divx and SVCD because divx has better compression. As a general rule 1 cd divx = 2 cd SVCD, 2 cd divx = 3 CD SVCD.

That average bitrate seems too low (hell, it's less than VCD), but I always use multipass so I don't know why it's so low. But I do know that movie should be on 2 cds.

Perhaps you should consider converting to XVCD using tmpgenc. My limited experience doing this with divx provided okay results, and it was fast.

[Mozart]

when using CCE with 1 pass VRB, the calculated average bitrate will be ever between min and max, of course. The crucial value is Qfactor. If Qfactor is equal to 1, the calculated average bitrate will be almost equal to the max bitrate that you use. Increasing Qfactor, you will decrease the avg bitrate.

[dalarthe]

is there a way to determine these ? for example i have a 120 min flick and the bitrate calculator gave 1580kbit/s for average and 2496 for max ... and its calculated considering i want to fit it on 2cds?

[Mozart]

Nope. Unless you are using Qfactor < 5, which gives you a CALCULATED bitrate equal to Max bitrate, there is no way to predict the average bitrate using 1 pass VBR.

[kdiddy]

Why dont you just use Multipss..and set it to make only 1 pass....that way you can set what you want your average bitrate to be.

[Mozart]

Why dont you just use Multipss..and set it to make only 1 pass....that way you can set what you want your average bitrate to be.

it is not so simple. The net quality with 1passVBR, even with Qfactor=60, is much better than multipass VBR=1.