2 Pass VBR in TMPGenc - help !

[VCDHunter]

I'm using TMPGenc to do some encoding using the CQ_VBR settings -

Resolution 352x288
Constant Quality 100
VBR Min 300
VBR Max 1150

I'd now like to try using 2Pass VBR (min 300 max 1150) but cannot seem to get the settings right. My files end up far larger than if I use CQ-VBR.

Can anyone point me in the right direction of a guide that could help ? I've tried looking through the guides section but cannot seem to find the settings for 2 pass.

Thanks

[MpegEncoder]

VBR also has an average bit rate setting. What's yours?

[VCDHunter]

average setting = 1150

I'm assuming this number should be somewhere between the min and max, is there a hard and fast rule I can apply here ?

[MpegEncoder]

With your average set to the same as MAX, you are making a CBR in VBR mode (and taking twice as long). What are you trying to accomplish? The method that you seem to be using will create a non-standard VCD. Is that what you want?

[jester1x]

You will get a better picture using VBR versus CBR even if your bitrates for minimum, average and maximum are set to the same values. Also, your file size prediction will come out fairly precise. I've done some experimenting with vcds and have always found the VBR (all bitrates at same value) picture to look much better than the CBR picture even if the same bitrates were used. Generally, I never set my bitrates minimum too low because the picture does suffer. I used these values for example: 700 Minimum, 1050 Average and 1250 Maximum. Yes, there is not a whole lot of "wiggle" room, but my vcd image quality was quite good. I used these figures to encode The Animatrix into a vcd and was able to fit all nine episodes onto one 80 minute CDR with no problems! I typically make non-standard vcds. The best method is to experiment with some values and compare the results. Also, "soften block noise" can be your friend!

[MpegEncoder]

I generally agree with all that you've said. VBR allocates bits where they're needed even when the average and max are the same. However the filesize will be exactly the same as CBR at the same bitrate. If VCDHunter wants to squeeze the size down he needs to lower the average bitrate.

[VCDHunter]

If VCDHunter wants to squeeze the size down he needs to lower the average bitrate.

I'm actually just testing to see the difference between CQ_VBR and 2 Pass VBR but I was a little puzzled about the average bit rate. I set it to 800 in the end and the finished product looked pretty good.

Is there a way to calculate the average bit rate needed in 2 pass ? I set it at 800 as a guess.

[ZippyP.]

Is there a way to calculate the average bit rate needed in 2 pass ?

That's what a bitrate calculator does, check the Tools section for one.