Tmpgenc: VBR or CQ?

[digital_frog]

As a recent convert to Tmpgenc from CCE, I'm a bit fuzzy on the whole 2pass VBR as opposed to CQ. I've read Lordsmurf's guide on Tmpgenc, which recommends CQ over 2VBR in the sense that it cuts down on time and gets more or less the same result, if not better.

My question is this: Lets say I'm transcoding a Divx file to 1/2 DV at 3000 kb/s average and 4000 kb/s max. What would be the equivalent setting in CQ vis-a-vis the "quality" slider assuming I keep the bitrate values the same?. 85%? 100%? Or doesn't it matter?

Thanks in advance for any replies.

DF

[rhegedus]

VBR vs Constant Quality

[digital_frog]

Thanks for the link. Even more confused now since arguments seem to go both ways. I guess its a question of testing and retesting on different clips to see what produces the best result. On the other hand, since this was an exercise in getting the best speed out of tmpgenc, spending all that time testing might take longer than a 2pass VBR encode anyway

In any case, thanks for the help. I'll read thru again in case I missed something.

DF

[bugster]

My question is this: Lets say I'm transcoding a Divx file to 1/2 DV at 3000 kb/s average and 4000 kb/s max. What would be the equivalent setting in CQ vis-a-vis the "quality" slider assuming I keep the bitrate values the same?. 85%? 100%? Or doesn't it matter?

Thanks in advance for any replies.

DF

Just from my own experience, I would say Cq 75 or 80 would often produce bitrates of around 3000 Avg when using 1/2 D1 res, (I assume thats what you meant).

[bugster]

You want a few more ideas/opinions on VBR Vs Cq Vc CBR. Take a look at this old thread HERE

[digital_frog]

Actually what I meant was that I'm using 3000avg/4000max with 2pass vbr now, but I wasn't sure what the quality slider should be (or does) with CQ. From what you're saying the quality slider should be at 75 or 80, but should i leave max bitrate at 4000? (keep in mind this is a medium quality divx - 4000 is probably too good, but better safe than sorry).

The thing is I gave a short clip a trial run in between posts using 75% and 4000 max bitrate, but I'd didn't really notice any significant improvement in encoding time. At present a half hour divx tv episode takes about 2 hours with 2pass VBR @4000kb/s + motion estimate + DC component 9. I was looking to maybe cut down on that a bit since 14 episodes x 2hrs = a lot of hours!