Question about TMPGEnc 's CBR & VBR

[A17]

HI, when encoding a svcd movie, which is better to choose from, CBR or VBR? and what are the differeces?

[ultradna]

At first, read the rule #12, please. I can't say you what is best!

But if you ask what the differences i can help you.

CBR = Constand Bit Rate
That means that in the video allways will be used ONE Bitrate. So if there's much action normaly it is used more bandwidth than in slow scenes. So it could happen that in action scenes is used too less bandwidth and in slow scenes too much bandwidth. But this kind of encoding is faster than 2-Pass

VBR = Variable Bit Rate
I use this in comparison with 2-Pass. So this bandwidth is variable. Is more action, it gets more bandwidth, is there less action it get less bandwidth. You get a much better quality! But it takes the double of time as CBR when using 2-pass.

[canoner]

I had similar questions, but couldn't find the answer. You just need to experiment a bit. This is what I have found out. (Maybe I am missing a lot, please let me know in that case, senior guys.)

If you are going to use CBR, CCE with avisynth 2.51 is a lot faster. However, if you do low bitrate, maybe you should stick with TMPG.

With TMPG, I found CQ gives me the best speed/quality combination. For drama, non-action moives, I use a file prediction factor of 0.980. For action movies, I use 0.950 just to be safe. (if you want to fully utilize the space on your cds, VBR may yield a bigger file, especially for movies like matrix). Overall, VBR takes much longer and provide marginal benefit. The quality CBR gives is just not up to my requirement. With CQ, I can encode a 90 min dvd in 120 min, which is good. I will try to get avisynth 2.51 work with TMPG, and hopefully it will further boost the speed.

[rsquirell]

I second the CQ. VBR 2-pass just doubles your render time and increases the size of the .mpg...since I'm not allowed to give a quality comparison, let's just say I choose CQ ( and I'm a finiky person.)