2pass-VBR and VBR

[torex88]

What's the difference between 2pass-VBR and VBR? Which one is better?
Between Variable Bit Rate and Constant bit rate, which one produce bigger file size and which one is better to use? Thanks 8)

[adam]

2-pass vbr encodes the file once just to gather information about it, and then it encodes it again for the final version. By scanning the file before encoding it is better able to allocate bits where needed most so you get the most effective use of your bitrate. An added bonus is that you can set a specific avg bitrate, you can exactly set the resulting filesize down to the mb, so that you can just fill your cdr/dvd-r. Some encoders even allow you to scan the movie more than one time to get the best bitrate allocation possible. I usually encode in 4-pass VBR in CCE.

Any encoding mode can produce any size file, it all depends on how much bitrate you use. If you encoded in VBR and used the same avg as the CBR file then they would be identical in size, but the VBR one should look much better. So the best way to encode is to use VBR and just try to get the avg set so that your file totally fills whatever type of disk you are burning on. So my suggestion is to always use 2-pass vbr and a bitrate calculator. It does take alot longer to do 2-pass vbr, but you are guaranteed perfect results everytime.

[ZippyP.]

What's the difference between 2pass-VBR and VBR? Which one is better?

That's a question guaranteed to start a fight!

VBR uses a varying bitrate to maintain quality while CBR uses a constant bitrate throughout the movie. VBR allocates higher rates to demanding, high action scenes and lower rates to less demanding scenes. For the same filesize, VBR makes better quality video compared to CBR. If size is not a concern then CBR and VBR can produce similar quality.

One pass VBR is called CQ in TMPGEnc, filesize in this mode is unpredictable. 2-pass produces a predictable filesize which is set by the average bitrate, but it takes twice as long to encode.

Personally, I use 2-pass almost always and fit most movies on two SVCD's. You need to experiment to find your preferred settings for minimum, maximum as well as a threshold for average. I use 500 min, 2500 max. and I don't like to go below 1700 avg. 8)

[Piccoro]

CBR should always be the bigger filesize because if you encode 2500kb/sec constant. VBR there will be times when it uses under that amount...so it will be less(assuming your not gonna set all VBR values to 2500) because you have a min value or even avg value lower then the max.

What are your values? i personally cut my svcds at 35mins or around and have never had one not fit on a svcd using CQ 100% default bitrate (bout 2500?)and this is a form of VBR. if i go over to 37-38 mins a file then sometimes it may not fit and have to re-encode at 35mins(i do it overnite..not an issue).
but if you want to keep your size down and go way past 35 mins on a cd then you could use 2pass VBR and end up w/a much better video than CBR. I would say you dont notice the difference in image quality much between 2pass and CQ. Choice wut u value(more on a disk or overboard quality), and take advantage of SVCDs/DVDs supporting VBR of some form rather than using CBR.

[DJRumpy]

Piccoro, using multipass VBR, with an AVG setting at the same value as a CBR encode will produce a file of the same size.

i personally cut my svcds at 35mins or around and have never had one not fit on a svcd using CQ 100% default bitrate (bout 2500?)and this is a form of VBR. if i go over to 37-38 mins a file then sometimes it may not fit and have to re-encode at 35mins(i do it overnite..not an issue).

I'm curious why you simply don't use multipass VBR if your encoding overnight? Why make a guess with CQ VBR that could end up requiring you to re-encode again the next night because your output is too big? You should use a bitrate calculator, and multipass, so you know exactly what size your output will be, and how many discs it will fit on.

I agree with Adam. Use at least 2-Pass VBR for the best quality. If your movie is 90 minutes or lower, aim for 2 SVCD's. If it's longer, consider using 3 SVCDs. Use a bitrate calculator to determine the highest possible AVG setting for the required number of discs.