When best to use HCEncoder VBR or CBR

[nicksteel]

Having read conflicting statements, when is it best to use VBR or CBR?

[AlanHK]

HCEnc doesn't do constant bit rate.

You can do 1-pass with a constant quantization factor.
That will be an unpredictable size.

You might do that if you were in a big hurry.

[nicksteel]

I should have been clearer with my question. I am concerned with quality, not speed. Need to know if 2 pass VBR or quantization factor produces higher quality.

[guns1inger]

In an ideal world, they will produce equally good results. The issue isn't which, it is when. If you have a definite size you must meet, then 2-pass VBR is the best method as it will hit a target size. If size isn't an issue then you might get better results from a CQ encode. FAVC employs a predictive quantization method whereby it encodes samples at different quant values until it finds the value that comes closest to the target size. For videos up to around 90 minutes, you will usually be hard pressed to spot the difference between this and a VBR encode. For longer videos, VBR is usually the better option.

[jagabo]

Need to know if 2 pass VBR or quantization factor produces higher quality.

When using 2-pass VBR you are specifying the file size want. The encoder gives you whatever quality it can for that size (bitrate). When using 1-pass quantizer you are specifying the quality you want. You get whatever file size is necessary to maintain that quality.

If you need files of a pariticular size (to fit a 2 hour movie on a 4.3 GB DVD, for example) you use 2-pass VBR encoding.