CCE: linear quantizer vs non-linear

[weak]

a statement from doom9's "getting the best out of CCE" guide:

"Quantscale is actually nonlinear which would lead us to believe to not check Linear quantizer scale but the original author of this method told me that linear quantizer scale yields better quality."

here's what cinemacraft writes in the CCE SP Guide:

"3.3.6 Setting quantization scale type
There are two types of quantization scales: linear and non-linear.
Linear quantization scale is a method used for MPEG-1, where the
quantization scale is allocated linearly. To set the linear quantization
scale, select Linear quantization scale in the video settings
screen. However, the non-linear quantization scale is recommended
unless there is a special reason."

which leads to better quality with dvd as source and dvd compliant mpeg2 as target ?
YOUR EXPERIENCES PLZ!

[Poplar]

For progressive frame source, I always check linear. Does it improve quality dramatically vs. non-linear? Perhaps not. If you do a test of linear vs. non-linear, I don't think you will see much of a difference, at least for the bitrate range I use (VBR 2300-2500kbps).

[weak]

well, i encode for dvd-r so i use bitrates at about 5000kps. i wonder if i'll see a diffrence between 1 and 4 passes

i was just wondering why cinemacraft says non-linear's better but most guides recommend to use linear.

[SLK001]

That's because "Guides" are just that - guides. Probably someone started out using linear quantization and had good results so stuck with it. Personally, I use non-linear (because of the CCE manual), but I can't really tell the difference between the two.

[Kdiddy]

Same as SLK, I use non-linear because of CCE. I figure hell they wrote that app, the should best know how to use their own app right? Dont see much difference where it worth even mentioning though.

[Anonymous65]

Linear VS non-linear quantizer, simply by the words themselves, means how the video is digitized. Does it use linear steps from black to white, or does it use steps of uneven height depending on white or black areas in the video. Under normal conditions, a linear digitizer is best. If you have very dark video, you might want more steps during the dark areas, and less steps during the white areas. This would give you better resolutions between the steps, and better quantization in that region of the video levels. Non-linear quantization most likely have a S or H-shaped curve between the black and white video levels.

[adam]

Every document I've ever read states that non-linear will always produce better quality. Since I can see no difference between the two, I stick to the decision that is most documented.

It should be noted though that non-linear quantization is considered an improvement over linear quantization and an enhancement implemented in mpeg2. Maybe it is just "separate but equal" but it certainly wasn't designed to be that way. I mean the mpeg consortion who created mpeg1 and mpeg2 claim this so I would really tend to believe them rather than something written in a guide.

[mb1]

The guides who claim that linear quantisation should be set are simply wrong.

Linear quantisation was developed for mpeg1 and its needed low bitrates for videodiscs (constrained parameters bitstreams). So use linear for bitrates of 1.860 kbps and below and mpeg1.

Nonlinear quantisation was introduced with mpeg2 to increase quantisation precision for now possible high bitrates and increase the dynamic range for low bitrates and mpeg2.

The dynamic range for linear quantisation and mpeg1 goes from 1 to 31.
The dynamic range for nonlinear quantisation and mpeg2 goes from 0.5 to 54.

This means even at a low bitrate mpeg2 (let's say 1.500 kbps) nonlinear should be used because of its higher dynamic range over the whole bandwidth.

Conclusion is very easy:
For mpeg1 always use linear (as the encoder normally doesn´t let you switch)
For mpeg2 always use nonlinear (using linear limits the encoders' possibilities)

regards
mb1

p.s. even my almost 2 year old guides recommend using nonlinear for mpeg2 (no matter what bitrate) 8)

[weak]

thx.
i didnt check it anyway cause of the CCE guide.
but that's the proof i needed to find some sleep again

[homerpez]

My head hurts. Now I have to look back and see which one I DO use. I don't remember seeing this setting.