One more question about adaptive quantizer matrices

[Axlemar]

What is the advantage, quality wise, of using AQM. I tried it out and it seemed to look good with regular movies, but blocky with animation. I am wondering if anyone has played around with it more or if they know the principle behind it.

(BTW, I loaded an avs file from the newest version into the newest cce SP and it didn't have disable adaptive quantizer matrix selected, so I don't know if they are disabled yet. If the quality is possibly better, there should probably just be an option to switch it on and off.)

[Fishman0919]

One more time :D

From the CCE SP manual:

3.8 Disable adaptive Q-matrix switching
Cinema Craft Encoder SP (later than 2.67) adjusts quantization matrix
automatically to improve the quality of image when Multipass
VBR is selected. However, some DVD player does not support such
MPEG streams as encoded with adaptive quantization matrix, and
may cause the block noise when playback. When you encounter the
problem, you can avoid it with this option.

What is adaptive Q-matrix switching ?
There are some cases that Cinema Craft Encoder SP cannot keep
the minimum bitrate. It is considered to be caused by that the lowest
quantization scale cannot raise the bitrate under a single quantization
matrix. To solve the problem, Cinema Craft Encoder SP automatically
creates other matrices cutting the value of each element in the
matrices by half, quarter and so on, and applies another one to produce
a much lower distortion for much higher bitrate. This switching
of quantization matrix can occur at every GOP.
Thus, adaptive Q-matrix switching can improve the quality of image,
especially with lower bitrate sources or CG works or the edge of
fading out.

[archaeo]

A couple questions (assuming I've enabled AQM switching, ie AQME=1):

How can you tell if CCE has created these other matrices? Where would I look for a clue that it had? Is this recorded in the ecl?

Has anyone else experienced the problems mentioned like block noise, skipping, etc?

What's your experience with using this feature?


I have been enabling this for the last few encodes, and am not quite sure if CCE has actually been creating these modified matrices. Haven't noticed any problems on playback, at least with my player. I tend to lean toward keeping this enabled, but wonder if it might create problems down the road.

[Fishman0919]

How can you tell if CCE has created these other matrices? Where would I look for a clue that it had? Is this recorded in the ecl?

No, it's something that happen on a GOP bases and is stored in the .vaf file

It is considered to be caused by that the lowest
quantization scale cannot raise the bitrate under a single quantization
matrix.
so it may not happen all the time, just when needed.

Has anyone else experienced the problems mentioned like block noise, skipping, etc?

What's your experience with using this feature?

I've been lucky with CCE SP 2.70 and had no problems with it... I have it on all the time and like what I get from it.

[Axlemar]

One of my JVC players hates AQM, but other than that even my ps2 and xbox have played them fine.

Btw, I think the command was CCEAQM=1 under [options]. Rebuilder will tell you during prepare if it is on.

Lastly, thanks for being so helpful Fishman0919.

[archaeo]

thanks