DVDShrink, Compression, and Quality

[GParent]

If you use MAX SHARP, and the percentage of your main title compression is 80% or higher, is it true that the AEC will not be initiated. If true, you should not pick that setting.

QUESTION:

What are the different compression percentages where MAX SHARP, SHARP, SMOOTH, MAX SMOOTH cause AEC to be turned on, and which ones cause AEC to turn off?

[Chetwood]

AEC is turned on - naturally - when you check the box in the quality settings tabs, easy as that. This has got nothing to do with the compression percentage you have.

[GParent]

Perhaps I've been reading too many posts. I thought that, regardless of the setting, Shrink did an override based on the level of compression and the level of sharpness (eg. MAX SHARPNESS), with SMOOTH being the one that was guaranteed to actually kick in, regardless of compression level. I must have had it wrong.

Any good rule of thumb as to when you should use SMOOTH vs SHARP (DEFAULT) vs MAX SHARP?

My guess is that it depends on compression amount and action secenes, but that's just a guess.

[Chetwood]

Originally posted by GParent

Any good rule of thumb as to when you should use SMOOTH vs SHARP (DEFAULT) vs MAX SHARP?

Nope cause I never use it. Do a search on the DVD Shrink forums for AEC and you should get some pointers to quality tests.

[nwg]

On my system I find that AEC speed can depend on how much compression. If I use a lot of compression then I get about 1000KB/s rate. If set the AEC default setting on a DVD with say 10% compression. It will not use AEC but encode at a lot faster around 3000+KB/s.

If Max Smooth is selected then the DVD is encoded at about 900KB/s all the time (even with only 1% compression).

[GParent]

Chetwood,

AEC takes longer to process, and that's good. It helps prevent artifacts. The setting is what has generated confusion and even the developer admits its more in the realm of alchmey and experimentation. I am not knocking your opinion, because its based on your personal experience. I'm just surprised.

[Chetwood]

Seems we're talking bout crossed purposes or I'm again having trouble to understand native speakers.

Originally posted by GParent
What are the different compression percentages where MAX SHARP, SHARP, SMOOTH, MAX SMOOTH cause AEC to be turned on, and which ones cause AEC to turn off?

I understand the sentence above as follows: which compression percentage do I need to set in DVD Shrink to make AEC kick in?

Is this correct?

My answer is: you either turn on AEC manually or you don't. AEC does not get turned on automatically when a certain compression threshold is reached. Of course it will show different results when

- using different amounts of compression
- using different settings like SHARP, SMOOTH

I hope I've made myself clear now ;)

[dragongodz]

its quite simple. after you go to the quality settings tab and AEC is selectable then it will be used if you tick it. if it is ghosted(turn all compressions to 90+% and you should see that happen) it wont be at all.

The setting is what has generated confusion and even the developer admits its more in the realm of alchmey and experimentation.
sharp setting hit B frames harde so depending on amount P frames and I frames may not always have to be touched, or if so not as much. while the smooth settings touch all frames so will obviously take longer. this has been explained before. it is not some big mystery or alchemy at all. of course nobody can say which setting will work best for a particular movie without testing it since no 2 movies are the same, this has also been said before.

[GParent]

>> I understand the sentence above as follows: which compression percentage do I need to set in DVD Shrink to make AEC kick in?
Is this correct?<<

YES

>>My answer is: you either turn on AEC manually or you don't. AEC does not get turned on automatically when a certain compression threshold is reached. Of course it will show different results when

- using different amounts of compression
- using different settings like SHARP, SMOOTH<<

I am talking about DVD SRINK overriding your setting(s).

Maybe I should have given an example.
Lets say DVDSHRINK says 85%, indicating the title, when compressed, will result in 15% compression of the original MPEG-2.
If I select AEC ON, then select MAXIMUM SHARPNESS, is DVD Shrink going to look at the 85% and decide to ignore my MAXIMUM SHARPNESS setting and essentially NOT USE AEC.

In other words, are there any compression points where DVD SHRINK will ignore your AEC setting (eg MAX SHARP or SHARP) and internally do something else, like not use AEC or change the setting to something else?

[GParent]

>> Sharp setting hit B frames harde so depending on amount P frames and I frames may not always have to be touched, or if so not as much. while the smooth settings touch all frames so will obviously take longer. this has been explained before. it is not some big mystery or alchemy at all. of course nobody can say which setting will work best for a particular movie without testing it since no 2 movies are the same, this has also been said before.<<

Yes, I read your post in another thread in this forum.

If this is accurate, would it have been helpful, if after analysis, DVD Shrink gave a pattern and percentage of the different frame types (I, B, P, ), thereby making it easier to pick a quality setting?

Lastly, in lieu of this information, is it worth while using another program to dicover that information before launching DVD Shrink. Perhaps a preprocessor that calls DVD Shrink, after doping out the details of the project.

[GParent]

Purely subjective. I did a little experiment using LOTR - Return of the King, the 1st Chapter of the movie 8 different ways. Used Deep Analysis with DVDSHRINK. All software is the latest version.

CH. 1 - No Compression (The Best).
CH. 2 - DVDSHRINK - 40% Compression - AEC/Max Sharpness.
CH. 3 - DVDSHRINK - 40% Compression - AEC/Sharp.
CH. 4 - DVDSHRINK - 40% Compression - AEC/Smooth.
CH. 5 - DVDSHRINK - 40% Compression - AEC/Max Smooth.
CH. 6 - DVDSHRINK - 40% Compression - AEC/OFF.
CH. 7 - CLONEDVD2 - 40% Compression.
CH. 8 - DVD2ONE - Constant Rate.

I would rate them in the above order, as they get progressive worse as you approach DVD2ONE. I may experiment with DVD2ONE to see if it can improve with variable rate.

[dragongodz]

of course thats just 1 movie. from what others have said about their experiences sharp/max sharp works fine for the majority of films. if however you get one where you get some bad macroblocking or jerky motion going to smooth fixes that. you do however lose some fine detail(so not as sharp in other words).

[GParent]

Thanks, I understand the scenario. Will be watchful of the breakups.