Unexpected File Size Results

[weaver4]

I was trying to back up a movie with several programs here are the results.

AutoGK-Xvid-Quality 67% - 610M
AutoGK-Xvid-Quaity 75% - 1266M
Avi.net-Xvid-Quantizer 3 - 623M
Dr2-Divx - Quantizer 4 - 617M
Dr2-Divx - Quantizer 3.5 - 700M

The AutoGK with a quality of 75% seems to be out of line when compared to the rest of these, plus it is a huge jump from 67% to 75%.

Any Comments?

[Pulp Catalyst]

you won't get much response from just posting the above, sorry but your being to vague for anyone to bother with this post.

besides to be honest with you, there could be a thousand reasons why this would happen, every program has there way, and most use different 3rd party utilities to make up the whole package which again in turn process video to there own way of design.

for example, i compress the same data with different compressor's

winrar
winzip
extractnow
winace
7z zip

all with ZIP option and my final archieve comes out at different sizes?

why is this.... see what i mean, no disrespect intended.

[weaver4]

What are you talking about pulp?

I run autogk in the default mode, use XviD set the quality to 67% and the filesize is 610K I move the quality up slightly to 75% and the filesize doubles. Pretty Simple. The rest of the examples are standard encoders using defaults that all show that file size should be somewhere around 600k to 700k for a good quality output.

If you are familiar with avi.net you will notice there are no options except for the quantizer value itself and it was using the same compression engine (XviD).

Sure you run a file through a bunch of compressors and if all the compressors compress the file to 600k except one, and that was 1200k your response might be "That one sucks, I wonder why, I think I will ask on the newsgroup."

I also have to disagree about a thousand reasons. There has to be a specific reason that AutoGK doubled the output size when quality was moved from 67% to 75%.

[manono]

There has to be a specific reason that AutoGK doubled the output size when quality was moved from 67% to 75%.

Maybe because you encoded only a tiny section of video, and an I-Frame (or several) of quant 2 was much larger than an I-Frame (or several) of quant 3 and made one much larger. Why not try the same thing with a complete movie, or at least a much larger section of video? I bet you don't get twice the size then.

[weaver4]

There has to be a specific reason that AutoGK doubled the output size when quality was moved from 67% to 75%.

Maybe because you encoded only a tiny section of video, and an I-Frame (or several) of quant 2 was much larger than an I-Frame (or several) of quant 3 and made one much larger. Why not try the same thing with a complete movie, or at least a much larger section of video? I bet you don't get twice the size then.

These are the whole movie. AGK at 67% was .610G and at 75% was 1.266G. I'm sorry, I see what you are saying now...it should of ben 622M not K...I will edit my first email. I did do the full movie the sizes were a typo.

[check]

Obviously the quality scales are different for every application - and the quality scales are not linear.
Comparing across applications is like comparing apples to oranges, especially when you don't post the codec settings, especially when you compare between different apps which use different quality measures anyway.

[manono]

Yeah check, but he has a point, I think. Now that I find out it was for a complete movie and measured in MB and not KB, I also don't quite understand why the size doubles with only an 8 point increase in the percentage.

You can't really compare the AutoGK results with the ones from AVINet and Dr. DivX, but as far as I know, all the settings are the same within AutoGK, except for the percentage chosen. The only way I could explain it is if the settings weren't the same. If maybe B-Frames weren't used above 70%, or the resolution changed, or something like that. But as far as I know none of those things happen.

Do you have the logs for those 2 AutoGK encodes, weaver4?