Log in

View Full Version : Custom Size AVIs always undersized with AutoGK 2.27


MarkV
21st July 2006, 12:40
Dear All,
I’m having some troubles with custom size encoding. I checked the threads that could have dealt with my problem but I couldn’t find any answer. Anyway, if the subject has actually been discussed somewhere forgive my slip and please give me the link.
I used AutoGK 2.26 till the first week of July and everything has always worked well. Then I installed version 2.27 and all my problems started from there. I always use the XviD codec and usually choose a custom size of about 900 MB. The point is that all the resulting target size AVIs are undersized. I read in the tutorial that this can happen as a result of some resolution settings but this is not my case because I always use the default Auto width and the compression test results are always in the ordinary range 60-80%. Some AVIs come out so heavily reduced (about 200 MB) that Windows Media Player cannot even render the files. Surprisingly, for some movies it seems that the more I increase the value in the custom size box, the more the final size moves downward. I find it difficult to understand the reason for all that, considering that the log file doesn’t seem to report anything odd. The initial definition of audio and video sizes is done according to the total target size I chose, and the expected quality correctly increases if I raise the custom size. Obviously the final AVIs don’t meet the quality value reported in the log file, since quality evaluation ends up by being based on a size that is only theoretical and much larger than the one of the final file. I don’t know if this problem may happen to me using DivX as well, I haven’t tried yet. Anyway, I prefer XviD and AutoGK 2.26 never caused me such troubles.
Hope someone can give me a few hints on how to remove this bad functioning.

Thank you for your attention.

jggimi
21st July 2006, 14:54
Hello, and welcome to the forum.

One common rate control problem -- the bitrate selected is not the bitrate actually used -- can be caused by installing XviD on top of an already installed XviD. Try removing the XviD codec completely, then reinstalling it. For many people, this solves the problem. Let us know if it works for you.

jorjet27
22nd July 2006, 01:25
Hi, I'm using Gordon Knot and I get the same problem.
Source video is about 5.5MBPS, I set up Gordon Knot with an average of 4MBPS and then also set the secondpass settings to 4MBPS. The end result is a video bitrate of 2MBPS, I can't get around this problem and I've also tried removing XviD then reinstalling.

Thanks

jggimi
22nd July 2006, 01:58
Hello, and welcome to the forum, jorjet.

In your case, even without seeing a log file, I would bet you are maxing out the codec. 4mbps is typically overkill with dvd sources. Sounds like you are not doing compressibility tests.

With GK, compressibility testing is strongly recommended -- AutoGK does them for you.

jorjet27
22nd July 2006, 02:12
Alright, thank you for the welcome :)
Never knew you could max out the codec. I'm also just encoding music vids, but I guess the same rules still apply.

Thank you

MarkV
27th July 2006, 11:19
Thank you very much, jggimi, for your welcome and immediate answer.

I completely removed the XviD codec and reinstalled it. Then I encoded the same movies again but I got the same undersized AVIs. I decided to try using DviX and this time the size of the final files perfectly matched the one I had set. It was clear that the data rate control problem only affected XviD. I thought of your words again, about the fact that the problem could be caused by two installations of the same application placed one on top of the other. This led me to uninstall the whole AutoGK package, including XviD. Then I restarted the system and installed all the tools once again. Fortunately, this solved the problem. Now all the final custom size XviD AVIs come out with exactly the size selected. I can start encoding movies again with AutoGK and XviD and enjoy the excellent results.

Hope this can be helpful for someone.

Best Regards

Pulp Catalyst
28th July 2006, 20:13
here's my 2 penny worth, had the same problem myself, but it does state in the AutoGK faq,

if the video achieve high compression ability then AutoGK won't waste bit's and that's why the file comes out smaller, because AugoGK knows that putting more bits on the the file will not increase quallity at all, So AutoGK has been disigned not to waster space

usually if there are dark areas in a stream, then this would natrually be more compressable, although there are exceptions.

Been using Fairuse wizard 2.5 and this doesn't seem to have this feature so target size is normally achieved, although i have seen FUW also undersize aswell, just not as much as AutoGK does,

which is better all depends on the situation, but with AutoGK a clue usually is in the compressibility test (as mentioned above),

i.e when encoding Startrek 1 i had a compressibility test of 133% so obviously target size could not be achieved, but have a look at the log and it tells you this asell, goes something like "trying to adjust settings" "unable to adjust settings, file will most likely be undersized" or something like that anyway.

live long and prosper

BigDid
28th July 2006, 22:49
... if the video achieve high compression ability then AutoGK won't waste bit's and that's why the file comes out smaller, because AugoGK knows that putting more bits on the the file will not increase quallity at all, So AutoGK has been disigned not to waster space
...
i.e when encoding Startrek 1 i had a compressibility test of 133% so obviously target size could not be achieved, but have a look at the log and it tells you this asell, goes something like "trying to adjust settings" "unable to adjust settings, file will most likely be undersized" or something like that anyway....
Hi,

Jggimi has covered it in his second post for jorjet "I would bet you are maxing out the codec"; This is also what I have posted (other point but same process) in this thread where you just posted: http://forum.doom9.org/showthread.php?p=856525#post856525

The initial issue of undersizing is different and in his first post for MarkV, jggimi also covered it "Try removing the XviD codec completely, then reinstalling it."

Did

Pulp Catalyst
29th July 2006, 00:06
sorry, didn't realize, didn't mean to step on your toes, i appologize,

BigDid
29th July 2006, 00:48
sorry, didn't realize, didn't mean to step on your toes,..
No toe stepped on, just wanted to inform (other thread) and clarify (this one). Thanks for coming back.

Did