Strange small Divx video file size

[Gugus]

Hi all!

I have a new strange problem:
I'm using FlaskMPEG XiS 3.0e for conversion and Divx 5.02 Pro (add).
It's not the first time that I do a conversion (I did a lot),
But here is my problem:

Trying do convert the movie Stalingrad "Enemy at the gates".
I using Divx Calculator for estimate the Bitrate
- Lenght : 125m39s
- Audio mp3 file: 149 Mo
- 2 CD (then, I want a video file of 1251 Mo)

The Divx Calculator give me 1395 kbps.

When I convert the movie (options QP, GMC and BE enabled) in 2-pass with 1395 kbps.

My video file do 758 Mo !!! (and not 1251 Mo!!!)

Then I do a test: I use 2000kbps... and my video file do ... 754 Mo..

I play the video file.... and the quality seem very good...

I try with another movie "American Beauty", and I have the same prolem: undersie divx file.

Where the problem ????

[benderman]

If you are using a low res like 512x216 or 400x300 or a reduced framerate and the video dosen't contain a lot of motion/noise this could happen. Maybe 650MB allready gives the best possible DivX-quality. If you want a bigger filesize maybe you can use a higher res.

[Gugus]

I'm using 640 X 480 of base resolution (after crop it change a little).
I don't chage the framerate (25fps).

And Stalingrad is a War film (with lot's of action).

[khp]

Try doing a 1-pass qualitybased encoding at 100%. If it comes out significantly larger than the files you produced, then something is wrong.

Or if you can, try running the attached script, on the second pass logfile, the one called analyse.log, not the firstpass logfile.
To run the script you will need to get the ActivePerl perl interpreter from www.activestate.com , place the file analyse.pl in the same directory as the analyse.log file, and double click analyse.pl.
This will create a file called second_pass_stats.log, post this here.

[Gugus]

Ok I download and will try it.
Thanks

[Gugus]

Hi !
Here is the log file.
Where I could found documentation for understand this log file ?

[khp]

Originally posted by Gugus
Hi !
Here is the log file.

Great, the log file states that all frames were encoded using quantizer 2, which means that the movie is encoded at maximum quality, with the current settings. So unless you got some obvious defects in the video, I think you should be happy with this.

But because B-frames are encoded with doubled quantizers, you might get better quality by encoding without B-frames, at the cost of a much bigger file of course.

Originally posted by Gugus

Where I could found documentation for understand this log file ?

Nowhere !

I'am sorry, it's just something I put together, trying to trackdown some undersizeing problems. Writeing documentation hasn't been a high priority for me.

The file just states the total number of frames, and the total number of I-frames,P-frames, and B-frames.

It then goes on to tell how many frames were encoded at each quantization level, for both I,P,B-frames and all of them combined.
And of course also calculates the average quantizer.

[khp]

You can find an explanation of I,P, and B-frames here

http://forum.doom9.org/showthread.php?s=&threadid=19436

And quantizers are explained here

http://forum.doom9.org/showthread.php?s=&threadid=21397

and in many other threads in this forum, and http://forum.doom9.net, and http://forums.divx.com

[jagarus]

Whats FlaskMPEG XiS 3.0e?

[Gugus]

Thanks for your answer khp !
Jagarus, FlaskMEPG Xis 3.0e is a version witch support YV12 and YUY2 encoding.
You could found it here:

http://www.digital-digest.com/dvd/downloads/flaskmpeg.html

[Glanz]

ok i did the same thing here is my log file what can u tell me about it
i as well am getting bad quality on my movie i tried to reinstall divx 5.02 but that didnt work i put in a 2 cd size file and around 1200 kbps and it comes out around 400 mb and like 300 kbps which looks bad can u maybe help me

[khp]

OK

This is very strange. According to the log, your file is nowhere near maximum quality, At maximum quality the file would probably be about 50%-70% larger (just a guess).

At the end of the analyse.log file there are two numbers marked progress and expected, could you post these. In the analyse log file these, numbers are noted for each frame, I'd like to know the numbers for the very last frame. This will tell us how close to the desired filesize the codec thought it was when it finished the movie.

To force the codec to produce higher quality you could do a quality based encoding at 100%. But of course you don't have any filesize prediction that way.

[Glanz]

i hope this is the right one

[Glanz]

how would i do a quality based encoding in gknot do u know what i mean ?

[khp]

Dammit I missed something...

your encoding must be well an truely messedup.

The frame count is only 13107, only about 10 minutes of video.

Could it be that the first pass is aborted prematurely ?. Could you post you _GKnot.log file.

Could you try running the encoding in virtualdub manually. Load the avs file that GKnot created into virtualdub set video->fast recompression, and configure the codec in video->compression, you will have to set both the first and second pass manually.