DivX files turning out smaller than they are

For a while now my divx files that i make are less than the bitrate i specify. For example if i specify 800kbit/s (100kb/s) and the file is 10 sec long i expect the video file to be 800kb, but it turns out 500kb. I dont know why. For Long movies that i want to turn out 700mb they come out 600mb and checking the properties of the file, the bitrate of the file is less than what i specified, HELP ME

 

Forgot to mention i use virtual dub, but it should not matter what i use, but i never know

 

I don't if I'm right or how much sense it makes but divx uses compression, so I imagine that it recudes the redundant code in the video and might be a little be less than what you thought. a movie file is normall comprised of an audio and video bitrate, but then I think divx compresses it . . . . does that sound right?

 

Sorry but what you said is a bit silly, as i specified the divx file to be eg. 800kbit/s and it turned out 500kbit/s (thats definatelly a problem there) and its different bitrates with different sized files

 

my apologies then, I misread your question or actually when I went to send a response I was interrupted and my response got skewed in my head. sorry. But if i'm not mistaken divx does compress using an algorhythm like winzip and rar, so that might change things. not sure.

 

Im using divx 5.02, the adware version
(((Dont worry about it Khisanth)))

 

Yes its the guide im using. The problem is not getting from dvd to divx but the final divx file made, being too small. Eg using the bitrate calculator it tells me i should have the video at 1200kbit/s to get a 700mb file. But my file becomes more like 500mb at the end.

 

Yes I do get a variable bit rate but it should average out to the bitrate i specified, like it used to. When u want a file to be 300mb u use the bitrate calculator, it tells u put 1259kbit/s to get a 300mb file for that specific time and audio

 

Just a thought - are you choosing the correct value for the AUDIO bitrate in the calculator?

 

yes, as ive said it worked fine for ages and the last couple of weeks it turns out too small. If i go to the properties of the file the bitrate of the video is less than what i specified eg i specified 800kbit/s (100kb/s) the file says 80kb/s

 

maybe this is too simple but have you tried uninstalling, rebooting and then reinstalling the software you use for converting and such?

 

hehehe yes i have 3 times actually Do you reckon there is a bug in divx, well if ive reinstalled it, it must be something else

 

I'm having the same problem! Everything was fine up until a day or two ago and I just can't understand it. I'm following exactly the same procedure as before, which always resulted in files at the specified file size (give or takes a MB or 2). I haven't changed any software, though I have installed a new hard drive and faster CPU but they can't be responsible! I managed to create 1 file today which was on target for size but about 6 others aren't. Must be a bug but I can't figure it out.

I'm using DivX Pro 5.02 btw.

Thanks,
Will

 

With single pass the codec tries to give constant quality within the bitrate specification, but CQ can only be achieved through two pass. Use 2-pass if the correct bitrate is important to you. If you are not aware, different parts of the same movie are more difficult to compress. With very low bitrates its simply a matter of hit and miss.

 

Like maggas, I am using a 2 pass encoding method and I have had no problems encoding to a specified file size before. My method hasn't changed so more any ideas?

Thanks for the input though.

Will

 

Finally someone with the same problem, join the club wjd Nothing will fix it even reinstallation, if i cant do anything else i might reinstall windows, but what if the problem happens again, i cant keep on reinstalling windows!

 

Well I might try and restore my working hard drive image and then see if I can spot the difference but I can't see how anything has changed.

I wondered if it was anything to do with the files generated from the first pass. Perhaps they aren't being written correctly so the second pass isn't working with correct data. I dunno, it's causing me a lot of grief and you seem to be the only other one I've found with this problem!

Will