Target file size not being met when converting to Xvid

[G)-(OST]

Hey

I have been converting from DVD to Xvid now for the last 3 years, I am not new to the proccess, though I have a question, when I do a DVD to Xvid convert, I always configured the "twopass - 2nd" pass with a target bitrate, but now I want to convert to a "target size" (700 or 1400mb), my question is, why isn't the encoder using up the whole of the size I have calculated, let me elaberate a little, I have ripped a DVD, then I demux the VOB's into seperate video & audio elementary streams, so now I have a AC3 file that is 322mb (which I will keep to use in the final Xvid) & the VOB's that were ripped from the original DVD, I then go to the built in bitrate calculator & pick my target size as 1433600kbytes (1400mb), then I put the video time in "1h 40m 46s", then I add the AC3 sound file, which is 330639kbytes (332mb) so I end up with a calculated size of 1099124kbytes (1073mb) with an average bitrate of 1489kbps to use for the video, no subtitle's are used, so, when I do the encode, I tell Virtualdub to save as segmented AVI's, I give the segment size as 699mb & then VD does it's thing, 2 hours later I get 2 files, the first is 699mb the 2nd is 622mb, why is it not using up the whole 1400mb, I don't understand, I have retried several times without succes, can anyone tell me why this is happening, if it was only 10 or 20MB, I wouldn't care, but almost 80MB that could have been used to add more bitrate to the whole video?

Denis

[redwudz]

Just guessing, but some codecs can be 'saturated' by using too much bitrate. At some point the file gets larger, but the quality stays the same. 1489Kbps seems fairly high for a 720 x 576 (?) source file converted to Xvid.

Or it may be just an error on the part of the encoder. You might try a short test encode at an even higher bitrate and see what happens. I don't know the mechanics of how the Xvid encoding actually works, but others have reported a similar problem where they couldn't get the encoder to create the size file they set it for.

[G)-(OST]

The thing is, the movie length is 1h 41m long, if I was to encode it to 1CD (700mb) then it wouldn't have enough bitrate, I don't think it is saturated with bitrate, I have encoded at an even higher bitrate without any problems, I am going to try to encode half the movie at a time, I think the problem is I am telling it to encode to 1400mb but also telling it to segement to 699mb parts, I still don't understand why this is happening though, I am only telling it to split the file it is creating into 2 parts really. I will try to encode the first half to a target size of 700mb & the same for the last half, encoding each half seperately, this should work, I hope

[lacywest]

DivX Author 1.5 ... does a good job converting DVD movie to Divx ... lots choices to choose from .... size ... quality ... it is all there. Even converts DVR-MS videos from MS Media Center Edition 2005

[G)-(OST]

I don't think it is the app that I am using to encode with (virtualdub), I have been happy with the previous results acheived by VD & would hate to change apps, I know VD like the back of my hand, but I have never encoded to a targeted file size before, so I am stumped, I have tried calculating with different bitrate calcs, thinking that the built in calc was giving me the wrong bitrate, but the other calcs I tried gave me vey similar bitrate result, so I am sure I am giving the encoder the right bitrate for that length of movie, why it wont use the full amount of space? I don't know, but there has to be an answer


EDIT:
Update: I have tried it the way I explained it above, but still came up short, I encoded half the video, 50mins, & ended up getting even more space left over, out of 700mb that I allowed, I ended up getting a file size of 566mb, I can't work it out for the life of me, has anyone else had this problem before, It can't be that complicated surely, but it's got me f$#@%d, can someone else work it out for me on there calc, I am starting to think my PC is corrupt.

Movie length is 1h 40m
Sound is AC3 @ 448kbps or 322mb in size
I want to create an xvid file size of 1400mb / 2 CD's
that leaves me with 1078mb for the video, right?

[ricardouk]

have you tried tools like avi.Net, AutoGk or StaxRip? all of them will let you pick 1400 (split or not) and let you keep ac3, they use vdub like you do.

[manono]

that leaves me with 1078mb for the video, right?

No. You should allow 3 MB for the muxing overhead. We don't know the settings (like resolution), and can't judge whether or not you've saturated the codec, as redwudz speculated earlier. If you installed a newer XviD over an older one without first uninstalling the prior version, that can account for undersized encodes. I'd suggest taking ricardouk's advice to use something like AutoGK. That way you'll get a log which may help to pinpoint the problem, if it occurs again.

[G)-(OST]

Hey, the 3 mb overhead you are talking of, I know about, but 3mb is not the problem, I just stated that figure, give or take a few mb's, I am missing out by a wopping 80mb, also, I have updated to the new xvid codec, but i did do a clean uninstall with revo uninstaller, so there should not be anything left over from the old codec, currently I am using version 1.2.1, the resolution I am using is 640 x 266, saying that, in the filters, I am selecting "codec-friendly sizing multiples of 16" so it adjust acordingly

[manono]

...but 3mb is not the problem

I didn't say it was. I was answering the statement that 1078 MB was left for the video.

...the resolution I am using is 640 x 266, saying that, in the filters, I am selecting "codec-friendly sizing multiples of 16" so it adjust acordingly

So 266 is a typo? Because it's sure not a codec-friendly sizing multiple of 16. Perhaps you meant to say 640x256.

You've answered the one about upgrading your XviD correctly, but unless you've run a compression test before doing the encoding (or run it through AutoGK and posted the log), we won't know if you've saturated the codec.

[G)-(OST]

Hey, typo or not, I select codec-friendly sizing multiple of 16 so it adjusts it for me anyway, I know it is not a multiple of 16, but that is what I get when I select the aspect as 2.40:1, but in any case, it gets rounded of to the nearest multiple of 16 by VD, which you are correct is 256, that is why VD has the option of rounding to a multiple of 4, 8 & 16, just put the size in & VD adjusts it for you acordingly

[jagabo]

I tried VirtualDub's Save Segmented AVI with Xvid and it delivered the correct size(s). Your source probably doesn't have enough detail to make a file of the size you requested. Also check Xvid's Min Quantizer settings. Make sure they are set to 1 (unless you have some other playback restriction). Try using a larger frame size like 704x304 (larger frames require more bitrate).

[G)-(OST]

Hey, I have just tried avi.NET, now I have the opposite happening, I set out put size to 1400mb, I ended up with a file that is 1.66GB.
The sourse i am using is directly ripped from a retail DVD, 5 vob's in total, I use the mpeg2 plugin by FccHandler to import into VD, I have tried both minimum quantizer settings 1 & 2, with no difference, I am seriously thinking of giving up & just encoding to a particular bitrate as I have always been doing, I was just hoping I could use up a whole DVD by having 6 lots of 700mb files, some longer movies being in two halves

EDIT:
I am trying on a different (Vista laptop) PC now, I am convinced that I may need to reformat my XP desktop PC, it hasn't been done in the last 3 years & is seriously overdue, I will update this post with the results

[jagabo]

Why do you need files that are 700 MB or 1400 MB? Or you storing your movies on CD? Why not just use constant quality encoding. Pick a quality level (target quantizer) you are happy with and encode. Every frame of every video will have that quality. The size (average bitrate) will turn out to whatever is required to get that quality.

With bitrate based encoding you are saying "I want a certain file size, I'll accept whatever quality I get from that size." With quality based encoding you are saying "I want a particular quality, I'll accept whatever size I get."

[G)-(OST]

Like I said earlier, I want to be able to fit as many movies as possible on 1 DVD, if I were to encode movies to 700mb, I know I can fit 6 x 700mb files on a DVD, I end up with 6 movies per DVD, if a particular movie is longer in length, I would allow 2 x 700mb, this ends up being more efficient per disk & close to 100% of the disk is used, I do know what you are saying, that is how I was doing it up until now, but I ended up with alot of room left on the disk that is waisted

UPDATE: What ever was causing the problem with my desktop, is now solved via my laptop, I am getting the exact target size & faster encoding, like a 3rd of the time it took my desktop, anyway the target size is solved now, thanks for all the help, looks like i am off to reformat my desktop which was causing all the headaches in the first place

Denis