TMPGEnc VBR conversion size problems

[spon23]

Ok, this is going to seem like a very easy question, but I've been searching the forums and various website's for about a week now and can't seem to get a solution.

I've been converting avi to DVD very successfully for over a year now- no problems at all. I've always used CBR b/c it was faster, and calculated the correct birrate with the bitrate calculator linked in the tools section of this website. no problems at all.

Recently, I decided to try 2 pass VBR in an effort to get a better picture after conversion. However, when I can NEVER get the resulting file size to be correct. I'll use the bitrate from the calc as the average bitrate, and then set the max to 8000 and the low to 2000. The resulting file is always oversize to fit on a DVD. The m2v file itself is always over 4800k size, before I mux back in the audio file.

I've read in many posts, that if you set the average bitrate to what it says in the bitrate calc, then the file size should be correct, so all I can think is that my setting is incorrect or something. I guess I could just take the bitrate given in the calc and subtract off like 1000, but I'd rather figure out what I'm doing wrong.

Thanks in advance for any help!

[spon23]

I hate to beg, but does anyone have any ideas? I tried again last night and here are the details. Movie is 106 minutes long. Audio will be 192kbs MP2 which I will add after the TMPGEnc encode. According to the bitrate calculator, the average bitrate should be around 5200. I set the VBR average to 5100 to be safe. After a few hours, I ended up with a video file that was 4900MB; without audio.

Any idea why this keeps happening? I guess I could go back to using CBR, but it's really bugging me that I can't figure this out. Thanks for any help.

[babyboo]

I have been noticing that as well and I have drawn my own conclusion. It is probably incorrect but I will share it with you. I captured using Virtiual Dub and Huffy. I have noticed that a VBR encode with an average of 4 and a max of 6 almost always comes out at 6 if my source is a VHS. When my capture source is direct from cable it is a lot closer to the average of 4. The only thing that I can figure is that since there is a lot more nosie in my VHS source it needs more bitrate...and since I set the maximum to 6 it uses all of that. Again...I am probably way off base but that is what seems to be happening with my encodes.

[rkr1958]

I have noticed that a VBR encode with an average of 4 and a max of 6 almost always comes out at 6 if my source is a VHS. When my capture source is direct from cable it is a lot closer to the average of 4. The only thing that I can figure is that since there is a lot more nosie in my VHS source it needs more bitrate...and since I set the maximum to 6 it uses all of that. Again...I am probably way off base but that is what seems to be happening with my encodes.

My understanding is that a 2-pass VBR will achieve the average. So if you set the average to 4000 kps then the average will be that.

I hate to beg, but does anyone have any ideas? I tried again last night and here are the details. Movie is 106 minutes long. Audio will be 192kbs MP2 which I will add after the TMPGEnc encode. According to the bitrate calculator, the average bitrate should be around 5200. I set the VBR average to 5100 to be safe. After a few hours, I ended up with a video file that was 4900MB; without audio.

I encoded a 2 hour and 15 minutes capture of a VHS tape. I encoded using TMPGEnc with an 8000-max, 4000-ave, 2000-min. The resultant video file was 4,310,000 bytes. After adding audio (ac3) and authoring the total size was 4,696,649,728 bytes. Concidently, ...
(5100-ave kps / 4000-ave kps) x (106-minutes / 135-minutes) = 1.0011.
Just with this simple scaling this means that your file should have come out to approximately the same size as mine. Is the difference in the audio encode? I encoded mine to ac3. What are you encoding yours to?

[dafreak]

spon23, what are you setting for your GOP structure? are you sure you have the length of the movie correct?

are you encoding ES video only?
if not, it could be the fault of vbr audio.

also make sure that your avi file is not corrupt. run a scan on the file using virtualdub. I've seen tmpgenc encode corrupt avi's past the point where the video ends. at the end of the movie or whatever all you'll see is just a blank picture.

also make sure your directshow priority is raised to the proper lvl.

[mh2360]

Tmpgenc 2 pass encoding is VERY unpredictable when its comes to file sizes, Not like CCE or Mainconcept. If your Mpeg2 files are a bit too large then author the DVD as normal, ignore the warnings about file size, and shrink the DVD using DVD Shrink.

[dafreak]

Tmpgenc 2 pass encoding is VERY unpredictable when its comes to file sizes, Not like CCE or Mainconcept. If your Mpeg2 files are a bit too large then author the DVD as normal, ignore the warnings about file size, and shrink the DVD using DVD Shrink.

hmm, i've done a ton of 2 pass vbr encodes using tmpgenc and have never had any problems with it.

the one time i've seen strange encoding using 2pass vbr was when using kvcd templates. It caused the encodes to be smaller than i wanted, but that's because of the type of GOP structure kvcd templates use.

[Shudder]

With mine I usually go for the % option, so 25% if you want 4 avis on a disc, etc.

You'll see the average set up for you already, let's say it's 3700. I set my max to 5700, my min to 1700 and I'm usually just fine at the end. If anything I'm slightly UNDERsized when I make a dvd, but not terribly much, and the picture's good anyway (hundred megs or 2)

[jimmalenko]

Never any probs with TMPGEnc 2-Pass VBR here, either.

[Capmaster]

I have been noticing that as well and I have drawn my own conclusion. It is probably incorrect but I will share it with you. I captured using Virtiual Dub and Huffy. I have noticed that a VBR encode with an average of 4 and a max of 6 almost always comes out at 6 if my source is a VHS. When my capture source is direct from cable it is a lot closer to the average of 4. The only thing that I can figure is that since there is a lot more nosie in my VHS source it needs more bitrate...and since I set the maximum to 6 it uses all of that. Again...I am probably way off base but that is what seems to be happening with my encodes.

That's usually the case. It tries to reproduce the noise and ends up using bitrate.

You might experiment with the input "VCR" filter if it has one. That will most often remove the annoying little specks that you see, and should bring your average closer to what you need.

It will soften the video a bit but I've found that the bitrate I've saved by using the filter will make up for any ill effects it might cause. The result is more pleasing to the eye than the source video