A minor rant and some questions about SVCD encoding...

[legionpc]

Firstly the question. When you download a movie, usually the .bin/.mpg almost completely fills a CD-R, being between 797-800MB big exactly. I was wondering what software can actually get it so precise? My encodes with TMPGEnc using 2-pass VBR (used bitrate calc as well) usually come up 20-80MB short of filling an entire disc. Is different software used to exactly fill a disc?

Secondly. Earlier I encoded a 45 minute XviD to SVCD. Final file came out at 781MB. Nero wouldn't let me burn this. It said the file was too long, and it was 89 minutes long This doesn't matter so much now, I just re-encoded the file, but is it a glitch or what? Be helpful to know if it ever happened again.

Onto the rant...

What is the point of the maximum bitrate setting in TMPGEnc? I set it to 2500 (my player gets picky if video is higher than that) and I run a bitrate analyser on the file, the maximum is about 3200. Real useful

Thanks to anyone who can help

[adam]

Any 2-pass encoding option in any encoder should be almost completely accurate. I don't know how, but TMPGenc does seem to stray away from your set avg bitrate sometimes, but usually by only a negligable amount.

I think your size variance is caused by other factors though. For instance, if you encode both audio and video together in TMPGenc then your file is not multiplexed correctly. Besides probably being non-compliant, the size may be inflated. Your best bet is to demux in TMPGenc and then remux in bbmpeg. In the future I would suggest encoding audio and video separately and then using bbmpeg to multiplex in the end. You can also do your cutting here and it makes the process very streamlined. Make sure and turn off the SVCD scan offsets though, this can add ~50-80MB's to your filesize.

The multiplexor you use and the authoring program you use can affect size slightly as well. You might want to check out FitCD, and if you like it you can get a more finalized version called Fit2Disk by donating a small amount to the author. These programs take pretty much all conceivable factors into consideration when determining the bitrate to use. I can literally hit my target size down to the BYTE level.

Well, I have never been a fan of Nero for authoring SVCDs. I know Nero used to have a strange bug where it would somehow derive the total filesize soley from the playtime, regardless of how big the actual file was. I thought this was fixed a while back though. Its possible that your file was multiplexed incorrectly, and this was causing Nero to misinterpret its filesize. Again, make sure you don't export your mpg directly from TMPGenc because it will often cause problems like this. Personally, I think the best way to author SVCDs is with VCDEasy, which is free. Might want to give that a try.

Back to TMPGenc. I too have noticed that max bitrate set is pretty much ignored. Its one of the bugs that drove me away from that encoder. I think this is caused by another bug which causes GOP lengths to vary despite what you set them as. This causes all sorts of problems, making your mpgs non-compliant, making manual I-Frame insertion useless (I-Frames don't go where you tell them to), making manual bitrate allocation useless, etc... The solution, though far from ideal, is to tick closed GOPs on the GOP Structure tab. This does decrease quality a little though. Even with this set, the max bitrate still doesn't always stay at what it tells you.

One last caveat. Not all bitrate calculators are perfectly accurate. Some of this variance may be caused by bugs outside of TMPGenc.

[legionpc]

The encode process I used was basically:

-Cut avi in half in vdub, extract audio to uncompressed wav for each part
-Open fitcd, calcukate bitrate
-Open TMPGEnc, load ntscfilm svcd template, change CBR to 2 pass VBR and input bitrate settings
-Unlock so that I can encode video only
-Encode audio to 224k 44.1khz mp2, multiplex in tmpgenc

Anyway... you say you were driven away from Tmpgenc. What do you use now?

[adam]

Well the method you use does sound pretty flawless. All I can suggest is to try and multiplex in bbmpeg, it seems to be more consistent than TMPGenc. Other than that, I don't know why your size is off.

I use various encoders for various sources and projects.

Anything interlaced that must stay interlaced ie: DV, I use Procoder with field based encoding.

To make VCDs (though I rarely do this anymore) I use Panasonic mpeg1 encoder.

To make xvcds (though I rarely do this anymore) I still use TMPGenc.

For everything else I use CCE. This is basically my main encoder of choice.

[uxbridge]

Hi
I used TMPGenc 2-pass VBR many times now and I see the same small difference in fitting the disk. If you use FITCD instead of the built-in calculator of TMPGenc, your CD will fit perfectly, assuming you remain above 1150 kbps in video stream.

Just input the result you get with FITCD into your TMPGenc settings, they'll be slightly higher than those autogenerated by TMPGenc. Of course you need to de-select the option that tells TMPGenc to auto compute the speed.

FITCD will compute your speed taking into consideration you burn with Nero. It is a very sophisticated tool.
Another advantage it has, it computes for 90min CD and 99 as well, while TMPGenc stops at 80min.
As far as speed is concerned, I would not go beyond 2520 or 2550 with SVCDs.

Ciao