2pass mpeg-1 in TMPGEnc doesn't hit right size.

[hamsolo]

I tried 2-3 days ago the make a VBR encoded xVCD with TMPGEnc:

Video: 2pass-vbr at average 1085kbps
audio: 160kbps
length: 43m 23s = 2603s
Result should be (1085kbps+160kbps)/8*2603s=405091,88kb=395,6mb
Result IS only 346mb

Why? I tried to encode it twise first with "2-pass" second with "2-pass (old)" just in case it malfunctioned with one of them. (I don't-know the difference between "2pass" and "2pass (old)"

I just finished encoding same file with CBR it turned out at 391,5mb alot closer when the 346mb.

Version used 2.53-plus Evaluation.

PS. I also did a SVCD with 2pass VBR same result nearly 50mb under what it should be.

[homerpez]

TMPGENc has always been inaccurate when it comes to exact file sizes using 2-Pass. Worse yet with CQ_VBR modes...

If you want to get EXACT file sizes, I strongly reccomend you use CCE multi-pass for your video stream, TMPGEnc for audio stream.

Calculate file size with FItCD, input the number there -5 bps (if it says 1254 bitrate average, do 1249). With me, it has never failed. It will alywas come within 5-10 megs below the size the CD holds (after re-multiplexing, etc)

[hamsolo]

CCE? I've seen people in here talk about it but what is it?

[sean madison]

i can calculate vbr, it's so freakin easy.

Just use my calc if u have it to get the max cbr value.

Then, import that number as the average, min-0 and max- 450+ bitrate that calc gave you.

Resulting file size- 784-792mb all the time. Been tested now on 8 different dvds.

Fit perfectly on 1 80min cd.

[homerpez]

CCE? I've seen people in here talk about it but what is it?

CinemaCraft Encoder... costs $1000 or more... sometimes.

I should have read more carefully, though... you're doing MPEG-1. Before I get you into a lot of trouble and you blame me... CCE is not known for the most stable MPEG-1 VBR encoding. Its strength is definitely for MPEG-2 VBR multipass.

You can certainly do multipass encoding with MPEG-1 using CCE, but it, well... it acts "funny". So I don't reccomend it for that...

One thing I would, though... with TMPGEnc... do you have "Detect Scene Change" turned on? This can cause problems, in more ways than one.

One thing it effects is the file size. When this is turned on, it will detect when a scene changes, and put a weighty "I" frame there. This adds a suprising amount to the file size.

[hamsolo]

Yes I have/had it on, but I only used it because it seemed to to be "standard" in TMPGEnc