File size prediction problems
 

Well, I seem to be having the opposite problems of everybody else.

I finally got past the 89.77 issue I was having, happily set up a full encode and took my weary bones to bed, full of confidence. Coincidentally, the 89.77 "bugged" CQ was also approximately the CORRECT CQ for my files. Lo and behold, I wake up this morning to discover that my file had encoded with a final CQ of 2.08 and the file size was about 300MB, rather than the decent CQ and 700MB file size I was expecting. I was crushed, needless to say.

I was also startled when I looked at the CQMatic log to discover that the "file size difference" was INCREASING with each prediction. Can somebody tell me what I'm doing wrong?

This is my .tpr file from TMPGEnc:

And this is my .avs file:

I can't find the CQMatic log on disk to copy, but the first File size difference = 0.369318, the CQ is then reduced from 70 to 25.85 and the resulting File size difference = 0.778977, the CQ was reduced again to 20.14, etc.

You live in south of equator and all things run the opposite way in your country :hihi:

Can you post the log, just to see how that can be ;-)

Edited my first message to include scripts and such, can't fine the log. . . :(

There is no log file but if you double click on the CQMAtic window when job is done, the log is copied to the clipboard and you can paste it in a message on the forum.

BTW, I think that file size diff is supposed to reach the value "1".

Note: you are talking about a target size of 700MB but everything in your tpr and your avs is set to do a KDVD ! (and not KVCD).

Are you sure you didn't make an error ?
What is the length in minute of your video and the average bitrate you put into cqmatic ?

I set it to 700MB so that I can put all 6 clips on one DVD. The clips are all 49 minutes and a varying number of seconds. CalcMatic gives me an average bitrate of between 1060 and 1069, depending on which clip.

Thanks for the copy hint! :) Had to redo this one to get the info again, so I cancelled before it was done, but you can see the pattern. If you are correct in the "approaching 1" assumption, possibly I should put a very high CQ in my .tpr and "override CQ" for the starting point of CQMatic so that it starts with a value greater than 1.

Can you try this : launch CQMatic as always, let tmpgenc starts to encode the first sample and then CLOSE Cqmatic. Wait for tmpgenc to finish.
Look at the size of the m2v file that you obtained. What it is ?
Open this m2v under wmp or other player. Is the length equals to 2 minutes or not ?
Look at the video entirely : no error ? Everything is fine till the end ?

Is this your first KVCD (or KDVD) or did you do other ones before ?
What is your tmpgenc version ?

I've been KVCDing for quite a while with great success once I got over the initial learning curve. These are my first KDVD attempts, as I recently acquired a DVD burner. :) The first three I did when I didn't realize that 89.77 was an error were right in the ballpark for file size. I'm sure you recognize your .avs script there (for which I thank you VERY much). I don't THINK I'm making any mistakes. I will try your suggestion and see what happens. I'll post the results in a few.

TMPGEnc version is 2.521.58.169

Okay, I tried twice, once each with 1X and 3X prediction.


With CQ 60, the 1X resulted in a file size of 40,253. It played perfectly in WinDVD and it was 1 min 5 secs long.

With CQ 60, the 3X resulted in a file size of 117,040 which also played perfectly end to end and was 3 min 11 secs long.

I fear these times are wrong. That happens often that winDVD doesn't give the correct time. Because CQMatic actually encode a 2 minute sample.

Check while tmpgenc is encoding a sample that the number of frame is 120*fps (that is 2880 is you are doing 23.976 fps, 3000 if 25fps and 3600 if 29.970).

But, let assume that it is actually 2 minutes. 40 MB for a 2 minutes sample will lead to a 40 * 49/2 = 980 MB video. You asked for a 700 MB video (that's include the audio, so the m2v must be only 650).

So for sure CQ60 is too big -> CQ Matic logically try to lower the CQ :!:

In other words : you won't be abble to put 6 of your videos on a DVD with such settings !

My advice : start to lower the max bitrate to 3000 except if these are high action movies. Or do a 4-video only DVD.

Look what you're trying to do :!:
You want to put ~294 minutes of video at 704x576 on one 700MB CD :!: 8O
You set the destination to DVD. Not 700MB :!:

-kwag

No Kwag, it didn't said to CQMatic he want to put 6 video on a CD. He know he needs to put 6 video on 4.3 GB so he set "custum size" to 700 MB and predict only for 1 video !

Look at the avgbitrate : 1069 for a 49 min long video. That is correct for 700 MB.

I can agree with the times being wrong, Dialhot. But what I honestly don't understand was why I wound with a 300MB file this morning, rather than the 700MB I was striving for. That may have to remain a mystery, I just want to be done with this project. :) I'm using the 1/2 DVD PAL template now, hoping I can get my proper file sizes with that.

Thanks again for all your help.

Hugs,

Dris

P.S. 1) I really am a "she." :)
2) Thanks for explaining to Kwag. I'm sure he thought I'd lost my everloving mind! :)

Doesn't add up :!:
Say 49 minutes at 128Kbps audio for a custom target of 700MB = 1822.5Kbps average bitrate

-kwag

Oh ! You're right ! How did I do my maths ? :oops:

192Kbps for the sound, Kwag.

And aren't you supposed to use the one next to the little box that says .57*average bit rate?

Then it would be 1758.5Kbps average :D

Edit: Where did you get the 1060 :?:

-kwag

That second little box in Calcmatic . . . :)

You're supposed to take the average bitrate from the text box: Average Bitrate: :!: :!: :!:

-kwag

Okay. *blush* Two questions, also. What's the other box for then? And, what effect will plugging in a faster bitrate have?

I'm trying to learn to UNDERSTAND this stuff, not just be the button pushing monkey I've been so far. :)

The 0.57 * average, is the value to use as MIN bitrate. This increases the prediction accuracy. You mean a higher bitrate :?:
The higher the bitrate, the larger your file size.

-kwag