PreProcessing Source/Divx5.02 -> Undersized

[Alain_French]

I encode some no-DVD MPEG2 file. (Capture with ATI TV)

Usually, i put my MPG in DVD2AVI->d2v->GKnot->Good file size.

But the problem is that my TV reception is bad. So i want to put some filtre of avisynth : SpatialSoften(3,5,5). But the encoding time is too high. 30hours for 40min of film :(

That's why i have tested the preprocessing source in the codec and the result is good et encoding time too. BUT the size is very bad. 43Mo undersized ! I put 1075kbps et the result is 1000kbps !

How can i have a good file sized ?
What happend when preprocessing source is active ? (i select extreme mode)

I m sorry for my english, i hope you'll understand me :D
Thanks for your answer

Alain

[hakko504]

Did you run a compression test? What value did you get, >100%, 80-100% or <80%?
>100%: You cannot reach this filesize. Try turning off b-frames or increasing audio bitrate.
80-100%: Codec problems, try using jonny's DivX5Enc instead in size prediction mode and run some prediction tests with average quant 2 or 2.1 (increase it 0.1 until you get correct filesize)
<80%: Shouldn't happen. You sure you made a compression test?You can also try Convolution3D. Noit quite as slow as spatialsoften. Oh, and almost everything of what I've written here is stuff you could have found if you had used the search button, keyword 'undersized' or simple read the sticky thread called Undersized files, why do you get them and what can you do about it (http://forum.doom9.org/showthread.php?s=&threadid=24584)

[Alain_French]

The compression test (on gknot) give me : 25,8% of 0.513 (in gknot) Perhaps i don't know how do a compressibility test.


I have endoded the same film. With or without the pre-processing source option in the codec 5.02.
Without : 350Mo the size is excellent. Encoded with GKnot directly.
With : 323Mo instead of 350Mo encoded with vdub (gknot can't put the pre-processing source option in the codec ?). I have entered, the bitrate give me by GKnot (1075kbps).

Thats why, i think this is a problem with this option.
I going to try the convolution3D !

Thank you

[N_F]

Just for fun, try encoding without preprocessing manually in VDub (as opposed to through GKnot) and see if you still get 350 MB.

[hakko504]

25% is very low. Usually you shouldn't go below 40% for reasonable quality, and 60% for normal quality. And when I see that I understand why you think there is a problem with the preprocessing in the codec. You shouldn't be able to get undersized files at that point.
You did remember to mux the audio with the video? In your first post you saidthat the file was 43MB undersized for a 40 min clip, and audio at 128kbps uses about 1MB/minute...

[jonny]

What hakko says is correct.
This thing sound strange to me too.

40 min = 2,400 sec
1,075 kbit/sec = 1,075,000 bit/sec = 134,375 byte/sec

2,400 sec * 134,375 byte/sec = 322,500,000 bytes or 308 MB + some avi overhead.

350 MB are too much! (here there is audio)

[Alain_French]

hakko> the value in my second post are OK. In my file the audio is muxed.
For the 25%, i don't know really how does it work !
I do the compressibility test on the MPEG. But i encode with TRIM to keep only the film and no the advertisement.
If, i put the time of film in gknot, the value of compressibility test is among 45%.

johnny>i am ok with your calcul. But in my size the audio is muxed.
So i have 27Mo undersized.

N_F>Before, i encode i understand GKnot could encode directly, i encoded all my film in virtual with the information give bu GKnot.
The sized was less correct, but in general, i had only 2/3Mo undersized.

*So with GKnot, 350Mo predicted, and the encoded file do 350Mo.
*With VDub, to apply preprocessing source, bitrate is 1075kbps, and the bitrate of the encoded file is among 1000kbps.

The size preticted is for 40min with sound 128kbps MP3.

[Alain_French]

Finally, it works !
I don't know what it was the problem, but i have restore codec defaults and after it works ! I have the good sized 348Mo for 350Mo predicted.

The difference beteewn the vdub scripts are in the setcompdata.
I look for into the forum for some explanation to decode the setcompdata. But i found nothing, only people who have the same problem.

[jonny]

If you send me the scripts i'm able to take a look ^^