Prediction with Vmesquita Guide 2.0? - digitalFAQ.com Forums [Archives]
 digitalFAQ.com Forums [Archives] Prediction with Vmesquita Guide 2.0?

#1
03-21-2004, 02:24 AM
 zagor Free Member Join Date: Feb 2004 Location: Italia Posts: 226 Thanks: 0 Thanked 0 Times in 0 Posts
I have followed the guide of vmesquita in order to calculate the sample. my dates are the following:

1st movie - 210.226frames 176m
2nd movie - 146.599frames 98m

then:
audio 1 - (192kbps) - 247,5 Mb
audio 2 - (192Kbps) - 137,8 Mb
audio total = 385,3 Mb

therefore:
4482-200(overmux)-386(audio) = 3896 Mb

356825(total frames)/274/15=86.8187

3896/86.8187=44.87 mb (45952Kb)

therefore I have used:
for 1st movie sample: 32892
2nd movie - sample: 12697

12697+32892 = 45589 < 45952

after encoder I have got for
1st. movie (only mpv): 3,136,910 Kb (3063.4 Mb)
2nd. movie (only mpv): 1,225,433 Kb (1196.7 Mb)

therefore:
1196.7+3063.4 (video)+
385,3 (audio)+
200 (overmux) = 4845,4 Mb > > > 4482 Mb

if I have not made errors, the proposed system does not work!
How ever I got a mistaken prediction?
by[/b]
Someday, 12:01 PM
 Site Staff / Ad Manager Join Date: Dec 2002 Posts: 42 Thanks: ∞ Thanked 42 Times in 42 Posts
#2
03-21-2004, 03:46 PM
 zagor Free Member Join Date: Feb 2004 Location: Italia Posts: 226 Thanks: 0 Thanked 0 Times in 0 Posts
Someone has never used this method?
thanks
#3
03-21-2004, 06:58 PM
 jorel Invalid Email / Banned / Spammer Join Date: Aug 2002 Location: Brasil - MG - third stone from the sun Posts: 5,570 Thanks: 0 Thanked 0 Times in 0 Posts
hy zagor!

if:
1st movie - 210.226frames 176m
2nd movie - 146.599frames 98m

then you wrote:
"therefore I have used:
for 1st movie sample: 12697
2nd movie - sample: 32892 "

and in the final:
" after encoder I have got for
1st. movie (only mpv): 1,225,433 Kb
2nd. movie (only mpv): 3,136,910 Kb"

how the final size of the 1st movie have less size than 2nd movie?

maybe the reason is that you got
"for 1st movie sample: 12697"
and
"2nd movie - sample: 32892 "
that is strange too because the 1st movie have more size than the 2nd movie
but in the final, the 2nd movie have more size than the 1st movie!

something is wrong in your prediction, don't?
#4
03-22-2004, 03:44 AM
 zagor Free Member Join Date: Feb 2004 Location: Italia Posts: 226 Thanks: 0 Thanked 0 Times in 0 Posts
ok, jorel
i have edited my previous post.
I had invert simply the two values.
thanks
#5
03-22-2004, 05:51 AM
 jorel Invalid Email / Banned / Spammer Join Date: Aug 2002 Location: Brasil - MG - third stone from the sun Posts: 5,570 Thanks: 0 Thanked 0 Times in 0 Posts
right zagor.

and can't find anything wrong now
only the final sizes of course!
using the values that you found after prediction !

i'm still think that have something strange, take a look:
see the proportional frames from 1st movie and the 2nd movie...,
1st movie - 210.226frames 176m
2nd movie - 146.599frames 98m

the 1st have ~double size/time of the 2nd but
the final size of the 1st is too big comparing with the final size of the 2nd !
means...more than double size of the 2nd.

1st. movie (only mpv): 3,136,910 Kb (3063.4 Mb)
2nd. movie (only mpv): 1,225,433 Kb (1196.7 Mb)

1st movie have 1839,7 MB more than 2nd movie.
the proportion, comparing with the sources is lost!

better is wait for vmesquita, he will help us!

#6
03-22-2004, 06:21 AM
 Dialhot Free Member Join Date: May 2003 Posts: 10,463 Thanks: 0 Thanked 0 Times in 0 Posts
FYI : did you see that Vmesquita acutally did a calc that give aotumatically the wanted sample size according to parameters of the video you plan to encode ?

Quote:
 if I have not made errors, the proposed system does not work!
No one never said that the predcition was 100% accurate ! That's the same as TMPGENC and CQMatic : the only way to be sure at 100% of the predicted value is to... take a sample taht is the length of the movie !
#7
03-22-2004, 06:52 AM
 zagor Free Member Join Date: Feb 2004 Location: Italia Posts: 226 Thanks: 0 Thanked 0 Times in 0 Posts
I think that there is an error in the formula.

4482-200(overmux)-386(audio) = 3896 Mb

356825(total frames)/274/15=86.8187 (why?)

3896/86.8187=44.87 mb (45952Kb)

I think that it's need to proceed in this way:

4482-200(overmux)-386(audio) = 3896 Mb
3896/100=38.96 mb

because when use sampler (lenghth=15) in the script, I have the relative sampling to 1/100 of frames totals of the movie!!!

it's all right?
#8
03-22-2004, 07:30 AM
 Dialhot Free Member Join Date: May 2003 Posts: 10,463 Thanks: 0 Thanked 0 Times in 0 Posts
Quote:
 Originally Posted by zagor because when use sampler (lenghth=15) in the script, I have the relative sampling to 1/100 of frames totals of the movie!!!
Not at all : sampler takes one sample per minute of the movie and each sample is "length" frame long.

That is why in you case (274 minutes and length = 15) you have the formula : 356825(total frames)/274/15

If you thought that sampler gives you exactly 1/100 of the total frame number it's probably because 176/25*15 = 105.6 (~100)
In other words, that is just a coincidence.
#9
03-22-2004, 08:20 AM
 zagor Free Member Join Date: Feb 2004 Location: Italia Posts: 226 Thanks: 0 Thanked 0 Times in 0 Posts
I have dowloaded the calc file, and as I said before:

Desired Sample Size is 38.8744 Mb

I can't post the image but it's so!

....and this is not a coincidence!!!

[/quote]
#10
03-22-2004, 09:01 AM
 Dialhot Free Member Join Date: May 2003 Posts: 10,463 Thanks: 0 Thanked 0 Times in 0 Posts
Ok, I found where your problem is :
Quote:
 1st movie - 210.226frames 176m
Assuming your sources are PAL, so 25 frame per seconds :

176 min * 60 * 25 = 264000 (and not 210266)

and

210266 / 60/25 = 140 min (and not 176)

#11
03-22-2004, 11:03 AM
 jorel Invalid Email / Banned / Spammer Join Date: Aug 2002 Location: Brasil - MG - third stone from the sun Posts: 5,570 Thanks: 0 Thanked 0 Times in 0 Posts
right Phil!...

the guide need corrections or i loose something?!?!?
i can't find it there for pal or ntsc sources.

#12
03-22-2004, 11:12 AM
 Dialhot Free Member Join Date: May 2003 Posts: 10,463 Thanks: 0 Thanked 0 Times in 0 Posts
Quote:
 Originally Posted by jorel Let's say you have 500000 frames, 353 minutes (5h53m), you would do: (500000/353/GOP). Put this number on the calc's memory. " the guide need corrections or i loose something?!?!?
You means because 500000 frames can't give 353 minutes whatever the framerate you use (23.976, 24, 25 or even 29.970) ? You are right.

But this is an EXAMPLE ! That is not a matter if an exemple isn't realist. The goal is to make understand the IDEA. And the idea is that you have to divide the number or frames by the number of minutes and then by the length of the GOP.
#13
03-22-2004, 11:17 AM
 jorel Invalid Email / Banned / Spammer Join Date: Aug 2002 Location: Brasil - MG - third stone from the sun Posts: 5,570 Thanks: 0 Thanked 0 Times in 0 Posts
i edited my last post cos was "too big" but you read before i edit.

i got the "idea" Phil, very clear!

Phil wrote:
"And the idea is that you have to divide the number or frames by the number of minutes and then by the length of the GOP."
#14
03-22-2004, 04:02 PM
 zagor Free Member Join Date: Feb 2004 Location: Italia Posts: 226 Thanks: 0 Thanked 0 Times in 0 Posts
I have found the error!
about to the first movie, the correct values are:
frames: 258098
Time: 2.52.03 (172.01m)
258098/172,01/60 = 25fps.

again:
404.697/(172.01+97.73)/15 = 100,02

now I want to codify the first one in ac3 to 320 and the second in sourround2 to 192.

therefore I will have:
172.01x2400 = 403,15 Mb
97,73 x1440 = 137,43 Mb
total audio: 540,58 Mb

at the end:
4482-200-540.48 = 3741.42/100.02=37,4067 Mb =

sample = 38.304 kb

calculate with vmesquita's Calc is:

37,4142 Mb!
yuuuuuuu

when I will have encoded I will make you to know the filesize.

byebye
#15
03-22-2004, 05:01 PM
 Dialhot Free Member Join Date: May 2003 Posts: 10,463 Thanks: 0 Thanked 0 Times in 0 Posts
Quote:
 Originally Posted by zagor I have found the error!
YOU found
Read my post at 3:01 pm

Quote:
 sample = 38.304 kb calculate with vmesquita's Calc is: 37,4142 Mb!
Actually I foudn also diff in VMesquita calc when you set the audio bitrate in the toggle, oy when you put manually the audio size in MB. I don't know why there as such diff.
#16
03-22-2004, 05:35 PM
 vmesquita Invalid Email / Banned / Spammer Join Date: May 2003 Posts: 3,726 Thanks: 0 Thanked 0 Times in 0 Posts
Oops, I came too late... I am glad you were able to figure out. Great!
#17
03-22-2004, 05:51 PM
 Dialhot Free Member Join Date: May 2003 Posts: 10,463 Thanks: 0 Thanked 0 Times in 0 Posts
Vmesquita, as you are there can you :

1/ tell me why when I put for instance "320" in audio bitrate, the sample size is 37 MB (is just an example) and if I put insteed of the bitrate the actual size of the audio file that I have on my disc, the sample size is 36.8 MB ?

-> it seems that your calc for audio file size according to the bitrate is wrong. May be a matter of convertion between Bytes and MB ?

2/ In you calc you forgot 384 as audio bitrate ! You have 320 and 448 but nothign beteween the two . Can you change that please ?
#18
03-23-2004, 03:50 AM
 zagor Free Member Join Date: Feb 2004 Location: Italia Posts: 226 Thanks: 0 Thanked 0 Times in 0 Posts
it is a po difficult to explain, but I will try it.
I had read yours post, only that I did not succeed to understand why Virtualdub had given those values to me:

1st movie - 210.226frames 176m

Then I have remembered to me that when I have used dvd2avi for
the first time, he seems me to have activated the option "Force Film" as written on the guide of vmesquita.
After I have understood that it did not have to activate such option, but I already had annotated those values for the first film.
For which the film he came codified in 20fps.
in fact 210226/176/60 = 20fps.

Therefore when I have written "I have found the error" I mean :
to have found from where the values of frame exited and Time of the first film.

@Dialhot. Yes, you have found the error! thanks. You have much "intuito" (I do not know it like translate)

Quote:
 2/ In you calc you forgot 384 as audio bitrate ! You have 320 and 448 but nothign beteween the two . Can you change that please ?
In mine version (1.1) i have 384 as audio bitrate! I don't have 320 kbps!

byebye
#19
03-23-2004, 05:41 AM
 Dialhot Free Member Join Date: May 2003 Posts: 10,463 Thanks: 0 Thanked 0 Times in 0 Posts
Quote:
 Originally Posted by zagor After I have understood that it did not have to activate such option, but I already had annotated those values for the first film. For which the film he came codified in 20fps. in fact 210226/176/60 = 20fps.
Okay
The option "force film" is related to NTSC video only. It's purpose is to "convert" 29.70 fps video into 23.976. If you apply this on a regular PAL video (25 fps) you obtain a 20 fps video.

Quote:
 In mine version (1.1) i have 384 as audio bitrate! I don't have 320 kbps!
Ugh... you are probably right. I know for sure that a value is missing, but I don't have the tool at my office. Perhaps is 320 the missing value.

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