Quantcast Weird Image Shrinking in TMPGEnc - digitalFAQ.com Forums [Archives]
  #1  
12-26-2004, 11:23 AM
rds_correia rds_correia is offline
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Hello,
I've been doing some tests with tmpgenc latelly and I've come up with something very strange.
At the time, I'm comparing tmpgenc 2.254.63.181 with Peter Cheat's NuEnc 0.01b.
All my tests are based on MPEG-1 encoding.
Here's the strange issue.
When comparing tmpgenc/nuenc's frames I noticed some very weird image shrinking in tmpgenc.
Here's the script I used on both encoders:
Code:
Mpeg2Source("D:\XMEN2\D2V\X2.d2v")
Letterbox(74,74,8,8)
Trim(0,5000)
Accoring to the Letterbox I'm using, I am doing an overlap overscan=1, right?
Now look at some screenshots from both encoders.
TMPGEnc CQ 63.3 - Frame# 2242 - Frame type=I


NuEnc CQ 85 - Frame# 2242 - Frame type=B


Thanks to ImageShack for Free Image Hosting

Now notice that tmpg's screenshot almost makes you think that I set up the overscan=2, right?
But I didn't
It's set up for overscan=1 from the script
Do notice that all the frame information is really in the screenshot.
It's just as if it shrinked the image by a fraction
Now notice nuenc's screenshot.
It looks normal, and it is fractionally worse than tmpg's, I mean quality wise.
But quality comparison is not the main issue here, even because the frame types don't match up with eachother
Can somebody try to replicate this, please?
Maybe I'm doing something wrong in tmpg.
BTW, I have tried several "Video arrange method"'s in tmpgenc, but they all look the same.
Here's some screenshots of my settings on both tmpgenc and nuenc:





(This one is too small to generate a thumbnail, that's why it's the original)

Hope somebody can try to replicate this and can even come up with a theory as to why tmpgenc does shrink the image.
Cheers

EDITED:
Here is a screenshot without the "shrinking" issue encoded with Video Arrange Method Full Screen, as
per Karl's suggestion
TMPGEnc CQ 63.3 - Frame# 2242 - Frame type=I

Please click on the thumbnails to see larger images.
And once again, Thanks to ImageShack for Free Image Hosting.
Cheers
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  #2  
12-26-2004, 11:59 AM
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a long time ago, before the wheel discovery i post about it but only get discussions( i was elected as st.., idi...and some more "cool" synonymous and people with strees to answer),then forget my opinion(maybe in portuguese i can told for you) but in one hint i "insist":
post the links and right vlick to open a new page for each picture,is easy to compare:

http://img70.exs.cx/img70/2057/x2tmpg2242i1kd.jpg

http://img62.exs.cx/img62/5176/x2nuenc2242b3cp.jpg



ps:
Correia, i'm talking with you and to myself:
why people delay months to see what i saw first? (poor english to write?...!)
search (if you have time/patience)and you will find exact what you're showing!
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  #3  
12-26-2004, 12:03 PM
kwag kwag is offline
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Hi Rui,

Set "Full Screen" in TMPEG under "Video arrange method". Not Full Screen (Keep Aspect)
That's why TMPEG cut off some edges

-kwag
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12-26-2004, 12:30 PM
rds_correia rds_correia is offline
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@Karl
Damn I am sure I have already tried that.
But I'm testing again.
Thanks for the tip.
I'll post the results in some minutes.
@Jeo
Thanks for the tip about the links.
But I'm affraid as soon as I figure out what's going on, I'll post the thumbs instead.
As for the poor English, forget it: there's no problems understanding you buddy.
Cheers
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12-26-2004, 12:48 PM
rds_correia rds_correia is offline
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@Karl
Ok, It was down to the Video Arrange Method .
I would swear I had already tried Full Screen before without curing it, but apparently I didn't.
I was almost believing tmpgenc had some problem .
BTW, I thought this VAM had something to do with the SAP.
Some SAP's would like Center better than Full Screen and some otherwise.
What about those other options that say "keep aspect ratio" and "keep aspect ratio 2"?
In which cases should they be used?
Does it have any influence the target your aiming KSVCD/KDVD and the VAM you choose?
I don't think so, but I'd be glad to be 100% sure.
Could you enlighten me on this matter?
Now that I come to think of it: I've done several KDVD using Center (keep aspect ratio).
Should I reencode those in FS?
Thanks for the tips.
Cheers
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12-26-2004, 12:58 PM
kwag kwag is offline
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Quote:
Originally Posted by rds_correia
@Karl
Ok, It was down to the Video Arrange Method .
I would swear I had already tried Full Screen before without curing it, but apparently I didn't.
Quote:
I was almost believing tmpgenc had some problem .
BTW, I thought this VAM had something to do with the SAP.
Some SAP's would like Center better than Full Screen and some otherwise.
If you are using an AviSynth script, using "Center" of "Full Screen" is the same thing.
Quote:
What about those other options that say "keep aspect ratio" and "keep aspect ratio 2"?
In which cases should they be used?
Under some rare conditions, and when you are NOT using AviSynth, only
Quote:
Does it have any influence the target your aiming KSVCD/KDVD and the VAM you choose?
Yes, because it will affect final aspect ratio and size.
Quote:
I don't think so, but I'd be glad to be 100% sure.
Could you enlighten me on this matter?
Now that I come to think of it: I've done several KDVD using Center (keep aspect ratio).
Should I reencode those in FS?
Yep. You shure should
Either "Center" or "Full Screen", but no "X_(keep aspect)" option.

-kwag
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  #7  
12-26-2004, 01:18 PM
rds_correia rds_correia is offline
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Quote:
Originally Posted by kwag
If you are using an AviSynth script, using "Center" of "Full Screen" is the same thing.
Yes indeed.
It seems that I only tested x_(keep aspect) VAM options .
Shame on me
Quote:
Under some rare conditions, and when you are NOT using AviSynth, only
Ok, since I'll only be using AVS as source, I'll be fine with Center/FS
Quote:
Yes, because it will affect final aspect ratio and size.
Damn, damn, damn!
Quote:
Yep. You shure should
Either "Center" or "Full Screen", but no "X_(keep aspect)" option.
And you don't believe me when I tell you I am still a big noob
Now, I'll have to reencode them all over again, grrrr
Thankfully, I put a label on everyone of them with the settings used, phew.
It won't be hard to locate them and reencode them
I've edited my 1st post to reflect the answer you guy gave me.
Thanks for all the tips.
Cheers all
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  #8  
12-26-2004, 01:20 PM
kwag kwag is offline
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Quote:
Originally Posted by rds_correia
Now, I'll have to reencode them all over again, grrrr
The good thing about that is that now you'll make them better
The more we encode, the better we get at it

-kwag
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  #9  
12-26-2004, 04:57 PM
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Quote:
Originally Posted by rds_correia
EDITED:
Here is a screenshot without the "shrinking" issue encoded with Video Arrange Method Full Screen, as
per Karl's suggestion
TMPGEnc CQ 63.3 - Frame# 2242 - Frame type=I
here we go again:.....

http://img70.exs.cx/img70/2057/x2tmpg2242i1kd.jpg

http://img62.exs.cx/img62/5176/x2nuenc2242b3cp.jpg

http://img137.exs.cx/img137/8342/x2tmpg2242igood5hi.jpg

you see differences between pictures 2 and 3 ?
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  #10  
12-26-2004, 05:01 PM
kwag kwag is offline
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Quote:
Originally Posted by jeo
you see differences between pictures 2 and 3 ?
There is no difference at all (aspect wise, I mean), if TMPEG is set to "Full Screen", and then the same script is used for TMPEG and NuEnc.
The result is identical.

-kwag
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  #11  
12-26-2004, 05:08 PM
jeo jeo is offline
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Quote:
Originally Posted by kwag
There is no difference (aspect wise, I mean), if TMPEG is set to "Full Screen", and then the same script is used for TMPEG and NuEnc.

-kwag
(of course, about aspect wise)
i still see less details in the very bottom (thin bright line) of tmpgenc picture!(but is irrelevant)

edited:
Correia, is possible a picture from the source?
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  #12  
12-26-2004, 05:12 PM
kwag kwag is offline
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Quote:
Originally Posted by jeo
i still see less details in the very bottom (thin bright line) of tmpgenc picture!(but is irrelevant)
Yes, it's not relevant, because Rui was not talking about details.
His post was about the aspect ratio, and it was because he was using "Keep Aspect" on TMPEG.
Yes, I do see differences in details, but that was not Rui's issue

-kwag
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  #13  
12-26-2004, 08:41 PM
rds_correia rds_correia is offline
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Quote:
Originally Posted by jeo
Correia, is possible a picture from the source?
All is possible, Jeo.
Here's the original frame:

BTW, I've talked with the Admins in private, regarding the "thumbnails/links to full screen images", and we have agreed to keep the thumbnails instead of the links.
It's not because we are not entitled to use the links, but more because it is much better for the future of Imageshack as they will have much more registered users

Quote:
Originally Posted by kwag
Yes, it's not relevant, because Rui was not talking about details.
His post was about the aspect ratio, and it was because he was using "Keep Aspect" on TMPEG.
Yes, I do see differences in details, but that was not Rui's issue
Yes Karl, you're right on it.
My goal was not picture details.
My goal was simply about Aspect Resolution coming from Tmpgenc.
Jeo, as we know, has a very good "eye" for picture quality.
I'll release a picture from the source so that he can take a look at it, quality wise.

@Mods
Please, split this thread from this post on.
It will have a more quality-wise approach from this point on.
And since I'm comparing NuEnc(libav) with Tmpgenc, I would think that the most appropriate place to drop it is the Freenc/Nuenc forum .
Cheers

EDITED:
Post splitted here

http://www.kvcd.net/forum/viewtopic....hlight=#114108
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12-26-2004, 08:59 PM
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Quote:
Originally Posted by rds_correia
On this last one it's amazing how both encoders are SO FAR AWAY from the original frame...
On all your examples it's clear that the # of the frame reported by the encoders and the original one is not the same. See your #1884
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  #15  
12-26-2004, 09:01 PM
rds_correia rds_correia is offline
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Damn.
You're right Phil.
Let me check what's happening with VDubMod.
TIA
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12-26-2004, 09:03 PM
kwag kwag is offline
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Quote:
Originally Posted by rds_correia
4-Tmpg output is much darker than the original VOB.
Could it be because you have "Output YUV data as Basic YCbCr not CCIR601" option "checked"

-kwag
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  #17  
12-26-2004, 09:09 PM
rds_correia rds_correia is offline
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Quote:
Originally Posted by kwag
Could it be because you have "Output YUV data as Basic YCbCr not CCIR601" option "checked"
Nope.
Karl, just checked it and it's disabled.
I'll get back to split this message myself.
Half will go to the NuEncs forum and the other half will stay here.
Stay tunned.
Cheers
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  #18  
12-26-2004, 09:42 PM
rds_correia rds_correia is offline
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Ok guys.
Unfortunately I had to split the post to the NuEncs forum because it didn't have much more to do with Tmpgenc anymore.
It's now about NuEnc's output quality.
But the mistery of the "dark" frames remain .
Here is a set of comparison frames.
Original:

NuEnc's:

Tmpg's:

Thanks to ImageShack for Free Image Hosting
A penny for your thoughts
Cheers
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  #19  
12-26-2004, 09:59 PM
Dialhot Dialhot is offline
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Can you add a "Limiter()" at the end of your script and do the comparison again ?

Else the problem can comes from internal RGB convertion (let me remind you that tmpgenc works in RGB24 and not RGB32 -> lost of luma here ? )
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  #20  
12-27-2004, 07:35 AM
rds_correia rds_correia is offline
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Will do.
I'll let you know after I run the test.
Godd thinking, btw.
Cheers
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