MeGui AR problem

[ubertoast]

I have searched the forums, but couldnt find something similar to what i am having. Some of the DVD i have been encoding recently with the new updates of megui play back completely streched. In VLC for example it stretches the video so that its almost a thin horizontal line. In MPC, it does the opposite and streches it vertically. I am not talking about a small stretch, i mean the video is played back at like 1000x50 or 50x1000 (not actual numbers)

However, when i merge the video with the audio using mkvmerge, putting int he correct AR, it fixes the problem. But it still bothers me. Anyone know what might be causing this?

[Avenger007]

If you already know the correct AR then use the --sar w:h option in x264.

[ZombiePimp]

Known bug
http://sourceforge.net/tracker/index.php?func=detail&aid=2010131&group_id=156112&atid=798476

[ubertoast]

Just wanted to update my situation.
I did some additional research and came across a thread on how to set the correct sar manually.

I use ntsc dvds, and added --sar 32:27 in the custom command, and it worked perfectly.

[chainring]

Just wanted to update my situation.
I did some additional research and came across a thread on how to set the correct sar manually.

I use ntsc dvds, and added --sar 32:27 in the custom command, and it worked perfectly.
For a bit more precision, use "--sar 40:33", which is MPEG-4 PAR.

[ubertoast]

@ chain: Yea i was just reading up a bit on the different sar tables, and someone else also recommended to use 40:33, so i will try that one out next time. I think i got lucky and had a generic dvd, so my resolution with 32:27 on my last encode matched perfectly with the dvd.

[jmnk]

40:33 id 4:3 AR while 32:27 is 16:9 AR
are you sure about that? Assuming we are talking NTSC DVD, and the numbers mean SAR (which is what chainring and ubertoast talk about) using --sar 40:33 is a perfectly valid SAR to get 16:9 display aspect ratio out of DVD encoded/cropped to 704x480. He is going to get 704 x 40 : 33 by 480 which is ~853 by 480 which is definitely 16:9 Display Aspect Ratio

[Sharc]

Assuming NTSC DVD, 16:9 DAR:
SAR 32:27 = 1.1852 => "Generic"
SAR 40:33 = 1.2121 => MPEG4 specification
SAR 5760:4739 = 1.2154 => Rec. ITU-R BT.601

Unless you know how the original DVD has been mastered you cannot be sure which SAR to choose. Fortunately they dont differ much, so one will hardly notice the aspect ratio error if you should choose the "wrong" SAR.
I would assume (not sure though) that most commercial DVDs follow the ITU-R specification, which is very close to the mpeg4 spec.

[Sharktooth]

are you sure about that? Assuming we are talking NTSC DVD, and the numbers mean SAR (which is what chainring and ubertoast talk about) using --sar 40:33 is a perfectly valid SAR to get 16:9 display aspect ratio out of DVD encoded/cropped to 704x480. He is going to get 704 x 40 : 33 by 480 which is ~853 by 480 which is definitely 16:9 Display Aspect Ratio
yes, you're right.
note to self: never talk when you're confused by meds...
Sharc has the ball and made a touch down though.

[chainring]

Assuming NTSC DVD, 16:9 DAR:
SAR 32:27 = 1.1852 => "Generic"
SAR 40:33 = 1.2121 => MPEG4 specification
SAR 5760:4739 = 1.2154 => Rec. ITU-R BT.601

Unless you know how the original DVD has been mastered you cannot be sure which SAR to choose. Fortunately they dont differ much, so one will hardly notice the aspect ratio error if you should choose the "wrong" SAR.
I would assume (not sure though) that most commercial DVDs follow the ITU-R specification, which is very close to the mpeg4 spec.
I agree 100%! After experiencing the AR bug with meGUI, and scratching my head following many encodes because the AR was off, I read up on SAR. Not too much searching lead me to a post by Brother John and his explanation of the different values quoted above. Well, some testing, more testing on different source material, screen shots, etc..., I ended up with --sar 40:33. It's close enough to the original AR, for my eyes and purposes, to call it done. I just have a few CRF profiles in meGUI, two for 16:9 sources (CRF 18 & 20, each with --sar 40:33), then one for 4:3 sources (CRF 20 with --sar 10:11). That's it; simple encodes after a mod-16 overcrop and commenting out the dar_x and dar_y values in the resulting .avs.

[jmnk]

yes, you're right.
note to self: never talk when you're confused by meds...
Sharc has the ball and made a touch down though.
I just wanted to make sure that no one quotes this particular post of yours later on. People do take your word as gospel - as they should I might add.
Hope you are better.

[Sharktooth]

sure... il delete it.
i think you were referring the the wrong one though. is it ok now?

[Octo-puss]

What are all the most used SARs btw? I just add --sar 64:45 to all my DVDs when encoding as they are 16:9.. which is all I know :) Well, they also are PAL, but.. I really don't understand this much.

[Sharc]

'Most used', or perhaps 'most practical' SARs for anamorphic DVDs, I would say:
NTSC 4:3 => sar 10:11 (or 8:9)
NTSC 16:9 => sar 40:33 (or 32:27)
PAL 4:3 => sar 12:11 (or 16:15)
PAL 16:9 => sar 16:11 (or 64:45)

[Octo-puss]

Hey hey! Hold your horses! :)
What's the "or" part? :)

I also saw some other values... big numbers... and different small ones too. So what's the deal?

edit: this is what I got copied from some post around here:
PAL 16:9 -- 64:45 || PAL 4:3 -- 64:60 || NTSC 16:9 -- 64:54 || NTSC 4:3 -- 64:72

[Sharc]

You may want to ask the studio how they mastered the DVD. It's not printed on the cover.
Anyway, the difference with the (or .....) is low enough and will normally not be noticed when watching the movie. So you may just forget the (or ....).
Of course you will find other values, but you asked for the most commonly used ones.
Btw. sar 64:60 = 1.06666 = sar 32:30 = sar 16:15 .... all the same, no difference.

[Octo-puss]

So of all common vaules, those "or" are used less frequently?
The resulting numbers do differ, of course :)
And yeah I guess you are right about the noticeability... but still :)

[Sharc]

So of all common vaules, those "or" are used less frequently?

I can't tell for sure, but when people complain about visible AR errors it is normally not because of this small difference of less than 3%.

[Octo-puss]

'Most used', or perhaps 'most practical' SARs for anamorphic DVDs, I would say:
NTSC 4:3 => sar 10:11 (or 8:9)
NTSC 16:9 => sar 40:33 (or 32:27)
PAL 4:3 => sar 12:11 (or 16:15)
PAL 16:9 => sar 16:11 (or 64:45)

You may want to ask the studio how they mastered the DVD. It's not printed on the cover.
Anyway, the difference with the (or .....) is low enough and will normally not be noticed when watching the movie. So you may just forget the (or ....).
Of course you will find other values, but you asked for the most commonly used ones.
Btw. sar 64:60 = 1.06666 = sar 32:30 = sar 16:15 .... all the same, no difference.

I must post a reply after today's testing.
12:11 is NOT a good ratio. When compared to the DVD, it's horizontally bigger and doesn't look too right.
16:15 on the other hand looks identical.
64:40 is 1.6 precisely, btw :) Only 32:30 and 16:15 are exactly same.
Might also be some kind of bug, but 64:40 turned the image to some ultra widescreen or what. 2:1 to be precise.

[J_Darnley]

12:11 is what is defined in the MPEG-4 spec. 16:15 is what mathematics tells you to turn a 5:4 picture into a 4:3 picture. Sharc never said 64:40, he said 64:60 which is the same as 32:30 and 16:15.

[Octo-puss]

oh, I mislooked


defined or not, compared to DVD it looked like crap :)
Why those different numbers when its mathematically the same though?

[J_Darnley]

Using 64:60, 32:30 or 16:15 will all produce identical output video because x264 will simplify the first two to 16:15.