--par as replacement or alternative for --sar

[stax76]

Would be nice to have --par as replacement or alternative for --sar, Sample Aspect Ratio appear to be a big mistake to me!

[roozhou]

It is easy to make a patch, either to code or to binary.

[nm]

Would be nice to have --par as replacement or alternative for --sar, Sample Aspect Ratio appear to be a big mistake to me!

By PAR, do you mean Picture Aspect Ratio? I'd prefer Display Aspect Ratio (DAR) to avoid confusion with Pixel Aspect Ratio (=SAR).

[Selur]

@stax76: what's the problem with '--sar' ?

[stax76]

It is easy to make a patch

That's indeed easy since it involves changing exactly only one character. :)

what's the problem with '--sar' ?

Did you think about what could be the problem?

By PAR, do you mean Picture Aspect Ratio

No, from where do you have Picture Aspect Ratio?

[nm]

That's indeed easy since it involves changing exactly only one character. :)

Ok, this explains what you mean.

No, from where do you have Picture Aspect Ratio?

You didn't say anything about Pixel Aspect Ratio, so I guessed.
Anyway, this confusion already demonstrated why SAR is used in x264.

[stax76]

I don't know the exact history, I was reading the MPEG-4 standard uses Sample Aspect Ratio. This appears to be brain dead to me for two reasons:

1. The MPEG-2 standard uses PAR for the same thing
2. The resulting acronym SAR was already established for Storage Aspect Ratio.

[Selur]

when you use: sar you 'collide' with Storage Aspect Ratio, when you use par you collide with Picture aspect ratio
-> No real gain from par, so I would stay with sar since it's a H.264 codec and like you said "the MPEG-4 standard uses Sample Aspect Ratio"

[stax76]

If people would agree that Picture Aspect Ratio and Sample Aspect Ratio is stupid then there wouldn't be a collision and people could use 3 letter acronyms again. x264 is responsible for the confusion since before that everybody was using PAR for Picture Aspect Ratio, DivX was using it in it's codec config dialog, XviD was using it in it's codec config dialog, everybody I knew until x264 came up with SAR for Sample aspect Ratio, first time I saw it I was hell of confused.

[Dark Shikari]

If people would agree that Picture Aspect Ratio and Sample Aspect Ratio is stupid then there wouldn't be a collision and people could use 3 letter acronyms again. x264 is responsible for the confusion since before that everybody was using PAR for Picture Aspect Ratio, DivX was using it in it's codec config dialog, XviD was using it in it's codec config dialog, everybody I knew until x264 came up with SAR for Sample aspect Ratio, first time I saw it I was hell of confused.The H.264 spec calls it the Sample Aspect Ratio. If you don't like it, take it up with the ITU, not us.

[stax76]

Ultimately the guy who wrote the spec is responsible for the collision of course but x264 is the software that people use and x264 can make the decisions to rather pass this issue down to the users or not. I would have preferred if it wouldn't have done this.

[Brother John]

No, from where do you have Picture Aspect Ratio?
Old Xvid versions said »Picture AR« in the GUI but really meant »Display AR«. They never abbreviated it to PAR though.

Actually what I see in use are these three meanings, anything else is a rare exception:

DAR = Display AR
PAR = Pixel AR
SAR = Sample AR

Using them with another meaning will almost always result in confusion.

I guess I know where you’re coming from. If we define DAR as the final playback aspect ratio (which is kind of common), what do we call the AR of the physical resolution stored in the video stream for a non-square pixel video. »Storage/Stream/Physical AR« all clash with the established acronyms. Maybe FAR for »File AR« or »SDAR« for »Stored DAR«? In the end imo it doesn’t really matter because it’s gonna be an unfamiliar acronym anyway. Just don’t redefine the three established ones.

[stax76]

Storage/Stream/Physical AR« all clash with the established acronyms

With which established acronym does Storage AR clash? Wasn't Storage AR established long before Sample AR was created?!

[Brother John]

I’ve only ever encountered SAR as storage AR in very few cases in forum posts. From the top of my head I couldn’t think of a single tutorial or software that uses it in that way. On the other hand SAR as sample AR is pretty much everywhere because of H.264’s popularity. Even if storage AR predates H.264, the meaning of »SAR« has changed.

Technically it’s not even that stupid to have both pixel AR and sample AR because you can distinguish between a pixel and a sample. For practical purposes it’s irrelevant, but that’s where the whole PAR/SAR thing comes from.

[stax76]

Storage Aspect Ratio has more google hits than Sample Aspect Ratio, in particularly when filtering for wikipedia.org

google

http://www.google.de/search?hl=de&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=o5a&q=%22storage+aspect+ratio%22&btnG=Suche&meta=&aq=f&oq=

http://www.google.de/search?hl=de&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=o5a&q=%22sample+aspect+ratio%22&btnG=Suche&meta=&aq=f&oq=

google site:wikipedia.org

http://www.google.de/search?hl=de&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&q=%22storage+aspect+ratio%22+site%3Awikipedia.org&btnG=Suche&meta=&aq=f&oq=

http://www.google.de/search?hl=de&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&q=%22sample+aspect+ratio%22+site%3Awikipedia.org&btnG=Suche&meta=&aq=f&oq=

[nurbs]

Not that I think google numbers should decide anything, but if you search forum.doom9.org sample aspect ratio has about ten times as many hits as storage aspect ratio. And in general the numbers for both meanings are in the same order of magnitude, which says a lot for sample aspect ratio considering only mpeg4 uses it.

[Brother John]

OK, obviously my perception is biased towards the MPEG-4 world.

Anyway, like Dark Shikari said, x264 won’t change its cli. And since x264 is possibly the video encoder of today doesn’t that already decide the matter?

[stax76]

Most people aren't concerned about the issue since it's not difficult to write 'Sample AR' instead SAR. My problem is StaxRip needs 3 letters acronyms and Sample AR has ruined this by introducing a 3 letter acronym collision. Overall the main dialog shows 5 aspect ratio values and all use 3 letter acronyms. Even though the SAR and PAR 3 letter acronyms are ruined StaxRip still uses them because there is only a limited amount of space available. Also 3 letters are easier to overview than full words which would contribute to overload the look and feel of the dialog. There are tooltips showing:

SAR: Storage Aspect Ratio
DAR: Display Aspect Ratio
PAR: Pixel Aspect Ratio

So there is a collision with the x264 dialog showing --sar and it means something different than what is shown in the main dialog, other than asking for a --par switch I don't have a idea how to solve this collision.

http://f.imagehost.org/t/0170/Untitled_4.jpg (http://f.imagehost.org/view/0170/Untitled_4)

[sneaker_ger]

Why don't you simply display the x264's SAR in your GUI's PAR then? :confused:

[stax76]

atm. I have:

SAR: Storage Aspect Ratio
DAR: Display Aspect Ratio
PAR: Pixel Aspect Ratio

You have a better idea?

SAR: Sample Aspect Ratio
DAR: Display Aspect Ratio
???: ??????? ??????? ????

I cannot use Storage AR since this would yield to SAR as acronym which Sample AR has stolen so what do I use now instead?

[Lam3rD]

Why not "Pixel Shape" or something like that. Who said that it has to be 3 letters?

[sneaker_ger]

Since "Pixel Aspect Ratio" and "Sample Aspect Ratio" are considered to be two different names for the same thing (that's why you suggested the change to PAR) just use PAR in your GUI.
x264 being an implementation of the H.264 standard and therefore using the terms mentioned in the standard is an argument one can hardly deny.

[Sharc]

atm. I have:

SAR: Storage Aspect Ratio
DAR: Display Aspect Ratio
PAR: Pixel Aspect Ratio

You have a better idea?

SAR: Sample Aspect Ratio
DAR: Display Aspect Ratio
???: ??????? ??????? ????

I cannot use Storage AR since this would yield to SAR as acronym which Sample AR has stolen so what do I use now instead?
May be you consider using FAR = Frame_Aspect_Ratio in place of your former Storage_Aspect_Ratio.
But please don't blame me if FAR should have 10 other meanings as well ..... :D

[Keiyakusha]

+1 to FAR. It also easier to understand IMHO since Frame width/Frame height. And what is storage? Someone can think of container or something.

[sneaker_ger]

You guys really think that introducing yet another term will help people to look through the already confusing SAR/DAR/PAR jungle? I don't think this is a good idea. Stick to the already existing terms. 99% of the users don't have a clue about them (and they don't need to in daily practice) and if they want to understand them they'll have to do a bit of reading anyways.

[Keiyakusha]

You guys really think that introducing yet another term will help people to look through the already confusing SAR/DAR/PAR jungle? I don't think this is a good idea. Stick to the already existing terms.
Yes, idea is not so good but if stax76 will stick to the existing terms, he need to replace Storage AR with something else. Also I don't think FAR is really new term, it used on avisynth wiki for some time...

[sneaker_ger]

Sorry, I just don't see the reason why he has to replace SAR. Is this a new law I missed?
Why don't stick to what he has been using until now: DAR (Display AR), SAR (Storage AR) and PAR (Pixel AR)? It's only for advanced users anyways and you have the unabbreviated terms in the tooltip. (+changing the terms might lead to new confusing for existing users of StaxRip.)

[Keiyakusha]

Sorry, I just don't see the reason why he has to replace SAR. Is this a new law I missed?

Because there is no PAR when we talking about h264 and as I understand he needs 3-letter abbreviations and he can't have two SAR's

[sneaker_ger]

There's no PAR when talking about H.264? I thought the consensus here was that "Sample Aspect Ratio" is the same as "Pixel Aspect Ratio" (http://mewiki.project357.com/wiki/X264_Settings#sar). That's why Stax suggested using "PAR" in x264 in the first place. Just because it is not mentioned in the H.264 standard doesn't mean that using the term in his GUI which is not restricted to H.264 is wrong.
And if you're against using PAR because it's not in H.264 than why use FAR? I bet it's not in there either.

[Keiyakusha]

I'm not against anything. In my opinion he can use whatever he wants in his gui.
But it seems Stax is not satisfied with current abbreviations and he asked about solving collision. FAR is just one of the ways proposed.

[sneaker_ger]

True.
Point is: in my opinion he won't be able to resolve confusions by changing the term. He either has to:
a.) try to be as "correct" as possible: stick to the terms used in the standards (based on what the user chooses as the output format) (not a bad idea in my opinion)
b.) stick to his existing terms, which are not wrong but are also not the same as used in the H.264 standard (also not bad)
c.) introduce "new" terms like FAR (bad idea because it will differ from past versions and will require looking up the terms even for experienced users)

[GodofaGap]

To be honest I don't find Storage (or Frame AR) really relevent. It's either equal to Display AR (Pixel/Sample AR is 1:1) or has not really any meaning at all.

[Wilbert]

I cannot use Storage AR since this would yield to SAR as acronym which Sample AR has stolen so what do I use now instead?

In all fairness, the abbreviation SAR (as in Sample Aspect Ratio) is also used in the mpeg-2 specs. I think these specs are older than StaxRip.

[stax76]

@Wilbert

IIRC you or someone else said in another thread Pixel Aspect Ratio is used in the MPEG-2 specs, I didn't expect one spec uses 2 different names for the same thing.

[Brother John]

I looked it up to make sure:
– MPEG-2 and MPEG-4 AVC use sample AR abbreviated to SAR.
– MPEG-4 Visual uses pixel AR abbreviated to PAR.
– MPEG-1 uses pel AR, pixel AR and picture AR, but they don’t abbreviate.

Frame aspect ratio (FAR) sounds good to me, btw.

[stax76]

Thanks for clarifying, Frame AR sounds good to me too but like sneaker_ger stated might be problematic changing it since existing users are already used to it...