Author Topic: XviD aspect bugs ?  (Read 25057 times)

AQUAR

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Re: XviD aspect bugs ?
« Reply #15 on: January 20, 2015, 12:39:43 PM »
I second that approach.
Very rarely do I bother going back to ADM 2.5 (even for recoding to Xvid).
I do still use a lot of Xvid as my standalone media player doesn't understand AVC.

(guess I am easily satisfied compared to other ADM end users!)
 
« Last Edit: January 20, 2015, 12:50:54 PM by AQUAR »

kapetr

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Re: XviD aspect bugs ?
« Reply #16 on: January 20, 2015, 03:59:06 PM »
<aquar>:Thanks for taking time to answer, but I'm afraid you probably did not read carefully my and <poutnik> posts.

I am assuming we are talking about the Xvid configuration dialog.
That dialog does not say PAR at all, it just references screen types by way of aspect ratios.

Sorry - you are wrong.
See attached screenshot of dialog of XvID in 2.6.8 AVD (Czech).
There is "Poměr stran pixelu."
https://translate.google.cz/#cs/en/Pom%C4%9Br%20stran%20pixelu
== "Pixel aspect ratio" - PAR.  ;)

Quote
Use it accordingly to re-define the DAR, to match the source video PAR and SAR (Stored Aspect Ratio) to digital screen types.
And of course it does not cover all cases (but presumes you understand what is covered).

Your experiences are perfectly understandable but they are not ADM issues.
Of course are they - ADM calls XviD with wrong config/params.

Quote
The  Xvid with ADM 2.6 is only there by request (I know as I made that request!), and IMHO is only intended as usefull for transcoding from AVC.
Else, and with more control over Xvid configurations wrt to aspect ratios, go back to ADM 2.5.
It should be no problem to repair the dialog. To run old version is really desperate solution.

Quote
Rather than yet another repeat explanation, a simple example will demonstrate:
Say you have a PAL anamorphic video (DVD) and want to recode using Xvid to give the correct DAR on your PC monitor.
The PAR of a PAL wide screen is 65:45 (the accepted median value for these virtual pixels).
To display the SAR with the correct DAR on a PC monitor you need to "recalculate" with a defined PAR of 65:45
 (as opposed to nothing if you use an analog TV, because it already has a virtual PAR of 65:45).

That gives you 45/65 (horizontal compression in the SAR) * 65/45 (PAR definition) = 1:1 (PC monitor)

So select PAL(16:9) in the dialog - as that is the intended display for that source material (ie not a bug in sight!).

Furthermore, altering the PAR here is at the meta data level, and has nothing to do with resampling to various SAR's as quoted above.
Also using this approach may give inconsistent results, depending on preferential treatment in reading PAR meta data, by modern AVC capable media players.

If you want to maintain the opinion that this is an Xvid aspect bug, then this becomes another case of "back on that old road again".
I'll just bow out and happily continue to use ADM as intended.
 

I have no idea what you try to explain or advocate - sorry.
Above is from me and from  <poutnik> detailed explanation of how the calculation works. And the buggy result proves, that we are right.

The problem - bug is in ADM, because erroneously assumes that PAL video has SAR=704:576. And it is in most cases NOT true.
« Last Edit: January 20, 2015, 05:24:17 PM by kapetr »

AQUAR

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Re: XviD aspect bugs ?
« Reply #17 on: January 21, 2015, 12:35:21 AM »
The only item here that is questionable is the translation of "aspect ratio" (English) to "pixel aspect ratio" (Czech) inside the dialog box.
Unfortunately you never mentioned you were loading the Czech language module (I don't have a crystal ball!).

However the dialog tab still clearly states "aspect ratio".
Despite that - there is no bug - and from my perspective you are just complaining about a lack of choice in Xvid PAR settings.

In fact is it really doesn't matter if that dialog has this small translation inconsistency.
I think we sort off agree that the intent of using this feature is to add information so as to display a stretched version of "DVD type" video images on digital monitors.
ADM assumes nothing about SAR, but in that dialog it just sets PAR meta data based on a few common choices.
For PAL(16:9) the PAR figure used is 64:45 (and this in no way changes the SAR of the video!).
If these choices don't suit (as you say for 720X576 material!) then don't use them.
Instead go back to ADM 2.5 as that is geared up for these older codecs, and be gratefull that ADM lets you transcode from AVC.

To me the intermediate redefinition is 720x64/45 : 576 =  1024 : 576 = 16 : 9.
Seems correct to me and the rest (interpretation & scaling) is up to the players.
The fact that you see eg 1048 : 576 has nothing to do with ADM being buggy in setting that PAR value.
Setup, preference detection, interpretation of metadata etc etc by media players and info programs like mediainfo are giving you resampling/scaling values that seem inconsistent with your expectation. Nothing to do with ADM as it just ads the value of 64/45.

Obviously we have a different concept of expectation for this feature.
I tried, I failed to convince, and now I have no further interest in arguing about it.

Final comment:
ADM 2.5 is not an "old" version just EOL (quite different under the hood from ADM 2.6!).
« Last Edit: January 21, 2015, 05:36:36 AM by AQUAR »

kapetr

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Re: XviD aspect bugs ?
« Reply #18 on: January 21, 2015, 07:48:08 AM »
Sorry  <AQUAR>, bud you are trying to defend the indefensible.
You do not understand because you do not want to understand.

And you contradict to itself. If ADM would assume, that 16:9 PAL video is with PAR 64:45 (as you preaching), then I would have (in most cases) no problem. I would get for 720x576 source correct DAR 16:9 (720*64/45=1024). But ADM uses less common PAR 16:11 (720*16/11=1048).

So please - if you just want to argue, so do it elsewhere! Thanks.
« Last Edit: January 21, 2015, 07:57:15 AM by kapetr »

Jan Gruuthuse

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Re: XviD aspect bugs ?
« Reply #19 on: January 21, 2015, 08:49:02 AM »
So please - if you just want to argue, so do it elsewhere! Thanks.
A little rude and offensive remark.  >:(

poutnik

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Re: XviD aspect bugs ?
« Reply #20 on: January 21, 2015, 09:10:12 AM »
Truth is, for DAR 16:9 is PAR 64:45 for SAR 720:576, or 16:11 for 704:576, as both SARs are common for PAL material.

Jan Gruuthuse

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Re: XviD aspect bugs ?
« Reply #21 on: January 21, 2015, 09:41:22 AM »
576i 16:9
Resolution
- 704×576
- 720×576 (horizontal blanking cropped)
- 720×576 (full frame)
The pixel aspect ratio is always the same for corresponding 720 and 704 pixel resolutions because the center part of a 720 pixels wide image is equal to the corresponding 704 pixels wide image.
Source: Pixel aspect ratio

kapetr

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Re: XviD aspect bugs ?
« Reply #22 on: January 21, 2015, 10:03:12 AM »
Very interesting!

Does this mean, that if there is full-picture 720x576 video (no black columns on sides(704->720)) then this video should be cropped to 704x576 and only then to be "resized" by player to 1024x576 DAR (in 16:9 case) using 16:11 PAR?

I have to say, I can't believe that much. I have never seen 720x576 video (from DVB, DVD, ...) which was played by any player this way.
(But truth is - by HW player (without stdout/stderr infos) it would be difficult to recognize by eyes 1024x576 XX [1048 cropped to 1024] x 576 aspect difference between 64:45 and 16:11 PARs).
« Last Edit: January 21, 2015, 10:15:37 AM by kapetr »

AQUAR

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Re: XviD aspect bugs ?
« Reply #23 on: January 21, 2015, 11:00:27 AM »
@ Jan,
Indeed all of the discussion here is just simplified wrt to presenting PAL video on a digital monitor.

@ kapetr,
ADM may well set PAR 16:11 instead of 64:45 (its whatever is correct to present actual image content from analog PAL!).
From all of the previous discussion is simply boils down to:
1: You classify this PAL(16:9) selection as an ADM 2.6 bug because it isn't giving you the PAR value you expect.
2: I disagree, advising you to use ADM 2.5 because it gives you more choices wrt PAR meta data.

Also I clearly pointed out that I don't wish to discuss it anymore because we view this issue from a different baseline.
So don't then tell me to go argue elsewhere because that is just simply an inconsiderate and rude attitude.


« Last Edit: January 21, 2015, 11:52:04 AM by AQUAR »

kapetr

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Re: XviD aspect bugs ?
« Reply #24 on: January 21, 2015, 11:48:23 AM »
<aquar>:
I use encoding for digital "PAL" (DVB), not analog PAL - not sure if somewhere in the World is analog PAL anymore.
Other ... No comment.

Just one:

You did NOT say: "I don't wish to discuss it anymore ..."
You did say:  "I have no further interest in arguing about it ..."
=> you was "inconsiderate and rude" first. And especially wrong. Sorry. END. POINT.
« Last Edit: January 21, 2015, 12:00:25 PM by kapetr »

AQUAR

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Re: XviD aspect bugs ?
« Reply #25 on: January 21, 2015, 12:26:21 PM »
Come on, Xvid dates from the analog era and is sort of an after thought inclusion in ADM 2.6.
That is why I keep saying that I view this issue from a different baseline.

You are egging me on, and if I defend myself in response, the only result here will be that the administrator will delete this thread.
Stating that I have no further interest in arguing about this, was not rude in the first place.
It's simply an admission I failed to provide my perspective without going into detail (see reaction 1).
The fact that I picked the other PAR ratio probably didn't help the cause (I am only human).
Let me correct that: for anamorphic PAL (both analog and DV-PAL) the PAR is 1024/702 (approx 16/11).   

You believe I am wrong! That's perfectly okay by me.
So how about you stop egging me on with selective symantics for the good of this thread!
 
« Last Edit: January 21, 2015, 01:05:35 PM by AQUAR »

kapetr

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Re: XviD aspect bugs ?
« Reply #26 on: January 21, 2015, 01:55:17 PM »
To talk about analog by transcoding from one digital format to another is little bit meaningless by itself .
Analog PAL has 625 lines (576 visible) and no horizontal resolution defined at all. Horizontal resolution was limited by analog path from camera to CRT tube display.

I have look in D-book (describing digital DVB broadcasting). There is for SD defined:
- for DVB-T
Code: [Select]
2.7.1.1. Zdrojové kódování obrazu
- dle standardu ISO/IEC 13818-2
- Main Profile @ Main Level
- snímková frekvence 25 Hz
[b]- rozlišení 720, 704, 544 a 480 (bodů) x 576 (řádků) se zobrazením „full screen“[/b]
- formát obrazu 4:3 a 16:9
- Indikace formátu obrazu 4:3 resp.16:9 je přenášena v elementárním obrazovém
datovém toku v položce aspect_ratio_information v hlavičce každého paketu
(sequence header).

- for DVB-T2
Code: [Select]
Zdrojové kódování obrazu
Podle ITU-T Recommendation H.264 / ISO / IEC 14496-10 (AVC).
2.7.2.1.1.
SDTV
- Main Profile @ Level 3
- snímková frekvence 25 Hz
- formát obrazu 4:3, 16:9
- rozlišení 720, 704, 544, 480 (bodů) x 576 (řádků).


That does mean, that 720, 704, 544, 480 x 576 are possible resolutions for „full screen“ displaying (4:3 or 16:9).
There is nothing about cropping (or growing) to 704. All combinations are possible and every of them has its own PAR for achieving 4:3 or 16:9 DAR.

E.g. for 16:9 the PARs are - 64:45 for 720, 16:11 for 704, and so on.
That is why I'm not sure about correctness or applicability of wiki info: http://en.wikipedia.org/wiki/Standard-definition_television#Pixel_aspect_ratio


For DVD video is it similar: http://en.wikipedia.org/wiki/DVD-Video
Code: [Select]
The following formats are allowed for H.262/MPEG-2 Part 2 video:

    At a display rate of 25 frames per second, interlaced (commonly used in regions with 50 Hz image scanning frequency):

    720x576 pixels (same resolution as D-1)
    704x576 pixels
    352x576 pixels (same as the China Video Disc standard)
    352x288 pixels


=> To assume, that for one or other  DAR is used just that or other PAR was/is/will be always wrong - for every codec (XviD, h.264, HEVC, ...).

I can just cite myself again:
Quote
The dialog should by corrected in x264 way
- to select/define PAR of source (source after resize filter applied) or
- to select target DAR (whatever PAR of (resized)source is)

Maybe should/could be the dialog same for all codecs ?


P.S.:
Note without "selective symantics": If I say "arguing", then it is "inconsiderate and rude". If ... says  "arguing", then it is not. Democratic.
« Last Edit: January 21, 2015, 02:10:00 PM by kapetr »

Jan Gruuthuse

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Re: XviD aspect bugs ?
« Reply #27 on: January 21, 2015, 02:28:03 PM »
>8 >8
Quote
I am assuming we are talking about the Xvid configuration dialog.
That dialog does not say PAR at all, it just references screen types by way of aspect ratios.

Sorry - you are wrong.
See attached screenshot of dialog of XvID in 2.6.8 AVD (Czech).
There is "Poměr stran pixelu."
https://translate.google.cz/#cs/en/Pom%C4%9Br%20stran%20pixelu
== "Pixel aspect ratio" - PAR.  ;)

as pointed out by AQUAR the Czech translation is incorrect: this is what the original shows in Avidemux 2.6.8 (English not translated):
« Last Edit: January 21, 2015, 02:45:34 PM by Jan Gruuthuse »

Jan Gruuthuse

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Re: XviD aspect bugs ?
« Reply #28 on: January 21, 2015, 02:34:37 PM »
Note without "selective symantics": If I say "arguing", then it is "inconsiderate and rude". If ... says  "arguing", then it is not. Democratic.
The rudeness is in the
Quote
so do it elsewhere
is the same as saying: "Go take a hike? What is take a hike!? A rude way of telling someone to leave.

As we are all guests on this forum: telling another guest that? ....

kapetr

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Re: XviD aspect bugs ?
« Reply #29 on: January 21, 2015, 03:24:50 PM »
<Jan>: I do not speak English - so it is for me difficult to express what I want with Google translator. And it may sounds different in different languages/lands.

It is an English word for someone, who loves to argue in forums without be really interesting on the topic, without reading carefully other posts, without  reacting on facts, evidences. Someone who sees only what he wants, ...
Forums are unfortunately full of such people. I am allergic to it.

I can't find out the word now. Something with fire ? But IMHO <AQUAR> seems to be near of this definition. Only what I did want was to STOP it and get back to useful things, questions, ...
And do not please forget - for everyone may be other things "inconsiderate and rude". For me was it the word "arguing" - especially from someone, who does it self IMO.

I really respect yours opinion, but I'm not convinced I did something wrong.
I hope, we can go back to  merits of the case.


Thank you.
« Last Edit: January 21, 2015, 05:34:55 PM by kapetr »