Dar, sar...

[drgt]

I think I am all confused about this



1. I converted an mkv / h264 video with frame size 716x424 to:

• a. an xvid .avi using OJOSoft total video converter maintaining the 716x424
• b. a DivX .Divx using DivX converter also maintainig the 716x424

I did that because my standalone will not play mkv / h264. I burned both on a dvd as data and with the standalone set up to play 16:9:

• "a" plays with black bars on top & bottom. Side note: sounds louder.
• "b" fills the entire screen (16:9 TV).

Why?

2. I have a DVD I want to convert to xvid for playback on my standalone. I open the IFO in AGK and it says:
"MPEG2 720x576 PAL 16:9 letbox pan&scan PGC1".

What is PGC1?

Now, to understand, this means that when this DVD is played the picture will get "expanded" by the x axis to fit the screen and whatever exceeds the screen on top and bottom will be cut off? For me, this frame is closer to 4:3, so it should play like that. Am I right?

The player should be set 16:9 or 4:3 according to the TV set or according to dvd? (Player's 4:3 has 2 subsettings letbox and pan&scan. When should we choose the one over the other?)

Anyway, while AGK gives the above info, when I open this DVD with DVDFab it reports the source resolution is 1024x576.

Why?

AGK made a target file 720x416 while DVDFab defaults to make a file with frame of 720x406.

My thinking is to maintain original frame so I have better target picture quality and let the player resize.


Who wants to explain?

[jagabo]

DAR = SAR * PAR

https://forum.videohelp.com/threads/322346-same-resolution-but-difference-in-display-w-...=1#post1995959
https://forum.videohelp.com/threads/299570-Correct-size-Resolution-for-AVI?p=1831347&vi...=1#post1831347

Some programs will use mod16 sizes when resizing for square pixel encoding. Hence 720x416 rather than 720x406 (mod2, which I would never use because some playback software and devices will choke on it).

Leave your videos at 720x576 and set PAR/DAR flags if your player supports it.

[drgt]

Ok. Thanks jagabo. I read your redirections in their entirety, (even though I feel I must take some pre-courses in order to fully understand that 2nd thread...)

I will try now to answer / repost my questions as well as elaborate further. Please tell me if I am right and fill in unanswered questions.

1. Why?

Because they have different DAR.

I did not see a DAR Flag setting in using the corresponding programs. Do you know if they have one?

This means my player does not ignore the DAR flag?

So when converting from one format to another is it a good idea to keep the source SAR?

(In OJO it kept it by itself. (Only VirtualDub cannot open the file it made. You know why?). DivX Converter wanted to use another SAR, I do not remember right now, I had to override it.)

2. What is PGC1?

?

Now, to understand, this means that when this DVD is played the picture will get "expanded" by the x axis to fit the screen and whatever exceeds the screen on top and bottom will be cut off? For me, this frame is closer to 4:3, so it should play like that. Am I right?

No. Nothing will be cut off. And no, it does not matter if it is closer to 4:3.

The player should be set 16:9 or 4:3 according to the TV set or according to dvd? (Player's 4:3 has 2 subsettings letbox and pan&scan. When should we choose the one over the other?)

?

DVDFab it reports the source resolution is 1024x576. Why?

?

AGK made a target file 720x416 while DVDFab defaults to make a file with frame of 720x406.

What is the logic in going from 720x576 to 720x416 (AGK auto setting).

Leave your videos at 720x576 and set PAR/DAR flags if your player supports it.

Can I do this in AGK and how? If not, please tell me the way to do it.

Thanks a lot.

[jagabo]

I don't use either of the programs you listed so I don't know if they have any PAR/DAR settings.

PGC1 means Program Chain 1. It's just indicating which program was chosen in the IFO file.

Whether your player should be set to 4:3 or 16:9 depends on the DVD player and what your TV does with the incoming signal. Usually you set the DVD player to 16:9. If you play a 16:9 video the player stretches the picture on the DVD to 16:9. When you play a 4:3 video it pillarboxes the video to make a final 16:9 picture.

DVD Fab is reporting the 720x576 16x9 DVD as 1024x576 because after stretching the image to account for the 16:9 frame it will be 1024x567 (576 * 16 / 9 = 1024).

Generally, you will get the best results when encoding with the same frame size as your source. So a 720x576 DVD would be encoded as a 720x576 Xvid or h.264 video with PAR/DAR flags that tell the player what display aspect ratio to use. But if your player doesn't support PAR/DAR flags you have to resize the source to a square pixel frame size that represents the DAR of the source 16:9 (eg, ~704x400) or 4:3 (720x540).

Someone who knows AutoGK can tell you how to force the frame width. I believe it starts with ctrl+F9.

Without seeing examples of your VOB files it's hard to answer any of your other questions. I recommend you use VirtualDub to extract some frames at the SAR of the sources.

One thing to be aware of is that x264 (and I think other encoders) uses the term SAR to mean the pixel aspect ratio in the equations I gave you earlier.

[drgt]

Thank you very much. I will get back with samples if I need more info.

By the way, in https://forum.videohelp.com/threads/299570-Correct-size-Resolution-for-AVI?p=1831583&vi...=1#post1831583 the first ratio does not belong in that group, does it?

[jagabo]

By the way, in https://forum.videohelp.com/threads/299570-Correct-size-Resolution-for-AVI?p=1831583&vi...=1#post1831583 the first ratio does not belong in that group, does it?

Good catch. I fixed it.

[drgt]

I can force AGK to do 720x576 on that DVD but I do not think It has a DAR setting. Can I do it afterwards with Mpeg4Modifier?

This is the VDub error trying to open the avi made by OJOSoft.

What else can I use to convert mkv / h264 to xvid, something with DAR setting preferable?

[jagabo]

Yes, you can use Mpeg4Modifier after encoding to set the PAR/DAR flags.

Try Xvid4PSP for your conversions from h.264 mkv to xvid AVI.

[drgt]

Well, I did not get anywhere.

I made the avi from the dvd using either DVDFab or AGK, keeping original SAR 720x576. When I played them (player set at 16:9 and TV 16:9) they fill the entire screen. No black bars! Strange.

Then I tried the avi I made from the mkv which, if you recall, plays with bars. I run mpeg4modifier on this and made 2 files. One with the setting PAR 16:9 PAL and one with DAR 16:9. Both of them played like the original with bars.
One would be quick to say here that my player does not support flags. However, this would be in contradiction to my 1st post where files with the same SAR, one fills the screen and the other plays with bars.

Can you shed some light? Or can you suggest some definitive tests that would give a clear picture of what is going on?
By the way my player is an LG DVX9900H.

[drgt]

Jagabo, are you there?.........

[jagabo]

The fact that Mpeg4Modifier modified files aren't showing with the correct final DAR implies that your player ignores PAR/DAR flags in Divx/Xvid AVI files. I don't know why the files in your first post play differently. Since I don't know those programs and you haven't provided detailed information about the file properties (do they have PAR/DAR flags? MediaInfo or GSpot can tell you. How big are the black borders? Is there a black border in the videos themselves?) I can't really guide you.

Attached are two Xvid AVI files encoded at 704x576. One has Xvid 16x9 PAL PAR flags (pixel aspect ratio 16:11) the other has Xvid 16x9 DAR flags. If these don't fill the screen of a 16:9 TV, and the white box in the middle isn't a square, then either your player doesn't support PAR/DAR flags in Xvid AVI, the player is set up incorrectly, the TV is set up incorrectly, or the TV isn't really 16:9 (some widescreen HDTVs don't have 16:9 screens -- I have a 19" HDTV that has a 16:10 screen).

[drgt]

This is a total mess!

The TV's screen is x=82.3, y=46.3 cm. All mesurements were done by ruler / measuring tape.

Both files looked exactly the same.

I am attaching scart and hdmi pictures with the player set at 16/9 and 4/3. (4/3 letbox shows no difference from 4/3 panscan).

As you can see, the 4/3 setting (of these files, not any files) fill more (not all) the screen.

[jagabo]

I am attaching scart and hdmi pictures with the player set at 16/9 and 4/3. (4/3 letbox shows no difference from 4/3 panscan)... As you can see, the 4/3 setting (of these files, not any files) fill more (not all) the screen.

That doesn't make any sense. In any case the 4:3 setting filling most of the screen is close enough. It may be that the player wants 720x576 instead of 704x576 to completely fill the 16:9 screen. Try this 720x576 16:9 DAR XVID AVI. Oops, I typed 24 fps instead of 25 fps. Should still work...

[drgt]

Ok. This one plays almost like the other 2 on the player's 4/3 setting (again panscan or letbox does not matter).

Line closest to 0 visible (HDMI):
Left: 5
Right: 0, except that the vertical black bar is now 10mm
Top: 4
Bottom: 3

And I forgot to mention that all these are with the TV set at 16/9. If I put the TV on 4/3, it makes the picture smaller.
Tell me if you want to see it.

Well, if it does not make sense to you, for me it is CRAZY.

[jagabo]

What happens when you play 16:9 DVDs? Do you have to use the same 4:3 setting on the DVD player to fill the 16:9 TV screen?

[drgt]

Ok. Just tested this. With the TV set at 16/9 a 16/9 DVD plays as follows:
With Player set at either 16/9 or 4/3 PanScan, the picture fills the entire screen.
With Player set at 4/3 LetBox, there are horizontal bars top and bottom.

Suggest a utility to extract info off this DVD that you might need.

This is what AGK reports opening the IFO: MPEG2 720x576 PAL 16:9 letbox pan&scan PGC 1.

By the way, I do not understand this 16:9 letbox pan&scan.
I thought LetBox and PanScan belong to the 4/3 format.

In fact, in my player setup, if I choose 16/9, "LetBox" & "PanScan" are dim (unavailable). I can only pick one or the other in the 4/3 setting.

[jagabo]

It sounds like your player is playing DVDs correctly. The Pan/Scan feature is used on 16:9 DVD to instruct the player on how to crop the frame for 4:3 output. Not all 16:9 DVDs include the Pan/Scan information. In the absence of Pan/Scan instructions the player may resort to 16:9 or letterbox in 4:3.

I guess you'll just have to switch your DVD player to 4:3 output when playing anamorphic Xvid AVI files.

Is your DVD player an upscaling player? What make/model?

By the way, it's normal for TVs to overscan. So it's expected that the very edges of the picture are not visible on the TV.

[drgt]

Is your DVD player an upscaling player? What make/model?

I am not sure what you mean "upscaling"; As I mentioned earlier in post 9 it is an LG DVX9900H.

Getting back to the 1st post:
The DivX file fills the screen at 16/9 setting while it plays with horizontal bars in the 4/3 setting.
The Avi / XVid file plays with horizontal bars whatever the setting.
This isn't quite the same as the samples you provided, or is it?
I mean, in the samples, the 16/9 player setting did not allow the picture to stretch along the x axis of the TV!

If the player does not recognize DAR flags, as we tested it with the MPEG4Modifier, what causes it to display 2 files with the same SAR differently?

Here is the info you asked.

[jagabo]

Neither of those AVI files has PAR/DAR flags (note where GSpot says "par 1.000 (1:1)". The two files have the same frame size so they should play back the same on the TV. Does one of them have black bars encoded into the picture?

[drgt]

No. Remember? They are both made off the mkv / h264 file. Did you see the txt file attachment in my previous post?
If the mkv had bars it would be in both, right?

Unless... the mkv file has bars as part of the frame and DivX Converter removed them? Is that possible?

How can I tell if the frame in the mkv has bars or not?

[jagabo]

A converter can add or remove bars. It can remove bars in the source (and they sometime remove picture content by accident) or add bars to compensate for slight aspect ratio errors when creating a mod16 frame size. MediaInfo and GSpot don't tell you if there are black bars in a video. Open your two AVI files in VirtualDub (it shows you the frames pixel-for-pixel) and see if there are any differences.

[drgt]

Open your two AVI files in VirtualDub (it shows you the frames pixel-for-pixel) and see if there are any differences.

That's for the avi / divx. What about the mkv file? (The source)

Or, how do I make a dummy 716x424 avi, burn that and compare.



P.S. Can't open that avi in VD, it gives that error I posted earlier. The DivX looks without bars.

[jagabo]

You can open an MKV file with VirtualDub with the DirectShow source plugin and a DirectShow MKV splitter like Haali. Ie, if you can play the MKV file with Windows Media Player you can open it in VirtualDub.

[drgt]

Cool, neat stuff I learn here!!!!!
Thanks.

No, NO BARS in the mkv file!

The mystery deepens!

...it can't be... but I will change the avi extension to divx and see what happens...

[jagabo]

You can also try changing the fourcc codes from DX50 to XVID or vice versa. Use avi fourcc code changer.

[drgt]

No, I could not fool the player just by changing the extension.

Something else is going on in order for the divx and avi files to play differently although they have tha same SAR.

Are we out of options?

[drgt]

I think I found something.

716/424 is close to 16/9

When playing the avi (converted from the mkv) those bars are quite thick. 7 cm!
That got me thinking.

Take a look at what the dixv converter says about the source and what it wanted to do with it before me stepping in and forcing 716/424.

Were we lied to about the mkv and the resulting (converted) avi resolution?

[jagabo]

That implies the video is 2.35:1 or 2.4:1. So the square pixel size should be something like 720x304. Which is close to their setting of 718x300 -- but you should never use mod 2 (718) frame sizes with Xvid. Your 716x424 AVI files with square pixels should still both have displayed identically and come close to filling the 16:9 screen. But the aspect ratio of the picture contents should be wrong -- everything should look too tall.

[drgt]

718 is what it chose to do by itself. You gotta tick custom resolution to change that. And it is DivX, not XVid. The same applies?

Anyway, why mediainfo and gspot told us the mkv and its child avi have 716x424?

[jagabo]

718 is what it chose to do by itself. You gotta tick custom resolution to change that. And it is DivX, not XVid. The same applies?

Yes.

Anyway, why mediainfo and gspot told us the mkv and its child avi have 716x424?

Because 716x424 is the frame size. Divx Converter is telling you the frame size after adjusting for PAR/DAR flags.