XviD - Resolutions PAR - DAR

[Cunhambebe]

I'm a bit confused encoding with XviD. Resoltuions for 1:1 are OK (1:1 - the size of the pixel for computer). The problem starts when I decide to encode at full resolutions (4:3 and 16:9). I've got a chart here for encoding at 4:3 and 16:9. Let's take a look at it:

When encoding to a 4:3 Aspect MPEG
SourceAspect NTSC/PAL DVD
1.33 - 720x480 / 720x576
1.78 - 720x360 / 720x432
1.85 - 720x348 / 720x416
2.20 - 720x292 / 720x344
2.35 - 720x272 / 720x324

Now, this is the chart for 16:9:

When encoding to a 16:9 Aspect MPEG
Source Aspect NTSC/PAL DVD
1.33 - 1.33 Not Applicable: See above table for 1.33 resolutions
1.78 - 720x480 / 720x576
1.85 - 720x460 / 720x552
2.20 - 720x388 / 720x464
2.35 - 720x360 / 720x432

First, I thought using 4:3 resoltions (regulat tv screen) would be OK for both 4:3 and 16:9, but now there are other figures for 16:9 screens (plasma/lcd). The question is: what should I do(or choose) to make it all compatible with both sizes (4:3 and 16:9)? I'm a bit confused. Thanks in advance.

[Baldrick]

Where did you find those charts? If you set the DAR you can use whatever resolution you like basicly and the player should resize it correctly.

But I always use 1:1 because many players ignores display aspect flags in avi xvids,divx.

[Cunhambebe]

Hi Baldrick; how've you been? Thanks for taking time to respond. I've found these charts here:
https://forum.videohelp.com/topic174200.html
What you do at 1:1 is exactly what I do. But some people say it's too small (for instance 640x272) for a plasma/lcd TV (16:9). So I started to post topics on this subject here and there and overthere (doom9). Some responded saying that 720x480; 720x360 (16:9) 720x272 (21:9) would be OK for a regular TV, but you would notice the difference on a plasma/lcd set. So, some, as the guy who wrote the guide above, said it'b be better to encode at a resolution intended for 16:9. Here's what he said:
https://forum.videohelp.com/topic174200-30.html#660470

"You probably wouldn't notice a difference on a 4:3 TV, assuming your AVI is good quality. I would suggest you do the 720x360 resize. DVD is compatible with both 4:3 displays, and 16:9 displays, so if you decide to move to widescreen later on, you won't be stuck with a video that DOES look bad on a 16:9 display."

What should I do???? Thanks in advance

[jagabo]

If your source is DVD, before cropping any black borders, the video is either 4:3 or 16:9 -- the only two DARs supported by DVD. You could just encode the MPEG file at the same resolution (720x480), with no cropping or resizing, and just set the Xvid DAR flag to 4:3 or 16:9.

From a clean source like DVD the black borders will hardly take any bitrate to compress. From noisy off-air or VHS recordings you will want to overwrite the borders with solid black so they don't eat up bitrate.

As has been noted, not all Divx/DVD players support Divx/Xvid DAR flags. So these may not display with the proper aspect ratio.

If you are looking to use square pixels with the maximum resolution safe for most Divx/DVD players, resize 4:3 sources to 720x540 then crop away the black borders (this will work for most letterboxed material). For 16:9 resize to 720x404 then crop away the black borders.

When cropping like this it's best to leave the height a multiple of 16. So frame heights of 288, 304, 320, etc. are good.

[Cunhambebe]

Hi there! It's been a long time, isn't it jagabo?! Hope everything is OK with ya.
First of all setting the XviD DAR flag seems not to work for PC. Furthermore, some people say most players won't "read" that flag correctly. Second of all, I've tried setting the XviD PAR - which works well (for instance, video is at 16:9, encoding as XviD at full resolution at 720x480 and setting the PAR at 16:9). This seems to work with Media Player Classic.
In fact I was looking for compatibility and all these resolution, sorry, but they are a real pain... Let's get that right. Encoding at 1:1 is easy but the frame is too small for new Plasma/LCD screens. So, what is the best way to encode the most popular sizes: 4:3 [1.33], 16:9 [1.78] and 21:9 [2.35] as well as [2.20]??? Couldn't we just encode at 720x480, 720x360, 720x272, etc as we do for square pixels [1:1]? Do you please have your own chart on how to do this? Thanks in advance. I flunked all my math exams lol

BTW, how did you find those figures: 720x540, 720x404 etc? Did you divide 720 by 1.33; 1.78; 2.35 etc? Thanks

[Baldrick]

jagabo told you the 1:1 720 resolutions,
720x540 (4:3)
720x404 (16:9)

and for the 2.35:1 16:9 you resize to 720x404 and then crop the black borders.

[Cunhambebe]

Thanks Baldrick, but wouldn't that be 720x322 for 2.35:1? Because 720/2.35 = 322 ; 720/322 =2.23

[jagabo]

Thanks Baldrick, but wouldn't that be 720x322 for 2.35:1? Because 720/2.35 = 322 ; 720/322 =2.23

jagabo told you the 1:1 720 resolutions,
720x540 (4:3)
720x404 (16:9)

and for the 2.35:1 16:9 you resize to 720x404 and then crop the black borders.

That will leave you with 720x322.

No matter what aspect ratio the movie is, with a 16:9 DVD, resizing the 720x480 frame to 720x404 and cutting away the black borders will give you the correct square pixel aspect ratio.

[Cunhambebe]

Thanks again jagabo. I understood in spite of the fact the final XviD file (not counting the sound file) is a little too big, almost as big as the MPEG2. About all that math above:

Thanks Baldrick, but wouldn't that be 720x322 for 2.35:1? Because 720/2.35 = 322 ; 720/322 =2.23

The correct thing is the following:
720/2.35 = 306 ; 720/306 = 2.35*
*for 1:1
Isn't there a solution for big file sizes? I hope to fit at least 2 movies on a 4,7 GB DVD.
How about high definition tv? Should we keep the DAR for instance, Blu-Ray at 1920x1080 ; 1440x1080 and just encode it, compressing as XviD or we should resize it too?
Thanks in advance - and sorry for the mistakes.

[jagabo]

About all that math above:

Thanks Baldrick, but wouldn't that be 720x322 for 2.35:1? Because 720/2.35 = 322 ; 720/322 =2.23

The correct thing is the following:
720/2.35 = 306 ; 720/306 = 2.35*

Ha! The math looked about right so I didn't check it. Yes, 720/2.35 ~= 306.

Isn't there a solution for big file sizes? I hope to fit at least 2 movies on a 4,7 GB DVD.

Yes, the bigger the frame, the higher a bitrate you will need to retain the quality. The file size is simply dependent on the bitrate (in CBR/VBR bitrate mode) or the quantizer in target quantizer mode (in target quantizer mode several other settings can cause differences in file size: Motion Search Precision, VHQ Mode, Maximum I-frame Interval, B-VOPs, etc.). To get a smaller file use a lower bitrate or a higher quantizer. Don't forget the audio bitrate adds to the file size too.

How about high definition tv? Should we keep the DAR for instance, Blu-Ray at 1920x1080 ; 1440x1080 and just encode it, compressing as XviD or we should resize it too?

1920x1080 and 1280x720 are already square pixel formats so you can keep them that size or shrink the frame proportionally: 1920x1080 -> 1280x720, 960x540, 640x360, etc. It all depends on, what your player accepts (most Divx/DVD players won't play frame sizes over 720x576), how much detail you want to keep, and the file size you're willing to put up with. With 1440x1080 sources you can either use the DAR/PAR flags or resize to square pixel.

[Cunhambebe]

Thanks so much for the detailed explanation - as always, jagabo. Thank you very much.

With 1440x1080 sources you can either use the DAR/PAR flags or resize to square pixel.

I don't wanna be boring, but how? Same kind of formula for resizing (I don't like those flags)? Thanks in advance

[jagabo]

With 1440x1080 sources you can either use the DAR/PAR flags or resize to square pixel.

I don't wanna be boring, but how? Same kind of formula for resizing (I don't like those flags)? Thanks in advance :oops:

Assuming the source is 16:9 DAR, resize to a 16:9 ratio frame size. 1920x1080, 1280x720, ~720x400, 640x360, etc. Remember, with square pixel encoding DAR = SAR. That is, the ratio of the frame dimensions is the same as the display aspect ratio.

[Cunhambebe]

Mmm... Thanks so much, jagabo.
Best regards,
Mark