KVCD: Aspect Ratios with Anamorphic Widescreen?
 

Hey all,

I'm having a bit of trauma with figuring out the aspect ratio deal with the 352X480 settings on the template. I'll do a DVDRip, and frameserve to TMPG through DVD2AVI. If I set the resolution in TMPG to 352X240, and in the advanced tab, select 16:9 and Full Screen (Keep Aspect Ratio), everything works fine.

However, when I have it set to 352x480, I am unable to get the file to come out correctly. If I use full screen, I it doesn't do the letterboxing, and stretches everything wrong. If I do full screen (maintain aspect ratio), it goes overboard with the letterboxing, and the video is only half as tall as it should be when I play it on my television.

Any hints as to how you guys do it to keep the aspect ratio on a DVD rip when the resolution is 352X480?

DrC

Re: Aspect Ratios with Anamorphic Widescreen
 

Hi DrChumley:

Go to Settings/Advanced in TMPEG and set under Video Arrange Method Center(custom size) 352 x 352 pixels.

Now check your output. ( On WinDVD or PowerDVD ) Not on WMP.

kwag

Try 352*360 in center custom size and choose 1:1 as input

hey , why dont we put our heads together and post our specs for each aspect ratio. we can include the source aspect ratio (SAR) and the center custom size (CSC) resolutions. this is what im thinking. correct me if im wrong.

1:2.35 movies----------(SAR)4:3/16:9----------(CSC)352x288

1:1.85 movies----------(SAR)4:3/16:9----------(CSC)352x352

1:1.33 movies----------(SAR)4:3/16:9----------(CSC)352x512

LETTERBOXED----------(SAR)1:1-----------------(CSC)352x480

**note: these resolutions are rounded to the closest multiple of 16.
**note: i havent tested these yet. im just going by what i have read.

Are these NTSC sizes?

The four display aspect ratios used in the UK are :

4x3 (12X9) Standard TV
14x9 Widescreen Terrestrial TV
16x9 Widescreen Digital TV
21x9 Cinema Widescreen

Here is some interesting reading regarding Aspect ratios.
http://www.thedigitalbits.com/articl...reenorama.html

Hmm.. didn't know there was 14:9 in UK, thought it was an asian format. you learn something new everyday :D :D

Anyway if you look closer at the numbers you notice that a standard vcd is either 352*288 or 352*240 and none of them are exact 4:3.
4:3 = 1,33
352:288 = 1,22
352:240 = 1,46
But thats "stretched" to the tv either vertical or horizontal for PAL/NTSC. I used to calculate the anamrphic 16/9(1,77777) by 352/1,77=198 but as we see in the above 288 is only 91,6% (1,22/1,33). Therefore the correct resolution will be 352*216 (352/1,77/0,916=216).

Lots of numbers but atleast check the link above, really good illustrations

Excelent link Mr Walker!

Thanks,
kwag

Maybe I can clearify a little:
If fullscreen is 100% vertical resolution, then 16:9 is 75% and 2,35:1 is about 56,7%. This should be working on both NTSC and PAL either it is 240/288 or 480/576.
(if any ntsc-user would like to try and confirm i'd be glad)

An exampel:

movie 16:9 to pal kvcd: 352*432 (576*0,75=432)

movie 2.35:1 to ntsc kvcd: 352*272 (480*0,567=272)

Just use % , calculate and type the numbers in "(center)custom size" or in Virtual dub if you use that for resizing and you should get the right AR.

You think you have problems working out aspect ratios, you should be working in here (BBC Northern Ireland). Currently we shoot news footage on Betacam SX cameras. These are in 16:9 format but we have set them to 4:3 (to match old library footage). However the cameraman is told to leave a safety at the top and bottom of the picture for "arcing" later (ARC=Aspect Ratio Conversion). This 4:3 source tape is then converted to 14:9 for terrestrial broadcast and 16:9 for satellite tx of the same programme at the same time!! Once I saw 3 different (and all quite wrong) aspect ratios within a 30 second report! ITV in the UK rarely broadcast programmes in the right aspect ratio. Once I saw a live 2 hour awards ceremony broadcast wrong for 1hr 50 mins before switching it correctly for the last 10 mins!! But the ultimate must have been recently when Channel 4 broadcast a programme in 4:3 letterbox (looking like 16:9) and then putting fullscreen images in every now and then to totally bugger up everybody!