pixel aspect ratio of VEGAS project

[compusic]

I just noticed that the PAL project (frame ratio=4:3) created by VEGAS has a pixtel aspect ratio of 1.0926. I usually use premiere, and for such pal project, the pixel aspect ratio is 1.067. why vegas has a different PAR?

[edDV]

I just noticed that the PAL project (frame ratio=4:3) created by VEGAS has a pixtel aspect ratio of 1.0926. I usually use premiere, and for such pal project, the pixel aspect ratio is 1.067. why vegas has a different PAR?

According to this website and the BBC Guide to Picture Size,
http://lipas.uwasa.fi/~f76998/video/conversion/
http://www.bbc.co.uk/commissioning/tvbranding/picturesize.shtml

128/117 = 1.094

is the correct PAR for PAL 720x 576, 704x576 and 702x576

In the PAL ITU-R BT.601 standard 702x576 defines the 4:3 picture.

In the first document above, #4 Frequently Asked Questions makes interesting reading.

[BJ_M]

real good links .....

1.0926 is considered a 'standard' though and close enough to the mathematically derived 1.094 as to be still correct ...


not sure where 1.067 came from -- in the past adobe was famous for getting the NTSC PAR wrong for many years ...

[edDV]

real good links .....

1.0926 is considered a 'standard' though and close enough to the mathematically derived 1.094 as to be still correct ...


not sure where 1.067 came from -- in the past adobe was famous for getting the NTSC PAR wrong for many years ...

Back in the early to mid 80's there was heated debate amongst manufacturers, old school broadcasters and the FCC whether 640x480 or later 704-720x480 video met standards for broadcast which was technically 486 lines high and filled the space between horizontal blanking. The FCC had even issued warning tickets to broadcasters using 640x480 digital to analog conversions. After years of squabble, the FCC lawyers decided to sidestep the issue by ruling that 640x480 or 704x480 converted material was mearly being cropped into a 486 line analog raster and that that was a programming content decision. So long as the area outside the crop fit within 7.5 IRE to 100 IRE luminance standards they were happy.

Years later ATSC SD 4:3 was defined as 704x480. Legacy 486 line material is now required to be cropped or resized to 480 lines.

[edDV]

real good links .....
..

RE: #4 FAQ in the link
http://lipas.uwasa.fi/~f76998/video/conversion/#faq

The FAQ should be titled
"You want the truth about aspect ratios?
You can't handle the truth about aspect ratios!"

[compusic]

after reading, thinking and calculating, just figure out how the 1.0924 and 1.067 PAR come into being.

VEGAS considers pal 4:3 frame has 702x576 rectangle pixels, then 702*1.0924/576=4:3. btw, 704x576 gives the similar result.

Premiere considers pal 4:3 frame has 720x576 rectangle poxels, then 720x1.067/576=4:3. and Premiere does not tell whether the actual active image is 702 or 720.

wow.... the world is in chaos!!!

[edDV]

According to the links above, Premiere got it wrong