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854x480 would be more correct. The "1.2" PAR is rounded up and is actually 1.1851851851...
But as 854 can't be divided by 16 or 8 it is probably preferable to go with 864x480. Many codecs operate on blocks of 8x8 or 16x16 pixels and may not work with dimensions which don't fit that scheme.
checked out the Wikipedia entry regarding PAR.
It says the actual PAR for DV NTSC 16:9 is 1.2121.
But I've seen your number as well somewhere else...
Which number is correct ?
The actual pixel ratio of widescreen NTSC is exactly 1.2. The confusion comes from using 480 as the number of horizontal lines. The ITU/R601 standard specify 486 lines of image information from the available 525 lines. The 480 number was selcted by the DV designer for many reasons (one of which was to make it divisible by 8 and 16). The missing 6 lines are just left blank when the analog signal is sent to the TV set. Similarly the PAR for full screen NTSC is also exactly 0.9.
And when you change the size of the frame, make sure the lower number is divisible by 72. That makes it divisible by both 8 and 9.
So, some of my favorites are 512X288 and 640X360
@ Stephen & Eddie
thanx for the link
thanx for the explanation - useful information, I still don't fully understand how that relates to some sources stating PAR for 16:9 is 1.2121 or 1.2 or 1.1852... ;)
including the 8 as a divisor makes sure it works great with the compressor ?
Thanx for your help !