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View Full Version : Yet another question abou AutoGK and ITU resize method


girotour
29th September 2007, 13:49
I'm doing some tests in order to find the right way to resize a MPEG2 file recorded from satellite.
As AutoGK says, the file has the following format:

[29/09/2007 13.56.15] Source resolution: 704x576
[29/09/2007 13.56.15] Found PAL source.
[29/09/2007 13.56.15] Source aspect ratio: 4:3

Since I don't know if it is correct to apply ITU resize method for this source, I've tried to compress it with and without "Force ITU resize method" checked.

In both my tests, I used the following settings:

Auto crop: off (by setting Threshold to 0)
Manual crop: Left=4, Right=4, Top=2, Bottom=2
Detect and force 4:3 AR: off
Output resolution: 640 pixels (fixed width)

In my understanding, in the first case (ITU on) the input PAR should be 1.094, so the output height should be:

(640 * (576 - 2 - 2)) / (1.094 * (704 - 4 - 4)) = 480.78 rounded to 480

In the second case (ITU off) the input PAR should be 1.067, so the output height should be:

(640 * (576 - 2 - 2)) / (1.067 * (704 - 4 - 4)) = 492.95 rounded to 496

Despite of this, I always obtain an output height of 480 pixel with or without ITU resize method checked.

What I'm doing wrong or not understanding?