Resizing with AviSynth

aldaco12

Hi. I experienced this strange thing and I wished to kow more about it.
Let's suppose I start with a X x Y AVI file which I wat to convert to SVCD.

If I use this script:

# script to load a X x Y AVI file which
# must be converted to a 480x576 MPV
AviSource(Movie.avi)
LanczosResize(448,Y)
AddBorders(16,b,16,b)
#it must be b = (576-Y)/2
ConvertToYUY2()

the output movie video is a perfect 480x576 video with proportions kept!

Please that I tested this with the following resolutions: 720x576, 720x384, 576x320 and 608x344.

Can someone tell me why?

Evrywhere I read about 'keeping aspect ratios' but keeping certain aspect ratois seems necessary only in a case: if you load a DVD using a D2V, you have to use spcrific destinations pixels, or you don't get anything from CCE.
But this seem only a question of 'interlaced' video or not, in fact it's not a problem of 'ratio'. In teh D2V aspect it is 'result=yes' or 'resut=not'. I never got such a problem such as keeping aspect ratio.

aldaco12

So, no answer? But this would be a nice thing to consider! A simple 480x480/576 movie could keep most of the resulution of a standard AVI file (like 640x360)!!

TimC

Just use DVD2SVCD & let it do this for you. The D2SRoBa front end is mandatory in my view.

bcn_246

As far as I know you are keeping the proportions for a file, but remember that 480x576 will be resized to 4:3. Therefore you will need to convert the aspect ratio manually like this. The problem is that it will be placing the original AR in the centre of a file that stretches the AR to 4:3, but is not the correct number of pixels to fit 4:3 AR.

original video
x/y=a
then do
576x4/3=768
768/480=1.6
so then do
576/a, then x by 1.6
then times by 4/3, call the answer b
then do 576-b, and divide by two, these will be the horizontal borders each side.
add 16 to the border on each side, and take away 32 from the x and y resize .
Then encode.

If you find this process to complex just post the dimensions of the original file I can work it out for you and post the script.

May I ask why you are using ConvertToYUY2? I always use ConvertToRGB32, CCE still accepts it and you wont lose colour quality. You may also need to check the original framerate is at 25fps, if not use (changefps=25), as 480x576 is the PAL SVCD format.

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