Resize 1904x1072 to 1920x1080 using avisynth

[Gwar]

hello guys,
I recorded a HD stream which has a very strange resolution of 1904x1072. I want to convert it to a BD compatible format. I'm using avisynth and x264 for that purpose.
I read that Spline64Resize is the best resizer and better than for example Lanczosresize.
I wonder if it's enough to just use "Spline64Resize(1920,1080) " or if I have to use "AddBorders(?,?,?,?)" as well so that the right 1.78 aspect ratio is kept intact
I'm pretty bad at mathematics so I would appreciate your help.
Thanks
regards
-Gwar

[hello_hello]

1904x1072 is almost 16:9, however 1904x1071 is exactly 16:9.

(1904 / 1071) = (16 / 9) or 1.77777778

You can use the Avisynth resizers to crop a single pixel when resizing. To crop a single pixel from the bottom to reduce the height to 1071 before resizing to 1920x1080:

Spline36Resize(1920,1080,0,0,0,-1)

I use Spline36 for just about everything. Spline64 would be fine. You'd probably need bionic eyes to see a difference for such a small amount upscaling.

By the way, if the source has square pixels, the resizing formula is pretty simple.

Original Height / Original width * New Width = New Height

1072 / 1904 * 1920 = 1081.0084

So even if you resized directly to 1920x1080 it'd only be "off" by a pixel. Not enough to notice any distortion. However....

1071 / 1904 * 1920 = 1080

[jagabo]

Every resizing has the potential to screw up the picture by creating/accentuating moire artifacts, creating oversharpening halos or blurring the picture. I wouldn't bother with resizing or worrying about the aspect ratio (unless it's way off, say, a 2.35:1 video anamorphically squeezed in a 1904x1072 frame). Just add black borders. Nobody will notice unless watching on a TV with a white bezel.

[manono]

I agree. Just add black:

AddBorders(8,4,8,4)

[Gwar]

thanks a lot guys. @Manono: Could you please explain how you get the 8,4,8,4 borders for the 1904x1072 resolution ? I want to understand how you calculate it. I understand that the 8 is probably to add 8 to 1072 to get a 1080. But I don't get what the 4's mean

thanks

[jagabo]

1920 - 1904 = 16 --> 16 / 2 = 8 pixels left and right
1080 - 1072 = 8 --> 8 / 2 = 4 pixels top and bottom

[Gwar]

thanks a lot