AVISynth Crop & resize

[Ejoc]

*If you have a movie thats is letterboxed fine, do you need to crop just the video, resize and add new black bars, or cant you just do a single resize.

example:
crop(0,60,720,360)
bicubicresize(480,360)
addborders(0,60,0,60)

versus:
bicubicresize(480,480)

In my head it seems like the bicubicresize(480,480) would do the same thing, only faster. Yet every guide seems to want to do the croping.

Now I have done the cropping when the video source was slightly off center and there was a black line on one side of the image, and the cropping was exactly what I needed to recenter it.

Anyone who doesnt use AVISnyth is missing out, Im totaly in love with it, it makes fixing Telecide / interlaced / subtitled sources a dream, and when everything is done in AVISynth TMPENC run so fast, and the .avs scripts are just a few lines long.

[Heavensent]

why not

BilinearResize(480,480)
Letterbox(70,70) or whatever you need it to be

you dont have to crop and add the black lines if you use letterbox.

[Ejoc]

BilinearResize(480,480)
Letterbox(70,70) or whatever you need it to be

That is a faster method then the
crop(...)
resize(...)
addborder(...)

but its basicly doing the exact same thing as it. I guess my question is more, if there are black bars above and below the picture, why remove them just to add em back?

/edit
when you crop out the black bars and use addborder or letterbox, are those black bars a part of the encoded image or is only the actual video encoded and the bars are added by the program/dvd player viewing it?

[Truman]

... if there are black bars above and below the picture, why remove them just to add em back?

If you don't want to change the aspect ratio, you don't need to resize and add borders. For example you have a 4:3 DVD source and want to convert to 4:3 SVCD, just resize to svcd resolution.

BilinearResize(480,480)

If the original bars are noisy, you will waste bitrate, then use Letterbox instead, that will cover that part with solid color borders.

BilinearResize(480,480)
Letterbox(60,60)

Of course those bars are a part of the encoded image.

[Ejoc]

Thanks, thats what I thought, but just couldnt get why it seemed like every AVISynth exampled did that.