Fixed Resolution independent from the viewport size

Hi!
I’m making a pixel art game with a 480x270 resolution. I want to use this resolution or a power of two of this resolution (480x270, 960x540 or 1920x1080). I don’t want any kind of scale. Can I force this resolution and aspect ratio or fake it ?

Thank you

I don’t believe there is any way to do this through Unity natively, but you can enforce the aspect ratio via letterboxing as in this script http://wiki.unity3d.com/index.php?title=AspectRatioEnforcer