The popular selective desaturation effect for videos! Select the color that you want to keep and everything else will be turned into grayscale.
Could not be simpler: you only need a few touches to set up the color and the tolerance, the app will do the rest. You can check the effect on any frame of the video before saving.
All videos are processed in full resolution. (note that this needs some time, as video processing is a slow thing: in this case filtering 1 minute of video may take up to 6-8 minutes, depending on video size, device type, etc)
requires iphone 3GS, iphone 4, or last generation iPod Touch (with camera)
" a fun app to play around with " - appadvice.com