About ColourLike:
WriteHistogram(clip, string outputFile, int every = 1)
'Every' lets you set every how many frames it samples the colors. 1 means every frame. So yes, it balances the color on a frame by frame basis.
I see no mention of a setting to find an average historgram for the whole film... and why would you want to?
The problem is, in my tests, ColourLike just doesn't work particularly well.
Most recently I attempted to use it to recolor the Matrix BD with the original DVD as the source color palette. It did next to nothing. I got better results mixing the BD luma with the DVD chroma (obviously not ideal).
Has anyone actually had good results with Colourlike? (Never heard of RGBmatch before.)