Fernando Cacciola wrote:
Now, off the pixel/color topic. rom the Quicktime format disccusion: is it possible to supersample (rather than subsample) an image? That is, to take two or more consequtive pixels in a row and pretend is just one pixel?
You're talking about a subsampling (or decimating) iterator, instead of an interpolating iterator? I believe the code structures necessary for both of these tasks are largely identical - once you've worked out how to do one, the other should be quite straight forward. However, for most purposes where this is desirable, it is probably more efficient to write a routine that resamples entire rows and columns at a time. On the other hand, if you care more about conserving memory than performance, interpolating iterators may be a good solution for image scaling/zooming, and are not limited to images with non-uniform sample structures.
I ask because the lack of uniformity in even/odd pixels in the v210 format could be elegantly solved this way (that is if IIUC the problem).
You'd be discarding information, though. The reason chroma has half the sampling frequency, in this case, is because it has been band-limited to half the bandwidth of luma (a perceptual optimization). If you decimate luma, you're going to loose information (given no assumptions about the input data). So, it's fails as a simplification, because it's not equivalent. Matt