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It certainly depends on what they tried - Loren Merritt of x264 fame looked at lapped transforms years ago as well, and concluded that they were inferior due to
by brigade 13y ago
It certainly depends on what they tried - Loren Merritt of x264 fame looked at lapped transforms years ago as well, and concluded that they were inferior due to the unfeasibility of spatial prediction. I remember he also concluded that frequency-domain prediction was inferior to spatial, probably based somewhat on how useless the frequency prediction was in mpeg4.
Personally, the amount of blur in those images worries me more than whatever On2 might have concluded, simply because we all know what happened with wavelets. But it's just the prediction we're seeing, not the result of the transform, so time will tell.
- StavrosK 13y agoWhat happened with wavelets?
- brigade 13y ago15 years ago they were the next big revolution in image coding. Then people made codecs based on them, which never beat DCT codecs perceptually. They did well in PSNR though, since they blurred instead of blocked. Of course, their main problem was that fine detail wound up in every decomposition band, so you had to code it multiple times and no one came up with good enough prediction to offset that. Lapped DCTs shouldn't have that issue any more than traditional DCTs.
- StavrosK 13y agoAh, good explanation, thank you. I did wonder why they never took off.
- aidenn0 13y agoThey specifically mention in their slides being aware of how crappy PSNR is with respect to blur, so I doubt they will fall down that particular pit.