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Comment by clouddrover | Hacker News Reader

It sounds counter-intuitive, but Cisco found that having more coding tools available actually helped their live, low latency video encoding use case for video conferencing and screen sharing. They discussed it in their presentation at Big Apple Video:

https://vimeo.com/344366650

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GP is right though. It's possible to add options that don't pay for themselves in terms of the entropy of encoding "don't use option X here." Here's an example of a feature that didn't make it into the Daala codec: https://people.xiph.org/~jm/daala/paint_demo/index.shtml

It's possible, but with adaptive probabilities, the cost for never using a feature is pretty negligible (roughly O(log N) bits of overhead to learn that the probability is ~zero, where N is the number of times you code the symbol... and potentially even smaller depending on your initial probability).

Intra paint was not defeated because of the cost of entropy coding "don't use feature X here", it was defeated because due to "lapping and block size alignment issues, we cannot just turn it on and off when we want" (last paragraph of the "Pretty Images" section).

It's analagous to optimizations for resource-starved systems. If you have trouble processing 16 of something, you don't really benefit from improving the O(n) at the cost of higher overhead, you benefit from the same algorithm processing each item twice as fast. Linear micro-optimizations rule the world.

Being able to use lots of tools and hybridize your engineering to get relatively bigger savings is a result of having the headroom for algorithmic complexity to start ruling, which for video might be a relatively recent phenomenon(I don't actually know the domain).

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