[daala] Curious about progress of codec
jmvalin at jmvalin.ca
Wed Apr 27 20:12:24 UTC 2016
On 04/27/2016 03:38 PM, Jarek Duda wrote:
> Sure there can happen probability distribution close to uniform, in
> which case starting with flat distribution is reasonable ... but
> definitely not always, especially for your data which for many IDs
> mainly consists of zeroes - you don't have to pay with ratio to learn
> that - you can start with a distribution characteristic for a given ID
> instead (and also optimized adaptation rate).
Note that in the example Tim gave, the actual distribution was very much
non-flat. It's just that the variable-speed initial adaptation was
giving us more gains than we lost from the initial flat probability.
Seriously, I would recommend you try it for yourself in the context of a
real codec like Daala. I can show you where the important symbols are
coded and you can try coming up with a better scheme that you can then
test on a variety of real sequences. It's quite possible you'll be able
to come up with something better than what we have now, but it's also
not as easy as it may seem from looking at the data out of context.
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