Re: comments about draft-ietf-httpbis-header-compression


This is what we used to help make the initial selection; I don’t believe that the compressor there has been updated to exactly match the spec; e.g., it doesn’t do huffman (Herve?).


> On 1 Jan 2015, at 10:35 am, Jyrki Alakuijala <> wrote:
> If the goal is to just make an algorithm that can work with a static entropy code with a static dictionary and no LZ77 outside the static dictionary, the current format (deflate) needs no changes. Deflate supports all these concepts. You only need a new encoder -- although zlib with setting a dictionary and running it with quality == 1 is a pretty close match already, only the static entropy coding is missing then.
> Was HPACK ever benchmarked against using deflate in such configuration? Would you accept help in setting up such an experiment?
> Note, that with a static dictionary I mean that we would generate a single deflate dynamic dictionary from a header corpus and always encode all data with that -- I don't refer to the static Huffman mode in deflate.
> On Wed, Dec 31, 2014 at 7:52 PM, Dave Garrett <> wrote:
> The goal of HPACK was never to produce ideal compression, just competent
> compression not vulnerable to known issues. Some people do want to attempt to
> use/create a far more efficient codec here, but it's now accepted to be outside of
> the initial scope. What could be very well received is an HTTP/2 extension to
> allow negotiation of alternate header compression methods. This would allow
> actual experimentation in an effort to find the most ideal route(s).
> Dave

Mark Nottingham

Received on Saturday, 3 January 2015 17:25:44 UTC