- From: Manu Sporny <msporny@digitalbazaar.com>
- Date: Fri, 24 Jul 2020 10:34:15 -0400
- To: public-credentials@w3.org
On 7/23/20 10:22 PM, Liam R. E. Quin wrote: > How does it compare to using EXI? (server-side parsing with a > compressed parsee event stream) Just like all compressions schemes, there are many similarities... encoding tags as bytes, building a compression dictionary for tags and values, optimizing for streaming, etc.. Here are just a few of the differences that I know of between EXI and CBOR-LD (you'll have to forgive me, I'm not an EXI expert): * EXI embeds its compression dictionary resulting in larger data sizes, CBOR-LD builds it's compression dictionary using a stable external resource. This matters for very small payloads < 1KB in size. * EXI doesn't attempt to compress data, CBOR-LD will do compression for values it understands. For example, EXI will put DateTimes "2018-04-12T14:23:13Z" (39 bytes with tag in XML) in a compression dictionary WITHOUT converting them to binary formats, where as CBOR-LD will compress that down to a 7 byte binary value... a 557% compression ratio. See[1], slide 14. Other than those two (key) items, there are a lot of similarities between CBOR-LD and just about any other structured data format compression technique. For example, you can apply LZ-compression (gzip/Deflate) on top of CBOR-LD and get further compression for repeated binary/string values... IF you have repeated content in your data (like a DID Document would). -- manu [1] https://docs.google.com/presentation/d/1ksh-gUdjJJwDpdleasvs9aRXEmeRvqhkVWqeitx5ZAE/edit#slide=id.g866980c4a6_2_146 -- Manu Sporny - https://www.linkedin.com/in/manusporny/ Founder/CEO - Digital Bazaar, Inc. blog: Veres One Decentralized Identifier Blockchain Launches https://tinyurl.com/veres-one-launches
Received on Friday, 24 July 2020 14:34:29 UTC