[Standards] mobile optimizations: binary xml

Johannes Wagener johannes.wagener at med.uni-muenchen.de
Mon Apr 7 15:41:35 UTC 2008


Fabio Forno wrote:
> (no jokes this time ;)
>
> Since one of the most requested features for mobiles is compression
> and binary xml is often proposed for this, I've tried to summarize few
> of the points in my blog (http://blog.bluendo.com/ff/real-binary-xmpp)
>
> The point (upon which we had rather consensus in the past) is that
> using binary xml for compressing is tough and perhaps you end with
> surprises (e.g. too much cpu time or, in general, lack of
> extensibility). The point of Android people, instead, was that xml +
> zlib is too heavy.
> So I did an experiment: a very fast xml serialization (inspired to
> ASN.1, just using binary token types and lengths before the tokens)
> with no compression at all, just a parser friendly encoding, and then
> I've applied zlib at the top of it. The results are very promising;
> here are the figures with the j2me parser I've written for testing:
>
> | method     | size (kB)  | time (ms) |
> | xml           | 7458         | 2200 |
> | xml + zlib | 535           | 3000 |
> | bin            | 6337         | 600   |
> | bin + zlib  | 541           |1200  |
>
> As you can see bin + zlib is comparable in size to xml + lib, but it
> is much faster (so less battery hungry) than xml alone!
>
> bye
>
>   
That's a really nice experiment, I really like it




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