Impossible! If your data is truly random.

You need a gnat's under 6.5 bits to represent each of your values and are currently using 8 bits. If you could pack it exactly (meaning using 1/2 bits), then the best you could achieve is 6.5/8 = 18.75%.

If you try dictionary lookup:

  1. The dictionary for 2 byte pairings requires 13 bits; no saving over 16.
  2. 3 byte pairings require 19.5, no saving over 24.
  3. Best you could do is using a 40-bit number to represent each of the 531441000000 6-byte pairings; giving 40/48 16.67% saving.

Beyond that, your into the luck of the draw. Some random datasets might contain enough common (sub)sequences to allow Lempel–Ziv or similar to get close to 50%, but for other datasets, the same algorithm will produce barely any reduction, (or even an increase).

See Kolmogorov_complexity for more.

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In reply to Re: Data compression by 50% + : is it possible? by BrowserUk
in thread Data compression by 50% + : is it possible? by baxy77bax

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