[flac-dev] Why Rice order in "--best" switch is limited to 6?

lvqcl lvqcl.mail at gmail.com
Wed Jan 8 00:07:15 PST 2014

Барт Гопник wrote:

> Yes, using "-p" and "-A" or more than one "-A" (up to 32) switches is
> really unreasonable, because using them very greatly increase the
> encoding time. But I did some tests and found that using "-r 8"
> instead of "-r 6" NOT greatly increase the encoding time (one of my
> tests: 24 sec instead of 18 sec for 10 min input on my machine).
> Increasing value of Rice order is not exhaustive, and increasing
> encoding time is predictable. IMHO 33% (for calculation sample of 100
> tracks was used) is not critical for "best" compression preset. People
> use "best" preset and expect to get "best"/"highest" results. It is
> basis of encode/decode time asymmetry! People who want to get
> "optimal" ("quality"/speed compromise) use default
> "--compression-level-5" or "--compression-level-7".
> Finally, I suggest to increase Rice order parameter in "--best"
> ("--compression-level-8") preset from 6 to 8. (I'm not suggest to
> increase Rice order in "--compression-level-7",
> "--compression-level-6", etc.

I encoded several albums (44.1/stereo/16bit) using "-l 12 -b 4096 -m -e -r 6"
and "-l 12 -b 4096 -m -e -r 8" settings.

The total size of FLAC files:
-r 6: 2866669702 bytes
-r 8: 2866647652 bytes
The difference is 22050 bytes, or 0,00077%

So basically you suggest to trade 33% decrease in speed
for 0,00077% increase in compression.

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