I need help with choosing a good precompressor.

[miyamoto]

Hello folks,
like the title says I need some really good precompressor.

I don't know which one too pick, there seem to be endless different tools.

Usually I do an ultra compression with freearc v0.666, but sometimes the files are waaay too big, they just won't compress good with the algo. I think this means I need to use a precompressor first, right?

Please help me to find the best:
precomp042 (I tried: precomp038 -slow -c9 -m8 -otestfile testfile.arc)
lprepaq v1.3
paq8o8pre v2 (prepaq v2)
srep20

Tell me your secrets wise masters, I must absorb your knowledge.

greetings

[m^2]

Try and you'll know. Srep might be useful. precomp too. The others are supposed as the last (and usually the only) step of compression.

[miyamoto]

Thanks for the help, I'll run a few experiments with some files. In the end speed is important as well.

[miyamoto]

I'm not very happy with precomp, it's crashing and freezing always. No matter if the switches are custom or default. Could the reason be that it can't handle files larger than 4GB?

Can someone explain me the switches srep20 a little more? How would a good batch file look with input output filenames etc, so I achieve the best compression when I use freearc afterwards?

Sorry for these newcomer questions, I don't know anyone else to tell me this.

[schnaader]

I'm not very happy with precomp, it's crashing and freezing always. No matter if the switches are custom or default. Could the reason be that it can't handle files larger than 4GB?

JPG recompression is quite unstable, it sometimes detects wrong JPG streams that lead to crashes. Using the switch "-t-j" should solve that. So I'd suggest following usage (Precomp 0.4.2):

precomp -c- -t-j -intense -ofile.out file.in

Files above 2 GB should work fine since Precomp 0.3.8.

For SREP, you should download the newest version 2.991. Just using "srep infile outfile" leads to good results.

Order should be:

Precompression (Precomp)
Deduplication (SREP)
Compression (7-Zip/Freearc...)

[miyamoto]

Yes, that's it! Everything is working perfect now, you have my utmost respect for your help Sir.

Edited:

Ich sehe gerade, ich haette mich auch einfach auf Deutsch bedanken koennen, insbesondere fuer das tolle Programm an sich