Verifying > Repair > Verifying > Repair > Verifying > Unrar ??

[Bazookaa]

Hello there,

I'm using sabnzbd since quite some time and it is amazing! There is just one thing that is a bit annoying:

I often have the phenomenon that sabnzb is doing multiple repairs in a row, why is that? Shouldn't be one par verifying and repair process be enough? I usually get this downloading larger files, like > 7 GB and this process takes a looong time on my machine. Am I missing something?

On a side note: I understand that sabnzbd uses the command line par tool, but I have a feeling that the file verifying is much slower than for example with quickpar. Manually verifying files with Quickpar on large downloads goes rather fast, while the par.exe takes an unreasonable amount of time. I could be wrong though! This was just an observation, I didn't do any timing or anything. Repairing time seems to be the same.

[shypike]

Quickpar is faster and can work incrementally.
It also completely useless in an automated solution.
par2.exe is all we can use.
BTW: par2 first does a "verification run" and then a "repair".
When more par2 files are needed, they are downloaded and par2 is run again.
That's the way it is.

[Bazookaa]

Hey, thanks for quick reply

Ok, good to know that QuickPar is indeed faster but too bad there is no command line version.

BTW: par2 first does a "verification run" and then a "repair".
When more par2 files are needed, they are downloaded and par2 is run again.

Yes that is what I understand how it should work, but my observation was different. After the first repair, it is doing another verification run and then doing another repair, I thought it should know how many repair blocks are needed in the first verification run? Something like: verification > download XX repair blocks > repair > unrar, but instead it is doing multiple verification and repair runs, is this by design?

[shypike]

Our internal verification is quite limited, determining the amount of missing blocks
is more complicated.
What we have now is just an optimization for the best case (which happens quite frequently).
BTW: the repair is the really time-consuming part (also very CPU intensitive).

[Bazookaa]

OK I understand.

I've been looking for some alternatives for par2cmdline, and what I have found is phpar2 ( http://paulhoule.com/phpar2/index.php )
According to his benchmarks, phpar2 is much faster at creating par files. (but should be also much faster at verifying/repairing)

    par2.exe (sourceforge)  234 secs
    QuickPar (0.9.1)        130 secs
    phpar2.exe                44 secs

Simply replacing par2.exe with phpar2.exe in the sabnzbd folder won't work I guess. It may have different command line options, and for the status updates in the Web UI you are propably reading the console output from par2.exe, is that about right? Maybe I will have a look if I can figure out how to replace it with phpar, I have no experience with Python tho, so most likely I will fail (I'm a C# programer)
So may I make a suggestion to also implement phpar2 and make it as an option?

[shypike]

Currently we're using chuchusoft's multi-core version of par2.
One of the team members is looking at phpar2 (or an alternative, cannot remember right now).
I think phpar2 should be compatible with SABnzbd, it's worth a try.
Note that SABnzbd will pick the 32bit or 64bit version depending on your OS.
(so you might need to replace both par2.exe files).

BTW: the numbers you listed are for creating par2 files, something SABnzbd never does

[Bazookaa]

Well, I tried to replace the default par2.exe with phpar2, and it works!! No problems.

I can tell you, it is VERY fast! I just had a 5 GB download which had to be repaired, and it was sooo much faster.

[usenow]

I will also like to say that phpar2 is insanely fast.
Also in creation of recovery files. My experience in creating pars for 15GB of data:

MultiPar = 1 hour
phpar2 = 13 minutes

Amazing.
(This is with 8-core i7 and SSD)

The only 'downside' is that it is command line only. But it is very easy to use, so doesn't really need a GUI.

[waryde]

For me, phpar2 is much faster than anything else, even faster than the 64bit version!
I would suggest to use phpar2 as default on every x86 and AMD64 Windows machine!

[shypike]

In my latest measurements, phpar2 was much slower than chuchusoft's par2.
It looks like "your mileage may vary".
BTW: it's a plugin replacement. Just overwrite par2.exe and remove the 64 bit version.