par2 question

[deiby]

Are par2 files only necessary when the archive fails to extract? In other words, say you download all the rar parts and you unzip/unrar it and it says all ok; is there a reason to get the par2 files?

[JustDOSE]

never download the pars unless the rars are corrupts........ nub (RIGHT_CLICK_-_VIEW_IMAGE) http://www.abload.de/img/untid8wzgy.png

[mjmacky]

Since the idiot above is not keen on intelligent explanations, I'll elaborate further.

There is 1 par2 file that's always a good idea to grab, it's used to check all your parts for errors (either through your NZB client or through QuickPar). It will have the same filename as the main filename, just with the par2 extension. All the other repair volumes will end in volxx+xx.par2 and you do not need those if all your archive parts are complete. You can however set them to download as well, as it won't necessarily effect anything negatively (besides extending download times and 5-10 % more data usage). The better clients automatically download the appropriate number of repair volumes as it checks the files, and only if it needs them.

[deiby]

mjmacky: hey thanks, that's what I thought, and everywhere I looked on the internet said the same thing: that they can be used to fix bad files or missing files. But there was this one site that said something strange... It seemed to imply that you may still need the par files even if you successfully extract the file... here's the link:
http://www.techsono.com/usenet/files/par2

the part where he goes:
So, you don’t need to download PAR files unless you need them to fix a damaged file in your possession. Of course, it is not always obvious if a file is damaged. For example, there could be small flaws in a video that you can’t find unless you watch the whole thing very closely.

So is that true? If you see a small flaw in a video (which you can't really know unless you watch the whole video) will the par files actually corect that too? Because if so, it seems like (according to this article) I would always have to download par files for video files in case there there are small but visible flaws apparent after watching it.

[JustDOSE]

no noob... if the file is corrupt it wont extract.. if it extracts and is fucked up thats because the ripper did a shit job and there is probably a proper out... silly noob go back to p2p

[cola]

the part where he goes:
So, you don’t need to download PAR files unless you need them to fix a damaged file in your possession. Of course, it is not always obvious if a file is damaged. For example, there could be small flaws in a video that you can’t find unless you watch the whole thing very closely.

So is that true? If you see a small flaw in a video (which you can't really know unless you watch the whole video) will the par files actually corect that too? Because if so, it seems like (according to this article) I would always have to download par files for video files in case there there are small but visible flaws apparent after watching it.

Pars will correct the files and verify that all the files are correct. Many programs will verify each rar after downloading. SABnzbd will automate the whole process for you. It'll only download additional pars if repairs are needed.

[mjmacky]

So is that true? If you see a small flaw in a video (which you can't really know unless you watch the whole video) will the par files actually corect that too? Because if so, it seems like (according to this article) I would always have to download par files for video files in case there there are small but visible flaws apparent after watching it.

If you see video glitches, chances are you're just watching a scene encode (e.g. Immerse and Dimension are likely culprits). Most of those encoders don't check their work since they are participating in an arbitrary race. You have to remember that many of the guys in the scene are just as limited in intelligence as as our dear friend justdosedwithmeth. Par2 files won't help you there.

[Rskan]

That's one of the things I particularly like about usenet actually though, I can download a couple of different releases if I'm iffy about the quality to compare. Comes in particularly handy since I tend to archive stuff.