What is a PAR file?
A .PAR(ity) file contains information on a group of files in an archive as well as information needed to complete a file that may have missing parts due to corruption, poster error, or if it just doesn't exist on the news server. Generally speaking, if you are missing 100mb from your archive, you need 100mb of .PAR2 files to fix the files. A good poster will post approx 10-15% of .PAR2 files relative to the archive size.
The process of creating PAR2 files breaks the archive files up into these blocks and stores enough information to verify a block is good and also information to fix a block that is bad. NewsBin's AutoPAR feature uses PAR2 files to determine which files belong in an archive and how many blocks need to be found to complete the archive.
If you want to know more about PAR2 files and how they work, then you can find a lot more information on the QuickPAR web site.
The previous section talked about the tasks that traditionally have to be performed after downloading files. As long as a file set is accompanied by PAR2 repair files then Newsbin can automate the following steps:
- Checking if all files are present in a file set
- Checking if the files are complete or are damaged
- Selecting for download the PAR2 files required to repair any damaged files
- Downloading the PAR2 files
- Repairing damaged files
- Decoding file set as long as it is a RAR, MasterSplitter or QuickPAR file set.
This set of facilities are known generically within newsbin as the AutoPAR set of facilities.
The pre-requisite for the AutoPAR facilities to work is the presence of the PAR2 repair files. If there is no PAR2 file present then AutoPAR is not triggered for that set of download files. However as virtually all none-trivial downloads are now accompanied by associated PAR2 files this turns out to not be much of a limitation.
|TipIf you would rather not use the Newsbin AutoPAR facility, then it can be disabled via the checkbox under Options->AutoPAR Options. This switches the AutoPAR facility off.|
Preparing for AutoPAR
The AutoPAR facility is basically automatic as long as you have queued the correct files. What you need to have done is:
- Queue a compacted file set to download which contains par2 files and a rar archive (usually found as multi-file archive).
You also need to check the settings under options->AutoPAR settings. The options you are most likely want set are:
- Disable AutoPAR: You need to make sure that the AutoPAr facility is NOT disabled under Options->AutoPAR options.
- Automatically Decode Complete files: This option needs to be set to get file sets automatically decoded (extracted). If it is not set then the automated processing will stop after checking and/or repairing the files.
- Delete RAR's and Pars after successful Decode: If this is set after Newsbin has successfully decoded the file set, then the files downloaded are deleted leaving just the files that resulted from the Decode action.
There are more options available for fine-tuning the AutoPAR behavior under Options->AutoPAR Options.
You can also disable the AutoPAR functionality for selected groups by setting this option under the Group Properties.
AutoPAR in Action
Most of the time the AutoPAR facility can be left to run itself.
There are 3 menu commands available by right clicking a set, which are also accessible from the AutoPar Properties.
QuickPAR will run QuickPAR with the selected par2 set if you have it installed.
Sample will UnRAR a partially downloaded archive and play a video file with your associated media player.
UnRAR will extract the archive on demand. This can be useful when the archive is complete according to QuickPAR but some Non-RAR files are not being found by AutoPAR.
If you want to access AutoPAR Properties on a set in the Download list, select the main line of a set that has already began downloading (not a file in the expanded list) then right-click and select Properties. Each entry shows how complete the file is from an AutoPAR perspective. As new files are downloaded and checked the block counts will increment and the progress bar will move towards completion.
UnRAR Path can be modified for the set at the bottom of this window.
The status bar at the bottom of the AutoPAR dialog will show a message indicating which action (if any) is currently being carried out.
AutoPAR Post UnRAR Filtering
Sometimes RAR/PAR sets include specific file types that you may not be interested in. For example, a poster may include images, information files, subtitle files, etc. Newsbin can filter these files out of the automatic UnRAR process by setting up a special Filter Profile then enabling the Post UnRAR Filter. Here are step by step instructions for telling Newsbin to exclude any .nfo files as an example:
- Click the Options menu item at the top of the Newsbin window and select "Filters..."
- On the bottom left of the Filter Options screen, click "New..."
- Enter a name for this filter profile, like "NoNFO" and click OK
- Highlight your new filter profile under the Filter Profile window by clicking once on it. This selects it and makes it the active filter profile for further configuration
- Set any file size filters you may want to apply
- Click on the Filename Reject tab
- Click the "Enable Filter" checkbox
- Type in a file type to reject using regular expressions. For example \.nfo will reject .nfo files.
- Click the "Add" Button
- Continue adding file types you want to reject by repeating the last two steps. Examples are \.sfv, \.sub, \.jpg, etc.
- Click Ok when done
- Click on the Options menu item again and select Options
- Click AutoPAR Options from the Newsbin Options screen.
- Click "Enable Post UnRAR Filter"
- Click the dropdown under that option and choose the filter profile name you just created.
- Click OK to exit the screen
After you complete these steps, the filter profile you created will be applied after Newsbin completes an UnRAR and any files matching your reject filter will not be saved.
Problems using AutoPAR
The problems using AutoPAR fall into several broad categories:
AutoPAR will not work at all
Some people seem to have problems getting AutoPAR to work for them. Possible reasons are:
- The AutoPAR2.db3 file in the Newsbin DATA folder has become corrupted. If this happens then the only recourse is to delete this file with newsbin closed) and let Newsbin recreate it. Note that any existing AutoPAR entries will be lost if you do this.
AutoPAR will not start repairing/decoding a file This would normally mean that the AutoPAR facility does not have enough repair blocks to fix the file. Occasionally the repair process may need to be manually triggered by right clicking the post and selecting AutoPAR -> Run QuickPAR and after repaired/verified you can use AutoPAR -> UnRAR/Join Files.
AutoPAR will not repair a file: This has been known to happen. If it does then the best solution is to use QuickPAR to check/repair the files. It is also possible to get files that cannot be reapired even by QuickPAR. This is due to a very obscure bug in the algorithm used to create the PAR2 files.
AutoPAR repair fails
Occasionally the AutoPAR repair facility fails for some reason. If this happens the easiest way to fix this is to use QuickPAR to repair the file as QuickPAR has slightly more comprehensive facilities in this area than AutoPAR. Once the file has been repaired with QuickPAR, then you can select the Refresh/Rescan option from within AutoPar and it will detect that the files have been repaired, and move onto the Decode phase.
AutoPAR decode fails
This has been known to happen. If it does then the best solution is to use QuickPAR to check/repair the files and WinRAR to decode (extract) them.