I've sort of forgotten exactly what I did when I tried to fix the incomplete download, that NL had joined and save, with PAR2's, but I might as well tell you what my testing has shown.
i'm trying to understand what could have gone wrong in your test, but i really can't figure it out (only thing i can imagine, is that instead of decoding 5/6 of the articles, you decoded a few less, but even then the numbers don't really fit). was the rar file exactly 3mb (3.145.728 bytes)? what par2 block size did you use? and when quickpar said it had 4 blocks and needed 8, where did those 4 come from, were they the repairblocks, or did they come from the decoded rar file?
Looking back at the example I gave, I think the reason it didn't work is because I should have made the PAR2 files (step 2) from the original RAR file, and not the 6 yEnc encoded parts (doh!). So I did another test.
Test 2 (Works)
1. Used yEnc32 to to encode Test.Rar (3,046KB or 2.97MB) into 5 parts (set to 640,000 bytes, but makes them 688,128 bytes or 650KB - Why is this?)
2. Used QuickPAR to create 2 recovery blocks from Test.rar (Recovery Data Size=2,561,456). Settings: Source Block Count=3, Block=1,280,000 bytes (Options: Preferred Block Size For Yenc = 5000 lines, Block size=640,000 bytes, Article Size=670,000 bytes)
3. Deleted Test.rar. Used QuickPar to load the PAR2 files made in step 2. Shows 2 recovery blocks available, 0 data blocks, needs 1 block.
4. Joining 2 or more yEnc parts to make Test.rar should enable QuickPAR to repair. It does BUT there's a BUG in QuickPAR - Clicking Add and selecting this Test.rar doesn't always work, but starting again by clicking on Open and selecting the PAR2 file allows QuickPAR to repair (the Test.rar is in the same directory as the PAR files, and QuickPAR sees it). This bug might be fixed in a newer version of QuickPAR than the one I'm using (v0.8.0.0).
NOTE: Only some yEnc decoded 2-part combinations work for QuickPAR (1+2-yes, 1+3-no, 1+4-no, 1+5-yes, 2+3-no, 2+4-no, 2+5-yes, 3+4-yes, 3+5-yes, 4+5-yes. So 5 and any other part work, or 1+2 or 3+4.)
So if NewsLeecher finds, for example, only parts 1+3, and downloads and saves them, yEnc decoded and combined, I wouldn't be able to use the resulting file with PARs to fix it. I guess this is just the way PAR's work, in that 1+2, 3+4, or 5 all constitute 1 block, but non-adjacent blocks like 1+3 don't
if you don't check the files after they've been joined, how do you do normal do your parring and unrarring?
do you add all the decoded articles into quickpar seperately?
if so you should be getting a hell of lot more incompletes than necessary.
I normally use Agent, in which I have to manually save the available parts to a file, and then decode this using yEnc32. So I AM loading a joined and yEnc decoded incomplete file into QuickPAR. Not sure why I couldn't get this to work with NewsLeecher the other day. Might be because of the bug mentioned above.
just tested this myself. i created a rar archive and usend yenc32 as well (same version, the quickpar version i used was 0.91, but that shouldn't matter) to make articles, then decoded the articles one by one.
What do you mean by decoded the articles one by one? I used yEnc32 to encode test.rar (2.97MB or 3,046KB), using 'Limit Size of Encoded Files to'=512KB which created 6 files (test.001.ntx - test.006.ntx (each 533KB except 006=505KB))
I then used yEnc32 to individually decode each of these 6 parts (IE selected test.001.ntx, decoded that, then selected test.002.ntx, decoded that, etc.) Decoding the first ntx file created a file (test.rar) which was 512KB and decoding each subsequent part increased this file by 512KB, until the 6th part which resulted in test.rar being 3,046KB file which opened without error in WinRAR (despite Yenc32 stating 'File test.rar is incomplete')
Then I tried again, but this time I renamed, and moved to a sub-directory, the test.rar after decoding each part. Again this created an inital test.rar of 512KB, which increased by 512KB each time, (so after renaming and moving I had test01.rar - test06.rar each of which was 512KB larger than the last, which seems wierd seeing as how each time I was only decoding one part), so decoding test.006.ntx resulted in a test.rar of 3,046KB. However trying to open this gave an error 'The archive is either in unknown format or damaged'. (NB. you can get the same result by only selecting and decoding test.006.ntx, there's no need to go through the whole process.)