PDA

View Full Version : TLH Shn Decoding Question + Torrent Question


EasilyFound
2009-03-23, 07:47 AM
Hi. New to this board. Two questions.

When decoding shn files in TLH, I repreatedly get an error message saying, "file is possibly truncated or corrupt." These files pass checksum without error, and the files and .wavs play fine. This occurs for shns that I create using mkwACT or shns received from others.

And what do I need to do to be able to d/l some of the great music in the d/l forum. I am not familiar with bit torrent.

Thanks.

U2Lynne
2009-03-23, 10:54 AM
Take a look at our FAQ, in particular this section - BitTorrent Help (http://www.thetradersden.org/forums/faq.php?faq=new_faq_item#faq_bittorrent)

roann
2009-03-23, 12:17 PM
... When decoding shn files in TLH, I repreatedly get an error message saying, "file is possibly truncated or corrupt." These files pass checksum without error, and the files and .wavs play fine. This occurs for shns that I create using mkwACT or shns received from others. ...If you get this error message

a) and the files pass checksum verification without error the checksum file was created after the file corruption took place (the md5 algorithm does not check whether the data stored in the file is valid; that's one reason why instead of a md5 a st5 checksum file should be created for .shn files).

b) usually there will be no decoded data on your drive. So how can you tell that the .wav files play fine?

EasilyFound
2009-03-23, 06:05 PM
I say that they play fine b/c I don't notice any obvious defect in the sound when they are played in shn or as .wav files. I made many of these files myself from cassette tapes, and the digital version sounds the same as the cassette version. So they don't sound "corrupted" compared to the source, and I don't know what it means for a file to be truncated.

U2Lynne
2009-03-23, 06:07 PM
Wait a sec..... you took these wav files you made yourself and converted them to shn, and then tried to convert them back to wav and you got the errors?

EasilyFound
2009-03-23, 06:09 PM
Yes. I get that error message while decoding shns I made myself as well as shns received from others in trading.

They will decode in mkwACT w/out giving me any kind of error message.

roann
2009-03-23, 06:36 PM
Yes. I get that error message while decoding shns I made myself as well as shns received from others in trading.

They will decode in mkwACT w/out giving me any kind of error message.What version of mkwACT, what version of TLH do you use? Does this error happen with files you create now or does it happen with shn files created some time ago?

EasilyFound
2009-03-23, 07:12 PM
I think I found out the answer. It seems to happen only with files created a while ago, and not with shn files created now with TLH. Seems that the md5 checksum file created by TLH has the following information in the beginning of the file:

"; wholefile md5 checksum file generated by Trader's Little Helper
; generated on March 23, 2009, at 6:57 pm"

followed by a blank line before you get to the data for the shn file (I don't know the technical name).

md5 checksum files created with some other program do not necessarily have the same information at the top. I guess TLH is programmed to look for that information, and if it doesn't find it, assumes that the file is corrupted or truncated.

When I tried to verify an md5 checksum in mkwACT, I got an error message that the md5 contains checksums for two files that are missing. I'm assuming it is referring to the two lines above. If I delete them from the md5 file, and then verify in mkwACT, it will verify w/out an error message?

Does that make sense? Got to run and make dinner for my kids. Will check back later.

roann
2009-03-24, 04:11 AM
I think I found out the answer. It seems to happen only with files created a while ago, and not with shn files created now with TLH. ...So most likely the shn files became corrupt, or the md5 checksums were created after the corruption took place.

... Seems that the md5 checksum file created by TLH has the following information in the beginning of the file:

"; wholefile md5 checksum file generated by Trader's Little Helper
; generated on March 23, 2009, at 6:57 pm"

followed by a blank line before you get to the data for the shn file (I don't know the technical name). ...This info header is just a comment (each line beginning with a semi-colon is considered to be a comment that can be ignored when verifying). If you do not want to have it in a checksum file created by TLH please do as follows: Open TLH, go to Options > Preferences ... > Create checksum file, uncheck the box in the Info at beginning of a checksum file section and press the Apply button. From now on there won't be any leading comment when you create a md5/ffp/st5 checksum file using TLH.

... md5 checksum files created with some other program do not necessarily have the same information at the top. I guess TLH is programmed to look for that information, and if it doesn't find it, assumes that the file is corrupted or truncated. ...No, TLH is not programmed to look for that information, it completely ignores it (the verifcation process works independent from any comments found in the checksum file).

... When I tried to verify an md5 checksum in mkwACT, I got an error message that the md5 contains checksums for two files that are missing. I'm assuming it is referring to the two lines above. If I delete them from the md5 file, and then verify in mkwACT, it will verify w/out an error message? ...mkwACT is one of the few programs that do not "understand" comment lines. That's why you're getting an error message. Just delete the first three lines (two comment lines and an empty line) of the checksum file.

EasilyFound
2009-03-24, 07:23 AM
Thanks for the info. What does it mean for a file to be truncated?

EasilyFound
2009-03-24, 07:52 AM
Any idea what the error message could mean if I don't hear any difference in the audio of the decoded shn file and the original .wav?

EasilyFound
2009-03-24, 08:18 AM
OK. I'm getting the error message during decoding even with a shn file that I made just now. I had a .wav file that I converted to shn. TLH told me that it was created without any errors. The md5 checksum file verified. When I decoded that shn file, I get the error message that I have been getting whenever I decode using TLH.

Next, I used the same .wav file and encoded to shn a second time, and verified the second shn file using the md5 checksum file from the first conversion, and the checksum from the first shn file matched the second shn file. And when I decode this second shn, I get the same error message: "file is possibly truncated or corrupt."

So I'm stumped.

Since I don't detect any flaw in the audio when it is played back, TLH either is telling me that there is the "possibility" of error, but there is no error, or there is some other kind of error that does not result in any discernable flaw in the audio.


FWIW, the version of mkwACT that I have is version 2.1, February 1999.

roann
2009-03-24, 09:31 AM
OK. I'm getting the error message during decoding even with a shn file that I made just now. I had a .wav file that I converted to shn. TLH told me that it was created without any errors. The md5 checksum file verified. ...Same on my side ...

... When I decoded that shn file, I get the error message that I have been getting whenever I decode using TLH. ...No problem at all on my side. Again my question: what version of *TLH* do you use? If it's not v2.4.1 build 160 please upgrade (see TLH homepage (http://tlh.easytree.org/)).

... Next, I used the same .wav file and encoded to shn a second time, and verified the second shn file using the md5 checksum file from the first conversion, and the checksum from the first shn file matched the second shn file. ...So at least the encoding process seems to work ...

... And when I decode this second shn, I get the same error message: "file is possibly truncated or corrupt."

So I'm stumped. ...(1) Please try the same with target format *flac*. Still an error when decoding?
(2) Did you replace any of the files in the subdirectory CmdlineApps of TLH's installation folder with another version?

... Since I don't detect any flaw in the audio when it is played back, TLH either is telling me that there is the "possibility" of error, but there is no error, or there is some other kind of error that does not result in any discernable flaw in the audio. ...An error in the shn data does not necessarily mean that you will hear any flaw. And btw, "truncated" tells you that the audio part of the file is shorter than it should be, i.e. audio data is missing (or the file header is corrupt).

... FWIW, the version of mkwACT that I have is version 2.1, February 1999.There *never* was a version 2.1 of mkwACT. Don't know exactly but the last release was 0.96 or 0.97.

EasilyFound
2009-03-24, 06:13 PM
Problem solved. I had an old version of TLH. I upgraded to the most current version and shn files decode without errors. Upgrade is great, btw, compared to the version I had been using. Thanks for your patience and information.