Strange behaviour with ALAC

[moikboy]

Recently I bought an iPod, and i started converting my FLAC files to apple lossless to get them played on my device. First i tried with iTunes, but when i played back some files, i've noticed some 1s-length glitchy noises randomly appearing in my music. (i found somebody who had similiar problems http://www.tomshardware.co.uk/forum/...itches-mystery)
They were in the same place each time, and converting back ALAC to WAV and comparing the checksum of the original WAV from the FLAC resulted crc mismatch - so i thought that something is wrong with the iTunes lossless encoder (maybe there was a buffer underrun during the conversion, because i ran several tasks while itunes were converting), and i've decided to try using dbpoweramp.

However when i tried converting an album from FLAC to ALAC, after the converting and verifying process, dbpoweramp reported that some of the files are corrupt and did not match the md5 checksum... And here comes the strangest part: when i converted these files back to WAV, and compared them with the original WAV's, despite they were report as corrupt, they were exactly the same... :confused:

When i started with WAV files, created from the FLAC, and converted the WAV to ALAC, everything was ok - none of the previously corrupt files were report...

After all, i don't really trust i apple lossless... Can anybody help me figuring out whats happening inside my alac files?

[Spoon]

Re: Strange behaviour with ALAC

Are you using the utility codec [Audio CRC] to verify if files are identical?

[moikboy]

Re: Strange behaviour with ALAC

Are you using the utility codec [Audio CRC] to verify if files are identical?

i'm comparing them - the two wave files: one from the source flac, and one from the resulted alac - with the total commander file compare function.

[LtData]

Re: Strange behaviour with ALAC

The tags might be different, you would be better off comparing the Audio CRC.

[moikboy]

Re: Strange behaviour with ALAC

The tags might be different, you would be better off comparing the Audio CRC.

Well, as far as i know, wav files don't use any kind of tags... However, since yesterday, i started converting my flacs with a process like this:

1. converting music from flac to alac with dbpoweramp
2. making a bit-compare with foobar2000 bit-compare plugin
3. if any file was different, go with them back to step 1.

After converting several albums, i found, that apple lossless codec can make these glitches during playback and during conversion also. The fact, that in some cases, the file which differed from the original flac at step 2., after re-comparing them, no difference were found, revealed me this.

In some files, when the glitchy noise was made during the encoding, it was actually in the written file, and appeared in the same position - reported by foobar - every time. Obviously, when the glitchy noise produced during playback, there was nothing at the position reported by foobar.

So, until this time, everything was so-called O.K, but i found a file which produces the same error after several tries. But i've found the solution this time too :D Convert it with iTunes! No errors, no differences to the original flac...

I don't really know why apple lossless behaves like this on my machine, because i did not hear about anybody who experienced the same with alac :D However, i'm happy until i can archive my collection safely into apple lossless with this process...:smile2: