Two different sizes but Foobar bit compare says identical files!

2007-12-08 22:40:25

This is really strange to me:

I've got this Clone CD image of an album:

battiato.ccd
battiato.img
battiato.sub

By opening the .ccd file, the image is loaded into my virtual drive (Virtual CloneDrive by Slysoft).

I then open EAC to rip single WavPack tracks from this virtual drive.

I made 3 different extraction: safe mode, fast mode, burst mode even I know it should be the same because it's not a real drive.

Every time all songs converted OK, the 3 EAC logs show no errors.

But for the last song of the album I got 3 different file size:
safe mode: 16,435,153 bytes
fast mode: 16,434,013 bytes
burst mode: 16,435,135 bytes.

The EAC log reports an identical CRC for #1 and #3 even if they should be different because of the different size!

Also Foobar Bit Compare says the first and the third are identical, while the second file (obtained in fast mode) is different for the other two.

I don't understand this:
1. why for just this song i got 3 different file sizes
2. same CRC for two
3. Foobar says two of them are identical


I hope someone can help me understand...

Thanks!

Two different sizes but Foobar bit compare says identical files!

Reply #1 – 2007-12-08 22:48:27

Instead of WavPack tracks, try WAV tracks and see the results. The fact that there are different sizes with WV does not mean the audio data is different. Possibly the metadata tags are different sizes... but I cannot imagine you changing settings in EAC for that to occur. As far as I know, that will not happen when ripping to WAVs.

I benchmark my REACT scripts with a virtual drive through Daemon and I have never seen anything like this, and I became quite familiar with the file sizes and hashes of the audio data.

Two different sizes but Foobar bit compare says identical files!

Reply #2 – 2007-12-08 23:09:08

Well, I did the experiment you suggested (saving as WAV) and this time it was ok (same bytes).
But it's still strange to me that before I got 3 different sizes, maybe it's the metadata tags.

Two different sizes but Foobar bit compare says identical files!

Reply #3 – 2007-12-08 23:18:29

What metadata went into the WV tracks? Were you using wavpack or a third party program that could have introduced other tag elements? If for instance you were importing the EAC log into the WV tracks, then each log would have been different since each specified a different ripping mode, thus creating different size WV tracks.

Other than that, I am at a loss how it would have been different.

Two different sizes but Foobar bit compare says identical files!

Reply #4 – 2007-12-08 23:56:05

My best guess is that EAC was configured to add ID3 tags, in which case it will include a tag to indicate what mode was used.

Now if the OP had included more information such as log files we wouldn't have to revert to guessing as often.

...still need to figure out what caused the discrepancies revealed by fb2k's bit compare.