HydrogenAudio

Lossless Audio Compression => FLAC => Topic started by: norton on 2004-08-27 22:22:40

Title: FLAC => Back to WAV ?
Post by: norton on 2004-08-27 22:22:40
Hi

I have converted all my CDs to FLAC files (for archiving).  I would like to convert 1 of those FLAC files, back to WAV format.  I want to see if I have lost something during the process "CD to FLAC".  I want to ear the two files (.flac & .wav) to see if they sound the same.  I am very scared that they will not sound the same.   

Info:  I used EAC to extract CDs and convert to FLAC. 

I have tried to convert a FLAC file back to WAV (with Foobar2000).  I have listened this WAV file, and I have listen this same song (not from FLAC) extracted (non-compress) with EAC...  They don't sound the same!!!   


So, maybe I didn't choose the right settings in Foobar2000 to convert this FLAC file back to WAV. (??)


Anyone can tell me exactly what setting I should choose in Foobar2000 (to bring back a FLAC file to WAV) ???



Thanks a lot for helping,


norton
Title: FLAC => Back to WAV ?
Post by: Jan S. on 2004-08-27 22:30:18
Please select the flac and and the wav file in foobar and right-click to do a bit-compare. There is no point in listening as the files should generate exactly the same output. If a difference is found something is wrong.
Title: FLAC => Back to WAV ?
Post by: Digisurfer on 2004-08-27 22:34:43
The default preset for converting any file back to wav format should be "WAV (PCM, fixed-point)". The resulting wav file that has been decoded from the FLAC file should be a bit for bit duplicate of the original wav used to create the FLAC. It has to be or it can't be called lossless. Comparing a decoded FLAC file to a completely new wav file may not be entirely helpful, especially if the new rip was achieved via different means than the original that the FLAC was made from. Another problem that can skew your comparison is whether you have applied replaygain or not, and whether you decoded your files with it applied or not. You might want to go to the Foobar website and download the ABX Comparator plug-in. That will allow you to do an A/B comparison on the fly between the FLAC file and your re-ripped wav file, and will also neutralize replaygain values for this purpose.
Title: FLAC => Back to WAV ?
Post by: Anacondo on 2004-08-27 22:34:45
Make sure you unchecked "Use DSP" and "Use ReplayGain" under preferences/components/diskwriter/processing in foobar. Alternatively, you can decompress via command line with "flac -d [inputfile]". Then you can check the two wavs in EAC under tools/compare wavs. If they're not identical something is wrong.

Hope this helps.
Title: FLAC => Back to WAV ?
Post by: Duble0Syx on 2004-08-27 22:35:46
Make sure if your using foobar to convert back to flac that it's not applying any of the DSP settings or anything else.  Personally I suggest just using the flac frontend.  Flac is lossless, meaning nothing will change from the original wav.  If they wav you flac'd was screwed up then the flac will sound the same and so will the extracted wav.
Title: FLAC => Back to WAV ?
Post by: norton on 2004-08-27 23:14:19
Quote
Please select the flac and and the wav file in foobar and right-click to do a bit-compare. There is no point in listening as the files should generate exactly the same output. If a difference is found something is wrong.
[a href="index.php?act=findpost&pid=237478"][{POST_SNAPBACK}][/a]


Ok.  I have done a bit-compare...  Exactly the same thing.  (I did the process CD to FLAC  &  CD to WAV  again with a new song)

Should I be happy?  Not really.  In fact I am more scared.   


Explanation:  The WAV file (from CD with EAC) that I compared to the other WAV file (from CD with EAC to FLAC, and back to WAV with Foobar2000) was extracted from my other computer...

WAV File #1 :  computer 1, CD => FLAC => WAV
WAV File #2 :  computer 2, CD => WAV

*Computer #1 & #2 used EAC for extracting from CD.


I am thinking, that maybe (?), the settings of EAC on computer #1 and #2 are not the same !?...  If it is (is it possible ?), that means that one of my EAC is not configured right!?

I don't know.  I am kinda lost.  I am checking that right now.  I hope that the EAC settings on my computer (the one I used to compress all my CD collection to FLAC) was right.

I'll be back.
Title: FLAC => Back to WAV ?
Post by: kalmark on 2004-08-27 23:29:25
If the two files are bit-by-bit the same, then all difference is placebo or imagination. You can try to do an ABX blind test to convince yourself that the 2 files are the same audio data.
Title: FLAC => Back to WAV ?
Post by: Omion on 2004-08-27 23:35:41
If the files you extracted from different computers are the same (according to foobar) then there's nothing to worry about. No need to check EAC's settings.

If the files are the same, and you can still hear a difference, then it's a classic case of placebo. You're worried that you might hear a difference, so your brain invents a difference.

Basically:
The files are the same! Cheer up!
Title: FLAC => Back to WAV ?
Post by: dreamliner77 on 2004-08-28 00:15:46
It could be that perhaps that two files from two different drives/computers would differ because of offset issues.  But they will still sound the same.  If you did a bit compare and they are bit-identical, they are identical.  The only way i could imagine that the flac and wav would sound different is if you played them back in a player that used different eq for different formats (winamp).
Title: FLAC => Back to WAV ?
Post by: norton on 2004-08-28 00:29:12
Quote
If the files you extracted from different computers are the same (according to foobar) then there's nothing to worry about. No need to check EAC's settings.

If the files are the same, and you can still hear a difference, then it's a classic case of placebo. You're worried that you might hear a difference, so your brain invents a difference.

Basically:
The files are the same! Cheer up!
[a href="index.php?act=findpost&pid=237499"][{POST_SNAPBACK}][/a]



I did all the tests you guys told me to do.

Final result:  The two songs are bit to bit, exactly the same.


Conclusion:  CLASSIC PLACEBO CASE 

Title: FLAC => Back to WAV ?
Post by: norton on 2004-08-28 00:31:53
ps:  Thanks to all of you.  I guess I will sleep tonight!

 

norton