Hello everyone, I'm new to this flac thing (started about a week ago) but I have read a lot about flac and replaygain. As far as I understand it, replaygain is lossless in the sense that I can tell my player to ignore the settings or I can even use foobar2000 to remove the tags entirely, hence getting back to the original audio. If that is the case, why is there a warning in the foobar2000 converter dialogue box stating that "applying ReplayGain adjustment during conversion will irreversibly alter data in encoded file, unlike ReplayGain scan after encode"? I used EAC and AutoFLAC to rip my CD collection. In the EAC command line options for flac.exe, I added the --replay-gain parameter and in the AutoFLAC setup, I enabled the "Add Replaygain" checkbox. I just downloaded foobar2000 and I can see that the replaygain values are there but after seeing that warning when converting my flac files to mp3, I became concerned. I used AutoFLAC so that I can easily take my flac files and recreate the CD's if I ever needed to (can't get my folks to buy mp3/flac players yet and their CD's tend to get abused). I want an exact copy of the original CD (as close as possible anyway). Seeing that warning above makes me think that since I applied replaygain to my flac files when creating them, that I no longer have an original rip. If I convert the flac files (with replay gain values) back to wav files (autoflac does this for me), will these converted wav files be the same as the wav files created during my original rip of the CD? Do I need to rip my CD collection again without the replaygain so that I can use these to create a copy of the original CD if needed? Thanks in advance.
On Sun, Apr 13, 2008 at 02:10:51AM -0500, Charles Velasquez wrote:> If that is the case, why is there a warning in the foobar2000 > converter dialogue box stating that "applying ReplayGain adjustment > during conversion will irreversibly alter data in encoded file, > unlike ReplayGain scan after encode"?ReplayGain, as the name implies, works by calculating a scaling-factor that should be used during playback. In flac the original audio data is left unalterred; tags are used to store the ReplayGain values. I haven't used foobar200, but that message you're seeing implies that if checked, the scaling-factor will be applied to the audio data before it is encoded in the new format (mp3, in your case). Hence the audio will be alterred and due to quantization (ie, rounding errors) it is in the mathematical sense irreversible.> I used EAC and AutoFLAC to rip my CD collection. In the EAC > command line options for flac.exe, I added the --replay-gain parameter > and in the AutoFLAC setup, I enabled the "Add Replaygain" checkbox. > I just downloaded foobar2000 and I can see that the replaygain > values are there but after seeing that warning when converting my > flac files to mp3, I became concerned. I used AutoFLAC so that I > can easily take my flac files and recreate the CD's if I ever needed > to (can't get my folks to buy mp3/flac players yet and their CD's > tend to get abused). I want an exact copy of the original CD (as > close as possible anyway).> Seeing that warning above makes me think > that since I applied replaygain to my flac files when creating them, > that I no longer have an original rip.This is probably incorrect. The audio data from the rip hasn't been changed by calculating ReplayGain; merely a few extra tags were added.> If I convert the flac files (with replay gain values) back to wav > files (autoflac does this for me), will these converted wav files > be the same as the wav files created during my original rip of the > CD?Yes, so long as that conversion does not 'bake in' the ReplayGain scaling.> Do I need to rip my CD collection again without the replaygain > so that I can use these to create a copy of the original CD if > needed?I doubt it. Check out <http://en.wikipedia.org/wiki/Replay_Gain> for a better understanding of how ReplayGain works. It shouldn't be necessary, but might help you understand the various knobs you're seeing in AutoFLAC, EAC and foobar2000. Cheers, - Andrew
Thank you very much for the reply. Hopefully if I get some time this weekend, I will re-rip a CD without the replay gain, this time making sure not to delete the wav files. Then I will convert the flac files with replay gain back to wav and compare them to my re-rip wav files. If they're the same, cool. If not, I guess I will re-rip everything. I don't know why I didn't think of this before. duh! Charles Velasquez Network Manager Midland College Pevehouse Admin. Bldg. #116 3600 N. Garfield Midland, TX 79705 USA Phone: 432.686.4824 Fax: 432.686.4206 velasquez at midland.edu>>> Andrew Snare <ajs at pigpond.com> 4/15/2008 3:34 AM >>>On Sun, Apr 13, 2008 at 02:10:51AM -0500, Charles Velasquez wrote:> If that is the case, why is there a warning in the foobar2000 > converter dialogue box stating that "applying ReplayGain adjustment > during conversion will irreversibly alter data in encoded file, > unlike ReplayGain scan after encode"?ReplayGain, as the name implies, works by calculating a scaling-factor that should be used during playback. In flac the original audio data is left unalterred; tags are used to store the ReplayGain values. I haven't used foobar200, but that message you're seeing implies that if checked, the scaling-factor will be applied to the audio data before it is encoded in the new format (mp3, in your case). Hence the audio will be alterred and due to quantization (ie, rounding errors) it is in the mathematical sense irreversible.> I used EAC and AutoFLAC to rip my CD collection. In the EAC > command line options for flac.exe, I added the --replay-gain parameter > and in the AutoFLAC setup, I enabled the "Add Replaygain" checkbox. > I just downloaded foobar2000 and I can see that the replaygain > values are there but after seeing that warning when converting my > flac files to mp3, I became concerned. I used AutoFLAC so that I > can easily take my flac files and recreate the CD's if I ever needed > to (can't get my folks to buy mp3/flac players yet and their CD's > tend to get abused). I want an exact copy of the original CD (as > close as possible anyway).> Seeing that warning above makes me think > that since I applied replaygain to my flac files when creating them, > that I no longer have an original rip.This is probably incorrect. The audio data from the rip hasn't been changed by calculating ReplayGain; merely a few extra tags were added.> If I convert the flac files (with replay gain values) back to wav > files (autoflac does this for me), will these converted wav files > be the same as the wav files created during my original rip of the > CD?Yes, so long as that conversion does not 'bake in' the ReplayGain scaling.> Do I need to rip my CD collection again without the replaygain > so that I can use these to create a copy of the original CD if > needed?I doubt it. Check out <http://en.wikipedia.org/wiki/Replay_Gain> for a better understanding of how ReplayGain works. It shouldn't be necessary, but might help you understand the various knobs you're seeing in AutoFLAC, EAC and foobar2000. Cheers, - Andrew
On Sunday 13 April 2008 8:10 am Charles Velasquez wrote:> I used EAC and AutoFLAC to rip my CD collection. In the EAC command line > options for flac.exe, I added the --replay-gain parameter and in the > AutoFLAC setup, I enabled the "Add Replaygain" checkbox. I just downloaded > foobar2000 and I can see that the replaygain values are there but after > seeing that warning when converting my flac files to mp3, I became > concerned. I used AutoFLAC so that I can easily take my flac files and > recreate the CD's if I ever needed to (can't get my folks to buy mp3/flac > players yet and their CD's tend to get abused). I want an exact copy of > the original CD (as close as possible anyway). Seeing that warning above > makes me think that since I applied replaygain to my flac files when > creating them, that I no longer have an original rip.The problem (if there is one) will be in the conversion stage. The ripping will, I am almost sure, have been done correctly by EAC, so you should not need to ever re-rip the CDs. The problem is that mp3 does not support replay gain, so you are given the option of scaling the actual data before the encoding (normally, the unscaled data are stored, and the scaling factor is sent to the hardware's volume setting to get it to output the lossless data at the right volume). Since mp3 is rubbish quality (compared flac certainly), this is probably what you want; the original flac file though is still lossless so can be used to make (except possibly for track padding) exact copies. Nicholas
Don't apply replay gain during conversion; there should be a checkbox in foobar to enable or disable this option. Replay Gain should only be applied during playback. See: http://shup.com/Shup/40316/1084792520-Shup-Image-Editor-108479250-Converter-Setup.png.png If you convert to MP3, you can calculate replay gain on them after the fact. Just because Replay Gain information is stored in the FLAC file doesn't mean the decoder has to use it :) -benski> Hello everyone, I'm new to this flac thing (started about a week ago) but > I have read a lot about flac and replaygain. As far as I understand it, > replaygain is lossless in the sense that I can tell my player to ignore > the settings or I can even use foobar2000 to remove the tags entirely, > hence getting back to the original audio. > > If that is the case, why is there a warning in the foobar2000 converter > dialogue box stating that "applying ReplayGain adjustment during > conversion will irreversibly alter data in encoded file, unlike ReplayGain > scan after encode"? > > I used EAC and AutoFLAC to rip my CD collection. In the EAC command line > options for flac.exe, I added the --replay-gain parameter and in the > AutoFLAC setup, I enabled the "Add Replaygain" checkbox. I just > downloaded foobar2000 and I can see that the replaygain values are there > but after seeing that warning when converting my flac files to mp3, I > became concerned. I used AutoFLAC so that I can easily take my flac files > and recreate the CD's if I ever needed to (can't get my folks to buy > mp3/flac players yet and their CD's tend to get abused). I want an exact > copy of the original CD (as close as possible anyway). Seeing that > warning above makes me think that since I applied replaygain to my flac > files when creating them, that I no longer have an original rip. > > If I convert the flac files (with replay gain values) back to wav files > (autoflac does this for me), will these converted wav files be the same as > the wav files created during my original rip of the CD? > > Do I need to rip my CD collection again without the replaygain so that I > can use these to create a copy of the original CD if needed? > > Thanks in advance. > > > _______________________________________________ > Flac mailing list > Flac at xiph.org > http://lists.xiph.org/mailman/listinfo/flac >