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level matching when comparing lossy to lossless
krabapple
post Feb 7 2013, 19:42
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I probably should have had this settled in my mind long ago, but -- how necessary is it to level match when you are comparing a lossless track, to its mp3 counterpart?

By way of investigation, I compared foobar2k's reported replaygain and track peak values for the same track encoded (LAME 3.98) as V2 (195kbps VBR) and at 320 kbps CBR

lossless:
Track gain -1.08
Track Peak 0.938171

195kbps VBR:
+0.11
0.954459

320kbps CBR:
+.10
0.934477

The track peak differences are negligable, but whence comes the >1db difference in RPG gain of lossless vs. lossy? Does this mean that one should level match according to those RPG values when doing an ABX?

This post has been edited by krabapple: Feb 7 2013, 19:42
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Garf
post Feb 7 2013, 20:03
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If they're encoded from the same source I see no reason to level match, *if* the encoder is not intentionally changing the volume. I understand LAME does this at least in some ABR modes to lower the amount of clipping.

1dB of ReplayGain difference between lossy and lossless is surprising. The ReplayGain calculation isn't perfect of course, but that's more than I'd have expected. Are you sure the same ReplayGain *algorithm* was used in both cases? (original ReplayGain vs R128?)
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krabapple
post Feb 7 2013, 20:28
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QUOTE (Garf @ Feb 7 2013, 14:03) *
If they're encoded from the same source I see no reason to level match, *if* the encoder is not intentionally changing the volume. I understand LAME does this at least in some ABR modes to lower the amount of clipping.

1dB of ReplayGain difference between lossy and lossless is surprising. The ReplayGain calculation isn't perfect of course, but that's more than I'd have expected. Are you sure the same ReplayGain *algorithm* was used in both cases? (original ReplayGain vs R128?)



Absolutely sure -- this was all done today, right before I posted, using Foobar's v1.2.2's replaygain scanner. The lame.exe is 3.98r that comes bundled with dbpoweramp (lame --license shows it as 3.98.4)

Perhaps others could try and see what they get? The track, btw, was 'Black Cow' , the first track on Steely Dan's Aja -- couldn't tell you exactly which CD version this is, I bought it many years ago.
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Posts in this topic
- krabapple   level matching when comparing lossy to lossless   Feb 7 2013, 19:42
- - lvqcl   The difference between lossless original and LAME...   Feb 7 2013, 20:01
- - Garf   If they're encoded from the same source I see ...   Feb 7 2013, 20:03
|- - krabapple   QUOTE (Garf @ Feb 7 2013, 14:03) If they...   Feb 7 2013, 20:28
- - Arnold B. Krueger   QUOTE (krabapple @ Feb 7 2013, 13:42) I p...   Feb 7 2013, 20:12
- - greynol   QUOTE (Arnold B. Krueger @ Feb 7 2013, 11...   Feb 7 2013, 20:32
|- - krabapple   QUOTE I find there is too great a tendency to trea...   Feb 7 2013, 20:46
|- - greynol   QUOTE (krabapple @ Feb 7 2013, 11:46) But...   Feb 7 2013, 20:59
- - krabapple   Here's what I get when I run the three tracks ...   Feb 7 2013, 20:37
|- - db1989   QUOTE (krabapple @ Feb 7 2013, 19:37) (So...   Feb 7 2013, 20:59
- - greynol   Thanks for the data. I believe those average RMS ...   Feb 7 2013, 20:41
- - lvqcl   Do you have foo_hdcd or use foo_dsp_effect for de-...   Feb 7 2013, 20:48
|- - krabapple   QUOTE (lvqcl @ Feb 7 2013, 14:48) Do you ...   Feb 7 2013, 20:51
- - lvqcl   foobar2000 always uses postprocessing plugins such...   Feb 7 2013, 20:56
|- - krabapple   QUOTE (lvqcl @ Feb 7 2013, 14:56) foobar2...   Feb 7 2013, 22:23
- - greynol   Without going into a prolonged discussion about it...   Feb 7 2013, 21:03
|- - [JAZ]   QUOTE (greynol @ Feb 7 2013, 21:03) Witho...   Feb 7 2013, 22:57
|- - greynol   QUOTE ([JAZ] @ Feb 7 2013, 13:57)...   Feb 7 2013, 23:11
|- - Kees de Visser   For critical work I still prefer to adjust for equ...   Feb 8 2013, 11:24
- - db1989   foobar2000 uses libebur128 since v1.1.7, so a diff...   Feb 7 2013, 21:15
- - 2Bdecided   If I understand it correctly, EBU R128 / ITU BS.17...   Feb 8 2013, 13:06
|- - DonP   QUOTE (2Bdecided @ Feb 8 2013, 07:06) Bef...   Feb 8 2013, 14:18
|- - 2Bdecided   QUOTE (DonP @ Feb 8 2013, 13:18) QUOTE (2...   Feb 8 2013, 14:56
- - 2Bdecided   I do not use automatic (RG/R128) loudness matching...   Feb 8 2013, 13:15
- - greynol   I'm glad that is all spelled out, though you c...   Feb 8 2013, 16:58
- - 2Bdecided   It's made me realise that I ought to do a tabl...   Feb 8 2013, 17:56
- - lvqcl   QUOTE (krabapple @ Feb 7 2013, 23:28) QUO...   Feb 8 2013, 23:19


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