Talk:ReplayGain

message: Hi, please don't add normalize to the article. It's an RMS-normalizer, not an RG-scanner. --Kjoonlee 03:01, 24 August 2006 (UTC)
replies: text: Maybe a link from the "Alternatives" section could work, but please don't list it as an RG-scanner. :) --Kjoonlee 06:31, 24 August 2006 (UTC)
thread_title: normalize

message: From version history of Winamp 5.25 beta build 868
* New: Replaygain support for MP3, AAC, Vorbis and M4A
* New: [ml_rg] replaygain scanner (access via Send To menu)
* Improved: [in_mp3] replaygain support for MP3 playback
Noccy80 10:38, 23 September 2006 (UTC)
thread_title:  WinAmp has native RG support  in 5.25 

message: I know that there is at least one hardware DAP, probably several, that support ReplayGain-tagged data. Notably the Rio_Karma. Mojo Tooth 23:52, 11 May 2007 (UTC)
thread_title:  Hardware support 

message: "Another benefit of Replay Gain scanning is that the peak information can also be used to prevent loud songs from clipping." (http://en.wikipedia.org/wiki/Replay_Gain) contradicts "Audio volume leveling, prominently Replay Gain, is perhaps the most widely used solution. It should be noted, however, that this can only reduce the volume of loud music so that it is not proportionately louder than the listener's other music. It cannot restore dynamics or undo clipping." (http://en.wikipedia.org/wiki/Loudness_War) --boarder's paradise (talk) 08:44, 8 August 2008 (UTC)
replies: text: Wrong. Replay Gain can increase volume. It cannot undo clipping, but it can prevent new clipping. --Kjoonlee 09:57, 8 August 2008 (UTC)

text: That contradiction is due to the common (but incorrect, IMO) practice of applying a post-gain after replaygain to try and make everything loud again.  (This is where the "prevent-clipping" options on many players come in.  They're detecting whether the post gain is greater than the RG attenuation by sufficient margin to put the peak at above full scale, and must either do something lossy to avoid clipping, or further attenuate the track, defeating the whole purpose of replaygain. A better way to accomplish the same goal of matching RG tagged and untagged tracks in level is to have a configurable fixed attenuation applied to all non-RG tagged tracks and then turn up the volume knob.  Foobar2000 does have this option, but it's quite rare otherwise.Nwimpney (talk) 21:46, 7 September 2015 (UTC)
replies: text: I have edited this section to clarify and hopefully avoid apparent contradiction. ~Kvng (talk) 23:15, 10 September 2015 (UTC)
thread_title:  contradiction 

message: Sure, one can multiply all samples by 2 or any other integer as long as they don't exceed the rails. But can one multiply all samples by 7/5 without introducing noise? --Damian Yerrick (talk | stalk) 01:05, 11 August 2008 (UTC)
replies: text: You can multiply all samples by 2 or 4 or any other power of 2 as long as it doesn't clip. Consider amplifying a 16 bit file 256 times to get a 24 bit file. --Kjoonlee 04:00, 11 August 2008 (UTC)
replies: text: I'm aware of that. And I can multiply all samples by 3 to get a 9.54 dB boost (20 log10 3) as long as all samples are within ±0.33. But if I multiply by something other than an integer, is it reversible? Specifically, if I reduce the volume of a pop song ripped from an overcompressed CD to a 16-bit PCM file, is it reversible? --Damian Yerrick (talk | stalk) 15:27, 11 August 2008 (UTC)

text: Headroom can arbitrarily be added at any point by adding bits to the top of your samples.  Where the inevitable problems occur is at the final playback stage, where everything is right against 0dBFS.  Even if you have calculated a perfect scaled output, you can't play it back without clipping at levels where the peaks will clip.  If you're playing it back at quieter levels, it makes more sense to always attenuate, and add your extra bits at the bottom instead.Nwimpney (talk) 21:53, 7 September 2015 (UTC)
thread_title:  Wave times two 

message: I thought "directly modifying" meant changing the samples, which as far as I know adds noise, and saving under the same name. This is the "destructive" approach. --Damian Yerrick (talk | stalk) 01:05, 11 August 2008 (UTC)
replies: text: I know of no utility that actually work that way. You could do it in any audio editor, but it would still be "saving a new copy with the volume modified." --Kjoonlee 04:02, 11 August 2008 (UTC)
thread_title:  Directly modifying 

message: To what precision does MP3 store its scalefactors? Can I scale all the scalefactors in an MP3 stream by 7/5 and then by 5/7 without introducing noise? And what other popular lossy codecs have values analogous to scalefactors? I'm guessing Vorbis "floor" curves are something like them. --Damian Yerrick (talk | stalk) 01:05, 11 August 2008 (UTC)
replies: text: Assuming you don't get wrap-around errors, normal changes to the scalefactor will be reversible. If you increase the scalefactor 1 unit, then volume will be increased by 1.5 dB. If you decrease the scalefactor 1 unit, then volume will be decreased by 1.5 dB. --Kjoonlee 03:54, 11 August 2008 (UTC)
replies: text: AAC has something similar as well. With Vorbis, it gets complicated. --Kjoonlee 03:56, 11 August 2008 (UTC)
thread_title:  MP3 scalefactors 

message: Who created this proposed standard? 86.174.124.149 (talk) 14:18, 1 August 2009 (UTC)
replies: text: David Robinson. Binksternet (talk) 14:49, 1 August 2009 (UTC)
thread_title: Who created this proposed standard?

message: Since the article discusses PMPs/MP3 players, it would be nice to know about any players with ReplayGain that work on mobile devices.
A.k.a. (talk) 18:08, 15 January 2010 (UTC)
thread_title: Windows Mobile or Google OS support

message: From the article: “the target loudness of most Replay Gain utilities is 89 dB”.  When we’re dealing with actual sounds, 89 dB is an objective measure.  But Replay Gain utilities deal with digital recordings.  The same digital recording will be played back at different dB levels on different hardware (sometimes drastically different—think movie theater vs. headphones).  So, what does this “89 dB” actually mean for digital recordings?  To put it simply, in a PCM range of 0.0 (silence) to 1.0 (full volume), where does this “89 dB” fall? John lindgren (talk) 03:01, 25 August 2010 (UTC)
replies: text: What I've gathered is that ReplayGain assumes 16-bit CD audio and references 0 dB to the noise floor and that makes 96 dB is full scale. 89 dB is 7 dB below full scale. A bit wacky. It is more common to use 0 dB as your full-scale reference (and -96 dB would be your noise floor for 16 bit audio) --Kvng (talk) 04:16, 25 August 2010 (UTC)
replies: text: ReplayGain is not referenced to 16-bit audio at all. The calibration is explained here... http://replaygain.hydrogenaudio.org/calibration.html ...all current implementations add 6 to the value before storing it, hence the reference is now 83+6=89dB. 85.158.45.57 (talk) 13:38, 8 September 2010 (UTC)
replies: text: Disregard my previous comment. Here's an up-to-date explanation of the reference level. --Kvng (talk) 22:39, 18 January 2011 (UTC)
thread_title:  89 db? 

message: Hello fellow Wikipedians,
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thread_title:  External links modified 

message: The section claims that ReplayGain’s target volume is 89 dB SPL, or −14 dBFS. This is not, and has never been, true.
The original ReplayGain specification defines the target as the loudness of a stereo pink noise signal played at −14 dBFS, or 89 dB SPL. ReplayGain 2.0 changes the loudness measurement algorithm to ITU BS.1770-3 and targets −18 LUFS, which is a value chosen to match the prior ‘pink noise at −14 dB’ target closely and keep compatibility (source). Most ReplayGain scanners use ReplayGain 2.0.
The section also claims that EBU R128 recommends 23 dB of headroom, i.e. a normalisation to −23 dBFS. This is likewise untrue; the recommendation is −23 LUFS. 2003:F3:4F23:F100:B317:D894:5714:2BB (talk) 16:42, 19 July 2023 (UTC)
replies: text: For the most part, the article covers the original specification and I don't see where it gets that wrong. Glad to hear that 2.0 has received attention but I'd like to see a source that backs up the claim that . Normalisation to −23 dBFS is 23 dB of headroom, by definition really. ~Kvng (talk) 14:40, 23 July 2023 (UTC)
thread_title:  ‘Target loudness’ section confusing volume (unweighted, measured in dBFS) and loudness (perceptually weighted, measured in LUFS)