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Hydrogenaudio Forum => General Audio => Topic started by: foorious on 2008-12-07 19:01:54

Title: ReplayGain Reference Loudness
Post by: foorious on 2008-12-07 19:01:54
Hi everybody,

I've noticed that some of my lossless files have a tag field called %replaygain_reference_loudness%, which value is always the same : "89.0 dB" (as one would expect)

AFAIK audio players don't use that field since its value is always the same and it's probably 'hardcoded' somewhere inside the players' cores. For example when you use foobar2000 to calculate ReplayGain, it stores the results in several relevant fields (track gain, album gain...) but it does not store anything in a %replaygain_reference_loudness% field.

So can I assume this %replaygain_reference_loudness% tag field is totally useless and can be safely removed from my files ?

Thanks in advance.
Title: ReplayGain Reference Loudness
Post by: David Nordin on 2008-12-07 19:13:09
Not sure this adheres to the same thing, but years ago we had a discussion about implementing such a tag/meta- space. This were to be for calibrated environments where you would be able to have actual dB-references to work with.
You'd measure up your environment, and set this value accordingly.

Although while writing this it seems more to me that this does not apply here


Edit: removed unnessesary quote
Title: ReplayGain Reference Loudness
Post by: benski on 2008-12-07 19:46:25
Definitely useless.  Targetting a different reference loudness might be good for tools such as MP3Gain which "bake in" the volume adjustment for non-RG players, but doesn't make a lot of sense for Replay Gain.  If the target reference level doesn't meet your needs, that's what the pre-amp is for (or the volume knob

That being said, there's always the chance that some RG scanner exists (or will exist) that lets you modify this value, and some unsuspecting user will change the setting.
Title: ReplayGain Reference Loudness
Post by: Soap on 2008-12-07 20:30:09
Is such a tag causing harm?  I suspect it is an "aesthetic" choice to remove it?  I can't imagine it adds a measurable increase in file size?
Title: ReplayGain Reference Loudness
Post by: foorious on 2008-12-07 20:32:30
Thanks for your help. I'm removing those useless tags then.

BTW, you can say it's an aesthetic choice but I hadn't really thought of that : I'm removing them simply because they are useless. But you may be right, since as a matter of fact I don't like them appearing in foobar's properties windows as <REPLAYGAIN_REFERENCE_LOUDNESS>. Useless and unaesthetic then.
Title: ReplayGain Reference Loudness
Post by: Soap on 2008-12-07 20:51:00
Don't get me wrong - I wasn't chiding you for making an "aesthetic" choice.  I do the same.
But I do think we have to admit that compulsive tag cleaning adds nothing of "real" value. 
Title: ReplayGain Reference Loudness
Post by: Moonbase on 2008-12-07 22:01:42
»Reference Loudness« would be used as an informational field if you’ve set your ReplayGain'ing application (i.e., metaflac) to something else than 89 dB, so one would know on what the ReplayGain values are based. Originally, this was meant to have some means of »re-adjusting« the RG values in case the file wasn’t gained to 89 dB.

Since not all RG tools generate this field, and I personally stick with the 89 dB settings, I also usually remove this tag (more often found in FLAC and OGG than in MP3 files).
Title: ReplayGain Reference Loudness
Post by: [JAZ] on 2008-12-08 20:08:19
Originally, the  replaygain target value was 83dB.
It was seen that this was too low for most content, and the 89dB value came in.

So basically, yes. The value indicates what the base of the track and album gain is. Do players have read it? Well, benski seems to suggest that Winamp does not. I can't comment on other players.

It does not have to do with the preamp. Effectively, a lower value for reference would imply a higher value for track and album gain, meaning the end result would be the same. (If the reference is taken in consideration).
Title: ReplayGain Reference Loudness
Post by: 2Bdecided on 2008-12-08 22:48:42
IMO It should not be there, and ReplayGain tags should always be quoted relative to 89dB. Having to rely on this tag breaks the standard.

It's different with hard coded gain adjustments, like mp3gain.

FWIW there was a player, J River Media Jukebox IIRC, that used 83dB. I don't know if it still does. IIRC There was a time when lame used 83dB, but it now uses 89dB. I think everyone else uses 89dB.

If there was any confusion (which I doubt), adding this tag wouldn't solve it because players will ignore it!

Cheers,
David.