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View Full Version : Smart Replay Gain where only one adjustment tag



WhaleOil
2009-04-04, 01:46
I know that there has been lots of discussion about Replay Gain, but I wonder if I could suggest a change/enhancement to the behaviour of 'Smart' Replay Gain.

As I understand it, the Smart setting recognises if you are playing a series of individual tracks or a complete album and picks the appropriate adjustment based upon the Track and Album replay gain tags in the file.

Now here comes the rub. I use iTunes to organise and tag my music and it only has one replay gain tag (actually called Sound Check in Apple world). I think that this is stored as a non-standard tag called iTunesNORM. There does not seem to be an easy way to set separate track and album tags. I guess I could use a different program, but I like iTunes and it works well for me with a mix of MP3 and Apple Lossless files.

SC seems to read the iTunes adjustment just fine, but because there is only one tag, it uses the same tag for both Track and Album adjustment and so the Smart setting makes no difference.

Could I suggest that where there is only one Volume Adjustment/Sound Check/Replay Gain tag (or equivalently when a specific Album Gain tag is not present) then the SC 'Smart' setting should use the adjustment in the tag for playing individual tracks and set a zero adjustment when playing albums. I recognise that this means there will be a jump in volume when moving from playing individual tracks to an album, but at least once you settle down to listen to an album you can just adjust the volume at the beginning. At the moment, I have to remember to bury down into the settings menu and turn Replay Gain off manually before listening to an album.

What do others think?

WhaleOil

Phil Leigh
2009-04-04, 02:59
I know that there has been lots of discussion about Replay Gain, but I wonder if I could suggest a change/enhancement to the behaviour of 'Smart' Replay Gain.

As I understand it, the Smart setting recognises if you are playing a series of individual tracks or a complete album and picks the appropriate adjustment based upon the Track and Album replay gain tags in the file.

Now here comes the rub. I use iTunes to organise and tag my music and it only has one replay gain tag (actually called Sound Check in Apple world). I think that this is stored as a non-standard tag called iTunesNORM. There does not seem to be an easy way to set separate track and album tags. I guess I could use a different program, but I like iTunes and it works well for me with a mix of MP3 and Apple Lossless files.

SC seems to read the iTunes adjustment just fine, but because there is only one tag, it uses the same tag for both Track and Album adjustment and so the Smart setting makes no difference.

Could I suggest that where there is only one Volume Adjustment/Sound Check/Replay Gain tag (or equivalently when a specific Album Gain tag is not present) then the SC 'Smart' setting should use the adjustment in the tag for playing individual tracks and set a zero adjustment when playing albums. I recognise that this means there will be a jump in volume when moving from playing individual tracks to an album, but at least once you settle down to listen to an album you can just adjust the volume at the beginning. At the moment, I have to remember to bury down into the settings menu and turn Replay Gain off manually before listening to an album.

What do others think?

WhaleOil
Not necessary - simply add proper track/album replaygain to your files in addition to the iTunes tag and SC will sort it out.

probedb
2009-04-04, 04:25
Yep, iTunes does not use Replaygain, it has it's own soundcheck field which is nothing to do with RG.

You need to scan and add RG tags using something else.

Chunkywizard
2009-04-04, 07:42
Foobar2000 does a good job of this, see: http://www.bobulous.org.uk/misc/Replay-Gain.html

HTH

CW

Moonbase
2009-04-04, 08:29
What do others think?

Others think that even big and ignorant companies like Apple should do things right and adhere to existing standards — instead of introducing half-baked new "features" every second week just to keep theirs a closed, proprietary world.

If you can’t get an album gain from Apple’s SoundCheck, go complain at Apple. SC does the best it can, and using track gain is much better than using none.

That said, there could be an easy solution to this, by using foobar2000 or another ReplayGain calculating software to add both values as tags into the file (iTunes would still use SoundCheck and ignore ReplayGain), but SqueezeCenter still "prefers" the SoundCheck value if both SoundCheck and "real" (track + album gain) Replay Gain tags are in the file. Sigh.

I (again) strongly suggest that SC should prefer the Replay Gain values if both Replay Gain and Apple SoundCheck value tags are found in any one file!

This would be a rather easy change and make more users happy, since they could have "best of both worlds", without having to wait for Apple to do something sensible (which will probably never happen).

Please vote for the long outstanding bug 4362 (http://bugs.slimdevices.com/show_bug.cgi?id=4362) if you want to see this happpen!

MrSinatra
2009-04-04, 13:39
i agree, SC should ONLY use RG tags if they are present, and not itunes garbage. it certainly should not use itunes over RG, or both together at the same time.

however, the OP seemed to be asking a different question...

his question seemed to be:

"if ONLY itunes is present, or if only ONE RG value is present (the track value i assume), can the "smart" setting on SC be "smart enough" to disable using RG at all if it thinks an album is being played?"

seems like a legit/valid request to me, at least in the case of files with ONLY itunes soundcheck.

its not quite as valid for files with only track RG tags, b/c usually those files don't have album RG tags b/c they don't have ALBUM name tags either, so how would SC know the tracks in the playlist were from the same album?

i suppose SC could guess at it using folder location and "guess tag format" etc... but this would be an instance where i think fixing tags makes more sense.

however, for someone only using soundcheck, this sounds like a valid enh request to me.

MrSinatra
2009-04-04, 13:50
moonbase, i wonder why the bug continues to languish?

i don't see why they tie it to the new schema? i don't think resolving it needs the new schema, not even close.

Moonbase
2009-04-04, 14:12
Re bug & new schema: I reckon 8303 is kinda "container" where all things are kept that mustn’t be forgotten when building up the new schema, that’s probably why it’s tied in there.

This doesn’t mean it can’t be fixed before — and I strongly hope for that …

@ WhaleOil:
I understand the thinking behind that, but also the thinking behind SC’s logic. Using RG (or SoundCheck) will usually (not always) reduce the volume by a substantial amount. Now if "Smart Gain" was in effect, it would detect an album being played (or parts of one, which could very well happen in a playlist) and suddenly switch off RG, you could end up with burned speakers, or — even worse — with serious hearing damage.

That is one of the reasons why using track gain might turn out to be a better choice than switching it off completely, especially with modern, highly compressed Rock and Pop CDs. (It’s usually better with classical or New Age CDs.)

So if one wanted to use iTunes/iPods with Volume Normalization, I would — eventually — recommend tagging both SoundCheck and Replay Gain values into the files, because one wouldn’t affect the other, and if SC would prefer RG over SoundCheck, you could have best of both worlds — perfect "smart" track + album gain with SC, perfect Volume Normalization with iTunes/iPods.

Nonreality
2009-04-04, 19:26
I agree that SC should use RG over Soundcheck if in the same track. I guess the bug that added RG and soundcheck together has been resolved in the latest versions so having both won't be a problem like it was a few versions ago.

WhaleOil
2009-04-05, 02:07
Hi, thanks for the replies.

I didn't really want to kick off an argument about Apple being evil for not conforming to standards and I can understand the problems when a file has both the Apple Sound Check adjustment and Replay Gain tags. I guess preferring the Replay Gain tags over Apple Sound Check where present makes sense - certainly adding the values together was always a strange thing to do, but I understand that this at least has been resolved.

I agree that I could add Replay Gain tags for both track and album to all of my files, but am reluctant to do so, mainly because I can find no easy way to do this on a Mac (an old Mac unable to run Windows).

I think the worry about blowing speakers or hearing damage from my suggestion seems a bit extreme. There is no need for such a safety warning when turning off the Smart Gain setting (ie "please check that you do not have your volume set to maximum when doing this because some songs will now become louder") and I thought Smart Gain chose the Track or Album setting at the outset based upon the nature of the playlist, so it shouldn't cause a problem in the middle of a playlist.

At the moment Smart Gain is clever enough to choose between T and A depending on the playlist (not sure how it does this, but that is another issue), but if A is not present it defaults to using T. All I am asking is that consideration is given instead to defaulting to zero if A is not present. I can see this as being relevant to a wider range of people than just those of us who have fallen for the evil Apple's charms.

Many thanks
WhaleOil

WhaleOil
2009-04-05, 02:18
PS...

I should have also noted that I am actually quite happy with the volume adjustment that I now get from the Apple Sound Check iTunesNORM tag. I use a a program called iVolume which takes a bit of time and (apparently) a more robust scientific approach to adjust the iTunesNORM tag calculated by iTunes to a level that seems to do a much better job at equalising volume levels.

Teus de Jong
2009-04-05, 04:16
I'm fervently opposed against only using one value. This always boils down to a form of track gain. And when you only use track gain, you help the loudness war by making the volume of each track about the same. This is one of the reasons I don't use play lists a lot: the volume leveling would result in a ballad being played too loud and a track that shouts 'play me loud' not loud enough. It's like listening to the radio, where the same leveling is applied (albeit in a different way). And imagine the effect of playing Mahler's 5th symphony with track gain: what a disaster that would be!

The whole idea of using RG is to automatically adjust for the difference in loudness used in recordings over the last decades (albums of the eighties have none or moderate negative album gain; recent albums generally have album gain in the -7 to -12 dB range). IMO, anyone who cares about the quality of music should only use it for this purpose and therefore use album gain (with the exception of parties with appropriate play lists).

It's a testimony to how much Apple cares about the quality of music that they only use one value.

(Sorry if this post sounds a bit aggressive, but I feel very strongly about this.)

Teus

garym
2009-04-05, 04:56
I prefer album gain in all cases. To get this with my IPOD, I use mp3tag and an "action" to convert soundcheck values to replaygain album gain values (search mp3tag forum for soundcheck and replaygain). So in the end, I have replaygain album and track values AND a soundcheck value that is equal to the album gain. This said, I strongly support the SB using replaygain values instead of soundcheck values when both exist. The smartgain option is really nice if it would work properly in the presence of replaygain and soundcheck.

Moonbase
2009-04-05, 05:19
[…] I use a a program called iVolume […]
And wise you are! iVolume actually uses the original Replay Gain algorithm and sticks the results into the iTunesNORM tag. Which effectively gets you the best out of this. :-)


[…] imagine the effect of playing Mahler's 5th symphony with track gain: what a disaster that would be! […]
Indeed! It makes me shudder thinking of that ;-)

@ All in favor of prefering RG over SoundCheck if both are tagged:
Don’t forget to vote for bug 4362 (http://bugs.slimdevices.com/show_bug.cgi?id=4362) — voting makes development see that there is an actual need. — Thank you!

WhaleOil
2009-04-05, 11:51
I agree entirely with the sentiments of Teus and Gary above.

When I sit down to listen to a whole album/symphony etc I want the quiet songs/movements to be quiet and the loud songs/movements to be loud (at least relatively - I of course use my amplifier's volume control to set the overall level depending on whether I want to wake up the neighbours or not!)

This is why at the moment I have to manually switch off SC's Smart Gain when I want to listen to an album/symphony etc. This is of course equivalent to having Album gain set to zero. My suggested change was simply for Smart Gain to do this for me automatically. I can live with using a different volume on my amp for 'loud' albums and 'quiet' albums - so don't really need a separate Album gain setting (although if there was an easy way for me to tag my music with one then I probably would).

However, I also frequently just set a Random mix going - and for that I need the Track gain.

Happy to vote for Replay Gain settings to take preference over Apple Sound Check settings if they are present. I would just like the default Album Gain setting to be zero if no explicit tag exists rather than set to equal the Track Gain setting.

WhaleOil

MrSinatra
2009-04-06, 13:36
whale oil,

i think you need to file your own enh request, so it isn't confused with the other bugs mentioned here.

i'm sure people here would be happy to help you craft writing it, if you wanted to try a rough draft in a post first.

http://bugs.slimdevices.com/