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[yonkiman]

It's been a while, thought I'd check to see if MC19 might be implementing Album Gain tags so it will be more compatible with my Rockbox (and other devices).

Detailed discussion from March 2012 is here:
http://yabb.jriver.com/interact/index.php?topic=71212.0

Cheers,
Fred

[Matt]

MC19 switches to R128 and uses a smart system to automatically switch between track and album levels.

I'm not sure what we're write to tags yet.  David Robinson, the author of Replay Gain, recommended writing the R128 gain shifted by 5dB into the Replay Gain track tag.

[6233638]

It might be worth writing ReplayGain Album tags into the files for compatibility with other devices, but having Media Center ignore them during playback.
Writing Sound Check data derived from R128 analysis into the files would be nice too.

[yonkiman]

It might be worth writing ReplayGain Album tags into the files for compatibility with other devices, but having Media Center ignore them during playback.

Yep.  That's all I've been asking for...

[ogs]

It might be worth writing ReplayGain Album tags into the files for compatibility with other devices, but having Media Center ignore them during playback.

Why should Media Center ignore Album gain? Or do you mean ignore 'ReplayGain Album gain', but use R128 Album gain?

[ogs]

MC19 switches to R128 and uses a smart system to automatically switch between track and album levels.

I'm not sure what we're write to tags yet.  David Robinson, the author of Replay Gain, recommended writing the R128 gain shifted by 5dB into the Replay Gain track tag.

In that case maybe the 5dB should be user selectable. I think I'd prefer actual R128 values in tags.

[6233638]

Why should Media Center ignore Album gain? Or do you mean ignore 'ReplayGain Album gain', but use R128 Album gain?

Media Center 19 now uses analysis of the playlist to determine whether "track gain" or "album gain" should be used, and "album gain" is now dynamic rather than a fixed value.

So if you have a playlist which is full of random tracks, it will use "track gain" for volume leveling. (adjusting each track to be played at approximately the same volume level)
But if you have a playlist made up of tracks from the same album played back-to-back, it will play them using a calculated "album gain" value - the average gain of those files.
This adjusts the overall volume of the album to match the volume level of other tracks, but retains the album dynamics. (e.g. track 7 is supposed to be quieter than the rest, or track 3 is meant to be louder etc.)


Album gain is no longer a fixed value, but based on the tracks which are actually in the playlist together.
So if you play an album but remove the bonus tracks from the playlist, the album gain might be a different value than if they were included.

This means that you can have tracks from the same album played together inside a mixed playlist, and those tracks will still retain the album dynamics (whether they were supposed to be louder or quieter than each other) but should be a better fit to the normalized level of the playlist than if you used the old method of calculating album gain, which produced a fixed adjustment rather than one based on which tracks are actually being played.

[ogs]

Thanks very much for this explanation! I some times use Logitech media server for playback and it's 'smart gain' is similar to what you describe, but maybe not as advanced

[MrC]

For those interested, here's the code that SMS/LMS uses to calculate Smart Gain:

    http://svn.slimdevices.com/repos/slim/7.8/trunk/server/Slim/Player/ReplayGain.pm

[Alex B]

I'm not sure what we're write to tags yet.  David Robinson, the author of Replay Gain, recommended writing the R128 gain shifted by 5dB into the Replay Gain track tag.

IMO, this is the way to go. We would get the best of both worlds.

After reanalysis any hardware and software player that supports the standard replaygain_track_gain can benefit from the more accurate R128 analysis method.

On the other hand, maybe not all users can immediately reanalyze their possibly huge and diversified file archives. They can continue to use the old replay gain tags as long as they want. Whenever the analyzer runs MC19 knows which files have already been analyzed using the R128 method and skips them.

In that case maybe the 5dB should be user selectable. I think I'd prefer actual R128 values in tags.

The 5 dB shift is just a value that has been tested to best fix the difference between the reference volumes (R128: -23 LUFS, RG: 89 dB). MC will know this and R128 will work exactly as designed. It is like using a different numeral system when a number is stored. It will not change the signal processing part anyhow.

[Alex B]

A bit more regarding the topic at hand, I would very much like to see the current album gain option preserved.

I just posted this on the closed beta board:

Album Gain

As I already said I would like to use Album Gain.

Here is a simple example playlist that does not work nicely when track gain is applied:



It contains two soft ballads (Angie and Michelle) and a few loud tracks. The ballads play as loud as the loud traks.
Do I need to explain this more?

In addition, the album gain field is informative. It gives a clue about the mastering quality.


P.S.

a quote from http://wiki.hydrogenaudio.org/index.php?title=ReplayGain_specification

Replay gain

Under some listening conditions, it's useful to have every track sound equally loud. The problem with a track-by-track approach is that tracks which should be quiet in the context of the album on which they reside will be brought up to the level of all the rest. For casual listening, or in a noisy background, this can be a good thing. For serious listening, it does not respect the intent of the artist or mastering engineer; a tender ballad track will be blasting at the same loudness as a hard rock track on the same album. It's generally ideal to leave the intentional loudness differences between tracks in place, yet still correct for unmusical and annoying loudness differences between albums. To accomplish this, ReplayGain suggests that two different gain adjustments should be stored as metadata with each sound file.

Album replay gain represents the ideal listening gain for an entire album. ReplayGain reads the collection of tracks that comprise a album, and calculates a single replay gain for the whole set. This single gain can be used for playback of all tracks of the album. Intentionally quiet tracks then stay appropriately quieter than the rest. It still solves the basic problem (annoying, unwanted level differences between discs) because quiet or loud discs are still adjusted overall—so the pop CD that's 20 dB louder than the classical CD will be brought into line.

Perhaps the smart logic system could be made to work in my example situation, but then it would be essentially the same as "Album Gain".

Then there is the actual topic: Should MC save the calculated album gain value to the file tag? I have the album gain values in my files, but I have analyzed those values with other programs (mostly foobar2000).

IMO, it would not harm to save the value if it is available as a calculated database field. However then it would not be a static value (i.e. derived from the original analysis). It could change when files are retagged, moved, deleted or added.