fb2k 1.3(.1) converter: ReplayGain transfer inconsistent

2014-01-18 15:59:41

First, I am aware simply transferring the ReplayGain info from lossless -> lossy is not accurate, I am willing to live with that, given that it probably won't be a 11db difference.

Now for the actual problem: when checking "transfer ReplayGain" info, for lossless, it works flawlessly, transferring Track Gain, Track Peak, Album Gain and the Album Peak tags (tested for FLAC, TAK, WV). However, doing the same for mpc or mp3 results in only Track Gain and Album Gain being copied.

I don't know why, but that leads to Rockbox ignoring the gain values completely, foobar still adjusts the volume correctly. Still, please fix this to transfer ALL ReplayGain tags.

Was running 1.3 but tested if it was stealthily fixed in 1.3.1 and it's not.

fb2k 1.3(.1) converter: ReplayGain transfer inconsistent

Reply #1 – 2014-01-18 17:37:24

I doubt it will be "fixed" as this behavior is by design*. While the gain values largely remain the same (or have a negligible difference) in a lossless to lossy transcoding, the same cannot be said of the peak values (where there can be a significant difference). While inaccurate info being transferred may not be a concern to you, it is a concern for those who use "prevent clipping according to peak" and for those who simply don't want inaccurate information in their files.

EDIT:

* http://www.hydrogenaudio.org/forums/index....0&st=0&

fb2k 1.3(.1) converter: ReplayGain transfer inconsistent

Reply #2 – 2014-01-18 19:05:17

I participated in the thread you linked, and so have you, but this has nothing to do with the issue I'm reporting.
As I already posted there, foobar2000 doesn't stop you even from transcoding of lossy -> lossy, it merely warns you and it's ultimately up to you.

Obviously, if some tags ARE transferred for the lossless -> lossy compression, then the devs decided to allow transfer of RG tags for this scenario as well. The problem is that not all info is transferred. Nor is the only affected format opus (which wouldn't prevent a transfer, merely require to store the tags in a certain way, from what I see).

edit: did my thread got moved to foobar general? I'm pretty sure I posted it in the tech support section, as it's a bug.

edit2: actually, after looking at that thread again, I see why you linked it. The decision doesn't really make sense to me, why would you want to transfer anything in the first place if the tags currently transferred are not enough to actually make RG work and you have to rescan the files anyway?

fb2k 1.3(.1) converter: ReplayGain transfer inconsistent

Reply #3 – 2014-01-19 11:40:44

Let me verify I understand how RG is supposed to work:
- track/album gain tags are there to adjust the volume of the song accordingly.
- track/album peak tags are there to make sure the volume adjusted according to the gain tags doesn't lie above the maximum, preventing clipping

If this is correct, then it also means that those two are actually independent in the sense that missing peak tags shouldn't prevent the player from adjusting the volume, right? This is how foobar seems to operate currently, but is it the standard? Rockbox does not, so if it's the standard, I guess I'd have to report that to the rockbox devs instead.

If the peak tags are required to adjust the volume without clipping as well, could someone please explain the reason why? Also, in that case, would it be possible for foobar to calculate the new peak as part of the encoding/tag writing process? The main reason why I need this is because I'm transcoding directly to the µSD of my clip+ and while scanning isn't a problem speed wise, applying newly scanned gain values takes as long as actually copying files to the SD card.

Sure, I could first encode to the HDD, then load them back to foobar, then scan, then apply, THEN copy to the µSD, but it's really inconvenient compared to simply converting the files as you'd do with lossless. That was the main reason I was simply copying the lossless files over to my clip+, even though it meant higher space usage. Clip+ started to act funny with flac files recently though, so I moved back to lossy once I saw the option to transfer RG tags.