Bugzilla – Bug 10655
Album ReplayGain values incorrectly added to other files
Last modified: 2009-06-09 12:33:05 UTC
Directory contains a mix of PCM and DTS FLAC tracks. Files are all tagged with the same artist and album name and tracks (as well as file names) are numbered sequentially with the PCM tracks at the end. The intent is to play the entire album with the main album tracks (DTS) playing first and the bonus tracks (PCM) playing at the end. Tags for Album and Track ReplayGain values exist *only* for the PCM tracks. Squeezecenter appears to be reading the Album gain tags from the PCM files and applying them to the DTS files. It seems that once an Album value has been encountered, it's stored in the database regardless of whether or not the tag exists for all files in an album and/or directory. "Smart Gain" is enabled in SqueezeCenter, so attempting to play the album results in the DTS tracks only producing white noise as the album ReplayGain tags are causing the DTS stream to be altered. In this particular case, the DTS tracks are DTS96/24 and the PCM tracks are 16-bit/48kHz. DTS96/24 is stored in a 48kHz file and has been repeatedly verified to work as long as no ReplayGain is applied. Have not checked to see if the same problem exists with AC-3 files, but it seems likely as SqueezeCenter is probably not aware that FLAC files may be DTS or AC-3.
I'm not sure this is a bug. SC thinks you have a single album since the album name is the same for all tracks and they are in the same directory. It is true that the album gain tag is set for the entire album even if not all tracks contain the tag. I'd say that you really have 2 different albums there. You should probably split them and change the album name of the DTS version to contain "(high-res DTS)" or something like that. Do you listen to both versions at the same time when you want to listen to that album?
Yes, I would normally listen to all the tracks sequentially. I moved the PCM tracks into a sub-directory under the DTS directory, renamed the album for those tracks to include the phrase "PCM bonus tracks" and did a new/changed rescan, but it's still trying to apply the Album ReplayGain value. I'm guessing that will be fixed with a full clear/rescan, but with 20,000+ tracks I'm just going to let that happen automatically during the night. It still seems odd to me that SqueezeCenter would find Album ReplayGain values in some files and decide to apply them to every file in the directory. What would happen if the files that had those values had *different* values? (Granted, that would be a ridiculous thing to actually do...)
In case it makes more sense: The albums causing me grief are a set of Depeche Mode reissues released on DVD. The main album and some additional material has been remixed into DTS while some of the bonus tracks only exist as PCM. So in my mind, if I want to hear "Violator", I want to hear everything that was on the DVD, both DTS and PCM material. It's obviously not a showstopper by any means--I just find it odd that I want to play the complete set of tracks by the laziest possible method while the SqueezeCenter developers have actually done real work to prevent me from doing so. :-)
OK, I misunderstood, I thought you had 2 versions of the same album in 2 different formats. So I think you do have a valid point. The simplest solution is to never apply gain or reduced volume to DTS or AC3 tracks.
I'm *not* applying the gain to the DTS tracks, that's my point...the tags only exist in the PCM files but are not in the DTS files. SqueezeCenter is apparently seeing missing values on the DTS files and deciding to use the values from the PCM files, since the arist + album + directory values all match. To me it seems less like an accidental bug than a deliberate attempt to "fix" a problem a user may create, that is, have an album in a directory but forget to apply the ReplayGain tags to all the tracks. It wouldn't surprise me if 90%+ of the time, that would make people happy, but in a weird case like this it's a problem.
Jeff, I think Andy was saying that the simplest solution, *for us*, would be to not apply gain to DTS or AC3 tracks. However, I'm not aware that we have a good way to know what tracks are DTS or AC3 as opposed to PCM. I think Jeff's solution of applying the gain per-track is the right thing to do, personally.