>b) According to http://wiki.xiph.org/OggOpus#Comment_Header >there should be no REPLAYGAIN_*** tags in Opus files; Opus uses >R128_TRACK_GAIN tag. If some audio player reads Opus tags then it should >be aware of the difference between ReplayGain and R128. But this doesn't >require REPLAYGAIN_REFERENCE_LOUDNESS tag. > >The Opus replaygain spec is fundamentally broken, so let's ignore that for now. It is discussed ad nauseam elsewhere, but isn't going to change any time soon. I agree any replaygain reference loudness tag should only apply to other REPLAYGAIN* tags, although placing R128 gain values (adjusted by some arbitrary amount or otherwise) in REPLAYGAIN* tags raises some interesting questions. As already discussed none of this *requires* a reference loudness tag, but if there is one then it may as well be parsed. Who knows, maybe it says something useful. Lastly, and perhaps most importantly, nobody is forcing you to use it or apply it to your music, so you shouldn't prevent people who want it from having it. --ian
Ian Nartowicz wrote:> The Opus replaygain spec is fundamentally broken, so let's ignore that for > now. It is discussed ad nauseam elsewhere, but isn't going to change any time > soon.;)> I agree any replaygain reference loudness tag should only apply to other > REPLAYGAIN* tags, although placing R128 gain values (adjusted by some > arbitrary amount or otherwise) in REPLAYGAIN* tags raises some interesting > questions. As already discussed none of this *requires* a reference loudness > tag, but if there is one then it may as well be parsed. Who knows, maybe it > says something useful. Lastly, and perhaps most importantly, nobody is forcing > you to use it or apply it to your music, so you shouldn't prevent people who > want it from having it.But *if* flac will switch to R128 algorithm, what should it write to REPLAYGAIN_REFERENCE_LOUDNESS tag? "89.0 dB" or "-18 LUFS"? (or "-18 LKFS"?)
Ian Nartowicz wrote:> The Opus replaygain spec is fundamentally broken, so let's ignore that for > now. It is discussed ad nauseam elsewhere, but isn't going to change any time > soon.I haven't seen anyone make any concrete proposals for how it should change. Maybe I missed something. AFAIK, the only objection to it is that there is no way to distinguish between whether the header gain is also an R128 album gain, or if it has some other semantic meaning. That seems simple to address, not "fundamentally broken". If I've gotten this wrong, please help educate me.
On Thu, 19 Jun 2014 03:30:15 +0400 lvqcl <lvqcl.mail at gmail.com> wrote:>Ian Nartowicz wrote: > >> The Opus replaygain spec is fundamentally broken, so let's ignore that for >> now. It is discussed ad nauseam elsewhere, but isn't going to change any >> time soon. > >;) > > >> I agree any replaygain reference loudness tag should only apply to other >> REPLAYGAIN* tags, although placing R128 gain values (adjusted by some >> arbitrary amount or otherwise) in REPLAYGAIN* tags raises some interesting >> questions. As already discussed none of this *requires* a reference loudness >> tag, but if there is one then it may as well be parsed. Who knows, maybe it >> says something useful. Lastly, and perhaps most importantly, nobody is >> forcing you to use it or apply it to your music, so you shouldn't prevent >> people who want it from having it. > >But *if* flac will switch to R128 algorithm, what should it write to >REPLAYGAIN_REFERENCE_LOUDNESS tag? "89.0 dB" or "-18 LUFS"? (or "-18 LKFS"?)I haven't seen a suggestion for what tags the R128 values would be placed in. Is it just assumed that they will be the same REPLAYGAIN* tags? The r128gain tool writes -23 LUFS into REPLAYGAIN_REFERENCE_LOUDNESS. I've also seen a suggestion for a REPLAYGAIN_ALGORITHM tag, but I don't think it will catch on. Certainly some indication of anything that doesn't very closely match the existing replaygain v2.0 secification should be indicated somewhere. --ian
On Wed, 18 Jun 2014 16:39:12 -0700 "Timothy B. Terriberry" <tterribe at xiph.org> wrote:>Ian Nartowicz wrote: >> The Opus replaygain spec is fundamentally broken, so let's ignore that for >> now. It is discussed ad nauseam elsewhere, but isn't going to change any >> time soon. > >I haven't seen anyone make any concrete proposals for how it should >change. Maybe I missed something. > >AFAIK, the only objection to it is that there is no way to distinguish >between whether the header gain is also an R128 album gain, or if it has >some other semantic meaning. That seems simple to address, not >"fundamentally broken". >It is certainly the biggest issue. Sure it should be simple to address, but nobody seems willing to do so. The only response I've had so far is that the output gain should *always* be applied, yet it *might* be an album gain. It can't be both and there is no way to tell which. Sorry, but that makes it unsuited for use in a music player without the sort of overly complex options I've had to add. Any half-decent music player allows the user to choose whether they want album gain, track gain, or neither, and following the Opus spec doesn't support this. The second issue is the lack of defined peak tags. I could care less, but some people care deeply and it is a relatively standard feature of music players. The Opus spec doesn't define such tags, but it does explicitly say not to use the REPLAYGAIN* tags. Again that's just not viable. --ian