I don’t have download releases but, then, you mean these releases are usually not continuous, including download versions of cover albums?
They could make continuous releases, though.
By using one of the formats or tags that makes continuous play in foobar2000, and probably in most players, no?
I wonder what all the fuss is about. MB is about identifying music, not pauses between music. Those should be left to the player.
For a major pop release example, Madonna’s “Confessions on a Dance Floor” was explicitly made gapless:
Musically, the record is structured like a DJ’s set. The songs are sequenced and blended so that they are played continuously without any gaps.
Confessions on a Dance Floor - Wikipedia
Tenth studio album, presented in a “continuously mixed” format (unless otherwise noted).
https://www.discogs.com/Madonna-Confessions-On-A-Dance-Floor/master/34205
I’ll point to ‘‘Dark Side of the Moon’’, and many other albums that are gapless. Though, like @jesus2099 I have just let EAC rip my CDs and never paid attention to any special setting. I’ve assumed that EAC is taking care of adding gaps to those albums that need them. I know when I play back gapless albums there are no gaps inserted by my players.
Aren’t the “gaps” just on the end of those tracks that have “gaps”? I don’t really know as I guess too much of my music is played as per original album format.
The “gaps”, if present, are part of each CD track: CDs are divided into up to 99 tracks and each track is further subdivided by up to 100 “indices” (00–99) – the time between index 00 and index 01 is the pregap. Usually this is silent but not always (HTOA is the most obvious case). If the CD was produced using an analog master you may hear noise during the gaps too.
You will usually see negative track timestamps displayed on a CD player during the pregap period.
Normally when ripping to separate files the gaps are appended to the previous track as this approximates the experience when selecting a specific track to play on a CD player. Or they are omitted completely (EAC has many options to tweak how pregaps are ripped).
If the CD is mastered for continuous playback with no silence between tracks there will likely be no pregaps indicated by the CD. That is almost certainly true of the linked Madonna album.
So the gap is part of the ripped recording, and therefore already in the database. That makes sense.
Thanks for the extra info, but it is also obvious when one looks closer. I was working on a bootleg last week where the bootlegger had trimmed all the gaps from the tracks to make more music fit on a CD.
The bootleg CD had been lifting tracks from various albums. I had been listening to them played back at the same time as the album as I was trying to calculate what else this bootlegger was trimming from the start and ends of the tracks. That was pretty clear that the “gap” was on the end of most rips EAC had made of my CDs. The Bootlegger had created a gapless CD (and butchered many intros and outros). This was mirrored in the ripped tracks.
Pretty sure this is standard for the players I use. And I have a lot of concept albums that would just sound weird if there was gaps inserted by any player. KODI, VLC, Winamp all behave like this. So does my Android phone and the stereo in my car.
I’ve owned live recordings on CD where there is audio (usually crowd noise or on-stage patter) stored in the pregap. If played back in a CD player these inter-track parts are included when the tracks are played in consecutive order, but are omitted on randomize/shuffle mode.
Cool. I’ve never heard of that.
Yes because when you skip to a track, you go to its INDEX 01 (INDEX == @draconx’s 99 indices).
But when you listen to the CD continuously, you go through all INDEX 00 then 01 then other indexes, if any, then next track’ 00, 01, etc. (except TRACK 01, INDEX 00is never played automatically).
CD format is so well thought out, IMO. 
For more about what the OP (me) is talking about, see the links above:
I mean “gapless” in the sense of the listener’s experience of playback of digital files, compared to the experience of playback of the original medium. The question here is specifically what extra information should be in a MusicBrainz Release entry in order to make a “gapless” playback experience possible. (Other things also need to be in place to achieve the “gapless” experience.)
Since the “gapless” I’m talking about here is the playback experience and the metadata in MusicBrainz, audio codecs which don’t alter the length of the audio are a necessary component for the experience, but aren’t part of what should be stored in MusicBrainz. A Release entry describes the original medium and release, not the behaviour of the audio file ripped from the original. There are plenty of codecs and settings which preserve the length of the original exactly, but there is still an issue for Release entries.
Again, a Release entry describes the original medium, not the playback software, so the details of the playback software aren’t part of what should be in the Release entry. However, the playback software may need information about the original medium — the length or absence of inter-track gaps — to be able to reproduce the original playback experience.
If the pauses between music were unimportant, then why did the Artist include them? Or choose not to include them?
This is an example of a “figure and ground issue”. The audible sounds are important, but the gaps, or the continuous play-though, are important because of how they separate or join the audible sounds. In general, for the player to reproduce the Artist’s intent, the player needs to know about the ground as well as the figure.
Imagine you are making a map of the US state of Hawai’i. It consists of 137 islands across 2,400 km. Is your map complete if it shows just the land area of the islands, without any information about the distances and bearings between islands? Surely it matters if the next island is 500km away, or is so close you can step across the gap. This is the same figure-ground issue.
In many cases it is not important. In come cases, it is. In many cases, the default behaviour of MusicBrainz and the rippers and playback gives acceptable results. In some cases, it does not.
Yes, exactly.
You are right, the details of playback software are irrelevant to the MB release.
Agreed, but I’m not sure I understand why this information would be relevant to MusicBrainz?
The gap at the end of a track is included in the lengths of tracks in MB. A piece of silence is as important as a few more bangs on a drum. And the lack of that silence especially important in gapless concept albums like Dark Side of the Moon.
But MB does not break down a track into components of how much drums, guitar and silence make up the track. The trouble is I cannot see any simple way of extracting this data from the mediums we have to hand. It is easy to get full track lengths (including gap) from our media players, but without sitting down with a stop watch on every CD and vinyl I cannot see where you get the lengths of the gaps from.
I read the first two links you supply and it is clear their problems are with their players and source of music. They are choosing the wrong kit and using services like Spotify. I stream music across my house from a KODI media server in gapless format without a trouble. No special kit required.
When I read the Wiki page I think I answer some of my question as to why it is not an issue for me. I rip to lossless FLAC using EAC and as noted on the wiki page all lossless audio file formats are inherently gapless.
IMHO “gapless” would be a candidate for the annotation or the disambiguation field, same as “mono” is used there.
iTunes actually has a gapless tag, at least for MP4. I am not entirely sure how it works, though. I think it disables iTunes cross-fading capabilities for tracks marked as gapless.
In general I think there are two separate issues here. One is what a lot of software players mean when they advertise gapless support. If you have separate files and just start playing the next file after the first ended you will add an additional small gap. If you have a CD ripped that has continuous audio without silence in between you will hear those small interruptions.
So a player supporting gapless playback will ensure the audio of the next file to play will be loaded slightly ahead of time so that it can consecutively send data to the audio output. This is one way to understand gapless support. In this most basic definition you might still have pauses in between tracks if the silence is part of the end or start of the track. If you have ripped your CDs with the silence included and you want to have them played back as they are on the CD this now works well. If there is a bit of silence between the tracks on the CD you will also get that silence on playback, if not it will be without silence.
Now players with gapless support can also sometimes detect and omit silence at the start or end of tracks. In this case you would get continuous audio even when playing back files that have silence at the end. If this is actually wanted everyone has to decide for themselves.
Now the problem as presented here is probably the most sophisticated: It would allow you to either already rip the audio without silence or have the player remove the silence, but then opt-in per file and maybe depending on the playback (album playback or random shuffled playlist) to have the player add a small gap again. It’s for sure the most flexible, but I don’t know of a player supporting this.
The disc ID doesn’t tell you if there is silence in between or not. Also getting the length of an audio file can be (depending on format and encoding) surprisingly tricky and in some cases it is even just a good guess.
I think one question that needs answering is: is the “gapless information” something intrinsic to the release that can be determined ambiguously, or is it something calculated by the ripping software or audio player on the fly and does this information differ between different programs? The former could be interesting information for MusicBrainz to have, the latter isn’t.
This. There may be gaps between the tracks on a CD, the gaps can contain audio or they can be totally silent. How gaps are ripped is totally up to the ripping software. e.g. EAC adds the gaps to previous track by default, if not using the copy image option, obviously. How the files will be played by any given piece of software is another story entirely.
Standalone players start playback of any track from the INDEX 01 position defined in the TOC, and continue towards the end of the media unless instructed otherwise. There is no skipping or even detecting of any gaps.
Trying to denote ‘gapless playback’ somehow on MB is uttely pointless, IMHO.
If the question here isn’t about DJ-mixes/crossfades, but actually about silence between tracks, then the answer is a stronger “No” because
recordings with variations in the length of silence at either end of tracks are merged.
I don’t think how software rips the gaps is relevant to how the MB database stores information about a medium.
For me what’s more relevant is, is the information about the gaps on the CD’s themselves consistent and measurable. And as far as I know, yes?
Just based off EAC cue sheets, and how they’re considered accurate. Someone correct me if I’m wrong.
Non-CD media is in its own little universe in this regard I suppose.