Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

How CD pregaps gained their hidden track superpowers

tedium.co

Post reply on HN
Print view View original

121–130 of 138 posts

Re: How CD pregaps gained their hidden track superpowers

#121

Post by dec0dedab0de »

Lammy wrote: post #20
dec0dedab0de wrote: post #14

I remember my friend accidentally found the negative track on a CD and called me up out of breath like aliens just landed. I think it was one of the early AFI albums.We spent the whole weekend checking for negative tracks on every CD we could find. The negatives between songs were also pretty cool sometimes, Mediocre Generica by Leftover Crack makes very good use of them. Listening to it over streaming or even mp3s r…

> I think it was one of the early AFI albums I wouldn't call it an “early” album but I found one of these (untitled 18-second intro) on AFI - DECEMBERUNDERGROUND: https://i.imgur.com/XAsFMSR.png Some others I've run across in my CD collection include… — on Jonathan Katz - Caffeinated https://i.imgur.com/4ghQadv.jpeg — the track "Every Time Is The Last Time" on Bloc Party's Silent Alarm https://i.imgur.com/knhbZhA.png…

I wouldn't call it an “early” album but I found one of these (untitled 18-second intro) on AFI - DECEMBERUNDERGROUND

I think it was answer that and stay fashionable. We all stopped listening to them when black sails came out, so if im right about it being AFI, it was one of the first 3 albums, or the all hallows EP.

Re: How CD pregaps gained their hidden track superpowers

#122

Post by hcs »

AkBKukU wrote: post #102
ssl-3 wrote: post #29

One less-secretive way I've seen pregaps used is for live recordings. The crowd noise betwixt songs can be contained in a pregap, so that it is only ever heard when listening to the album straight-through (instead of in shuffle or track-program mode). --- Another fun feature of audio CDs is indexes. A disc can have 99 tracks, and each track can have some pregap (including track 1, as the article discusses). And each…

I'm curious if you have a specific example of an album with the crowd noise between tracks like that? I collect and rip hundreds of CDs and am always on the look out for edge case discs to further hone my tools. On your pregap + 99 indexes remark, the "pregap" is the space between index 00 and 01 which continues on up to index 99. Players seek to index 01 as the start point of the track. There is no separate pregap d…

Seven minute pregap on disc 1 track 4 of https://vgmdb.net/album/5549 , it's a whole long discussion between songs, with some audience cheering. VGMdb follows the "append pregap to previous track" convention, that's why track 3 looks so long. There's similar but shorter gaps with banter on tracks 2 and 7.

Cuesheet looks like:

    TRACK 04 AUDIO
      INDEX 00 00:00:00
      INDEX 01 07:34:43
Edit: Probably covered by your sfx disc, but this one has 17 indexes on track 1: https://vgmdb.net/album/3091

That messed with a tool that only anticipated one index in track 1 for detecting hidden pregap audio, cuesheet is like:

    TRACK 01 AUDIO
      INDEX 00 00:00:00
      INDEX 01 00:00:37
      INDEX 02 00:11:40
      INDEX 03 00:37:33
      ...

Re: How CD pregaps gained their hidden track superpowers

#123

Post by IndySun »

caf wrote: post #74
ssl-3 wrote: post #61

Earlier quoted context omitted.

You're not wrong. New music isn't frequently recorded with the intent for it to be heard in an album-oriented way. But the albums I like to listen to as albums will remain cohesive albums for an eternity. Lots of stuff from Roger Waters is cohesive in that way, which is perhaps something a person might expect me to say. But also lots of stuff from Maynard James Keenan, Trent Reznor, and even Marilyn Manson is also th…

Billy Eilish's latest is intended to be listened as a complete album (but of course the fact that this is known as an exception proves the general rule...)

Billy Eilish is not exceptional in this regard. 100s of 1000s of albums are. There's absolutely no need to single out an artist.

Re: How CD pregaps gained their hidden track superpowers

#124

Post by giobox »

pseudosavant wrote: post #116
ssl-3 wrote: post #64

Earlier quoted context omitted.

I've had visions of putting a CD together that was that way, but with pregaps and indexes utilized as well. "WTF? The time counter keeps going forward, and then sometimes it goes backwards! And using the track seek buttons completely eliminates some parts that I can hear if I don't touch anything! It's a whole different song entirely when you program tracks 39, 40, and 52 in a loop, and IDFK what it is with this Inde…

I thought I'd really (ab)used the CD specs, but don't recall ever trying indexes. Curious how most CD players, which only had a two-digit track indicator, handled indexes. I would have used that if I had known about it.

I wasn't aware these existed either. I suspect the answer is incredibly boring: most CD players simply wont seek to an index, pressing skip track will just skip to the next track ignoring any indexes present.

Re: How CD pregaps gained their hidden track superpowers

#125

Post by throwaway2037 »

egypturnash wrote: post #110
ssl-3 wrote: post #84

Earlier quoted context omitted.

Was this better with the crazily fast-loading chonka-chonk slam-slam nature of a Pioneer 6-disc cartridge changer, or with something slower and perhaps more-civilized like a period-correct Technics 5-disc changer, with its nearly-silent and relatively exquisite, seemingly-careful demeanor? (Both have their merits, but I unfortunately have neither at hand. And I only have one of these 2 albums. And one of those albums…

Presumably Spotify has glommed all the Fingertips into one file. On the original CD release it was twenty-one separate tracks; there was a bit in the liner notes that explicitly encouraged you to put it on shuffle. https://tmbw.net/wiki/Fingertips I could not tell you what brand the all-in-one turntable/radio/tape deck/cd player I had at the time was. There was a big tray with room for five CDs and I have absolutely…

Here it is on Spotify: https://open.spotify.com/track/1VdLQlGXMvaEUZIL9KuG35?si=29f...

In my location, it shows as a single track that is 4:33.

Re: How CD pregaps gained their hidden track superpowers

#126

Post by taneliv »

d332 wrote: post #36
ssl-3 wrote: post #27

Earlier quoted context omitted.

Audio CDs were never ripped/transferred as ISO files. ISO-9660 is a filesystem that came years later, and Redbook audio CDs simply do not contain files. If you want to look at the structure of a whole audio CD, then one way is to rip it with a decent tool (perhaps cdrdao or EAC) and generate a bin/cue file pair as an output.

But that's not my goal. I'd like to be able to observe every grove, the physical encoding of data, and see if I could implement decoding from scratch. First problem is though that I don't know how to get a microscopic image of the disc.

You might do well enough with https://en.wikipedia.org/wiki/Cdparanoia without needing use different hardware to scan the disc. Instead it relies on the CD drive's ability to report on inaccuracies in keeping in sync with the grooves.

Re: How CD pregaps gained their hidden track superpowers

#128

Post by edude03 »

thristian wrote: post #58
d332 wrote: post #23

This inspired me to read up on the low-level details of CD structure. I'm curious if anybody scanned an entire CD and shared the results, so that we could work with a raw image of disc that contains all its quirks, as opposed to the typical .iso format?

It's really difficult. Unlike floppy disks, where you tell the drive to seek and get back raw magnetic pulses (so you can produce raw flux images), or hard disks where you tell the drive to read an arbitrary sector and get a blob of data (so you can produce sector-level images), the protocol for talking to a CD ROM involves asking for track/sector addresses, which means you have to trust the drive to interpret all th…

Apparently makemkv forum members created some patched firmware that lets you raw read BRs for the sake of extracting metadata that’s intentionally hidden for DRM. Though I’ll have to recheck my understanding since you’re saying you can’t actually raw read disks anyway

Re: How CD pregaps gained their hidden track superpowers

#129

Post by mckn1ght »

afavour wrote: post #21

One memorable album using this was Queens of the Stone Age’s Songs for the Deaf. If you rewound from the start of the first track you got 90 seconds of strange sounding (but tuneful) rumbles and bleeps and bloops. When I looked it up online I found out it was called “The Real Song for the Deaf”. It was literally a song for deaf people, the idea was that if they turned it up enough they’d be able to hear the vibration…

Same for 311’s Transistor. I remember accidentally doing it and wondering if I’d somehow distorted the fabric of spacetime. Took me a while to figure it out.

Re: How CD pregaps gained their hidden track superpowers

#130

Post by qingcharles »

sumtechguy wrote: post #99
ssl-3 wrote: post #62

Earlier quoted context omitted.

Ideally, I think I'd want a singular container (of whatever sort) that has the album's audio, the music-related timing metadata (as applicable), and whatever other metadata may be appropriate (lyrics? liner note graphics? music videos? sure!). The audio should be able to be FLAC. But it should also be able to be anything else, like Vorbis or MP3 or AAC or IDK. It needs to be able to be played continuously without abe…

You are almost describing the MAME CHD format. As they have the problem that the object (hard drive, cd, dvd, etc) must be in one file. Have the ability to do differences (writable in some cases). But also compressed (compressed hunks of data). They also need that sub track data too as some systems do interesting things with that sub data. As some even hide their encryption format in the SBI fields. The CHD format is…

This could be a good avenue. It might be possible the CHD format could be extended and be backward-compatible, or even just as simple as bodging all the extra data onto the end of the file and hope it is ignored by other readers. This is an avenue worth exploring, thank you.
Post reply on HN