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Topic: Why do ~70 of 220 CDs contain HTOA of around 32 frames? (Read 19846 times) previous topic - next topic
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Why do ~70 of 220 CDs contain HTOA of around 32 frames?

I have written a tool for encoding EAC WAV images to FLAC.
It splits them according to the CUE with shntool.
shntool will produce a separate track 0 for any HTOA, no matter how long it is.

I have run my tool over around 220 EAC rips of genuine CDs and around 70 of them contained HTOA. Non of the HTOA was longer than a second, it is usually around ~32 frames.
I will post the full list of frame lengths in a reply.

The used EAC settings are fully documented here.

Is this a bug in EAC or is the mastering of that many CDs wrong?

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #1
Code: [Select]
Album: Angélique Kidjo - Ayé
Hidden track one audio found. Length: 33 frames
Album: Angélique Kidjo - Logozo
Hidden track one audio found. Length: 33 frames
Album: Beck - Mellow Gold
Hidden track one audio found. Length: 33 frames
Album: Bryan Adams - Reckless
Hidden track one audio found. Length: 32 frames
Album: Chuck Berry - The Best Of
Hidden track one audio found. Length: 32 frames
Album: Deep Blue Something - Breakfast at Tiffany's
Hidden track one audio found. Length: 32 frames
Album: Deep Purple - Nobody's Perfect
Hidden track one audio found. Length: 32 frames
Album: Deep Purple - The Compact Disc Anthology (disc 1)
Hidden track one audio found. Length: 33 frames
Album: Deep Purple - The Compact Disc Anthology (disc 2)
Hidden track one audio found. Length: 33 frames
Album: Die Ärzte - Das Beste von kurz nach früher bis jetze (disc 1)
Hidden track one audio found. Length: 32 frames
Album: Die Ärzte - Das Beste von kurz nach früher bis jetze (disc 2)
Album: Dire Straits - Brothers in Arms
Hidden track one audio found. Length: 32 frames
Album: Dire Straits - Live at the BBC
Hidden track one audio found. Length: 32 frames
Album: Dire Straits - Love Over Gold
Hidden track one audio found. Length: 32 frames
Album: Dire Straits - Making Movies
Hidden track one audio found. Length: 32 frames
Album: Dire Straits - On Every Street
Hidden track one audio found. Length: 32 frames
Album: Dire Straits - Remastered
Hidden track one audio found. Length: 32 frames
Album: Eagles - Hell Freezes Over
Hidden track one audio found. Length: 32 frames
Album: Emerson, Lake & Palmer - Black Moon
Hidden track one audio found. Length: 32 frames
Album: Eric Clapton - The Cream of Clapton
Hidden track one audio found. Length: 33 frames
Album: Fury in the Slaughterhouse - Mono
Hidden track one audio found. Length: 32 frames
Album: Guns N' Roses - Use Your Illusion I
Hidden track one audio found. Length: 32 frames
Album: Guns N' Roses - Use Your Illusion II
Hidden track one audio found. Length: 33 frames
Album: J.J. Cale - 5
Hidden track one audio found. Length: 32 frames
Album: J.J. Cale - Grasshopper
Hidden track one audio found. Length: 33 frames
Album: J.J. Cale - Naturally
Hidden track one audio found. Length: 33 frames
Album: J.J. Cale - Okie
Hidden track one audio found. Length: 33 frames
Album: J.J. Cale - Troubadour
Hidden track one audio found. Length: 32 frames
Album: Jean-Jacques Goldman - Traces
Hidden track one audio found. Length: 32 frames
Album: Jethro Tull - Farm on the Highway
Hidden track one audio found. Length: 33 frames
Album: Jimi Hendrix - Experience Hendrix_ The Best of Jimi Hendrix
Hidden track one audio found. Length: 32 frames
Album: Johannes Brahms - Ein Deutsches Requiem, Op. 45 (Berliner Philharmoniker, Schwedischer Rundfunkchor, Eric-Ericson-Kammerchor feat. conductor Claudio Abbado)
Hidden track one audio found. Length: 33 frames
Album: John Williams - Schindler's List
Hidden track one audio found. Length: 33 frames
Album: Khadja Nin - Ya Pili...
Hidden track one audio found. Length: 32 frames
Album: Manfred Mann - The Greatest Hits
Hidden track one audio found. Length: 33 frames
Album: Manfred Mann - The Singles Plus
Hidden track one audio found. Length: 32 frames
Album: Mannheim Steamroller - Fresh Aire Interludes
Hidden track one audio found. Length: 2 frames
Album: Mark Knopfler - Last Exit to Brooklyn
Hidden track one audio found. Length: 33 frames
Album: Mark Knopfler - The Princess Bride
Hidden track one audio found. Length: 33 frames
Album: Mike Oldfield - Crises
Hidden track one audio found. Length: 33 frames
Album: Nirvana - Nevermind
Hidden track one audio found. Length: 42 frames
Album: Peter, Paul & Mary - No Easy Walk to Freedom
Hidden track one audio found. Length: 50 frames
Album: Pink Floyd - A Momentary Lapse of Reason
Hidden track one audio found. Length: 32 frames
Album: Pink Floyd - Animals
Hidden track one audio found. Length: 33 frames
Album: Pink Floyd - A Saucerful of Secrets
Hidden track one audio found. Length: 33 frames
Album: Pink Floyd - Delicate Sound of Thunder (disc 1)
Hidden track one audio found. Length: 33 frames
Album: Pink Floyd - Delicate Sound of Thunder (disc 2)
Hidden track one audio found. Length: 33 frames
Album: Pink Floyd - Meddle
Hidden track one audio found. Length: 33 frames
Album: Pink Floyd - The Dark Side of the Moon
Hidden track one audio found. Length: 33 frames
Album: Pink Floyd - Wish You Were Here
Hidden track one audio found. Length: 33 frames
Album: Rory Gallagher - Deuce
Hidden track one audio found. Length: 32 frames
Album: Shadows - Wonderful Land
Hidden track one audio found. Length: 43 frames
Album: Spencer Davis - Keep On Running
Hidden track one audio found. Length: 33 frames
Album: Suzanne Vega - Solitude Standing
Hidden track one audio found. Length: 32 frames
Album: The Alan Parsons Project - Pop Classics
Hidden track one audio found. Length: 33 frames
Album: The Beach Boys - California Gold_ The Very Best of the Beach Boys (disc 1)
Hidden track one audio found. Length: 33 frames
Album: The Beach Boys - California Gold_ The Very Best of the Beach Boys (disc 2)
Hidden track one audio found. Length: 33 frames
Album: The Beatles - Please Please Me
Hidden track one audio found. Length: 33 frames
Album: The Byrds - The Collection
Hidden track one audio found. Length: 33 frames
Album: The Jimi Hendrix Experience - BBC Sessions (disc 1)
Hidden track one audio found. Length: 32 frames
Album: The Jimi Hendrix Experience - BBC Sessions (disc 2)
Hidden track one audio found. Length: 32 frames
Album: The Kinks - The Singles Collection
Hidden track one audio found. Length: 32 frames
Album: The Shadows - Dance With the Shadows _ Sound of the Shadows
Hidden track one audio found. Length: 33 frames
Album: The Shadows - Guardian Angel
Hidden track one audio found. Length: 33 frames
Album: The Shadows - The Shadows _ Out of the Shadows
Hidden track one audio found. Length: 33 frames
Album: The Spencer Davis Group - The Best of Spencer Davis Group Featuring Stevie Winwood
Hidden track one audio found. Length: 33 frames
Album: Mark Knopfler - The Princess Bride
Hidden track one audio found. Length: 33 frames
Album: The Troggs - From Nowhere the Troggs
Hidden track one audio found. Length: 33 frames
Album: Traveling Wilburys - Traveling Wilburys, Volume 1
Hidden track one audio found. Length: 33 frames
Album: Yann Tiersen - L'Absente
Hidden track one audio found. Length: 30 frames

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #2
I asked a couple years ago, I never got an answer
That 32-33 frame pregap doesn't seem to serve any purpose.


Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #4
It's perfectly normal.


I can see that it's "normal" (as in, relatively widespread), but WHY?

Edit: it matters because it fucks up my script that computes a Musicbrainz DiscID from FLAC files, since rippers ignore that pregap.

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #5
WHY?

Fuck if I know.

The OP asked if it was a bug.  It is not a bug.

His question suggests the mastering is wrong if it is not a bug.  I'd say that's presumptuous.

it fucks up my script

Fix your script.

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #6
Good to know that I am not the only one who observes this. This at least shows that my ripping setup is not flawed. Thanks.

Edit: it matters because it fucks up my script that computes a Musicbrainz DiscID from FLAC files, since rippers ignore that pregap.

You might want to check out my perfect-flac-encode script which I have advertised to you several times already
The goal behind it is to produce single track FLACs which can be re-joined to an image which matches the original image checksum. And I guess thats what you want when computing the MBID - an image which matches the original one.
It joins track 0 with track 1 if it is shorter than one second and keeps it as a separate track if it is not. Nothing is lost.

 

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #7
His question suggests the mastering is wrong if it is not a bug.  I'd say that's presumptuous.

I was explained that the red book does not allow an INDEX 00 on Track 1 (= hidden track), which is why I claimed that the mastering is wrong.
Correct me if I'm wrong?

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #8
Fix your script.


I can't invent data that's not there.

The goal behind it is to produce single track FLACs which can be re-joined to an image which matches the original image checksum.


Except that I don't want to do single file rips. They're poorly supported and downright inconvenient for various reasons (IMO).


Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #10
Fix your script.


I can't invent data that's not there.

The goal behind it is to produce single track FLACs which can be re-joined to an image which matches the original image checksum.


Except that I don't want to do single file rips. They're poorly supported and downright inconvenient for various reasons (IMO).

You just gave the explanation of why single file rips are the way to go before telling us that you don't want them.

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #11
I can't invent data that's not there.

Use a program that can extract it.

Seriously, stop acting like a victim.

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #12
You just gave the explanation of why single file rips are the way to go before telling us that you don't want them.

Nah, I think he's just trying to hijack the discussion.

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #13
You just gave the explanation of why single file rips are the way to go before telling us that you don't want them.


Advantage of single file rips: you can compute DiscIDs, you get fewer files.
Drawbacks: poor playback support, poor tagging support, parallelizing encoding is not possible without a codec that supports threading natively (and even then, you get lower performance than when parallelizing transcoding of separate tracks).



Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #16
As to whether it is invalid for TRACK 01 to have a pregap: It would be trivial to resolve this question if we were not expected to pay $372 merely to read the Red Book. However, I am almost certain it is false. It is widely cited that the first track should have a silent pregap of two seconds in length. Thus, I highly doubt that it is invalid to add an INDEX 00 to TRACK 01—quite the opposite, most likely.

Showing my lack of experience (or interest) in such technicalities of the format, but according to various sources, burners will write an initial two seconds of silence regardless of whether or not it is specified in the cuesheet; thus, any pregap specified would be added afterwards. Assuming this is correct, for which I would welcome confirmation, a declared INDEX 00 to TRACK 01 of 32 frames in length would actually correspond to an additional 32 frames of silence after the standard two seconds.

On a related note to these general sentiments, and also raising the worthwhile question of whether support in players need actually reflect any standard (or the lack thereof), I found this post that I think is worthy of quoting:
A minority of regular CD players can play the hidden track of Factory Showroom - I suppose your CD is something similar.  Actually, in my experience, older players do the best on it (you can't skip back a track, but rewinding one minute from the beginning of the first track does it).  OTOH, just because CD players have trouble with it, does not mean that it's doesn't conform to a standard.  I've seen a CD player that will have trouble with any CD with more than 32 tracks and another that had trouble with more than 60 (I think there was a "The Offspring" CD with a hidden track at 69 that would give it trouble).  Redbook allows up to 99 tracks IIRC.

In conclusion, the standard is proprietary, possibly quite cryptic or vague even for those who can afford to access it, and not necessarily supported equally well across the board! So I am unsure whether worrying about strict compliance is always worthwhile. However, as I indicated above, any demystification by users who have the relevant technical experience can only be a good thing.

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #17
Heh, this conversation made me recall that I have one CD with 40 minutes of HTOA.  THAT can't be Red Book compliant.


Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #19
burners will write an initial two seconds of silence regardless of whether or not it is specified in the cuesheet; thus, any pregap specified would be added afterwards. Assuming this is correct, for which I would welcome confirmation, a declared INDEX 00 to TRACK 01 of 32 frames in length would actually correspond to an additional 32 frames of silence after the standard two seconds.


It's been a while and I no longer have all the documents and research, but the 2 second pregap is mandatory, and any additional pregap comes after that indeed.

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #20
Heh, this conversation made me recall that I have one CD with 40 minutes of HTOA.  THAT can't be Red Book compliant.


As HTOA is simply an index in a track, it shouldn't matter whether it is half a minute or 40 minutes. But some CDs have data in the pregap (sounding like static). It could be by mistake, but allegedly such schemes were implemented as an attempt at copy protection, where CD-ROM drives would read this first (while audio CD players would not).

I have no idea if this copy protection scheme would actually work if Red Book compliant, and – apart from legal issues – there is hardly any reason for the manufactorers to comply with the specification farther than to the point where the vast majority of audio CD players would find and go to track 01 index 01.

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #21
Answering the OP - your data would make me assume that there's some commonly used professional mastering software that just does that by default. Maybe it improved compatibility with some dodgy CD player(s) in some way, and didn't harm any others, so they added it?

The standard is important, but at some point practicalities take over. Some of the copy protection methods are all about what mostly works in practice, and don't care too much about the standard.

Cheers,
David.

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #22
Not sure if this will be relevant for the discussion, but the CTDB website includes a page with a few stadistics regarding the submissions, including one about the pregap lengths:  http://db.cuetools.net/stats.php

Looks like more of the 80% of the CDs in the database with pregaps are sharing a value between 32, 33 and 37 as the main ones, although there are a lot of different values as well beyond those.

Curiously enough, out of my 200 CDs collection the most common pregap is 37 frames which I assumed it was the usual value until I saw that graph.

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #23
It needs to be mentioned that it is mostly older CDs (from the 80s and 90s) that have these 32, 33, 37 pregaps... I haven't see a newer CD with it for a long time. It was probably some old mastering hardware systems that added it automatically.

Why do ~70 of 220 CDs contain HTOA of around 32 frames?

Reply #24
I was explained that the red book does not allow an INDEX 00 on Track 1

Reference?

I know one CD mastering book says audio content is forbidden in track 01 index 00, but that's much different from saying the index can't exist.

The Red Book (at least, in its IEC 60908 / BS 60908 form) implies that audio content is divided into "program items" called tracks, and it says that every track is preceded by a pause, indicated by a start flag ("1" bit) in the P subcode and by index "00" in the Q subcode. The pause must be at least 2 seconds (150 frames), and it must be between 2 and 3 seconds (225 frames) for the first track and for the lead-out.

So, the spec doesn't just permit track 01 index 00 to exist, it requires it. I'm not sure how this squares with the SCSI/CD-ROM standards governing DAE; I have them, but am too lazy to look it up now. It may be that the first 2 seconds are actually not accessible, and what we think of as track 01 index 00 is really just the portion after those first 2 seconds.

Elsewhere in the Red Book it says that the entire program area contains encoded audio data. Implicitly, this includes the index 00 portions. It doesn't say they have to be digital silence, nor does it impose any requirements on the player for interpreting those sections. So whether actual audio content is truly "forbidden" in the pregaps is up for debate.