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Track gap consistency

Hello,

What are the correct expectations concerning the consistency of track gaps in cue sheets (the 'INDEX 00' lines)?

Say if I were to rip a given CD (or even just create cue sheets without ripping the music), would I get exactly the same gaps

(1) using different rippers (software) but on the same drive,
(2) using the same ripper but on different drives, and
(3) using the same ripper on the same drive, multiple times?

As for case 1, I created two cue sheets with EAC and CueTools (CueRipper) on a Judy Collins CD ('Send In The Clowns - The Collection').

On EAC, 'method A' was used (couldn't get method B or C to work), and detection accuracy was set to 'Secure'.

One CueTools, Secure mode with 'Test & Copy' were used.

In either case, the cue sheets were for ripping into individual tracks, with gaps appending to previous tracks.

The 'INDEX 00' lines were extracted from the cue sheets and a side-by-side comparison was made. Here is the result:

EACCueTools
02:36:0902:36:09
03:14:0803:14:07
05:39:2605:39:25
03:39:0503:39:04
02:54:6502:54:64
04:00:4504:00:44
03:04:3903:04:38
04:51:6204:51:61
04:10:5804:10:57
04:35:5304:35:52
03:10:2103:10:20
03:13:6703:13:66
02:58:4102:58:40
03:17:5503:17:54
04:05:6904:05:68
03:52:4703:52:46
05:49:3405:49:32
05:00:6705:00:66
03:27:5903:27:58

The gaps are very slightly different.

Thanks you for your help.

Re: Track gap consistency

Reply #1
I'm not familiar with the processes you're using, however, the results you're listing may simply be a mathematical rounding issue - where one column is being rounded up, the other rounded down...
In the beginning there was ONLY noise, then came the signal.

Re: Track gap consistency

Reply #2
What are the correct expectations concerning the consistency of track gaps in cue sheets (the 'INDEX 00' lines)?

For detected pre-track gaps
http://www.exactaudiocopy.de/en/index.php/overview/basic-technology/gap-technology/
Quote
Please note: Because the pre-track gaps are determined by looking up CD positions, it is possible that it will not be 100% accurate. But in most cases it will be correct, the deviance should be lower than 2-3 sectors.

All tracks in your example fall within the documented 2-3 sector variance. For answers to (1), (2) and (3), feel free to test for yourself.
korth

 

Re: Track gap consistency

Reply #3
This post is quite helpful:

https://hydrogenaud.io/index.php/topic,91150.msg771337.html#msg771337

especially this paragraph about subcode (where the pre-track gaps are stored):

Quote
The ripper doesn't have access to the raw multiplexed data. CD drives demux it in the hardware & firmware, and only provide software access to interpreted streams. The ripper can ask for the audio data only, or the subcode only. I don't know any technical details, but based on comments I've seen by the developers of cdrtools, PerfectRip, and CUETools, it seems that subcode-reading is an inexact science with variable support in CD drives, which is why you can get different results from different drives or different reading methods, or even from read to read on the same drive. I also saw a mention that the subcode data is sometimes offset from the audio data it corresponds to.

I'd stick with CueRipper's gap values for now.

Re: Track gap consistency

Reply #4
however, the results you're listing may simply be a mathematical rounding issue - where one column is being rounded up, the other rounded down...

That would explain all but the third-to-last: 05:49:34 vs 05:49:32.
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