EAC Drive Options

From Hydrogenaudio Knowledgebase

The EAC Drive Options dialog (shortcut: F10) offers several options for configuring how EAC reads and writes audio data from the currently selected drive.

Used EAC version: V0.99 prebeta 5

Extraction Method

Secure Mode

You will need to detect & apply drive features when using secure mode. Even if you chose to use the configuration wizard, it's a good idea to repeat the test a couple of times in order to be sure that the results are consistent (see link). Beware that these features are unique to every drive.

Drive has 'Accurate Stream' feature

Back around the turn of the century when digital audio extraction (DAE) was relatively new, some drives couldn't provide audio data from precise locations. Each time it was told to read a block of audio, a drive might produce data that was shifted slightly ahead or slightly behind. When an adjacent block of data from a subsequent read is shifted, it will either begin with samples repeated from the previous block, or samples between the blocks will be omitted. In DAE, this phenomenon is often called jitter or synchronization error. To compensate for this problem, EAC is able to overlap every read in order to detect and correct any misalignment.
Essentially all drives produced today have a feature called 'Accurate Stream' which significantly reduces (if not completely eliminates) the chance that audio data will be shifted between successive reads. When informed that a drive has this feature, EAC will only periodically overlap its reads to check for synchronization problems.
  • If the "Detect Read Features..." function reports "Accurate Stream : Yes", it is safe to check the "Drive has 'Accurate Stream' feature" box. This will result in a significant increase in ripping speed.

Drive caches audio data

In order for secure mode to work properly, every read request made by EAC must cause the drive to seek data from the CD. If your drive caches audio, subsequent requests for the same data may result in the drive only fetching this data from its buffer, rather than from the physical disc. To prevent this from happening, EAC has a routine to ensure previously requested data gets flushed from drive's cache. This is done by having the drive read extra data from the disc—more data than the cache can store.
  • If the "Detect Read Features..." function reports "Caching : Yes", it is important that you enable the cache flushing routine by checking the "Drive caches audio data" box.
  • If the "Detect Read Features..." function reports "Caching : No", it is not necessary to enable the flushing routine. Checking the "Drive caches audio data" box with drives that are reported by EAC as not caching will not improve EAC's accuracy. It won't improve EAC's ability to detect errors nor EAC's ability to correct them. What it will do however, is reduce your ripping speed and shorten the life of your drive.
Tip #1: If you're concerned that your drive caches audio data even though EAC is saying otherwise, try ripping a scratched disc (one known to produce errors easily). Make sure you uncheck the "Drive caches audio data" setting AND uncheck the "Drive is capable of retrieving C2 error information" setting. Make sure you also set the error recovery quality to "Low" (this setting can be found under the Extraction tab in the EAC Options dialog). If EAC is capable of displaying a read error then cache flushing isn't necessary. Ignore any sync errors that may be displayed; they are irrelevant to this test.
Tip #2: Tip #1 is all you need to know, but if you're still paranoid that your drive caches audio, feel free to try Feurio'swbm audio caching test (Ctrl+Alt+P\Test device\Cache test) or spath's cache explorer (also forked as cachex). Tests should be performed with an audio CD in the drive. If either determine that your drive doesn't cache or caches less than 64 KB of data, then cache flushing isn't necessary (ignore the reported buffer size when using cache explorer). The reason for the 64 KB barrier is that EAC will never request less than this amount while ripping link).
Note: If "Drive has 'Accurate Stream' feature" is deselected, then "Drive caches audio data" is automatically checked, regardless of whether the drive actually caches audio data.

Drive is capable of retrieving C2 error information

This setting was designed to speed up the ripping process by trusting the drive's ability to reliably report uncorrectable errors.[1] If this setting is enabled, EAC will not re-read and try to get consistent data from sectors which the drive reports as being error-free. Unfortunately, not all drives adhere to the same standard as to how this should be done. As a result, errors can go undetected.
EAC has two tests for this feature. The "Detect Read Features..." function only tests if the drive says it can provide C2 error information. The "Examine C2 Feature..." function tests whether the drive can actually report an uncorrectable error. Neither test can be used to determine whether all uncorrectable errors are reported, so these tests don't tell you whether the setting can be used reliably.
  • You may be able to determine if your drive's C2 reporting is reliable in EAC by using DAE Quality. This involves creating a special CD and testing it.
  • Unless you know that you can use this setting reliably, disable it. If you choose to enable it, make sure you also rely on AccurateRip or a test CRC to compare with the read CRC if AccurateRip doesn't have data for your disc.

Paranoid Mode

This is an old mode that has been superseded by secure mode. It is highly unlikely that this mode will provide any benefit over secure mode.

Fast Mode

This is another old mode for drives that cannot provide a synchronized stream when ripping in burst mode. Since synchronization error is no longer a problem with modern drives, it is highly unlikely that this mode will provide any benefit over burst mode.

Burst Mode

Burst mode performs extraction without any error checking. It is handy for discs that do not require re-reading in order to be ripped accurately, especially with drives that cache audio data. It is also handy for discs that trigger re-reading in secure mode but cannot be ripped accurately. When used in conjunction with AccurateRip, or in conjunction with a test CRC to compare with the read CRC in the event that AccurateRip doesn't have data for your disc, burst mode is completely secure.


Drive read command

(Default: Autodetect read command, Recommended: use the Autodetect read command now button)

This drop-down list allows users to configure which read command to use with the drive to extract audio.

Autodetect read command now

This button will set the proper read command in the Drive read command drop-down list.

"Big Endian" byte order (Motorola)

(Default: disabled)

This option reverses the byte order of the audio data coming from the drive. If the ripped audio is loud static, change this setting.

Swap channels

(Default: disabled)

This setting reverses the stereo channels of the ripped audio. If you find that your drive reverses channels, it is probably due to a two-byte offset which cannot be corrected properly with this option. Try upgrading your drive's firmware or replace it with a different model.

Spin up drive before extraction

(Default: disabled)

This option may or may not improve performance. Enable it if your drive doesn't otherwise operate smoothly or cannot rip the beginning of a track correctly.

Offset / Speed

Use read sample offset correction

Detect read sample offset correction...

Use combined read/write sample offset correction

Overread into Lead-In and Lead-Out

Speed selection

Allow speed reduction during extraction

CD-Text Read capable drive

Gap Detection

The goal with both of these settings is to help EAC get reasonable gap values in a reasonable amount of scanning time. There is no way to know if the values are 100% correct.

Gap/Index retrieval method

EAC offers three methods: A, B, and C; the difference between them is unknown. Method A is a good initial setting, as it is usually fast and provides good results, but on some discs and some drives, B or C might be better.

Detection accuracy

This affects how many times the gap info is read. Inaccurate is one read, so it will be fastest. Accurate and Secure are multiple reads, which will be slower but may perform better on some CDs, especially if scratched or defective.

Background info:

Indexes are track subdivisions. All tracks have index 01 for the main content. Some also have a "gap" (index 00) for a between-song pause (silence or very quiet hiss), or for a non-silent interlude, count-in, or applause. On rare occasion, tracks will have higher-numbered indexes as well.

The start of each track's index 01 is listed in the CD's table of contents, so it is known as soon as the disc is inserted. The other indexes are stored in the disc's subcode, which can be difficult to read correctly. CDs also have slight variances in how and where this info is stored. EAC's Gap Detection settings help cope with these issues.

What are reasonable results?

  • Gaps are all different lengths, and in a range of about 1 to 5 seconds each.
  • Gaps are all exactly 2 seconds each (for a CD-R burned in TAO mode).

What are suspicious results?

  • Gaps are all the same length, and not exactly 2 seconds each.
  • Gaps are all very short—e.g., less than 1 second each.
  • Gaps are all very long—e.g., over 1 minute, or equal to the track length.
  • Gaps extend well beyond the end of a pause/interlude in the music.
  • Gaps get progressively longer.

These are general guidelines; there will be occasional exceptions.


Writes samples offset

Create Offset Test CD

After Burning Finished

reset drive by ejecting and loading CD-R
only eject CD-R
do not eject CD-R

Drive is able to write UPS/ISRC

Drive is able to write CD-Text

Detect Write Features...

Notes and references

  1. "Uncorrectable" doesn't mean the data is bad, necessarily. In fact, it's normal for at least a portion of data marked uncorrectable to actually be correct; it just wasn't made correct by the C2 system.

External links