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Rip Audio CD [Frequently Asked Questions]

CD ripper

If you have CD collection, an you want to listen to it on a computer or mobile phone, you can rip CD. Read answers to the frequently asked questions about ripping of audio CD to music files.


Author: Yuri Korzunov,
Audiophile Inventory's developer with 25+ year experience in digital signal processing,
author of the articles that make audio easy for beginners
CD rip | Frequently Asked Questions



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What the best CD ripper?

In general, the best CD ripper should provide minimum number of ripping errors comparing other ones.
Unfortunately, there are no research results, that are known to the author.
Read details here >
Also, automatic obtaining of metadata from the Internet is an important CD ripper ability.



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What about fast CD ripping?

Fast CD ripping is reading CD audio once at maximum speed. Any CD drive has a built-in error-detecting and correction system.
As rule, compact disk drives report detected/corrected errors (C2-flags). A safe CD ripper is capable of additional analysis to find errors and recover music data.
Read details >



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What is quality difference between converters?

CD ripper should provide a minimal number of reading errors. After reading CD the audio stuff should be stored in to sound file without losses. Audio file formats WAV, FLAC, AIFF, ALAC allow storing audio data that are binary identical to the reading content.
More recommendations read here >



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What is CD ripping errors?

The most important ripper ability is a minimization of reading error number. As rule, for users, sureness in error detection is very important.

Compact disk standard provides for error detection and recovery. But without 100% guarantee of error detection.

CD ripping errors may have several levels of detection and elimination:

  • detecting and correcting during reading from optical disk into drive device;
  • detecting and correcting via CD ripper software.

CD ripper also doesn't provide 100% error detection.

Read more about safe CD ripping here...



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How impact speed of processing to quality?

Many CD rippers can access online databases to obtain track name, album, performer, etc. As rule, CD ripper generates a unique ID of CD, based on CD data (it is not a standard ID). This ID may vary for different databases.

Information is queried from the database by this ID. Sometimes several metadata options may be stored in the database for single CD.

There are databases with album artworks.

Databases with CD metadata: (former      Discogs       Gracenote



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What is difference between copying .aiff files from CD and CD ripping on Mac?

Mac OSX allows copying CD audio tracks from CD to hard disk as usual .aiff files. The author supposes, that there is used the same way as ripping in iTunes.

If you use other CD ripping software, there may be used other error detection way. Probably (no guarantee) it allows error detection, that is not displayed during copying to .aiff.

Read more about how ripper software may copy CD here...



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Why I can't copy music via copying .cda files?

Under Windows, on CD audio disk, we can see .cda files. But these files have too small size for music. Also copying of these files doesn't allow copy music.

.cda files are not musical files. It is index files only. Each of these files points to relevant track.

CD has a table of content (TOC), that contains positions of the tracks in solid raw audio stream. These positions contain inside .cda files.

To copy audio data, CD rippers read the table of content (as rule, directly - without .cda files) and read tracks from CD's raw audio stream according to track positions.



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Can I rip to FLAC on Mac?

Yes. You can use CD rippers, that support FLAC format.



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Can I rip to AIFF on Windows?

Yes. You can use CD rippers, that support AIFF and ALAC formats.



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How do I rip old CDs?

You can rip old CDs according to the guide...



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Is it real matter, that format use for ripping audio CD?

If lossless formats (WAV, FLAC, AIFF, ALAC, other) is used to rip CD into audio files, format does not matter.

When you use lossy file formats (mp3, aac, other) sound quality depends on format and its codec settings.

Read more about ripping formats here >



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What is metadata format into the ripped audio files?

Audio files mp3, wav, aiff, dsf uses ID3 metadata standard.

FLAC use VORBIS standard.

Also, WAV can use LIST chunk (data block) with metadata information.

These formats are compatible in general. But some matters of format converting may be applied in different ways. It can cause compatibility issues.
Not all metadata information by music providers may be described in metadata standards. Though the latest standard versions have wide range of formalized information kinds.

Many software may read these formats. But there are may be reading and displaying issues.



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What is difference between CD ripping at computer and playback at HiFi hardware CD player?

In the table difference between CD ripper computer software and CD player (musical device) is shown.

  CD ripper (computer software) CD player (musical device)
Reading raw digital stream Yes Yes
Smart interpolation of damaged raw data fragment Author don't know such implementations Yes
Low level error detection and correction into optical device Yes Yes
Higher level error detection and correction (statistical processing) Depend on implementation Author don't know such implementations
Pre-emphasis correction Depend on implementation Yes
Reading CD-text Depend on implementation Depend on implementation
Reading track metadata (track name, album, performer, artwork, etc.) from internet database Depend on implementation Author don't know such implementations
Decoding HDCD Depend on implementation Depend on implementation



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Could computer-ripped files have worse sound quality, than HiFi hardware CD player?

There may be issues:

  • CD-audio information captured via audio output of CD drive;
  • pre-emphasis is not corrected.

Modern CD rippers have access to digital audio stream from CD directly.

The author supposes that pre-emphasis is not used on modern CDs.

Also, sound quality depends on error correction ability of CD drive and ripping software.



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What is sound quality for CD ripping?

Sound quality for CD ripping is CD-reading error number.



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Could CD ripper degrade sound transparency of ripped record?

Theoretically, it is possible, that there are many insignificant errors in the lowest bits of 16-bit sample. But this case has a very low probability in the real life.

As rule, incorrect CD reading causes coarse sound distortions:

  • silence,
  • clicks,
  • interruptions.

CD player (musical device) may try to fix some of these issues via interpolation.



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There is different ripping sound quality on Mac and Windows?

If CD's raw data stream is read under Mac OSX and Windows same way, there is no difference.

But different ripping software may have different algorithms of CD reading. So we can get different result (error number) for different software independently on operation system.

If CD is read stable (without errors), there is no dependence on operation system or CD ripper software or optical disk.



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There is different ripping sound quality for different optical CD-drives?

Different optical CD-drives can cause different reading-error number. But it is coarse errors (silence, clicks, etc.) rather.



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What is pre-emphasis?

Pre-emphasis is noise reduction method. It implemented via high frequency boosting in the audio stuff recorded on CD.

During playback applied inverse boosting (filtering, de-emphasis) of high frequencies.

If pre-emphasis correction is not compensated, degrading sound quality may be caused.

If pre-emphasis is applied on CD, it is written as special flag on the CD.

As author know, pre-emphasis was used at some old CDs.



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Why CD ripping speed may be so low?

Safe CD ripping use multiple re-readings of the same fragments of the compact disk's audio stream. Each re-reading consume additional time.



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Why CD ripping speed is different for vary CDs?

CD reading speed depend on error number or reading issues, that have this CD. As example, places with detected errors may be re-readed additionally by CD-drive and ripper software.


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Why different CD-rippers have different ripping speed?

CD rippers may use different methods of CD reading or different parameters of the same method.



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When I convert ripped mp3 to WAV, can I get original CD content?

When you rip CD to mp3, you can't restore original content of CD.



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What is C2?

C2 if flag, that display CD ripping error, generated by optical CD-drive.

One C2 flag show reading state of one byte of raw audio data from CD.

Implementation of C2 may be different.

C2 flag don't obligatorily mean, that raw data at optical drive output is damaged.



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What is online CD ripping database (checksum database)?

CD ripping online database (checksum database) collect checksums of ripped CD's. New ripped CD may be compared with checksums of same CD's.

If there is difference in just ripped and collected checksums, probably there is ripping error. Read more below.



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Do any CD contains in the database?

The database contains big number of CDs. However, no warranty, that rare CD will contains in the database.



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Do checksum database can improve CD-ripping quality?

CD-drive and ripper as system can detect CD-ripping errors.  Different systems have different error detection probabiity.

Checksum database is filled from uncertified sources. Checksum calculated by ripped stuff instead files that was used to producing of the CD.

In general, there is no way of correct error detection with 100% probability. Correct error detection probability of the database is unknown.

So we don't know exactly, that correct error detection is better (that correct error detection probability is higher): CD-ripper+drive system's or checksum database's.

Read details here >



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convert ISO to DSF - Frequently Asked Questions


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