Burning music files to a CD





Audio CDs
There are two main types of CDs that you can create with CD burning software: audio CDs and data CDs.


 * To ensure that you create a CD that will play anywhere it is important to choose the option to burn an "Audio CD" or "Music CD" and not a "Data CD". A data CD containing for example MP3 or WAV files will play happily on your computer but is unlikely to play in a standalone CD player or in-car CD player (note that some modern CD players will play data CDs).  An audio CD will play on any standalone or in-car CD player and in your computer and in modern DVD players.


 * Audio CDs are generally limited to 74 minutes playing time on a 650 MB disc ("Red Book Standard") or 80 minutes on a 700 MB disc.


 * When buying blank CDs for burning, it is strongly recommended that you purchase good quality CD-Rs (that can be burnt just once) and not the rewritable CD-RWs.

Audacity setup
Audio CDs always contain uncompressed PCM stereo audio at 44100 Hz sample rate, 16-bit sample format. So to burn an audio CD, export the file(s) you want to burn as a 44100 Hz 16-bit stereo WAV or AIFF file.

To configure Audacity for this:
 * 1) At the bottom left of the Audacity window, set the Project Rate to 44100 Hz.
 * 2) Some CD burning software require you to have a stereo track. If your Project does not already contain a stereo track, click . It does not matter that this track is empty, its purpose is just to make Audacity export your recording as a stereo file. This step is not needed if you are burning to CD with iTunes or Toast.
 * 3) Click  and choose "WAV (Microsoft) signed 16 bit PCM"  in the "Save as type" box.

It may be possible to use other formats if your CD-burning software supports them, but they may not give the best quality or they may not be playable on all CD players.

Multiple songs
If you are exporting a long Audacity track that contains multiple songs, please see "Splitting a recording into separate tracks" for how to export multiple files for each of the songs by using labels to identify songs for the Export Multiple command to operate on.

An alternative method is to use Cue Sheets to define individual songs.

Burning software
In order to burn an audio CD you will need a CD burning program. Most computers already come with media player software that can burn CDs. For example, you can use Windows Media Player built into Windows or iTunes built into Macs. In either of these programs, drag the files you want to burn from the location you exported them to into a "playlist" ready for burning.

Ensure in either Windows Media Player or iTunes that you select the option for burning a "Music CD" and not a "Data CD" as mentioned above.

You can also use a standalone Windows burning program like CDBurnerXP, Deep Burner or Nero (or Burn or Toast  for Mac OS X) to burn your exported files. Most Linux distributions include Brasero or K3B for CD burning. When using standalone burning programs, open the files from within that software, do not drag and drop them from your file manager. Once again don't forget to select the setting to burn an "Audio CD" or "Music CD" as explained above.

Gapless burning
By default, many CD burning programs add a two-second gap between CD tracks as part of the standard for audio CDs. So be aware of CD track gaps when placing labels between album tracks for Export Multiple and consider deleting excess silences between tracks.

However most CD burning programs have an option to burn the CD with no gaps between tracks. This is useful for recordings such as live concerts, allowing the CD to play continuously if the player supports gapless playback while still permitting skipping to individual CD tracks. If burning a gapless CD, you will need to place the Audacity labels exactly where you intend the burner to mark the track splits. Some CD burning programs (for example, older versions of Windows Media Player) have no option to burn without gaps. Gapless burning is also only available if the optical drive supports Disc-At-Once (DAO).

Additionally, make sure you don't export MP3 files for burning to your gapless CD, even if you're burning a "data CD", because MP3s have inherent silence padding due to a restriction of the MP3 format.

Note you may still hear the most momentary gaps between tracks even on DAO burned CDs, unless the CD player supports true gapless playback. Many CD players do not support gapless playback properly because the hardware simply doesn't buffer the audio data properly. However quite a few computer-based media players can use DSP effects when playing back audio to give proper gapless playback, even of CDs not burned with DAO. An example of such a player is Apple's iTunes. {{note|1=

Cue Sheets
An alternative solution is to not split the track up at all in Audacity. The best way to get apparently gapless playback of a live concert recording or live album is to burn as one WAV file with with DAO and a "cue sheet" that marks the starting times of each CD track. Cue sheets can be created as simple plain text files.

Each track in a Cue Sheet is of this format:


 * TRACK (number) AUDIO
 * TITLE "(name)"
 * PERFORMER "(name)"
 * INDEX 01 (start time) in the format minutes:seconds:frames with the first track always being 00:00:00

Audacity cannot currently export Cue Sheets but it is possible to use the command to export a text file representing the label positions, then on Windows and Linux use label2cue to convert the minutes and seconds data in the text file to minutes, seconds and frames data laid out in cue sheet format. You can read more about cue sheets on Wikipedia here. }}

Burning longer recordings to disc
As stated above audio CDs are generally limited to either 74 or 80 minutes, however it is sometimes possible to achive longer times by using Overburning. Alternatively, for longer recordings, you may be able to use data discs provided your player will support and play these. (A data CD will not normally play on older standalone CD players. It will play on computers, most DVD players and in MP3 CD players).

{{ednote|1= Peter 2Apr13: Full detailed text retained here in case we need to restore it later if this detailed material is excised from the Wiki page on CDs.

Overburning
Because audio CDs must always contain uncompressed 44100 Hz 16-bit stereo audio, they are necessarily limited on a 650 MB ("Red Book Standard") or 700 MB audio CD to 74 or 80 minutes playing time respectively. If you need more playing time (for example, to try and accommodate a C90 cassette or two LPs onto one CD) some CD burners will let you "overburn" into the blank CD space so as to extend the playing time by a further few minutes, so giving you the possibility of up to 80 minutes playing time on a 650 MB disc or up to 86 minutes on a 700 MB disc. Overburning (if your burning software and burner supports it) is always done using Disc at Once (DAO) mode in which the tracks are burnt continuously without turning the laser off.

It is also theoretically possible to overburn using "90 minute" (790 MB) or "99 minute" (870 MB) CD-R discs. However there is no guarantee whatsoever that your CD burner will accept such CD-R discs, or that your CD player will play anything other than a Red Book Standard 650 MB disc burned with 74 minutes of audio.

Data CDs and Data DVDs
For burning really long files to optical media, you must burn either a data CD or a data DVD which can contain a set of WAV, MP3 or other audio format files.

For example, burning MP3 files to a 700 MB data CD (sometimes called an "MP3 CD"), and using Audacity's default 128 kbps MP3 export bit rate gives over 11.5 hours playing time. But if 64 kbps MP3 bit rate was chosen (in "MP3 Export Setup" in the File Formats tab of Preferences, or "Options" at time of export) about 23 hours of audio would fit on the CD. Note that the penalty of reducing the bit rate would be reduced sound quality (especially so for music but less so for speech).

A single layer 4.7 GB data DVD can accommodate nearly 80 hours of 128 kbps MP3 audio, though some older DVD players won't play DVD data discs, or only those containing certain audio or video formats.

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