Creating an Audio CD (CLI)

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This chapter contains information about creating and editing audio CD images. It contains the following sections:

  • About Digital Audio (DA)
  • Creating an Audio Image
  • Audio tracks in sessions > 1?
  • Changing Recorder Settings for Disc-At-Once

About Digital Audio (DA) Digital Audio (DA) is the standard track type for audio CDs. This robust format permits the creation of as many as 99 Red book compliant tracks within the same disc image. If you choose to create a hybrid disc, an ISO or XA track may be added. However, you will then be allowed to create only 98 DA tracks because of the non-audio track When DA tracks are created, they must always conform to the following Red book specifications: The sample frequency must be 44.1 kHz. Audio must be stereo. Each sample must contain 16 bits. The byte order must be the identical to the byte order used by your computer, unless you are using a WAVE file. Wave files are always LSB. If you load a WAVE file into a virtual audio track, GEAR will automatically compensate for the MSB/LSB difference. Depending on the audio editing package they came from, some audio files may contain a sound header. Audio files/tracks should not contain sound headers. If sound headers are not removed before recording, they will cause a sharp click during playback from the CD. Use the readtrack command to copy digital audio tracks from a CD to your hard drive. By default the readtrack command will not create a header and produce a Redbook audio file in the byte order of your system (MSB or LSB), unless you specify the `-wave' option. So files copied in this manner may be recorded without any further editing on your behalf. GEAR PRO Unix supports the following formats: Digital Audio/Red Book WAVE .IFF Sound Designer II WAVE files are typically in LSB format, AIFF files are typically in MSB format.

Creating an Audio Image To create a new audio image with GEAR, enter: newvol <80|74|63|18> DA Following this command, a new GEAR Volume is created, containing one empty digital audio (DA) track. The administration file for the GEAR image is located in your working directory, it's name will consists of the eight character image name you chose with the addition of the extension .vol, for example: MY_MUSIC.vol.

Adding audio tracks and loading audio files: Additional audio tracks in the GEAR Volume can be created with the newtrk command (up to 99). newtrk DA [] A track will be created and selected automatically. Audio files can be added (copied) directly from your hard drive to your Audio CD image. To copy audio files into the current track image you can use the cp command: cp /usr/me/myaudio/myredbookaudiofile.rdb . Remember, only Red book, .WAV, and .AIFF files are supported by GEAR. Using the readtrack command discussed earlier, you can also create an audio file first directly from an existing audio track on a music CD. The readtrack command will save audio files with the appropriate byte order for recording with GEAR. Simply follow these steps: Place the music CD you want to read from in your CD-R drive. Type readtrack Select the track you want to read from the dialog that appears. Enter a file name for the song. Press Enter to copy the selected track. Continue to repeat steps 1-5 to add more music to your image. If you already know the number of the track you want to copy you can save time by using the following command: readtrack Any audio file you wish to record to a Digital Audio CD must comply with the Red Book standard. Your file must conform to the following criteria: The sampling frequency must be 44.1 KHz. Audio must be stereo. Each sample must consist of 16 bits.

Audio tracks in Sessions > 1? Any time you record an audio CD, you should make an effort to conduct your recording in a single-session of a blank CD-R disc. This is because conventional CD audio players (Like your home and car stereo) are single-session readers. Consequently, you'll be unable to enjoy your music on these devices if you record your audio tracks in sessions > 1. Only the first session will be recognized by the CD audio players.

Changing Recorder Settings for Disc-At-Once For writing your audio CD you can use either the track-at-once or the disc-at-once recording method. The recording method (and other recording parameters) can be changed with the setcdrparms command of the recorder module. To view the current recording parameters use the getcdrparms command. To edit one of the parameters, type the following command: setcdrparms Writing in disc-at-once mode has the advantage that you can manipulate the pauses (= index 0) between the audio tracks. With track-at-once, the pauses will be fixed to two seconds (= 150 sectors). With disc-at-once you can set the pauses of audio tracks > 1 to any value.

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