Compress Audio to fit onto CD - Need Advice Please

Discussion in 'iPod' started by dalvin200, Sep 13, 2007.

  1. dalvin200 macrumors 68040

    Mar 24, 2006
    Nottingham, UK
    My dad recently recorded some audio at a live event and wants to burn that onto a regular CD to listen to in the car etc..

    He's managed to rip the audio from his camcorder into mp3 format (128kbps).
    The file is only 96mb in size, but is 1hr 45mins long.

    We are finding that the file will not burn onto an audio CD (not mp3 cd) - I guess this is obviously to do with the fact that the length of the audio clip is 1hr 45mins and not the standard 80min of a CD-R.

    Is there anyway that the audio can be compressed? will a reduction is quality help?

    I mean, the mp3 is only 96mb so I would of thought it easily fit onto a 700mb CD-R?

    iTunes just says that you need more than 1 CD to burn? But how would that work?
    Would it create say 2/3 proper Audio CD's which had the 1hr 45mins spanned over them?

    I would ideally want it all on the one disc if there is a way - maybe there is some software that will allow overburning?

    Any help is greatly appreciated.

  2. Nermal Moderator


    Staff Member

    Dec 7, 2002
    New Zealand
    If you want to be able to listen to it on a standard CD player then you're limited to 80 minutes. You can, of course, put the MP3 file on the CD directly if your player is compatible.

    The other option is to split the file over two CDs.
  3. Avatar74 macrumors 65816


    Feb 5, 2007
    If what you want to do is listen to it in a CD player that doesn't play MP3 CD's, you're out of luck.

    The Compact Disc Digital Audio (CDDA, "Red Book" standard) specification uses one format and one format alone... 16-bit Linear Pulse Code Modulation. This format uses 16-bit samples, sampled at a fixed data rate of 44.1kHz.

    This results in a fixed data rate of 1411 Kbps for stereo.

    i.e. 2 ch x 16-bits per sample x 44.1kHz sampling rate = 1.411 Kbps

    There is simply no way to alter this, as the data cannot be encoded to a Red Book compliant CD at any other data rate, in any other format, with any compression. Linear PCM is an uncompressed format, by the way.

    Any reformatting into anything other than 16-bit Linear PCM will result in a file that is not encodable to a Red Book compliant CD and therefore not playable in any conventional CD player.

    The only alternatives are:

    1. Break up the file into two segments and encode them to two separate discs.

    2. Encode as MP3 to an MP3 CD and play on a device that will read MP3 CD's.

    3. Record to a digital media player like an iPod and play through an audio cable or other interconnect to the head unit of the car stereo.

    4. (for sake of argument, though not a solution I suppose you would like...) Speed up the audio to shorten the track length to 74 minutes or less, then you can encode it to one disc but now you've got a recording of Alvin and the Chipmunks...
  4. greg555 macrumors 6502a

    Mar 24, 2005
    You could perhaps put the first half on the left channel and the second half on the right channel. Then he could listen to it all (on one CD) by playing it twice, first with the fader to the left, then with the fader to the right.

  5. Nermal Moderator


    Staff Member

    Dec 7, 2002
    New Zealand
    That's a novel way of doing it! Recording in "mono mode" crossed my mind but I didn't think it was possible. Of course, nothing stops you from doing a fake mono like that :)

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