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  1. #1
    Big science. Hallelujah. noddin0ff's Avatar
    Join Date
    Mar 2004

    Calculations: Compression vs Lossless

    Just thought I'd share my observations. Obviously I have too much free time today. But this could be helpful for those considering moving their CDs to a hard drive on a large scale.

    I'm slowly re-ripping my CD collection to Apple Lossless. I decided to do that instead of FLAC because I'm a Mac person and I don't want to wait for FLAC support. I don't think the numbers would move all that much for a different lossless compression format.

    I'm just dumping some numbers out here, for those who're interested.

    My CD collection is pretty significant. Based on total playing time the breakdown is

    22% Jazz
    15% Classical
    63% Other (mostly Alt/College Rock)

    I originally ripped my entire collection with iTunes AAC encoder, mostly @ 192kbps. The bulk statistics are

    758 Albums
    9504 Songs
    29.3 Days of Music
    61.79 Gigabytes (@192kbps)

    A few CDs a day, and I've re-ripped most of my Jazz collection and some miscellaneous rock (75% Jazz). The total so far...

    160 Albums
    1737 Songs
    6.1 Days of Music
    49.49 Gigabytes

    From this I extrapolate that 29.3 days of music that took 62 Gigs @ 192kbps will take up 237 Gigs in Apple Lossless. (29.3/6.1X49.49=237).

    OR in simple units for storage on a hard drive.
    Apple Lossless uses on average 340Mb/hour music
    Apple AAC @192kbps uses about 88Mb/hour
    Uncompressed is about 600Mb/hour

    I took a guess as to what I'd need for storage before I started and thought I'd need a 250G hard drive to do it. Formatted my 250G hard drive has 233G available space. I might make it, so far my guess is within 4GB of my calculation…but I can't buy any more music! I can see a another drive in my future when prices drop some more. The 250G drive was just over $100, no enclosure.

    I also tried to see what the average bit rate of Apple lossless was. It varies a lot (with lower bitrates perhaps associated with slower more melodic music?)

    Anyway, on a per track basis I see

    60 Songs @ >1000 kbps
    305 @ 900-1000
    535 @ 800-900
    402 @ 700-800
    266 @ 600-700
    103 @ 500-600
    29 @ 400-500
    37 @ 300-400

    So the sweet spot is in the 800’s. CD’s are 1411kbps.

    You can wake up now….

  2. #2
    Forum Regular
    Join Date
    Apr 2005
    noddin0ff, I assume that you have an ipod. Go to and you can install their free software on to your ipod and it will support FLAC and many other formats, even ac3. I use their software on my iriver mp3 player and I never looked back to the original software. Far superior to any companies front end program. I would definetly check it out.
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  3. #3
    Big science. Hallelujah. noddin0ff's Avatar
    Join Date
    Mar 2004
    Thanks I'll check out the link. Sounds like a good hack. I'm not really much of a portable audio person. I own a second hand 1G iPod Shuffle. Mostly it gets used as a flash drive at work. I'm starting to use it for night listening while I read. I put 3 or 4 cd's in WAV format (it doesn't support Apple Lossless for some reason) and plug in my Senns 570. Sounds nice.

  4. #4
    AR Newbie Registered Member
    Join Date
    Aug 2005
    Currently on my music server I have in iTunes:

    9687 songs, 259.94 gigs all in apple lossless.

  5. #5
    Big science. Hallelujah. noddin0ff's Avatar
    Join Date
    Mar 2004
    Sound about right. I'm still re-ripping to Apple lossless. Today I do Rock Ki-Je. I guess I'm about 2/3 of the way through. I figure if I ever want to convert to flac or something I'll just hook up a couple drives to the Apple Lossless library and let my computer burn itself out for a week or more!

    10,400 songs, 32.5 days, 183 GB (about 6300 songs in lossless, the rest a mix of 192 and 250.

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