At 02:12 PM 1/23/2003 -0600, Premise Checker wrote:
>In a Single DVD Changer, Hundreds of Movies and MP3's
>[1.5 years is 1.5 x 365 x 86,400 sec. = 4.73 x 10^7 seconds.
>[A DVD has 4.7 x 10^9 bytes. 301 DVDs, then, have 1.42 x 10^12 bytes.
>[Therefore, an MP3 file eats up 43 KB/sec. Is this about right?

Your question is not really answerable since the bitrate of an MP3 is
selectable at encoding. "Near-CD-quality" is usually taken to be 128 Kbps
or 16 KB/sec. 43 KB/sec is probably meant to be 48 KB/sec ("just under")
and would be 344 Kbps, the highest rate frequently used for MP3s. Apart
from the alternative compressors (WMA, MP3Pro, MP4 and Ogg Vorbis among
them), the lossless compression schemes (Shorten, Monkey's Audio) are not
that much less efficient; on monaural material, they will take under 400
Kbps for the same sample rate (44.1 ksps). Of course, the electronics in
the changer need to support these other codecs.

>[Mike's 2 million 78s, at 480 seconds (8 min.) each, is 9.6 x 10^8
>seconds, or 30 years. Is *this* about right?

I get 30.4 years (allowing for leap years).

The key here (IMHO) is that these materials would not be recorded at 344.
Only allowing for them to be in monaural would reduce the rate to 172 Kbps.
Recognizing the limited frequency response, substantially more savings can
be effected.

For some years now, I have been producing volumes of what I call an "Audio
Encyclopedia". See the pages at my WWW site for more information on that.
With few exceptions, the recordings are at 32 Kbps as are the audio
selections I post at my WWW site. A CD-ROM (the format I use) holds about
45 hours of such programming.

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