How Much Audio Can You Burn On a CD-RThis is a tutorial to help you figure out how much stereo 44.1 kHz 16-bit audio data you can burn on a CD-R.AMOUNT OF DATA: Uncompressed digital 16 bit, stereo audio at 44.1 kHz is exactly 176,404 bytes per second (172.27 kilobytes/second). So 1 minute is 10,584,240 bytes (10.09 megabytes), X 74 minutes (on a standard CD-R) = a maximum of 783,233,760 bytes (746.94 megabytes) of audio (with no 2 second gaps between songs). Now a standard 74 minute CD-R says it holds only 650 megabytes of data (681,574,400 bytes), so how is it possible that you can fit up to 746.94 megabytes of audio (74 minutes) on a standard CD-R which appears to only hold 650 megabytes of data? There is no compression used on CD audio, the answer is that a standard 74 minute CD-R that claims to only be able to hold 650 MB, can actual hold 746.94 MB of CD-DA (Compact Disc Digital Audio) IF you use no error correction code. When Phillips & Sony invented the audio CD they built in enough extra storage (14.915% extra) so that redundant error correction code would take care of scratches & marks on the surface of the CD. This error correction code (if used) brings the amount of data down to 87% of a discs capacity which is why a CD-R capable of recording 746.94 MB of data is only rated at 650 MB. REDUNDANT ERROR CORRECTION CODE: Unfortunately, most audio CD-R burning software (including Adaptec's Easy CD Creator) doesn't take advantage of the error correction code capabilities for a CD-DA. Error correction code for audio is skipped so that a CD-R can hold as much music as the original factory pressed CD had. Factory pressed CDs hold more data than CD-R burnable CDs. So, if you were able to burn audio onto a 650MB CD-R using error correction code (called mode 1 red book CD-DA), you would only get a maximum of about 64:23 minutes, not 74 minutes like the packaging claims, or if you used an 80 minute CD-R you would only get about 69:21 minutes with error correction code. Most people don't know that the 74 & 80 minute audio claim on the CD-R packaging is without any error correction code. This means that a CD-R burned without error correction code is more susceptible to music distortions or flaws because of scratches, marks & other surface imperfections, than the original factory pressed CD which has error correction. ERROR CORRECTION CODE FOR CD-R BURNING AUDIO SOFTWARE:
So, does anyone make CD-R burning software that allows for
error correction code for CD-DA audio? Well at least one CD burning
software call Musicmatch
Jukebox 8.2 NON AUDIO DATA RECORDINGS: All current brands of CD-R burning software do use error correction code when burning data CD-Rs. Unlike music CDs where a tiny little bit of missing or damaged information is usually tolerable & often won't be heard by the average listener, a data CD (such as a computer program or work file), needs to be a perfect & exact replication of the data, so the extra areas on the CD-R reserved for error correction code are used automatically on data CDs. When burning data CD-Rs you will get up to 650 MB of data on a CD-R rated for 650 MB, plus error correction code. OVERSIZED CD-Rs: As previously mentioned, there are CD-Rs that can hold 700 megabytes (734,003,200 bytes) of error corrected data, or 80 minutes of stereo 16 bit 44.1 kHz audio (846,739,200 bytes) (807.51 megabytes) without error correction code. CLOSE THE DISC, WRITE ONE SESSION: Remember that
if you want your music CD-R to be able to play on a non-computer
based CD audio player, you must write the music in a single session
& "Close the Disc". Normally a non-computer based
CD audio player will only play the first closed audio session (they
are not usually multi-session), so burn your entire CD-R audio in
one session if you expect to be able to play all the selections
on a non-computer based CD audio player. TWO SECOND BLANK SPACE BETWEEN SONGS: Keep in mind that it is normally desirable to have a 2 second blank space between each song, so deduct that from the 74 minutes (or 80 minutes) of audio space available, to determine how much you can actually fit on a disc. Each 2 second space is 352,808 bytes (see chart below). If you need the extra space, you can eliminate the 2 second gap between songs when burning your CDs by using the "Disk-At-Once" feature, but this is not normally done because songs are then butt up against each other with no cueing space. CHART OF HOW MUCH AUDIO FITS ON A 650 MB CD-R: The following chart shows the amount of data used for blank spaces between songs & what is left over to record audio files when burning an audio CD-R with no error correction code. For example, a CD with 10 tracks will have 9 two second spaces totaling 3,175,272 bytes (or 3.02 MB), leaving 780,058,488 bytes (or 743.92 MB) left over for music. When totaling the sum of your wav files in File Manager or Exploring, this chart will tell you how much music you can fit on a standard 650 MB CD with no error correction code. Tracks Spaces Left for audio CHART OF HOW MUCH AUDIO FITS ON A 700 MB CD-R: The following are examples of the amount of audio data available on an 80 minute 700MB oversized CD with no error correction code. Tracks Spaces Left for audio Much more in depth articles on CD-R burning can be found at http://www.mrichter.com By Doug Hembruff. |
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