Please explain why I can get an 800MB wav onto a 700MB cd

[joburnet]

I have an 800MB wav file that is 79 minutes long and it burnt fine onto an 80 min/700MB cd. It seems odd that a file that large would fit onto a cd. Why is this possible?

 

[Dulanic]

Its called Overburning, and depending on the quality of the media used you can get more or less. Most recent CDRWs support it.

 

[joburnet]

I don't think it's overburning, it says on the media that it can hold 80min of audio but an 80min wav file is 800MB.

 

[dee]

The file on the cd isn't actually a wav file, its just a raw data file & so is smaller than a wav.

When you record a wav to a cd the recording software converts the wav on the fly to the file type needed for the cd. The opposite happens with ripping software.

 

[Noriaki]

Wave file size does not equal CD Audio size in MB.

For CD Audio you have measure in time, not MB size.

If that 800MB wav is <80minutes, then it will fit on a &quot;700MB&quot; CD, becuase that CD is 80minutes.

 

[DaddyG]

I do believ that it all depends on the file format type when the wave is saved. It can be saved as an actual 'wave' or it can be converted and stored as Digital Media.

 

[Soccerman]

heh, surprised no-one knew this:

CDs really have more then what they list, simply for error correction. I believe its called parity, or something like that. after all, what happens when one of those 700 million bytes has a 0 instead of a 1 in it? or what if there's a spec of dust on the CD? or a scratch??

Audio CDs use that for all of the data, IE no error correction (AFAIK though, I'm probably wrong on that part).

think about it, an 80 minute 16 bit 44100hz sample rate, stereo WAVE has to have 846 720 000 bytes, or about 846 megs. that's more then an 80 minute DATA CD is *supposed* to store, not becuase the WAV file includes extra data (it's in its RAW form when in PCM WAV).

 

[esung]

Soccerman is correct. each sector on a CD has 2336 bytes, on CDDA or mode2 form2, all of them were stored for data. on the regular data format (yellow book, mode1, mode2 form1), there's only 2048 bytes used for data storage, and the extra 288 bytes is used for ECC.