So I was watching this (https://www.youtube.com/watch?v=WkIR23emsWY) by technology connections and I just realized that I have no idea how CDs work. The video is about how some CD players can read audio of a CD where the data is just copied directly onto a CD with a computer whereas older players only had hardware compatible with CDs formatted as …. digital audio?
I was trying to figure it out on wikipedia, how is a commercial CD you’d buy in a store different from a CD with files copies onto it?
I remember my dad used to use a burning tool to make images. Why are they called images? How is an image different from a CD?
Why are some CDs readable and writable but some aren’t?
In: Technology
When CDs were first brought to the mass market in the early 80s, they were a form of high-end music media, competing for the audiophile space. The distinguishing factor was that they were able to deliver uncompressed audio. As digital audio production took on in the 80s, this meant the CD you listened to was pretty much the exact waveforms the producer heard with the final mix.
These CDs were initially incredibly expensive (an album in 1985 usually went for $20, that’s nearly $60 in today’s dollars), but you got what you paid for – a CD could hold up to 650mb of storage, which was a unthinkable amount of data back then. The caveat here was that CDs were pressed at the factory, and couldn’t be rewritten.
However, by the mid 90s, the production costs of CDs were dropping quickly, and the average person was buying CDs regularly. As costs dropped, another technology that took off was the writable CD – a blank CD anybody could write to, provided they had a burner and the requisite software. That initially was around $1000 in the early to mid 90s, but that price quickly dropped too.
Writable CD media, coincidentally, rose around the same time as the mass adoption of the internet. It didn’t take long before people to put two and two together and realize that they could “rip” a CD of its contents and share it to people over the internet. The problem here is going back to the media – CDs, being the audiophile media, usually contained uncompressed audio. A full length album could easily fill all 650mb. A typical hard drive of the mid 90s was around 500mb; nevermind that most people were also on a 56k modem – averaging .056 Mbps.
The compromise here was that eventually people selected a new file type for the ripped media to share online, one that could drastically reduce audio file sizes. That’s where MP3 came in – it was a file type that could drastically reduce the file size through compression at the cost of audio quality, but that was obviously a trade people were willing to make then in order to share and download music over the internet.
The factory pressed CDs used the Red Book Audio standard, which was a very specific way that you had order and structure the contents in order to be able to be read by a CD player. A “normal” CD player at the time, therefore, couldn’t actually play the MP3s because it wasn’t the Red Book that the player expected. Manufacturers quickly begin to understand the demand though, and added the ability for CD players to begin playing MP3s. Eventually companies realized that the “CD” part of this whole process was unnecessary – which led to the creation of the MP3 player and the rest is history.
Latest Answers