Ripping: Encyclopedia II - Ripping - Ripping speed

Ripping - Ripping speed

The speed at which a CD or DVD can be ripped is often expressed as a multiplier: 12X (means 12 times faster than just playing it). Important in estimating ripping speeds are:

• the media-player's speed: a CD has a maximum rotation speed (so it does not break due to rotational forces) and the media players get closer and closer to that limit (e.g. a player that can read a CD at 60x the normal speed). It is also important where the laserhead is. It starts reading closest to the center (lowest bitrate for a given rotation speed) and goes to the border of the CD (highest bitrate)
• the interface between the player and the encoding device: this might be extremely fast (SCSI) to very slow (USB 1.1 or even over an Ethernet network)
• the encoding device (in most cases a PC) will encode the digital input to a compressed format. This is a purely CPU-related task, so a Pentium III running at 120MHz will do that twice as fast as a similar 60MHz chip. Some CPU architectures are better suited than others for encoding (e.g. a Pentium 4 will be faster than a Celeron with the same clock speed, or AMD Sempron with the same PR rating)
• the encoding algorithm/quality: WMA encoding is generally faster than MP3, 64 kbit/s encoding might be faster/slower than 192 kbit/s
• the compressed file is then written to a disk. Again this might be very fast (SCSI or FireWire) or rather slow (over 10 Mbit/s Ethernet or to a flash card)
• Some rippers, like Exact Audio Copy will rip multiple times and compare the result to make sure that the ripped file is accurate. This slows down the ripping but will make sure that the output is an accurate copy, and let the user know if the output has any faults.

The combination of these elements will define what the maximum ripping speed is.

Adapted from the Wikipedia article "Ripping speed", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki