The meaning of "capture"
The recording to be captured must be played, for example on a turntable, while being simultaneously converted to a digital file for subsequent processing. Hooking the audio system into the computer may be as simple as plugging a 3.5mm stereo jack into the computer's sound input socket. The possibilities are endless, and beyond the scope of this site. For a thorough treatment of everything you need to know, from connecting your audio system to your computer, to editing and burning CDs, I recommend reading Clive Backham's and/or Alan Reny's web pages.
These page are confined to a few important things you need to know if you want to use the software on this site as part of the restoration process.
In order to use the audio restoration software on this site, you must first capture the audio as uncompressed sound files, 16 or 24 bit, in either AIFF or WAVE format. My applications will accept either mono or stereo files, with a sample rate up to 192 kHz. The minimum I would recommend in any case is CD quality (see below). Capture at 24 bits rather than 16 bits makes subsequent processing much easier, since it may be made at a lower level, to avoid overloading and clipping. The level is then restored, using an audio editor, as the last step. If you want to do the restoration at a higher sample rate, 96kHz is a good choice. I do not recommend 48kHz if you intend to subsequently down-sample to 44.1kHz, although it is fine for other purposes.
As a reference, note that CDs use a sample size of 16 bits and a sample rate of 44.1kHz (44100 samples per second). This gives a theoretical dynamic range of about 80dB, and a theoretical maximum frequency of 22kHz, just adequate for the full range of human auditory perception. Nowadays , good players are available, making the standard CD perfectly acceptable to the majority of music listeners.