The sample rate of an audio signal refers to how often an analog waveform is sampled each second. The higher the sample rate, the closer the match to the original analog wave.
In audio theory, the upper limit of frequencies that can be adequately represented by a given sample rate is called the Nyquist frequency. Human hearing is typically limited to sounds of frequency 22kHz or less. To represent this Nyquist frequency, the sample rate must be at least double this. So a frequency of 44.1 kHz–he sample rate used in traditional compact disc mastering–is considered sufficient to faithfully reproduce everything a human can hear.
However, since higher frequency sounds can interact with the listening environment to produce lower frequency sounds, there is a trend to higher sample rates for more faithful sounds reproduction and processing. Common sample rates for audio production are 96kHz and 192kHz.
bit depth – see analog v. digital
broadcast safe refers to a video signal that conforms to a given regional broadcast specification. It sets specific voltage levels for the blacks and whites of a video image, as well as the colors that can be accurately represented in the broadcast signal. Different specifications exist for different regions and formats. Broadcast safe specifications include standards for both audio and video formatting.
Color grading and non-linear editing software include waveforms and vectorscopes to analyze an image for broadcast safe compliance, as well as tools to adjust or clamp images in violation of the standards.