![]() ![]() Because there are only 16 colours to play with, the natural colour of the rabbit photo is reduced to blocks of the nearest available colour in the palette. The above image uses a 4-bit colour palette: that is to say that it is made from 16 colours (15 in binary is 1111 - in other words 4 binary dig its - and zero makes 16). If samples are like frames of animation, bit depth is like the size of the image being animated, or, more accurately, like the number of colours being used in that image.Ī 4-bit colour palette reduces our bunny to blocks of simple colour. In theory, 60 kHz is considered to be more detailed than the human ear can discern, and 48 kHz is considered the standard rate for most uses.īit depth is the amount of information being recorded in each sample. The free sound editing tool Audacity supports rates from 8 kHz to 384 kHz. ![]() That's why CD audio has a sample rate of 44,100 Hz (or 44.1 kHz). A sample rate of 8,000 Hz serves for basic telephone communication (though ess-es sound like effs), but to properly capture human hearing you need to be able to pick up two points in the vibration at the highest pitch we can hear (in other words double 20,000 Hz). Sound needs a lot more frames to be understandable, not least because sound itself is made up of tiny vibrations: human hearing can discern vibrations between 20 and 20,000 Hz as different pitches, so 24 samples per second is not going to come remotely close to replicating the nuances of those sounds. Most cinema film animates at 24 fps (24 Hz): that's sufficient to trick the eye for most humans. The above gif is made up of 15 still images (numbered 2-16) animating at 10 frames per second (10 fps or 10 Hz). The sample rate is the number of samples being made in a given period of time.
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