Before we go on with Plone and see how we can enhance the story of audio processing and manipulate audio data, we will glance at audio formats. We will see how raw audio data is compressed to enable effective audio storage and streaming. We need to have some basic audio know-how about some of the terminology to understand how we can effectively process audio for our own purposes.
As with images, there are several formats in which audio content can be stored. We want to learn a bit of theoretical background. This eases the decision of choosing the right format for our use case.
An analog acoustic signal can be displayed as a wave:
If digitalized, the wave gets approximated by small rectangles below the curve. The more rectangles are used the better is the sound (fidelity) of the digital variant. The width of the rectangles is called the sampling rate.
44.1 kHz (44,100 samples per second): CD quality
32 kHz: Speech
14.5 kHz: FM radio bandwidth
10 kHz...