Glossary

From Audacity Development Manual
Revision as of 20:27, 10 January 2008 by Windinthew (talk | contribs) (added ADC and DAC placeholders)
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This page gives very brief explanations of these terms, with some links to Wikipedia for much more comprehensive explanations.

ToDo We need to decide how to anchor all the glossary entries. The easy way is with <H5> headers. It isn't very space-efficient (even in a table, doing which may have accessibility issues) but I think if not in a table it may be less tiring on the eye for actually reading chunks of it? The AllowAnchorTags extension might help, if  it works with <a name> as well as <a href>. See the examples below.

Even after 1.4.0 if needs be, we must also have an Index. And when we do, I think these terms are part of it (because of the overlap between the Index to our pages and the Glossary items). -Gale

I was hoping to get it so that clicking on Wikipedia1.png would take you to the relevant wikipedia page. This is just an idea. Happy to see other formats tried on other parts of the table, and then we pick whatever we like best -James. I know of no way on a Wiki where you can click on an image and do other than go to the image. This is the big problem with the "Audacity for the Impatient" image. I can get rid of the pointed arrow, but won't the export saddle us with the [1], [2] anyway? If it does not do so, then are we fussed about having external links looking different to links internal to this Wiki? It may be easier to color the Wiki links as #339966 which is a color associated with Wikipedia. Gale

General Terms

Link Term Description
 
ADC:
 
Algorithm:
 
Audacity Project Format (.aup):
 
Audio CDs:
Wikipedia1.png[1] Amplitude:
Bit
Bit Rate:

The number of computer bits that are conveyed or processed per unit of time. Normally expressed in kilobits per second (kbps).

CBR:
Cepstrum:

Some description here. It's kinda like a logarithm of a Fourier transform. Gotta getta better description [2]

Clipping:
  • Compressed Audio Format:
  • Compression:
  • Cycle:
  • DAC:
  • Data CDs:
  • dB: (decibels) A logarithmic unit (typically of sound pressure) describing the ratio of that unit to a reference level.
  • Dynamic Range: The difference between the loudest and softest part in an audio recording, the maximum possible being determined by its sample format. For a device, the difference between its maximum possible undistorted signal and its Noise Floor.
  • FFT: (Fast Fourier Transform). A method for performing Fourier transforms (see below) quickly.
  • Filter: A sound effect that lets some frequencies through and suppresses others.
  • Fourier Transform: A method for converting a waveform to a spectrum, and back.
  • Frequency: Audio frequency determines the pitch of a sound. Measured in Hz (see below), higher frequencies have higher pitch.
  • Gain:
  • Interpolation:
  • Harmonics: Most sounds are made up of a mix of different frequencies. In musical sounds, the component frequencies are simple multiples of each other, for example 100Hz, 200Hz, 300Hz. These are called harmonics of the lowest frequency sound.
  • High Pass Filter: A filter that lets high frequencies through.
  • Hz (Hertz): Measures a frequency event in number of cycles per second. See Frequency and Sample Rate, both of which are measured in Hz.
  • LAME:
  • Linear:
  • Logarithmic:
  • Lossless:
  • Lossy:
  • Low Pass Filter: A filter that lets low (bass) frequencies through.
  • MP3 CDs:
  • Noise Floor:
  • Pitch:
  • RMS:
  • Sample Rate: Measured in Hz like Frequency, this represents the number of digital samples captured per second in order to represent the waveform.
  • Sample Format: Also known as Bit Depth. The number of computer bits present in each audio sample. Determines the dynamic range of the audio.
  • Spectrum: Presentation of a sound in terms of its component frequencies.
  • Uncompressed Audio Format:
  • VBR:
  • Waveform:
  • Wavelength:

Audio File Formats

Unsure if a separate section is a good idea given I think we need entries for lossy/lossless and uncompressed / compressed audio format in the main glossary (e.g. to explain difference between audio signal and audio file compression). A lot depends if we have Audio File Formats as one page as an appendix. Play it by ear but I don't think this table has quite enough detail for each format at the moment, even with a Wikipedia link.- Gale
ToDo As we have now decided not to have separate pages for the different formats (only separate pages for format export options), we need to rethink where these Glossary entries link to - best left until we decide if we have an appendix containing details of "audio file formats" - Gale
Term Description
Wikipedia1.png
AIFF
Wikipedia1.png
FLAC: An Open Source lossless compressed audio format [3]
Wikipedia1.png
MIDI: A format for audio which represents individual notes. Usually MIDI audio files are captured from a keyboard instrument as pitch and duration of keys pressed, rather than being captured from the sound. [4]
Wikipedia1.png
MP2: A compressed audio format [5]
Wikipedia1.png
MP3: A compressed audio format [6]
Wikipedia1.png
Ogg Vorbis: An Open Source compressed audio format [7]
Wikipedia1.png
WAV: An uncompressed audio format [8]