Beginners guide to Praat

Quick guide to sound file formats


[Contents][Quick guides][File formats]

Praat saves and reads nearly a dozen widely recognised sound file formats, including:

  • AIFC: A sound file format for Macintosh. N.b. Praat does not compress AIFC files and does not read compressed AIFC files
  • AIFF: Also for Macintosh
  • Binary: a standard format for sound files, independent of computer system (if nothing else works, this could be a way of exporting data to other programs on other systems)
  • Kay: The format used by Computer Speech Laboratory (Kay Corporation)
  • NeXT/Sun: A format used by NeXT computers and Sun computers
  • NIST: A format used by the TIMIT data base (American English, produced by Texas Instruments and Massachussetts Institute of Technology)
  • WAV: A format for Microsoft Windows

Your choice of format is mainly determined by what is recognised by your computer and its sound system, and by any external program you intend to use your data with

As long as you are only using Praat you are free to use at least AIFC (uncompressed), NeXT, NIST, or WAV, since the program can read them all independently of any computer system you may happen to move between

  • Atrac, MP3: Strictly speaking these are methods for sound data compression used in minidisk recorders (Atrac is exclusive to Sony products), but files downloaded from the recorders are still in the respective compression format.  Praat does not handle either format, so compressed files will need to be converted to one of the formats listed above. For Atrac you need the software supplied with the device. MP3 is a more general format and conversion is available in various commercial or shareware sound editing programs or CD burning programs (or your sound system might be able to do it).
    • Warning: Both methods use lossy compression that degrades the original sound, which limits their usefulness for speech analysis (you cannot be sure that what you want to analyse and measure has not been altered). Atrac is said to be closer to the original sound than MP3, but the intended use of both formats is listening to music from personal stereo players under "normal" conditions (i.e. small earphones in noisy public places). They are not intended for faithful recording of speech for research or for hifi enjoyment. If you are tempted, remember that fieldwork is more expensive than cheap taperecorders.
      • Make comparative tests before you do fieldwork, to make sure that the specific speech characteristics you intend to measure have not been degraded.
      • Mark all compressed recordings and subsequent decompressed sound files as having been compressed at some time, so that no-one will think they are full quality. Better still, include and keep the method in filenames. A filename like dagestaniMP3.wav will always remind you how the recording was acquired.
    • Warning: The degradation is multiplied every time a recording is converted to and fro, so conversion must be a once-only trip, from a compressed file and never back again.

 


[Contents][Quick guides][File formats]

Praat for beginners - Sidney Wood - 2 Oct 2004

 Copyright (c) 1995-2004 Sidney Wood. All rights reserved.