Mercurial > hg > octave-lyh
diff scripts/audio/loadaudio.m @ 1636:21fe2afb3692
[project @ 1995-11-16 19:16:11 by jwe]
Initial revision
author | jwe |
---|---|
date | Thu, 16 Nov 1995 19:16:11 +0000 |
parents | |
children | 5cffc4b8de57 |
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new file mode 100644 --- /dev/null +++ b/scripts/audio/loadaudio.m @@ -0,0 +1,63 @@ +function X = loadaudio (name, ext, bit) + +# usage: X = loadaudio (name [, ext [, bit]]) +# +# Loads audio data from the file "name.ext" into the data vector X. +# Default value for the "ext" argument, which has to be written +# without the initial ".", is "lin". +# Currently, the following audio formats are supported: +# *) mu-law encoding with extension "mu", "au" or "snd" +# *) linear encoding with extension "lin" or "raw" +# +# The `bit' argument can be either 8 (default) or 16. +# Depending on the value of bit, linearly encoded files are +# interpreted as being in 8 and 16 bit format, respectively, and +# mu-law encoded files are transformed to 8 and 16-bit linear +# format, respectively. + +# Written by AW (Andreas.Weingessel@ci.tuwien.ac.at) on Apr 10, 1994 +# Last modified by AW on Oct 29, 1994 + + if (nargin == 0 || nargin > 3) + usage ("loadaudio (name [, ext [, bit]])"); + endif + + if (nargin == 1) + ext = "lin"; + endif + + if (nargin < 3) + bit = 8; + elseif (bit != 8 && bit != 16) + error ("loadaudio: bit must be either 8 or 16"); + endif + + name = [name, ".", ext]; + num = fopen (name, "r"); + + if (strcmp (ext, "lin") || strcmp (ext, "raw")) + if (bit == 8) + [Y, c] = fread (num, inf, "uchar"); + X = Y - 127; + else + [X, c] = fread (num, inf, "short"); + endif + elseif (strcmp (ext, "mu") || strcmp (ext, "au") || strcmp (ext, "snd")) + [Y, c] = fread (num, inf, "uchar"); + # remove file header + m = max (find (Y(1:64) == 0)); + if (! isempty (m)) + Y(1:m) = []; + endif + X = mu2lin (Y, bit); + else + fclose (num); + error ("loadaudio does not support given extension"); + endif + + fclose (num); + +endfunction + + +