Telecommunications & Signal Processing Laboratory
AFsp Programs and Routines
The AFsp package provides audio file utility programs
and a library of routines for reading and writing audio files.
Audio File Utilities:
- CompAudio
- Compare audio files, producing statistics and signal-to-noise
ratio figures.
- CopyAudio
- Copy audio files. This program combines samples from input
audio files (an arbitrary linear combination) and writes them
to the output file in a user selectable format. One application
is to provide format conversion for an audio file; another is
to combine or select samples from multi-channel files.
- FiltAudio
- Filter audio files. This program filters an audio file with
an FIR, IIR or all-pole filter. This program can be used with
an appropriate filter for sample rate conversion. The AFsp
package includes a number of filters from the ITU-T Software
Tool Library (G.191) in a form that can be used directly
with the FiltAudio program.
- GenNoise
- Generate noise. This program generates an audio file containing
Gaussian white noise.
- GenTone
- Generate a sinusoid. This program generates an audio file
containing a sine wave of a given amplitude and frequency.
- InfoAudio
- Display information about an audio file.
- LPanal
- Demonstration program to do LPC analysis on a speech file.
- LPsyn
- Demonstration program to do LPC synthesis from a residual
file.
- ResampAudio
- Resample data from an audio file. This process involves interpolating
between the samples in the original file to create a new sequence
of samples with a new spacing (sampling rate).
Audio File Library Routines:
The audio file open routine automatically senses the input
file type. The data format for the file is passed to the audio
file reading routines. The audio file reading routine does byte
swapping and format conversion on the fly as the file is read.
The user sees float data without needing to worry about the underlying
data format.
Once a file is opened for writing, the user calls routines
which take the user's float data and do byte swapping and format
conversion of the data transparently.
The library routines supplied in AFsp package form part
of the libtsp signal processing library. The AFsp routines
are written in C and have been tested on Unix and Windows.
- AFclose
- Close an audio file
- AFopenRead
- Open an audio file for reading
- AFopenWrite
- Open an audio file for writing
- AFreadData
- Read data from an audio file (return float values)
- AFsetFileType
- Explicitly set the input audio file type
- AFsetHinfo
- Set the audio file header information string
- AFsetNHpar
- Set defaults for headerless audio files
- AFwriteData
- Write data to an audio file (float input values)
Audio File Formats:
The following file formats are supported for reading.
- Headerless audio files
- AU audio files
- RIFF WAVE files
- AIFF/AIFF-C audio files
- NIST SPHERE audio files
- IRCAM soundfiles
- INRS-Telecom audio files
- ESPS sampled data feature files
- Comdisco SPW Signal files
- Text audio files
The following file formats are supported for writing.
- Headerless audio files (including text data)
- AU audio files
- RIFF WAVE files
- AIFF-C audio files
Audio File Data Types:
The following (uncompressed) data types are supported.
- 8-bit mu-law and A-law
- 8-bit signed and unsigned fixed-point
- 9-bit to 32-bit signed fixed-point
- 32-bit floating-point
- 64-bit floating-point
- text data