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HP-UX 11i Version 3: February 2007

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convert — convert an audio file


/opt/audio/bin/convert [source_file] [target_file] [-sfmt format ] [-dfmt format ] [-ddata data_type ] [-srate rate ] [-drate rate ] [-schannels number ] [-dchannels number ]


This command converts audio files from one supported file format, data format, sampling rate, and number of channels to another. The unconverted file is retained as a source file.

-sfmt format -dfmt format

are the file formats for the source and destination files. Each format can be one of these:


Sun file format


NeXT file format


Microsoft RIFF Waveform file format


MuLaw format




linear 16-bit format


offset (unsigned) linear 8-bit format


linear 8-bit format

If you omit -sfmt, convert uses the header or filename extension in the source file. You can omit -dfmt if you supply a filename extension for the destination file.

-ddata data_type

is the data type for the destination files. data_type can be one of these:






linear 16-bit


offset (unsigned) linear 8-bit data


linear 8-bit data

If you omit -ddata, convert uses an appropriate data type, normally the data type of the source file.

-srate rate -drate rate

are the number of samples per second for the source and destination file. Typical sampling rates range from 8 to 11k (for voice quality) to 44,100 (for CD quality). You can use k to indicate thousands. For example, 8k means 8,000 samples per second.

If you omit -srate, convert uses a rate defined by the source file header or its filename extension. For a raw file with no extension, 8,000 is used. By playing the file, you can determine if 8,000 samples is too fast or too slow.

If you omit -drate, convert uses a sampling rate appropriate for the destination file format; if possible, it matches the sampling rate of the source file.

-schannels number -dchannels number

are the number of channels in the source and destination files. Use 1 for mono; 2 for stereo. If -schannels is omitted, convert uses the information in the header; for raw data files, it uses mono.

If -dchannels is omitted, convert matches what was used for the source file (through the header or -schannels option); for raw data files, it uses mono.


Convert a raw data file to a headered file.

cd /opt/audio/bin convert beep.l16 beep.au

Convert a raw data file to a headered file when the source has no extension, was sampled at 11,025 per second, and has stereo data.

cd /opt/audio/bin convert beep beep.au -sfmt l16 -srate 11025 -schannels 2

To save disk space, convert an audio file with CD quality sound to voice quality sound.

cd /opt/audio/bin convert idea.au idea2.au -ddata u -drate 8k -dchannels 1


convert was developed by HP.

Sun is a trademark of Sun MicroSystems, Inc.

NeXT is a trademark of NeXT Computers, Inc.

Microsoft is a trademark of Microsoft Corporation.


attributes(1), send_sound(1), asecure(1M), aserver(1M), Audio(5).

Using the Audio Developer's Kit

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