Linux Certif

Toute la documentation sur la certification Linux LPI

audiotool

NAME

audiotool - manipulate telephony audio files.

SYNOPSIS

audiotool [options] command files...

DESCRIPTION

The audiotool command is used to examine and manipulate telephony audio files such as those which might be used in GNU Bayonne. It can be used to convert audio to different formats or join audio files together as well. Current releases of audiotool do not support resampling, and are principally focused on either raw audio samples or SUN .au contained audio. In the future .wav contained audio files may also be supported.

OPTIONS

-buffer msecs

Specify ``size'' of user space buffering in milliseconds. Buffering is used to reduce how frequently user space audio data has to be pushed into kernel space file operations. Because some codecs and conversions have fixed and specific frame sizes, you want to choose a value that will be a good multiplier of any possible codec that might be used. The default is 120 milliseconds, which is good for the list of suggested framing values. This also allows for predictive I/O scheduling.

-codecs

Lists codec channel encoding formats that are supported.

-encoding format

Specify the encoding format that audiotool will use for internal operations. Files opened in different encoding formats will be transcoded to this format if possible. The default is pcmu. The list of supported formats is shown with the -codecs option.

-framing msecs

Specify audio framing in milliseconds. Generally you should use values like 10, 15, 20, 30, 50, or 60 milliseconds. If no framing is used, then the default requirements of the codec will be selected, and this is often 20 milliseconds. Some commands are only supported if ulaw or linear is chosen.

-help

Outputs help screen for the user.

-note ``text''

Specify a file annotation when creating a new file.

-output format

Specify the output encoding that audiotool wil use for creating a new file such as for the create command. This is useful when it cannot be determined from the file extension alone, such as when one wants to use a specific codec format for creating a .au file.

-verbose

Display extra debugging information for some commands.

-version

Outputs package version and copyright notice.

COMMANDS

append newfile files...

Append to existing audio file, converting other files in the process.

create newfile files...

Create a new audio file, converting existing files in the process. The encoding for the target file might be specified by the file extension, or optionally through the -output option.

info files...

Output core library information and (when verbose) buffering stats for each of the files listed. When used verbose, this can be useful to better understand how buffering factors and framing works as well.

pipe files...

Pipe the raw output of the specified files to stdout based on the channel encoding format. The encoding format is by default 8khz ulaw, and hence the output can be directly piped to and played on a oss /dev/audio or sun audio device if the format is left unchanged.

text file

Output the annotation stored in a SUN .au (and later .wav) file.

verify file

Tests if audio file is readable. If used verbose, it will report frames read successfully vs I/O context switches to kernel space.

EXIT STATUS

Normally exit status is 0 if the request was successfully processed by the sipwitch service daemon. An exit status of 1 indicates a file referenced does not exist or cannot be accessed. A 2 indicates that the encoding format of the specified file is unsupported or cannot be converted. An exit status of 3 indicates an I/O failure happened. Any command syntax error will return a 4.

AUTHOR

audiotool was written by David Sugar <dyfet@gnutelephony.org>.

REPORTING BUGS

Report bugs to sipwitch-devel@gnu.org.

COPYRIGHT

Copyright © 2009 David Sugar, Tycho Softworks.
This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.