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Audio::ESD - Perl extension for talking to the Enlightened Sound Daemon |
Audio::ESD - Perl extension for talking to the Enlightened Sound Daemon
use Audio::ESD;
my $stream = Audio::ESD->play_stream({ # these are the defaults
sample_rate => 16000,
channels => 1,
fallback => 0,
bits_sample => 16,
encoding => 'linear' })
or die "Failed to open ESD stream: $!\n";
print $stream $data; # etcetera
This module provides a Perl wrapper around the Enlightened Sound Daemon's client library. Input, output, and monitoring streams are supported, as well as some (but not all) of the control functions. Samples are supported but untested.
Audio streams can be opened for playback, recording, monitoring, or filtering. There are separate `constructor' class methods for doing all of these things. All of these methods accept a single optional argument, which is a reference to a hash possibly containing the following stream parameters (defaults are supplied if the parameters are not present):
To open a stream for playback, use play_stream:
my $stream = Audio::ESD->play_stream(\%opts);
This method also supports an extra option, 'fallback'. If this is true, the Esound library will ``fall back'' to the local audio device if a connection to the ESD server could not be made (or so the documentation says, at least).
To open a stream for recording, use record_stream:
my $stream = Audio::ESD->record_stream(\%opts);
This method also supports the 'fallback' option.
To open a stream for monitoring (i.e. capturing the mixed output stream from the server), use monitor_stream:
my $stream = Audio::ESD->monitor_stream(\%opts);
To open a stream for filtering, use filter_stream:
my $stream = Audio::ESD->filter_stream(\%opts);
Apparently, this allows you read blocks of data from the output stream, do some transformations on them, then write them back, and have ESD play them.
To open a general-purpose control connection to the ESD server, use the open_sound class method:
my $esd = Audio::ESD->open_sound($hostname);
If $hostname is undefined, a local ESD will be contacted via a Unix
domain socket.
As with the audio streams, you can read and write to this connection as if it were a normal filehandle (since, in fact, that is what it is...) and thus, if you want to take your chances with the ``over-the-wire'' protocol you are free to do so.
However, you most likely just want to use this connection to access various parameters in the server, and don't worry, there are some methods for that:
$esd->send_auth();
$esd->lock();
$esd->unlock();
$esd->standby();
$esd->resume();
$esd->sample_cache($format, $rate, $length, $name);
$esd->confirm_sample_cache();
my $sample_id = $esd->sample_getid($name);
$esd->sample_play($sample_id);
$esd->sample_loop($sample_id);
$esd->sample_stop($sample_id);
$esd->sample_free($sample_id);
$esd->set_stream_pan($stream_id, $left_scale, $right_scale);
$esd->set_default_sample($stream_id, $left_scale, $right_scale);
my $latency = $esd->get_latency();
my $standby = $esd->get_standby_mode();
my $server_info = $esd->get_server_info();
my $info = $esd->get_all_info();
$server_info->print_server_info();
$info->print_all_info();
The following constants can be imported from Audio::ESD. They are
mostly useful for the format argument to some functions. You can
import all of them with the :standard tag.
ESD_ADPCM
ESD_BITS16
ESD_BITS8
ESD_BUF_SIZE
ESD_DEFAULT_PORT
ESD_DEFAULT_RATE
ESD_ENDIAN_KEY
ESD_KEY_LEN
ESD_LOOP
ESD_MASK_BITS
ESD_MASK_CHAN
ESD_MASK_FUNC
ESD_MASK_MODE
ESD_MONITOR
ESD_MONO
ESD_NAME_MAX
ESD_PLAY
ESD_RECORD
ESD_SAMPLE
ESD_STEREO
ESD_STOP
ESD_STREAM
ESD_VOLUME_BASE
It probably leaks file descriptors or worse. Lots of stuff is untested and undocumented, and since the Esound API is full of happy surprises it's likely not to work.
David Huggins-Daines <dhd@cepstral.com>
perl(1), esd(1).
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Audio::ESD - Perl extension for talking to the Enlightened Sound Daemon |