lib-audio-resample

Wrapper for libsamplerate (AKA Secret Rabbit Code).

Dependencies

You'll need the libsamplerate library.

On Ubuntu distributions;

sudo apt install libsamplerate0-dev

Note

Currently limited to 16 bit audio.

Installation

perl Makefile.PL
make test
sudo make install

Example

use Nick::Audio::Resample '%SR_QUALITY';
use Nick::Audio::FLAC;
use Nick::Audio::PulseAudio;

my $sample_rate_out = 48000;

my( $buff_in, $buff_out );
my $flac = Nick::Audio::FLAC -> new(
    'test.flac',
    'buffer_out' => \$buff_in
);

my $resample = Nick::Audio::Resample -> new(
    'rate_in'       => $flac -> get_sample_rate(),
    'rate_out'      => $sample_rate_out,
    'channels'      => $flac -> get_channels(),
    'buffer_in'     => \$buff_in,
    'buffer_out'    => \$buff_out,
    'quality'       => $SR_QUALITY{'MEDIUM'}
);

my $pulse = Nick::Audio::PulseAudio -> new(
    'sample_rate'   => $sample_rate_out,
    'channels'      => $flac -> get_channels(),
    'buffer_in'     => \$buff_out
);

while ( $flac -> read() ) {
    $resample -> process()
        and $pulse -> play();
}
$resample -> process( 1 )
    and $pulse -> play();

Methods

new()

Instantiates a new Nick::Audio::Resample object.

Arguments are interpreted as a hash.

There are three mandatory keys.

• rate_in

  Sample rate of PCM data read from buffer_in.

• rate_out

  Sample rate of PCM data written to buffer_out.

• channels

  Number of audio channels.

The following are optional.

• buffer_in

  Scalar that'll be used to read PCM audio from.

• buffer_out

  Scalar that'll be used to read PCM audio from.

• quality

  Value from 0 to 4, with 0 being the best quality.

  You can import the %SR_QUALITY hash which has the aliases BEST, MEDIUM, FASTEST, ZERO_ORDER_HOLD and LINEAR.

  default: 0

process()

Reads PCM audio from buffer_in and possibly writes resampled audio to buffer_out, returning number of bytes of PCM written to buffer_out.

If the optional argument is 1, any buffers will be flushed.

get_buffer_in_ref()

Returns the scalar currently being used to read PCM audio from.

get_buffer_out_ref()

Returns the scalar currently being used to write PCM audio to.