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lib/Audio/StreamGenerator.pm  view on Meta::CPAN

=head2 skip_fade_seconds

When 'skipping' to the next song using the L</"skip"> method (for example, after a user clicked a "next song" button on some web interface), we mix less seconds than normally, simply because mixing 5+ seconds in the middle of the old track sounds pre...

=head2 sample_rate

The amount of samples per second (both incoming & outgoing), normally this is 44100 for standard CD-quality audio.

=head2 channels_amount

Amount of audio channels, this is normally 2 (stereo).

=head2 max_vol_before_mix_fraction

This tells StreamGenerator what the minimum volume of a 'loud' sample is. It is expressed as a fraction of the maximum volume.
When mixing 2 tracks, StreamGenerator needs to find out what the last loud sample of the old track is so that it can start the next song immediately after that.

=head2 skip_silence

If enabled, audio softer than L</"min_audible_vol_fraction"> at the beginning of a track, and at the end of tracks (but within the last L</"buffer_length_seconds"> seconds) will be skipped.

=head2 min_audible_vol_fraction

Audio softer than this volume fraction at the end of a track (and within the buffer) or at the beginning of a track will be skipped, if skip_silence is enabled.

=head2 debug

Log debugging information. If the value is a code reference, the logs will be passed to that sub. Otherwise the value will be treated as a boolean. If true, logs will be printed to C<STDERR> .

=head1 METHODS

=head2 stream

    $streamer->stream();

Start the actual audio stream.

=head2 get_streamer

    my $streamer_sub = $streamer->get_streamer($sec_per_call);

    while (1) {
        $streamer_sub->();
    }

Get an anonymous subroutine that will produce C<$sec_per_call> seconds of a stream when called.

C<$sec_per_call> is optional, and is by default C<1>.

Use this method instead of L</"stream"> if you want to have more control over the streaming process, for example, running the streamer inside an event loop:

    use Mojo::IOLoop;

    my $loop = Mojo::IOLoop->singleton;
    my $streamer_sub = $streamer->get_streamer(0.5);

    $loop->recurring(0.05 => $streamer_sub);
    $loop->start;

Note: event loop will be blocked for up to 0.5 seconds every time the timer is done. The timer/streamer ratio should be sizeable enough for the loop to run smoothly, including the mixing process. This may vary depending on the speed of the machine wh...

=head2 skip

    $streamer->skip();

Skip to the next track without finishing the current one. This can be called from the L</"run_every_second"> sub, for example after checking whether a 'skip' flag was set in a database, or whether a file exists.

=head2 get_elapsed_samples

    my $elapsed_samples = $streamer->get_elapsed_samples();
    print "$elapsed_samples played so far\r";

Get the amount of played samples in the current track - this can be called from the L</"run_every_second"> sub.

=head2 get_elapsed_seconds

    my $elapsed_seconds = $streamer->get_elapsed_seconds();
    print "now at position $elapsed_seconds of the current track\r";

Get the amount of elapsed seconds in the current track - in other words the current position in the track. This equals to C<get_elapsed_samples / sample_rate > .