--------------------------------------------------------------------- README file for Audio::Wav (0.06). --------------------------------------------------------------------- Modules for reading & writing Microsoft WAV files. --------------------------------------------------------------------- INSTALLATION --------------------------------------------------------------------- tar zxvf Audio-Wav-0.06.tar.gz cd Audio-Wav-0.06 perl Makefile.PL make test make install --------------------------------------------------------------------- DOCUMENTATION --------------------------------------------------------------------- Audio::Wav Modules for reading & writing Microsoft WAV files. --------------------------------------------------------------------- NAME Audio::Wav - Modules for reading & writing Microsoft WAV files. SYNOPSIS # copying a file and adding some cue points to the output file use Audio::Wav; my $wav = new Audio::Wav; my $read = $wav -> read( 'input.wav' ); my $write = $wav -> write( 'output.wav', $read -> details() ); print "input is ", $read -> length_seconds(), " seconds long\n"; $write -> set_info( 'software' => 'Audio::Wav' ); my $data; #read 512 bytes while ( defined( $data = $read -> read_raw( 512 ) ) ) { $write -> write_raw( $data ); } my $length = $read -> length_samples(); my( $third, $half, $twothirds ) = map int( $length / $_ ), ( 3, 2, 1.5 ); my %samp_loop = ( 'start' => $third, 'end' => $twothirds, ); $write -> add_sampler_loop( %samp_loop ); $write -> add_cue( $half, "cue label 1", "cue note 1" ); $write -> finish(); # splitting a multi-channel file to seperate mono files (slowly!); use Audio::Wav; my $read = $wav -> read( '4ch.wav' ); my $details = $read -> details(); my %out_details = map { $_ => $details -> {$_} } 'bits_sample', 'sample_rate'; $out_details{'channels'} = 1; my @out_files; my $in_channels = $details -> {'channels'}; foreach my $channel ( 1 .. $in_channels ) { push @out_files, $wav -> write( 'multi_' . $channel . '.wav', \%out_details ); } while ( 1 ) { my @channels = $read -> read(); last unless @channels; foreach my $channel_id ( 0 .. $#channels ) { $out_files[$channel_id] -> write( $channels[$channel_id] ); } } # not entirely neccessary as finish is done in DESTROY now (if the file hasn't been finished already). foreach my $write ( @out_files ) { $write -> finish(); } NOTES All sample positions are now in sample offsets (unless option '.01compatible' is true). There is now *very* basic support for WAVEFORMATEXTENSIBLE (in fact it only recognises that the file is in this format). The key 'wave-ex' is used in the detail hash to denote this format when reading or writing. I'd like to do more with this, but don't have any hardware or software to test these files, also don't really have any spare time to do the implementation at present. One day I plan to learn enough C to do the sample reading/ writing in XS, but for the time being it's done using pack/ unpack in Perl and is slow. Working with the raw format doesn't suffer in this way. It's likely that reading/ writing files with bit-depth greater than 16 won't work properly, I need to look at this at some point. DESCRIPTION These modules provide a method of reading & writing uncompressed Microsoft WAV files. METHODS new Returns a blessed Audio::Wav object. All the parameters are optional and default to 0 my %options = ( '.01compatible' => 0, 'oldcooledithack' => 0, 'debug' => 0, ); my $wav = Audio::Wav -> new( %options ); write Returns a blessed Audio::Wav::Write object. my $details = { 'bits_sample' => 16, 'sample_rate' => 44100, 'channels' => 2, }; my $write = $wav -> write( 'testout.wav', $details ); See Audio::Wav::Write for methods. read Returns a blessed Audio::Wav::Read object. my $read = $wav -> read( 'testout.wav' ); See Audio::Wav::Read for methods. set_error_handler Specifies a subroutine for catching errors. The subroutine should take a hash as input. The keys in the hash are 'filename', 'message' (error message), and 'warning'. If no error handler is set, die and warn will be used. sub myErrorHandler { my( %parameters ) = @_; if ( $parameters{'warning'} ) { # This is a non-critical warning warn "Warning: $parameters{'filename'}: $parameters{'message'}\n"; } else { # Critical error! die "ERROR: $parameters{'filename'}: $parameters{'message'}\n"; } } $wav -> set_error_handler( \&myErrorHandler ); --------------------------------------------------------------------- Audio::Wav::Read Module for reading Microsoft WAV files. --------------------------------------------------------------------- NAME Audio::Wav::Read - Module for reading Microsoft WAV files. SYNOPSIS use Audio::Wav; my $wav = new Audio::Wav; my $read = $wav -> read( 'filename.wav' ); OR my $read = Audio::Wav -> read( 'filename.wav' ); my $details = $read -> details(); DESCRIPTION Reads Microsoft Wav files. SEE ALSO Audio::Wav Audio::Wav::Write NOTES This module shouldn't be used directly, a blessed object can be returned from Audio::Wav. METHODS file_name Returns the file name. my $file = $read -> file_name(); get_info Returns information contained within the wav file. my $info = $read -> get_info(); Returns a reference to a hash containing; (for example, a file marked up for use in Audio::Mix) { 'keywords' => 'bpm:126 key:a', 'name' => 'Mission Venice', 'artist' => 'Nightmares on Wax' }; get_cues Returns the cuepoints marked within the wav file. my $cues = $read -> get_cues(); Returns a reference to a hash containing; (for example, a file marked up for use in Audio::Mix) (position is sample position) { 1 => { label => 'sig', position => 764343, note => 'first' }, 2 => { label => 'fade_in', position => 1661774, note => 'trig' }, 3 => { label => 'sig', position => 18033735, note => 'last' }, 4 => { label => 'fade_out', position => 17145150, note => 'trig' }, 5 => { label => 'end', position => 18271676 } } read_raw Reads raw packed bytes from the current audio data position in the file. my $data = $self -> read_raw( $byte_length ); read_raw_samples Reads raw packed samples from the current audio data position in the file. my $data = $self -> read_raw_samples( $samples ); read Returns the current audio data position sample across all channels. my @channels = $self -> read(); Returns an array of unpacked samples. Each element is a channel i.e ( left, right ). The numbers will be in the range; where $samp_max = ( 2 ** bits_per_sample ) / 2 -$samp_max to +$samp_max position Returns the current audio data position (as byte offset). my $byte_offset = $read -> position(); position_samples Returns the current audio data position (in samples). my $samples = $read -> position_samples(); move_to Moves the current audio data position to byte offset. $read -> move_to( $byte_offset ); move_to_sample Moves the current audio data position to sample offset. $read -> move_to_sample( $sample_offset ); length Returns the number of bytes of audio data in the file. my $audio_bytes = $read -> length(); length_samples Returns the number of samples of audio data in the file. my $audio_samples = $read -> length_samples(); length_seconds Returns the number of seconds of audio data in the file. my $audio_seconds = $read -> length_seconds(); details Returns a reference to a hash of lots of details about the file. Too many to list here, try it with Data::Dumper..... use Data::Dumper; my $details = $read -> details(); print Data::Dumper->Dump([ $details ]); reread_length Rereads the length of the file in case it is being written to as we are reading it. my $new_data_length = $read -> reread_length(); --------------------------------------------------------------------- Audio::Wav::Write Module for writing Microsoft WAV files. --------------------------------------------------------------------- NAME Audio::Wav::Write - Module for writing Microsoft WAV files. SYNOPSIS use Audio::Wav; my $wav = new Audio::Wav; my $sample_rate = 44100; my $bits_sample = 16; my $details = { 'bits_sample' => $bits_sample, 'sample_rate' => $sample_rate, 'channels' => 1, # if you'd like this module not to use a write cache, uncomment the next line #'no_cache' => 1, }; my $write = $wav -> write( 'testout.wav', $details ); &add_sine( 200, 1 ); sub add_sine { my $hz = shift; my $length = shift; my $pi = ( 22 / 7 ) * 2; $length *= $sample_rate; my $max_no = ( 2 ** $bits_sample ) / 2; for my $pos ( 0 .. $length ) { $time = $pos / $sample_rate; $time *= $hz; my $val = sin $pi * $time; my $samp = $val * $max_no; $write -> write( $samp ); } } $write -> finish(); DESCRIPTION Currently only writes to a file. SEE ALSO Audio::Wav Audio::Wav::Read NOTES This module shouldn't be used directly, a blessed object can be returned from Audio::Wav. METHODS finish Finishes off & closes the current wav file. $write -> finish(); add_cue Adds a cue point to the wav file. If $sample is undefined then the position will be the current position (end of all data written so far). # $byte_offset for 01 compatibility mode $write -> add_cue( $sample, "label", "note" ); set_sampler_info All parameters are optional. my %info = ( 'midi_pitch_fraction' => 0, 'smpte_format' => 0, 'smpte_offset' => 0, 'product' => 0, 'sample_period' => 0, 'manufacturer' => 0, 'sample_data' => 0, 'midi_unity_note' => 65, ); $write -> set_sampler_info( %info ); add_sampler_loop All parameters are optional except start & end. my $length = $read -> length_samples(); my( $third, $twothirds ) = map int( $length / $_ ), ( 3, 1.5 ); my %loop = ( 'start' => $third, 'end' => $twothirds, 'fraction' => 0, 'type' => 0, ); $write -> add_sampler_loop( %loop ); add_display set_info Sets information to be contained in the wav file. $write -> set_info( 'artist' => 'Nightmares on Wax', 'name' => 'Mission Venice' ); file_name Returns the current filename. my $file = $write -> file_name(); write Adds a sample to the current file. $write -> write( @sample_channels ); Each element in @sample_channels should be in the range of; where $samp_max = ( 2 ** bits_per_sample ) / 2 -$samp_max to +$samp_max write_raw Adds some pre-packed data to the current file. $write -> write_raw( $data, $data_length ); Where; $data is the packed data $data_length (optional) is the length in bytes of the data write_raw_samples Adds some pre-packed data to the current file, returns number of samples written. $write -> write_raw_samples( $data, $data_length ); Where; $data is the packed data $data_length (optional) is the length in bytes of the data --------------------------------------------------------------------- AUTHORS --------------------------------------------------------------------- Brian Szymanski (0.07-0.08) Nick Peskett (see http://www.peskett.co.uk/ for contact details). Kurt George Gjerde . (0.02-0.03) --------------------------------------------------------------------- END ---------------------------------------------------------------------