use SDL::Audio ();
and access them directly:
SDL::Audio::AUDIO_S16SYS;
or by choosing the export tags below:
Export tag: ':format'
AUDIO_U8 AUDIO_S8 AUDIO_U16LSB AUDIO_S16LSB AUDIO_U16MSB AUDIO_S16MSB AUDIO_U16 AUDIO_S16 AUDIO_U16SYS AUDIO_S16SYS
Export tag: ':status'
SDL_AUDIO_STOPPED SDL_AUDIO_PLAYING SDL_AUDIO_PAUSED
use SDL; use SDL::Audio; SDL::init(SDL_INIT_AUDIO); my $desired = SDL::AudioSpec->new(); my $obtained; SDL::Audio::open( $desired, $obtained ); # $obtained->... (A new SDL::AudioSpec now);
This function opens the audio device with the desired parameters, and returns 0 if successful, placing the actual hardware parameters in the structure pointed to by obtained. If obtained is NULL, the audio data passed to the callback function will be guaranteed to be in the requested format, and will be automatically converted to the hardware audio format if necessary. This function returns -1 if it failed to open the audio device, or couldn't set up the audio thread.
To open the audio device a desired SDL::AudioSpec must be created.
my $desired = SDL::AudioSpec->new();
You must then fill this structure with your desired audio specifications.
$desired->freq
$desired->format
$desired->channels
$desired->samples
$desired->callback
my $callback = sub{ my ($userdata, $stream, $len) = @_; };
$userdata is a reference stored in the userdata field of the SDL::AudioSpec.
$stream is a pointer to the audio buffer you want to fill with information and $len is the length of the audio buffer in bytes.
$desired->userdata
This pointer is passed as the first parameter to the callback function.
SDL::Audio::open reads these fields from the desired SDL::AudioSpec structure passed to the function and attempts to find an audio configuration matching your desired. As mentioned above, if the obtained parameter is NULL then SDL with convert from your desired audio settings to the hardware settings as it plays.
If obtained is NULL then the desired SDL::AudioSpec is your working specification, otherwise the obtained SDL::AudioSpec becomes the working specification and the desired specification can be deleted. The data in the working specification is used when building SDL::AudioCVT's for converting loaded data to the hardware format.
SDL::Audio::open calculates the size and silence fields for both the $desired and $obtained specifications. The size field stores the total size of the audio buffer in bytes, while the silence stores the value used to represent silence in the audio buffer
The audio device starts out playing silence when it's opened, and should be enabled for playing by calling SDL::Audio::pause(0) when you are ready for your audio callback function to be called. Since the audio driver may modify the requested size of the audio buffer, you should allocate any local mixing buffers after you open the audio device.
pause( $bool )
This function pauses and unpauses the audio callback processing. It should be called with "$bool = 0" after opening the audio device to start playing sound. This is so you can safely initialize data for your callback function after opening the audio device. Silence will be written to the audio device during the pause.
int get_status();
Returns either "SDL_AUDIO_STOPPED", "SDL_AUDIO_PLAYING" or "SDL_AUDIO_PAUSED" depending on the current audio state.
SDL::AudioSpec load_wav( $filename, $spec );
This function loads a WAVE file into memory.
If this function succeeds, it returns the given "SDL::AudioSpec", filled with the audio data format of the wave data, and sets "buf" to a buffer containing the audio data, and sets "len" to the length of that audio buffer, in bytes. You need to free the audio buffer with "SDL::Audio::free_wav" when you are done with it.
This function returns NULL and sets the SDL error message if the wave file cannot be opened, uses an unknown data format, or is corrupt. Currently raw, MS-ADPCM and IMA-ADPCM WAVE files are supported.
Example:
use SDL; use SDL::Audio; use SDL::AudioSpec; SDL::init(SDL_INIT_AUDIO); # Converting some WAV data to hardware format my $desired = SDL::AudioSpec->new(); my $obtained = SDL::AudioSpec->new(); # Set desired format $desired->freq(22050); $desired->channels(1); $desired->format(AUDIO_S16); $desired->samples(8192); # Open the audio device if( SDL::Audio::open($desired, $obtained) < 0 ) { printf( STDERR "Couldn't open audio: %s\n", SDL::get_error() ); exit(-1); } # Load the test.wav my $wav_ref = SDL::Audio::load_wav('../../test/data/sample.wav', $obtained); unless( $wav_ref ) { warn( "Could not open sample.wav: %s\n", SDL::get_error() ); SDL::Audio::close_audio(); SDL::quit; exit(-1); } my ( $wav_spec, $wav_buf, $wav_len ) = @{$wav_ref};
free_wav( $buffer )
After a WAVE file has been opened with "load_wav" its data can eventually be freed with "free_wav". "buffer" is the buffer created by "load_wav".
SDL::Audio->convert( cvt, data, len )
Converts audio data to a desired audio format.
"convert" takes as first parameter "cvt", which was previously initialized. Initializing a "SDL::AudioCVT" is a two step process. First of all, the structure must be created via "SDL::AudioCVT->build" along with source and destination format parameters. Secondly, the "data" and "len" fields must be setup. "data" should point to the audio data buffer being source and destination at once and "len" should be set to the buffer length in bytes. Remember, the length of the buffer pointed to by buf should be "len*len_mult" bytes in length.
Once the "SDL::AudioCVT" structure is initialized, we can pass it to "convert", which will convert the audio data pointed to by "data". If "convert" fails "undef" is returned, otherwise the converted "SDL::AudioCVT" structure.
If the conversion completed successfully then the converted audio data can be read from "cvt->buf". The amount of valid, converted, audio data in the buffer is equal to "cvt->len*cvt->len_ratio".
Example:
use SDL; use SDL::Audio; use SDL::AudioSpec; use SDL::AudioCVT; SDL::init(SDL_INIT_AUDIO); # Converting some WAV data to hardware format my $desired = SDL::AudioSpec->new(); my $obtained = SDL::AudioSpec->new(); # Set desired format $desired->freq(22050); $desired->channels(1); $desired->format(AUDIO_S16); $desired->samples(8192); # Open the audio device if( SDL::Audio::open($desired, $obtained) < 0 ) { printf( STDERR "Couldn't open audio: %s\n", SDL::get_error() ); exit(-1); } # Load the test.wav my $wav_ref = SDL::Audio::load_wav('../../test/data/sample.wav', $obtained); unless( $wav_ref ) { warn( "Could not open sample.wav: %s\n", SDL::get_error() ); SDL::Audio::close_audio(); SDL::quit; exit(-1); } my ( $wav_spec, $wav_buf, $wav_len ) = @{$wav_ref}; # Build AudioCVT my $wav_cvt = SDL::AudioCVT->build( $wav_spec->format, $wav_spec->channels, $wav_spec->freq, $obtained->format, $obtained->channels, $obtained->freq); # Check that the convert was built if( $wav_cvt == -1 ) { warn( "Couldn't build converter!\n" ); SDL::Audio::close(); SDL::Audio::free_wav($wav_buf); SDL::quit(); exit(-1); } # And now we're ready to convert SDL::Audio::convert($wav_cvt, $wav_buf, $wav_len); # We can free original WAV data now SDL::Audio::free_wav($wav_buf);
TODO: What to do with it? How to use callback? See http://www.libsdl.org/cgi/docwiki.cgi/SDL_ConvertAudio
Not implemented yet. See: <http://www.libsdl.org/cgi/docwiki.cgi/SDL_MixAudio>
lock();
The lock manipulated by these functions protects the callback function. During a "lock" period, you can be guaranteed that the callback function is not running. Do not call this from the callback function or you will cause deadlock.
unlock();
Unlocks a previous "lock" call.
close();
Shuts down audio processing and closes the audio device.