play_audio_stream(3alleg4) [suse man page]

play_audio_stream(3alleg4)					  Allegro manual					play_audio_stream(3alleg4)

NAME

       play_audio_stream - Creates a new audio stream and starts playing it. Allegro game programming library.

SYNOPSIS

       #include <allegro.h>

       AUDIOSTREAM *play_audio_stream(int len, int bits, int stereo, int freq, int vol, int pan);

DESCRIPTION

       This  function  creates	a  new	audio  stream  and starts playing it. The length is the size of each transfer buffer in sample frames (not
       bytes), where a sample frame is a single sample value for mono data or a pair of interleaved sample values (left first)	for  stereo  data.
       The  length  should  normally  be  (but doesn't have to be) a power of 2 somewhere around 1k in size. Larger buffers are more efficient and
       require fewer updates, but result in more latency between you providing the data and it actually being played.

       The `bits' parameter must be 8 or 16. `freq' is the sample rate of the data in Hertz. The `vol' and `pan' values use the same 0-255  ranges
       as the regular sample playing functions. The `stereo' parameter should be set to 1 for stereo streams, or 0 otherwise.

       If  you	want  to  adjust  the  pitch,  volume, or panning of a stream once it is playing, you can use the regular voice_*() functions with
       stream->voice as a parameter. The format of the sample data is described in the SAMPLE entry of the "Structures and types defined by  Alle-
       gro" chapter. The formula to get the size of the buffers in bytes could be:

	  bytes = length * (bits / 8) * (stereo ? 2 : 1)
       Example:

	  /* Create a 22KHz 8bit mono audio stream. */
	  stream = play_audio_stream(1024, 8, FALSE, 22050, 255, 128);
	  if (!stream)
	     abort_on_error("Error creating audio stream!
");

RETURN VALUE

       This function returns a pointer to the audio stream or NULL if it could not be created.

SEE ALSO

       install_sound(3alleg4), get_audio_stream_buffer(3alleg4), stop_audio_stream(3alleg4), AUDIOSTREAM(3alleg4), exstream(3alleg4)

Allegro 							   version 4.4.2					play_audio_stream(3alleg4)

SDL_AudioSpec(3)						 SDL API Reference						  SDL_AudioSpec(3)

NAME

       SDL_AudioSpec - Audio Specification Structure

STRUCTURE DEFINITION

       typedef struct{
	 int freq;
	 Uint16 format;
	 Uint8 channels;
	 Uint8 silence;
	 Uint16 samples;
	 Uint32 size;
	 void (*callback)(void *userdata, Uint8 *stream, int len);
	 void *userdata;
       } SDL_AudioSpec;

STRUCTURE DATA

       freq		   Audio frequency in samples per second

       format		   Audio data format

       channels 	   Number of channels: 1 mono, 2 stereo

       silence		   Audio buffer silence value (calculated)

       samples		   Audio buffer size in samples

       size		   Audio buffer size in bytes (calculated)

       callback(..)	   Callback function for filling the audio buffer

       userdata 	   Pointer the user data which is passed to the callback function

DESCRIPTION

       The  SDL_AudioSpec  structure  is  used to describe the format of some audio data. This structure is used by SDL_OpenAudio and SDL_LoadWAV.
       While all fields are used by SDL_OpenAudio only freq, format, samples and channels are used by SDL_LoadWAV. We  will  detail  these  common
       members here.

       freq		   The	number	of samples sent to the sound device every second. Common values are 11025, 22050 and 44100. The higher the
			   better.

       format		   Specifies the size and type of each sample element

       AUDIO_U8

       AUDIO_S8

       AUDIO_U16 or AUDIO_U16LSB

       AUDIO_S16 or AUDIO_S16LSB

       AUDIO_U16MSB

       AUDIO_S16MSB

       AUDIO_U16SYS

       AUDIO_S16SYS

       channels 	   The number of seperate sound channels. 1 is mono (single channel), 2 is stereo (dual channel).

       samples		   When used with SDL_OpenAudio this refers to the size of the audio buffer in samples. A sample a chunk of audio data	of
			   the size specified in format mulitplied by the number of channels. When the SDL_AudioSpec is used with SDL_LoadWAV sam-
			   ples is set to 4096.

SEE ALSO

       SDL_OpenAudio, SDL_LoadWAV

SDL
							      Tue 11 Sep 2001, 22:58						  SDL_AudioSpec(3)