Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
play_audio_stream(3)		Allegro	manual		  play_audio_stream(3)

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

       #include	<allegro.h>

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

       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 some-
       where 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 de-
       scribed in the SAMPLE entry of the "Structures and types	defined	by Al-
       legro"  chapter.	 The  formula  to get the size of the buffers in bytes
       could be:

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

	  /* 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!\n");

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

       install_sound(3), get_audio_stream_buffer(3), stop_audio_stream(3), AU-
       DIOSTREAM(3), exstream(3)

Allegro				 version 4.4.3		  play_audio_stream(3)


Want to link to this manual page? Use this URL:

home | help