Mercurial > sdl-ios-xcode
view docs/html/guideaudioexamples.html @ 4347:38f22ed3a433 SDL-1.2
Option to fix bug #851
For some people setting the period size works better (and is what SDL 1.2.13 did), but for most people it's the same or worse. You can use an environment variable to pick which one you want.
author | Sam Lantinga <slouken@libsdl.org> |
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date | Sat, 17 Oct 2009 06:55:17 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >Audio Examples</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="Examples" HREF="guideexamples.html"><LINK REL="PREVIOUS" TITLE="Event Examples" HREF="guideeventexamples.html"><LINK REL="NEXT" TITLE="CDROM Examples" HREF="guidecdromexamples.html"></HEAD ><BODY CLASS="SECT1" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="guideeventexamples.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 4. Examples</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="guidecdromexamples.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="GUIDEAUDIOEXAMPLES" ></A >Audio Examples</H1 ><P ></P ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="AEN382" ></A >Opening the audio device</H2 ><P ><PRE CLASS="PROGRAMLISTING" > SDL_AudioSpec wanted; extern void fill_audio(void *udata, Uint8 *stream, int len); /* Set the audio format */ wanted.freq = 22050; wanted.format = AUDIO_S16; wanted.channels = 2; /* 1 = mono, 2 = stereo */ wanted.samples = 1024; /* Good low-latency value for callback */ wanted.callback = fill_audio; wanted.userdata = NULL; /* Open the audio device, forcing the desired format */ if ( SDL_OpenAudio(&wanted, NULL) < 0 ) { fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError()); return(-1); } return(0);</PRE ></P ></DIV ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="AEN386" ></A >Playing audio</H2 ><P ><PRE CLASS="PROGRAMLISTING" > static Uint8 *audio_chunk; static Uint32 audio_len; static Uint8 *audio_pos; /* The audio function callback takes the following parameters: stream: A pointer to the audio buffer to be filled len: The length (in bytes) of the audio buffer */ void fill_audio(void *udata, Uint8 *stream, int len) { /* Only play if we have data left */ if ( audio_len == 0 ) return; /* Mix as much data as possible */ len = ( len > audio_len ? audio_len : len ); SDL_MixAudio(stream, audio_pos, len, SDL_MIX_MAXVOLUME); audio_pos += len; audio_len -= len; } /* Load the audio data ... */ ;;;;; audio_pos = audio_chunk; /* Let the callback function play the audio chunk */ SDL_PauseAudio(0); /* Do some processing */ ;;;;; /* Wait for sound to complete */ while ( audio_len > 0 ) { SDL_Delay(100); /* Sleep 1/10 second */ } SDL_CloseAudio();</PRE ></P ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="guideeventexamples.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="guidecdromexamples.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Event Examples</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="guideexamples.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >CDROM Examples</TD ></TR ></TABLE ></DIV ></BODY ></HTML >