Mercurial > sdl-ios-xcode
view docs/html/sdlloadwav.html @ 2042:3908e1f808e1
Fixed bug #292
I might be on crack here.
It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and
right channels of a stereo stream together, and clamps the new mono channel if
it would overflow.
Shouldn't it be dividing by 2 to average the two sample points instead of
clamping? Otherwise the mono sample point's volume doubles in the conversion.
This would also make the conversion faster, as it replaces two branches per
sample frame with a bitwise shift.
--ryan.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sun, 24 Sep 2006 15:56:36 +0000 |
parents | 355632dca928 |
children |
line wrap: on
line source
<HTML ><HEAD ><TITLE >SDL_LoadWAV</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="Audio" HREF="audio.html"><LINK REL="PREVIOUS" TITLE="SDL_GetAudioStatus" HREF="sdlgetaudiostatus.html"><LINK REL="NEXT" TITLE="SDL_FreeWAV" HREF="sdlfreewav.html"></HEAD ><BODY CLASS="REFENTRY" 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="sdlgetaudiostatus.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlfreewav.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLLOADWAV" ></A >SDL_LoadWAV</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN6816" ></A ><H2 >Name</H2 >SDL_LoadWAV -- Load a WAVE file</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN6819" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN6820" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >SDL_AudioSpec *<B CLASS="FSFUNC" >SDL_LoadWAV</B ></CODE >(const char *file, SDL_AudioSpec *spec, Uint8 **audio_buf, Uint32 *audio_len);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN6826" ></A ><H2 >Description</H2 ><P ><TT CLASS="FUNCTION" >SDL_LoadWAV</TT > This function loads a WAVE <TT CLASS="PARAMETER" ><I >file</I ></TT > into memory.</P ><P >If this function succeeds, it returns the given <A HREF="sdlaudiospec.html" ><TT CLASS="FUNCTION" >SDL_AudioSpec</TT ></A >, filled with the audio data format of the wave data, and sets <TT CLASS="PARAMETER" ><I >audio_buf</I ></TT > to a <TT CLASS="FUNCTION" >malloc</TT >'d buffer containing the audio data, and sets <TT CLASS="PARAMETER" ><I >audio_len</I ></TT > to the length of that audio buffer, in bytes. You need to free the audio buffer with <A HREF="sdlfreewav.html" ><TT CLASS="FUNCTION" >SDL_FreeWAV</TT ></A > when you are done with it.</P ><P >This function returns <TT CLASS="LITERAL" >NULL</TT > 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.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN6841" ></A ><H2 >Example</H2 ><PRE CLASS="PROGRAMLISTING" >SDL_AudioSpec wav_spec; Uint32 wav_length; Uint8 *wav_buffer; /* Load the WAV */ if( SDL_LoadWAV("test.wav", &wav_spec, &wav_buffer, &wav_length) == NULL ){ fprintf(stderr, "Could not open test.wav: %s\n", SDL_GetError()); exit(-1); } . . . /* Do stuff with the WAV */ . . /* Free It */ SDL_FreeWAV(wav_buffer);</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN6844" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlaudiospec.html" ><SPAN CLASS="STRUCTNAME" >SDL_AudioSpec</SPAN ></A >, <A HREF="sdlopenaudio.html" ><TT CLASS="FUNCTION" >SDL_OpenAudio</TT ></A >, <A HREF="sdlfreewav.html" ><TT CLASS="FUNCTION" >SDL_FreeWAV</TT ></A ></P ></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="sdlgetaudiostatus.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="sdlfreewav.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_GetAudioStatus</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="audio.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_FreeWAV</TD ></TR ></TABLE ></DIV ></BODY ></HTML >