Mercurial > sdl-ios-xcode
annotate docs/html/sdllockaudio.html @ 3880:74e828c64315 SDL-1.2
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 15:45:37 +0000 |
| parents | 355632dca928 |
| children |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_LockAudio</TITLE | |
| 5 ><META | |
| 6 NAME="GENERATOR" | |
|
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ |
| 0 | 8 "><LINK |
| 9 REL="HOME" | |
| 10 TITLE="SDL Library Documentation" | |
| 11 HREF="index.html"><LINK | |
| 12 REL="UP" | |
| 13 TITLE="Audio" | |
| 14 HREF="audio.html"><LINK | |
| 15 REL="PREVIOUS" | |
| 16 TITLE="SDL_MixAudio" | |
| 17 HREF="sdlmixaudio.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_UnlockAudio" | |
| 20 HREF="sdlunlockaudio.html"></HEAD | |
| 21 ><BODY | |
| 22 CLASS="REFENTRY" | |
| 23 BGCOLOR="#FFF8DC" | |
| 24 TEXT="#000000" | |
| 25 LINK="#0000ee" | |
| 26 VLINK="#551a8b" | |
| 27 ALINK="#ff0000" | |
| 28 ><DIV | |
| 29 CLASS="NAVHEADER" | |
| 30 ><TABLE | |
|
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31 SUMMARY="Header navigation table" |
| 0 | 32 WIDTH="100%" |
| 33 BORDER="0" | |
| 34 CELLPADDING="0" | |
| 35 CELLSPACING="0" | |
| 36 ><TR | |
| 37 ><TH | |
| 38 COLSPAN="3" | |
| 39 ALIGN="center" | |
| 40 >SDL Library Documentation</TH | |
| 41 ></TR | |
| 42 ><TR | |
| 43 ><TD | |
| 44 WIDTH="10%" | |
| 45 ALIGN="left" | |
| 46 VALIGN="bottom" | |
| 47 ><A | |
| 48 HREF="sdlmixaudio.html" | |
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49 ACCESSKEY="P" |
| 0 | 50 >Prev</A |
| 51 ></TD | |
| 52 ><TD | |
| 53 WIDTH="80%" | |
| 54 ALIGN="center" | |
| 55 VALIGN="bottom" | |
| 56 ></TD | |
| 57 ><TD | |
| 58 WIDTH="10%" | |
| 59 ALIGN="right" | |
| 60 VALIGN="bottom" | |
| 61 ><A | |
| 62 HREF="sdlunlockaudio.html" | |
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63 ACCESSKEY="N" |
| 0 | 64 >Next</A |
| 65 ></TD | |
| 66 ></TR | |
| 67 ></TABLE | |
| 68 ><HR | |
| 69 ALIGN="LEFT" | |
| 70 WIDTH="100%"></DIV | |
| 71 ><H1 | |
| 72 ><A | |
| 73 NAME="SDLLOCKAUDIO" | |
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74 ></A |
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75 >SDL_LockAudio</H1 |
| 0 | 76 ><DIV |
| 77 CLASS="REFNAMEDIV" | |
| 78 ><A | |
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79 NAME="AEN7134" |
| 0 | 80 ></A |
| 81 ><H2 | |
| 82 >Name</H2 | |
| 83 >SDL_LockAudio -- Lock out the callback function</DIV | |
| 84 ><DIV | |
| 85 CLASS="REFSYNOPSISDIV" | |
| 86 ><A | |
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87 NAME="AEN7137" |
| 0 | 88 ></A |
| 89 ><H2 | |
| 90 >Synopsis</H2 | |
| 91 ><DIV | |
| 92 CLASS="FUNCSYNOPSIS" | |
| 93 ><A | |
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94 NAME="AEN7138" |
| 0 | 95 ></A |
| 96 ><P | |
| 97 ></P | |
| 98 ><PRE | |
| 99 CLASS="FUNCSYNOPSISINFO" | |
| 100 >#include "SDL.h"</PRE | |
| 101 ><P | |
| 102 ><CODE | |
| 103 ><CODE | |
| 104 CLASS="FUNCDEF" | |
| 105 >void <B | |
| 106 CLASS="FSFUNC" | |
| 107 >SDL_LockAudio</B | |
| 108 ></CODE | |
| 109 >(void);</CODE | |
| 110 ></P | |
| 111 ><P | |
| 112 ></P | |
| 113 ></DIV | |
| 114 ></DIV | |
| 115 ><DIV | |
| 116 CLASS="REFSECT1" | |
| 117 ><A | |
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118 NAME="AEN7144" |
| 0 | 119 ></A |
| 120 ><H2 | |
| 121 >Description</H2 | |
| 122 ><P | |
| 123 >The lock manipulated by these functions protects the callback function. | |
| 124 During a LockAudio period, you can be guaranteed that the | |
| 125 callback function is not running. Do not call these from the callback | |
| 126 function or you will cause deadlock.</P | |
| 127 ></DIV | |
| 128 ><DIV | |
| 129 CLASS="REFSECT1" | |
| 130 ><A | |
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131 NAME="AEN7147" |
| 0 | 132 ></A |
| 133 ><H2 | |
| 134 >See Also</H2 | |
| 135 ><P | |
| 136 ><A | |
| 137 HREF="sdlopenaudio.html" | |
| 138 ><TT | |
| 139 CLASS="FUNCTION" | |
| 140 >SDL_OpenAudio</TT | |
| 141 ></A | |
| 142 ></P | |
| 143 ></DIV | |
| 144 ><DIV | |
| 145 CLASS="NAVFOOTER" | |
| 146 ><HR | |
| 147 ALIGN="LEFT" | |
| 148 WIDTH="100%"><TABLE | |
|
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149 SUMMARY="Footer navigation table" |
| 0 | 150 WIDTH="100%" |
| 151 BORDER="0" | |
| 152 CELLPADDING="0" | |
| 153 CELLSPACING="0" | |
| 154 ><TR | |
| 155 ><TD | |
| 156 WIDTH="33%" | |
| 157 ALIGN="left" | |
| 158 VALIGN="top" | |
| 159 ><A | |
| 160 HREF="sdlmixaudio.html" | |
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161 ACCESSKEY="P" |
| 0 | 162 >Prev</A |
| 163 ></TD | |
| 164 ><TD | |
| 165 WIDTH="34%" | |
| 166 ALIGN="center" | |
| 167 VALIGN="top" | |
| 168 ><A | |
| 169 HREF="index.html" | |
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parents:
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170 ACCESSKEY="H" |
| 0 | 171 >Home</A |
| 172 ></TD | |
| 173 ><TD | |
| 174 WIDTH="33%" | |
| 175 ALIGN="right" | |
| 176 VALIGN="top" | |
| 177 ><A | |
| 178 HREF="sdlunlockaudio.html" | |
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parents:
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179 ACCESSKEY="N" |
| 0 | 180 >Next</A |
| 181 ></TD | |
| 182 ></TR | |
| 183 ><TR | |
| 184 ><TD | |
| 185 WIDTH="33%" | |
| 186 ALIGN="left" | |
| 187 VALIGN="top" | |
| 188 >SDL_MixAudio</TD | |
| 189 ><TD | |
| 190 WIDTH="34%" | |
| 191 ALIGN="center" | |
| 192 VALIGN="top" | |
| 193 ><A | |
| 194 HREF="audio.html" | |
|
803
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parents:
181
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195 ACCESSKEY="U" |
| 0 | 196 >Up</A |
| 197 ></TD | |
| 198 ><TD | |
| 199 WIDTH="33%" | |
| 200 ALIGN="right" | |
| 201 VALIGN="top" | |
| 202 >SDL_UnlockAudio</TD | |
| 203 ></TR | |
| 204 ></TABLE | |
| 205 ></DIV | |
| 206 ></BODY | |
| 207 ></HTML | |
| 208 > |