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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
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<HTML
><HEAD
><TITLE
>SDL_CDPlayTracks</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="CD-ROM"
HREF="cdrom.html"><LINK
REL="PREVIOUS"
TITLE="SDL_CDPlay"
HREF="sdlcdplay.html"><LINK
REL="NEXT"
TITLE="SDL_CDPause"
HREF="sdlcdpause.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="sdlcdplay.html"
ACCESSKEY="P"
>Prev</A
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><TD
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><A
HREF="sdlcdpause.html"
ACCESSKEY="N"
>Next</A
></TD
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></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="SDLCDPLAYTRACKS"
></A
>SDL_CDPlayTracks</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN7375"
></A
><H2
>Name</H2
>SDL_CDPlayTracks&nbsp;--&nbsp;Play the given CD track(s)</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN7378"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN7379"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_CDPlayTracks</B
></CODE
>(SDL_CD *cdrom, int start_track, int start_frame, int ntracks, int nframes));</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN7385"
></A
><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_CDPlayTracks</TT
> plays the given CD starting at track
<TT
CLASS="PARAMETER"
><I
>start_track</I
></TT
>, for <TT
CLASS="PARAMETER"
><I
>ntracks</I
></TT
> tracks.  </P
><P
><TT
CLASS="PARAMETER"
><I
>start_frame</I
></TT
> is the frame offset, from the beginning of the <TT
CLASS="PARAMETER"
><I
>start_track</I
></TT
>, at which to start. <TT
CLASS="PARAMETER"
><I
>nframes</I
></TT
> is the frame offset, from the beginning of the last track (<TT
CLASS="PARAMETER"
><I
>start_track</I
></TT
>+<TT
CLASS="PARAMETER"
><I
>ntracks</I
></TT
>), at which to end playing.</P
><P
><TT
CLASS="FUNCTION"
>SDL_CDPlayTracks</TT
> should only be called after calling 
<A
HREF="sdlcdstatus.html"
><TT
CLASS="FUNCTION"
>SDL_CDStatus</TT
></A
> 
to get track information about the CD.</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>Data tracks are ignored.</P
></BLOCKQUOTE
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN7403"
></A
><H2
>Return Value</H2
><P
>Returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
>, or <SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> 
if there was an error.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN7408"
></A
><H2
>Examples</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>/* assuming cdrom is a previously opened device */
/* Play the entire CD */
if(CD_INDRIVE(SDL_CDStatus(cdrom)))
  SDL_CDPlayTracks(cdrom, 0, 0, 0, 0);

/* Play the first track */
if(CD_INDRIVE(SDL_CDStatus(cdrom)))
  SDL_CDPlayTracks(cdrom, 0, 0, 1, 0);

/* Play first 15 seconds of the 2nd track */
if(CD_INDRIVE(SDL_CDStatus(cdrom)))
  SDL_CDPlayTracks(cdrom, 1, 0, 0, CD_FPS*15);</PRE
>
&#13;</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN7412"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlcdplay.html"
><TT
CLASS="FUNCTION"
>SDL_CDPlay</TT
></A
>,
<A
HREF="sdlcdstatus.html"
><TT
CLASS="FUNCTION"
>SDL_CDStatus</TT
></A
>,
<A
HREF="sdlcd.html"
><TT
CLASS="FUNCTION"
>SDL_CD</TT
></A
></P
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>Prev</A
></TD
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HREF="index.html"
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>Home</A
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><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>SDL_CDPlay</TD
><TD
WIDTH="34%"
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HREF="cdrom.html"
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