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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_LockYUVOverlay</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="Video"
HREF="video.html"><LINK
REL="PREVIOUS"
TITLE="SDL_CreateYUVOverlay"
HREF="sdlcreateyuvoverlay.html"><LINK
REL="NEXT"
TITLE="SDL_UnlockYUVOverlay"
HREF="sdlunlockyuvoverlay.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="sdlcreateyuvoverlay.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="sdlunlockyuvoverlay.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="SDLLOCKYUVOVERLAY"
></A
>SDL_LockYUVOverlay</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN2844"
></A
><H2
>Name</H2
>SDL_LockYUVOverlay&nbsp;--&nbsp;Lock an overlay</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN2847"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN2848"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_LockYUVOverlay</B
></CODE
>(SDL_Overlay *overlay);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2854"
></A
><H2
>Description</H2
><P
>Much the same as <A
HREF="sdllocksurface.html"
><TT
CLASS="FUNCTION"
>SDL_LockSurface</TT
></A
>, <TT
CLASS="FUNCTION"
>SDL_LockYUVOverlay</TT
> locks the <A
HREF="sdloverlay.html"
><TT
CLASS="PARAMETER"
><I
>overlay</I
></TT
></A
> for direct access to pixel data.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2862"
></A
><H2
>Return Value</H2
><P
>Returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
> on success, or <SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> on an error.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2867"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlunlockyuvoverlay.html"
><TT
CLASS="FUNCTION"
>SDL_UnlockYUVOverlay</TT
></A
>,
<A
HREF="sdlcreateyuvoverlay.html"
><TT
CLASS="FUNCTION"
>SDL_CreateYUVOverlay</TT
></A
>,
<A
HREF="sdloverlay.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Overlay</SPAN
></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="sdlcreateyuvoverlay.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="sdlunlockyuvoverlay.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>SDL_CreateYUVOverlay</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="video.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>SDL_UnlockYUVOverlay</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>