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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 15:45:37 +0000
parents 355632dca928
children
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>SDL_BuildAudioCVT</H1
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><H2
>Name</H2
>SDL_BuildAudioCVT&nbsp;--&nbsp;Initializes a SDL_AudioCVT structure for conversion</DIV
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>Synopsis</H2
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><P
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><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_BuildAudioCVT</B
></CODE
>(SDL_AudioCVT *cvt, Uint16 src_format, Uint8 src_channels, int src_rate, Uint16 dst_format, Uint8 dst_channels, int dst_rate);</CODE
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><H2
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><P
>Before an <A
HREF="sdlaudiocvt.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_AudioCVT</SPAN
></A
> structure can be used to convert audio data it must be initialized with source and destination information. </P
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><TT
CLASS="PARAMETER"
><I
>src_format</I
></TT
> and <TT
CLASS="PARAMETER"
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>dst_format</I
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> are the source and destination format of the conversion. (For information on audio formats see <A
HREF="sdlaudiospec.html"
><SPAN
CLASS="STRUCTNAME"
> SDL_AudioSpec</SPAN
></A
>). <TT
CLASS="PARAMETER"
><I
>src_channels</I
></TT
> and <TT
CLASS="PARAMETER"
><I
>dst_channels</I
></TT
> are the number of channels in the source and destination formats. Finally, <TT
CLASS="PARAMETER"
><I
>src_rate</I
></TT
> and <TT
CLASS="PARAMETER"
><I
>dst_rate</I
></TT
> are the frequency or samples-per-second of the source and destination formats. Once again, see <A
HREF="sdlaudiospec.html"
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>SDL_AudioSpec</SPAN
></A
>.</P
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><H2
>Return Values</H2
><P
>Returns <SPAN
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>-1</SPAN
> if the filter could not be built or 1 if it could.</P
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>See <A
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>SDL_ConvertAudio</TT
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>SDL_ConvertAudio</TT
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>,
<A
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