view src/audio/SDL_mixer_MMX_VC.h @ 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 c121d94672cb
children 99210400e8b9
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"


#if ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
/* headers for MMX assembler version of SDL_MixAudio
   Copyright 2002 Stephane Marchesin (stephane.marchesin@wanadoo.fr)
   Converted to Intel ASM notation by Cth
   This code is licensed under the LGPL (see COPYING for details)
   
   Assumes buffer size in bytes is a multiple of 16
   Assumes SDL_MIX_MAXVOLUME = 128
*/
void SDL_MixAudio_MMX_S16_VC(char *, char *, unsigned int, int);
void SDL_MixAudio_MMX_S8_VC(char *, char *, unsigned int, int);
#endif
/* vi: set ts=4 sw=4 expandtab: */