view src/audio/arts/SDL_artsaudio.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 5f6550e5184f 9dc81c6acaf5
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/*
    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"

#ifndef _SDL_artscaudio_h
#define _SDL_artscaudio_h

#include <artsc.h>

#include "../SDL_sysaudio.h"

/* Hidden "this" pointer for the video functions */
#define _THIS	SDL_AudioDevice *this

struct SDL_PrivateAudioData
{
    /* The stream descriptor for the audio device */
    arts_stream_t stream;

    /* The parent process id, to detect when application quits */
    pid_t parent;

    /* Raw mixing buffer */
    Uint8 *mixbuf;
    int mixlen;

    /* Support for audio timing using a timer, in addition to select() */
    float frame_ticks;
    float next_frame;
};
#define FUDGE_TICKS	10      /* The scheduler overhead ticks per frame */

/* Old variable names */
#define stream			(this->hidden->stream)
#define parent			(this->hidden->parent)
#define mixbuf			(this->hidden->mixbuf)
#define mixlen			(this->hidden->mixlen)
#define frame_ticks		(this->hidden->frame_ticks)
#define next_frame		(this->hidden->next_frame)

#endif /* _SDL_artscaudio_h */
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