Mercurial > sdl-ios-xcode
view src/cdrom/macos/SDL_syscdrom_c.h @ 3880:74e828c64315 SDL-1.2
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 | d910939febfa |
children | 782fd950bd46 a1b03ba2fcd0 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2004 Sam Lantinga This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 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 Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with this library; if not, write to the Free Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Sam Lantinga slouken@libsdl.org */ #include "SDL_config.h" /* This is the MacOS specific header for the SDL CD-ROM API Contributed by Matt Slot */ /* AppleCD Control calls */ #define kVerifyTheDisc 5 /* Returns noErr if there is disc inserted */ #define kEjectTheDisc 7 /* Eject disc from drive */ #define kUserEject 80 /* Enable/disable the CD-ROM eject button */ #define kReadTOC 100 /* Extract various TOC information from the disc */ #define kReadQ 101 /* Extract Q subcode info for the current track */ #define kAudioTrackSearch 103 /* Start playback from the indicated position */ #define kAudioPlay 104 /* Start playback from the indicated position */ #define kAudioPause 105 /* Pause/continue the playback */ #define kAudioStop 106 /* Stop playback at the indicated position */ #define kAudioStatus 107 /* Return audio play status */ #define kAudioControl 109 /* Set the output volume for the audio channels */ #define kReadAudioVolume 112 /* Get the output volume for the audio channels */ #define kSetTrackList 122 /* Set the track program for the audio CD to play */ #define kGetTrackList 123 /* Get the track program the audio CD is playing */ #define kGetTrackIndex 124 /* Get the track index the audio CD is playing */ #define kSetPlayMode 125 /* Set the audio tracks play mode */ #define kGetPlayMode 126 /* Get the audio tracks play mode */ /* AppleCD Status calls */ #define kGetDriveType 96 /* Get the type of the physical CD-ROM drive */ #define kWhoIsThere 97 /* Get a bitmap of SCSI IDs the driver controls */ #define kGetBlockSize 98 /* Get current block size of the CD-ROM drive */ /* AppleCD other constants */ #define kBlockPosition 0 /* Position at the specified logical block number */ #define kAbsMSFPosition 1 /* Position at the specified Min/Sec/Frame (in BCD) */ #define kTrackPosition 2 /* Position at the specified track number (in BCD) */ #define kIndexPosition 3 /* Position at the nth track in program (in BCD) */ #define kMutedPlayMode 0 /* Play the audio track with no output */ #define kStereoPlayMode 9 /* Play the audio track in normal stereo */ #define kControlFieldMask 0x0D /* Bits 3,2,0 in the nibble */ #define kDataTrackMask 0x04 /* Indicates Data Track */ #define kGetTrackRange 1 /* Query TOC for track numbers */ #define kGetLeadOutArea 2 /* Query TOC for "Lead Out" end of audio data */ #define kGetTrackEntries 3 /* Query TOC for track starts and data types */ #define kStatusPlaying 0 /* Audio Play operation in progress */ #define kStatusPaused 1 /* CD-ROM device in Hold Track ("Pause") state */ #define kStatusMuted 2 /* MUTING-ON operation in progress */ #define kStatusDone 3 /* Audio Play completed */ #define kStatusError 4 /* Error occurred during audio play operation */ #define kStatusStopped 5 /* Audio play operation not requested */ #define kPlayModeSequential 0 /* Play tracks in order */ #define kPlayModeShuffled 1 /* Play tracks randomly */ #define kPlayModeProgrammed 2 /* Use custom playlist */ /* AppleCD Gestalt selectors */ #define kGestaltAudioCDSelector 'aucd' #define kDriverVersion52 0x00000520 #define kDriverVersion51 0x00000510 #define kDriverVersion50 0x00000500 /* Drive type constants */ #define kDriveAppleCD_SC 1 #define kDriveAppleCD_SCPlus_or_150 2 #define kDriveAppleCD_300_or_300Plus 3 /* Misc constants */ #define kFirstSCSIDevice -33 #define kLastSCSIDevice -40 #if PRAGMA_STRUCT_ALIGN #pragma options align=mac68k #endif /* AppleCD driver parameter block */ typedef struct CDCntrlParam { QElemPtr qLink; short qType; short ioTrap; Ptr ioCmdAddr; IOCompletionUPP ioCompletion; OSErr ioResult; StringPtr ioNamePtr; short ioVRefNum; short ioCRefNum; short csCode; union { long longs[6]; short words[11]; unsigned char bytes[22]; struct { unsigned char status; unsigned char play; unsigned char control; unsigned char minute; unsigned char second; unsigned char frame; } cd; } csParam; } CDCntrlParam, *CDCntrlParamPtr; typedef union CDTrackData { long value; /* Treat as a longword value */ struct { unsigned char reserved : 4; /* Unused by AppleCD driver */ unsigned char control : 4; /* Track flags (data track?) */ unsigned char min; /* Start of track (BCD) */ unsigned char sec; /* Start of track (BCD) */ unsigned char frame; /* Start of track (BCD) */ } entry; /* Broken into fields */ } CDTrackData, *CDTrackPtr; #if PRAGMA_STRUCT_ALIGN #pragma options align=reset #endif