src/audio/SDL_mixer.c
author Ryan C. Gordon <icculus@icculus.org>
Thu, 24 Aug 2006 12:10:46 +0000
changeset 1982 3b4ce57c6215
parent 1895 c121d94672cb
child 1985 8055185ae4ed
permissions -rw-r--r--
First shot at new audio data types (int32 and float32).

Notable changes:
- Converters between types are autogenerated. Instead of making multiple
passes over the data with seperate filters for endianess, size, signedness,
etc, converting between data types is always one specialized filter. This
simplifies SDL_BuildAudioCVT(), which otherwise had a million edge cases
with the new types, and makes the actually conversions more CPU cache
friendly. Left a stub for adding specific optimized versions of these
routines (SSE/MMX/Altivec, assembler, etc)
- Autogenerated converters are built by SDL/src/audio/sdlgenaudiocvt.pl. This
does not need to be run unless tweaking the code, and thus doesn't need
integration into the build system.
- Went through all the drivers and tried to weed out all the "Uint16"
references that are better specified with the new SDL_AudioFormat typedef.
- Cleaned out a bunch of hardcoded bitwise magic numbers and replaced them
with new SDL_AUDIO_* macros.
- Added initial float32 and int32 support code. Theoretically, existing
drivers will push these through converters to get the data they want to
feed to the hardware.

Still TODO:
- Optimize and debug new converters.
- Update the CoreAudio backend to accept float32 data directly.
- Other backends, too?
- SDL_LoadWAV() needs to be updated to support int32 and float32 .wav files
(both of which exist and can be generated by 'sox' for testing purposes).
- Update the mixer to handle new datatypes.
- Optionally update SDL_sound and SDL_mixer, etc.
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997-2006 Sam Lantinga
     4 
     5     This library is free software; you can redistribute it and/or
     6     modify it under the terms of the GNU Lesser General Public
     7     License as published by the Free Software Foundation; either
     8     version 2.1 of the License, or (at your option) any later version.
     9 
    10     This library is distributed in the hope that it will be useful,
    11     but WITHOUT ANY WARRANTY; without even the implied warranty of
    12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    13     Lesser General Public License for more details.
    14 
    15     You should have received a copy of the GNU Lesser General Public
    16     License along with this library; if not, write to the Free Software
    17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    18 
    19     Sam Lantinga
    20     slouken@libsdl.org
    21 */
    22 #include "SDL_config.h"
    23 
    24 /* This provides the default mixing callback for the SDL audio routines */
    25 
    26 #include "SDL_cpuinfo.h"
    27 #include "SDL_timer.h"
    28 #include "SDL_audio.h"
    29 #include "SDL_sysaudio.h"
    30 #include "SDL_mixer_MMX.h"
    31 #include "SDL_mixer_MMX_VC.h"
    32 #include "SDL_mixer_m68k.h"
    33 
    34 /* This table is used to add two sound values together and pin
    35  * the value to avoid overflow.  (used with permission from ARDI)
    36  * Changed to use 0xFE instead of 0xFF for better sound quality.
    37  */
    38 static const Uint8 mix8[] = {
    39     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    40     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    41     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    42     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    43     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    44     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    45     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    46     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    47     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    48     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    49     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    50     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03,
    51     0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
    52     0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
    53     0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24,
    54     0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
    55     0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A,
    56     0x3B, 0x3C, 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45,
    57     0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
    58     0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B,
    59     0x5C, 0x5D, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
    60     0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71,
    61     0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C,
    62     0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
    63     0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x91, 0x92,
    64     0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D,
    65     0x9E, 0x9F, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8,
    66     0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xB0, 0xB1, 0xB2, 0xB3,
    67     0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE,
    68     0xBF, 0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9,
    69     0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4,
    70     0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
    71     0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA,
    72     0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5,
    73     0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFE, 0xFE,
    74     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    75     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    76     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    77     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    78     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    79     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    80     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    81     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    82     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    83     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    84     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    85     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE
    86 };
    87 
    88 /* The volume ranges from 0 - 128 */
    89 #define ADJUST_VOLUME(s, v)	(s = (s*v)/SDL_MIX_MAXVOLUME)
    90 #define ADJUST_VOLUME_U8(s, v)	(s = (((s-128)*v)/SDL_MIX_MAXVOLUME)+128)
    91 
    92 void
    93 SDL_MixAudio(Uint8 * dst, const Uint8 * src, Uint32 len, int volume)
    94 {
    95     /* Mix the user-level audio format */
    96     if (current_audio) {
    97         SDL_AudioFormat format;
    98         if (current_audio->convert.needed) {
    99             format = current_audio->convert.src_format;
   100         } else {
   101             format = current_audio->spec.format;
   102         }
   103         SDL_MixAudioFormat(dst, src, format, len, volume);
   104     }
   105 }
   106 
   107 
   108 void
   109 SDL_MixAudioFormat(Uint8 * dst, const Uint8 * src, SDL_AudioFormat format,
   110                    Uint32 len, int volume)
   111 {
   112     if (volume == 0) {
   113         return;
   114     }
   115 
   116     switch (format) {
   117 
   118     case AUDIO_U8:
   119         {
   120 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
   121             SDL_MixAudio_m68k_U8((char *) dst, (char *) src,
   122                                  (unsigned long) len, (long) volume,
   123                                  (char *) mix8);
   124 #else
   125             Uint8 src_sample;
   126 
   127             while (len--) {
   128                 src_sample = *src;
   129                 ADJUST_VOLUME_U8(src_sample, volume);
   130                 *dst = mix8[*dst + src_sample];
   131                 ++dst;
   132                 ++src;
   133             }
   134 #endif
   135         }
   136         break;
   137 
   138     case AUDIO_S8:
   139         {
   140 #if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
   141             if (SDL_HasMMX()) {
   142                 SDL_MixAudio_MMX_S8((char *) dst, (char *) src,
   143                                     (unsigned int) len, (int) volume);
   144             } else
   145 #elif ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
   146             if (SDL_HasMMX()) {
   147                 SDL_MixAudio_MMX_S8_VC((char *) dst, (char *) src,
   148                                        (unsigned int) len, (int) volume);
   149             } else
   150 #endif
   151 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
   152                 SDL_MixAudio_m68k_S8((char *) dst, (char *) src,
   153                                      (unsigned long) len, (long) volume);
   154 #else
   155             {
   156                 Sint8 *dst8, *src8;
   157                 Sint8 src_sample;
   158                 int dst_sample;
   159                 const int max_audioval = ((1 << (8 - 1)) - 1);
   160                 const int min_audioval = -(1 << (8 - 1));
   161 
   162                 src8 = (Sint8 *) src;
   163                 dst8 = (Sint8 *) dst;
   164                 while (len--) {
   165                     src_sample = *src8;
   166                     ADJUST_VOLUME(src_sample, volume);
   167                     dst_sample = *dst8 + src_sample;
   168                     if (dst_sample > max_audioval) {
   169                         *dst8 = max_audioval;
   170                     } else if (dst_sample < min_audioval) {
   171                         *dst8 = min_audioval;
   172                     } else {
   173                         *dst8 = dst_sample;
   174                     }
   175                     ++dst8;
   176                     ++src8;
   177                 }
   178             }
   179 #endif
   180         }
   181         break;
   182 
   183     case AUDIO_S16LSB:
   184         {
   185 #if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
   186             if (SDL_HasMMX()) {
   187                 SDL_MixAudio_MMX_S16((char *) dst, (char *) src,
   188                                      (unsigned int) len, (int) volume);
   189             } else
   190 #elif ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
   191             if (SDL_HasMMX()) {
   192                 SDL_MixAudio_MMX_S16_VC((char *) dst, (char *) src,
   193                                         (unsigned int) len, (int) volume);
   194             } else
   195 #endif
   196 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
   197                 SDL_MixAudio_m68k_S16LSB((short *) dst, (short *) src,
   198                                          (unsigned long) len, (long) volume);
   199 #else
   200             {
   201                 Sint16 src1, src2;
   202                 int dst_sample;
   203                 const int max_audioval = ((1 << (16 - 1)) - 1);
   204                 const int min_audioval = -(1 << (16 - 1));
   205 
   206                 len /= 2;
   207                 while (len--) {
   208                     src1 = ((src[1]) << 8 | src[0]);
   209                     ADJUST_VOLUME(src1, volume);
   210                     src2 = ((dst[1]) << 8 | dst[0]);
   211                     src += 2;
   212                     dst_sample = src1 + src2;
   213                     if (dst_sample > max_audioval) {
   214                         dst_sample = max_audioval;
   215                     } else if (dst_sample < min_audioval) {
   216                         dst_sample = min_audioval;
   217                     }
   218                     dst[0] = dst_sample & 0xFF;
   219                     dst_sample >>= 8;
   220                     dst[1] = dst_sample & 0xFF;
   221                     dst += 2;
   222                 }
   223             }
   224 #endif
   225         }
   226         break;
   227 
   228     case AUDIO_S16MSB:
   229         {
   230 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
   231             SDL_MixAudio_m68k_S16MSB((short *) dst, (short *) src,
   232                                      (unsigned long) len, (long) volume);
   233 #else
   234             Sint16 src1, src2;
   235             int dst_sample;
   236             const int max_audioval = ((1 << (16 - 1)) - 1);
   237             const int min_audioval = -(1 << (16 - 1));
   238 
   239             len /= 2;
   240             while (len--) {
   241                 src1 = ((src[0]) << 8 | src[1]);
   242                 ADJUST_VOLUME(src1, volume);
   243                 src2 = ((dst[0]) << 8 | dst[1]);
   244                 src += 2;
   245                 dst_sample = src1 + src2;
   246                 if (dst_sample > max_audioval) {
   247                     dst_sample = max_audioval;
   248                 } else if (dst_sample < min_audioval) {
   249                     dst_sample = min_audioval;
   250                 }
   251                 dst[1] = dst_sample & 0xFF;
   252                 dst_sample >>= 8;
   253                 dst[0] = dst_sample & 0xFF;
   254                 dst += 2;
   255             }
   256 #endif
   257         }
   258         break;
   259 
   260     case AUDIO_S32LSB:
   261         {
   262             const Uint32 *src32 = (Uint32 *) src;
   263             Uint32 *dst32 = (Uint32 *) dst;
   264             Sint32 src1, src2;
   265             Sint64 dst_sample;
   266             const Sint64 max_audioval = ((((Sint64)1) << (32 - 1)) - 1);
   267             const Sint64 min_audioval = -(((Sint64)1) << (32 - 1));
   268 
   269             len /= 4;
   270             while (len--) {
   271                 src1 = (Sint32) SDL_SwapLE32(*src32);
   272                 src32++;
   273                 ADJUST_VOLUME(src1, volume);
   274                 src2 = (Sint32) SDL_SwapLE32(*dst32);
   275                 dst_sample = src1 + src2;
   276                 if (dst_sample > max_audioval) {
   277                     dst_sample = max_audioval;
   278                 } else if (dst_sample < min_audioval) {
   279                     dst_sample = min_audioval;
   280                 }
   281                 *(dst32++) = SDL_SwapLE32((Uint32) ((Sint32) dst_sample));
   282             }
   283         }
   284         break;
   285 
   286     case AUDIO_S32MSB:
   287         {
   288             const Uint32 *src32 = (Uint32 *) src;
   289             Uint32 *dst32 = (Uint32 *) dst;
   290             Sint32 src1, src2;
   291             Sint64 dst_sample;
   292             const Sint64 max_audioval = ((((Sint64)1) << (32 - 1)) - 1);
   293             const Sint64 min_audioval = -(((Sint64)1) << (32 - 1));
   294 
   295             len /= 4;
   296             while (len--) {
   297                 src1 = (Sint32) SDL_SwapBE32(*src32);
   298                 src32++;
   299                 ADJUST_VOLUME(src1, volume);
   300                 src2 = (Sint32) SDL_SwapBE32(*dst32);
   301                 dst_sample = src1 + src2;
   302                 if (dst_sample > max_audioval) {
   303                     dst_sample = max_audioval;
   304                 } else if (dst_sample < min_audioval) {
   305                     dst_sample = min_audioval;
   306                 }
   307                 *(dst32++) = SDL_SwapBE32((Uint32) ((Sint32) dst_sample));
   308             }
   309         }
   310         break;
   311 
   312     case AUDIO_F32LSB:
   313         {
   314             const float fmaxvolume = 1.0f / ((float) SDL_MIX_MAXVOLUME);
   315             const float fvolume = (float) volume;
   316             const float *src32 = (float *) src;
   317             float *dst32 = (float *) dst;
   318             float src1, src2;
   319             double dst_sample;
   320             /* !!! FIXME: are these right? */
   321             const double max_audioval = 3.40282347e+38F;
   322             const double min_audioval = -3.40282347e+38F;
   323 
   324             /* !!! FIXME: this is a little nasty. */
   325             union { float f; Uint32 ui32; } cvt;
   326 
   327             len /= 4;
   328             while (len--) {
   329                 cvt.f = *(src32++);
   330                 cvt.ui32 = SDL_SwapLE32(cvt.ui32);
   331                 src1 = ((cvt.f * fvolume) * fmaxvolume);
   332 
   333                 cvt.f = *dst32;
   334                 cvt.ui32 = SDL_SwapLE32(cvt.ui32);
   335                 src2 = cvt.f;
   336 
   337                 dst_sample = src1 + src2;
   338                 if (dst_sample > max_audioval) {
   339                     dst_sample = max_audioval;
   340                 } else if (dst_sample < min_audioval) {
   341                     dst_sample = min_audioval;
   342                 }
   343                 cvt.f = ((float) dst_sample);
   344                 cvt.ui32 = SDL_SwapLE32(cvt.ui32);
   345                 *(dst32++) = cvt.f;
   346             }
   347         }
   348         break;
   349 
   350     case AUDIO_F32MSB:
   351         {
   352             const float fmaxvolume = 1.0f / ((float) SDL_MIX_MAXVOLUME);
   353             const float fvolume = (float) volume;
   354             const float *src32 = (float *) src;
   355             float *dst32 = (float *) dst;
   356             float src1, src2;
   357             double dst_sample;
   358             /* !!! FIXME: are these right? */
   359             const double max_audioval = 3.40282347e+38F;
   360             const double min_audioval = -3.40282347e+38F;
   361 
   362             /* !!! FIXME: this is a little nasty. */
   363             union { float f; Uint32 ui32; } cvt;
   364 
   365             len /= 4;
   366             while (len--) {
   367                 cvt.f = *(src32++);
   368                 cvt.ui32 = SDL_SwapBE32(cvt.ui32);
   369                 src1 = ((cvt.f * fvolume) * fmaxvolume);
   370 
   371                 cvt.f = *dst32;
   372                 cvt.ui32 = SDL_SwapBE32(cvt.ui32);
   373                 src2 = cvt.f;
   374 
   375                 dst_sample = src1 + src2;
   376                 if (dst_sample > max_audioval) {
   377                     dst_sample = max_audioval;
   378                 } else if (dst_sample < min_audioval) {
   379                     dst_sample = min_audioval;
   380                 }
   381                 cvt.f = ((float) dst_sample);
   382                 cvt.ui32 = SDL_SwapBE32(cvt.ui32);
   383                 *(dst32++) = cvt.f;
   384             }
   385         }
   386         break;
   387 
   388     default:                   /* If this happens... FIXME! */
   389         SDL_SetError("SDL_MixAudio(): unknown audio format");
   390         return;
   391     }
   392 }
   393 
   394 /* vi: set ts=4 sw=4 expandtab: */