snd_mix.c

   1 /*
   2 Copyright (C) 1996-1997 Id Software, Inc.
   3
   4 This program is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU General Public License
   6 as published by the Free Software Foundation; either version 2
   7 of the License, or (at your option) any later version.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  12
  13 See the GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  18
  19 */
  20
  21 #include "quakedef.h"
  22 #include "snd_main.h"
  23
  24 extern cvar_t snd_softclip;
  25
  26 static portable_sampleframe_t paintbuffer[PAINTBUFFER_SIZE];
  27 static portable_sampleframe_t paintbuffer_unswapped[PAINTBUFFER_SIZE];
  28
  29 extern speakerlayout_t snd_speakerlayout; // for querying the listeners
  30
  31 #ifdef CONFIG_VIDEO_CAPTURE
  32 static void S_CaptureAVISound(const portable_sampleframe_t *paintbuffer, size_t length)
  33 {
  34         size_t i;
  35         unsigned int j;
  36
  37         if (!cls.capturevideo.active)
  38                 return;
  39
  40         // undo whatever swapping the channel layout (swapstereo, ALSA) did
  41         for(j = 0; j < snd_speakerlayout.channels; ++j)
  42         {
  43                 unsigned int j0 = snd_speakerlayout.listeners[j].channel_unswapped;
  44                 for(i = 0; i < length; ++i)
  45                         paintbuffer_unswapped[i].sample[j0] = paintbuffer[i].sample[j];
  46         }
  47
  48         SCR_CaptureVideo_SoundFrame(paintbuffer_unswapped, length);
  49 }
  50 #endif
  51
  52 extern cvar_t snd_softclip;
  53
  54 static void S_SoftClipPaintBuffer(portable_sampleframe_t *painted_ptr, int nbframes, int width, int nchannels)
  55 {
  56         int i;
  57
  58         if((snd_softclip.integer == 1 && width <= 2) || snd_softclip.integer > 1)
  59         {
  60                 portable_sampleframe_t *p = painted_ptr;
  61
  62 #if 0
  63 /* Soft clipping, the sound of a dream, thanks to Jon Wattes
  64    post to Musicdsp.org */
  65 #define SOFTCLIP(x) (x) = sin(bound(-M_PI/2, (x), M_PI/2)) * 0.25
  66 #endif
  67
  68                 // let's do a simple limiter instead, seems to sound better
  69                 static float maxvol = 0;
  70                 maxvol = max(1.0f, maxvol * (1.0f - nbframes / (0.4f * snd_renderbuffer->format.speed)));
  71 #define SOFTCLIP(x) if(fabs(x)>maxvol) maxvol=fabs(x); (x) /= maxvol;
  72
  73                 if (nchannels == 8)  // 7.1 surround
  74                 {
  75                         for (i = 0;i < nbframes;i++, p++)
  76                         {
  77                                 SOFTCLIP(p->sample[0]);
  78                                 SOFTCLIP(p->sample[1]);
  79                                 SOFTCLIP(p->sample[2]);
  80                                 SOFTCLIP(p->sample[3]);
  81                                 SOFTCLIP(p->sample[4]);
  82                                 SOFTCLIP(p->sample[5]);
  83                                 SOFTCLIP(p->sample[6]);
  84                                 SOFTCLIP(p->sample[7]);
  85                         }
  86                 }
  87                 else if (nchannels == 6)  // 5.1 surround
  88                 {
  89                         for (i = 0; i < nbframes; i++, p++)
  90                         {
  91                                 SOFTCLIP(p->sample[0]);
  92                                 SOFTCLIP(p->sample[1]);
  93                                 SOFTCLIP(p->sample[2]);
  94                                 SOFTCLIP(p->sample[3]);
  95                                 SOFTCLIP(p->sample[4]);
  96                                 SOFTCLIP(p->sample[5]);
  97                         }
  98                 }
  99                 else if (nchannels == 4)  // 4.0 surround
 100                 {
 101                         for (i = 0; i < nbframes; i++, p++)
 102                         {
 103                                 SOFTCLIP(p->sample[0]);
 104                                 SOFTCLIP(p->sample[1]);
 105                                 SOFTCLIP(p->sample[2]);
 106                                 SOFTCLIP(p->sample[3]);
 107                         }
 108                 }
 109                 else if (nchannels == 2)  // 2.0 stereo
 110                 {
 111                         for (i = 0; i < nbframes; i++, p++)
 112                         {
 113                                 SOFTCLIP(p->sample[0]);
 114                                 SOFTCLIP(p->sample[1]);
 115                         }
 116                 }
 117                 else if (nchannels == 1)  // 1.0 mono
 118                 {
 119                         for (i = 0; i < nbframes; i++, p++)
 120                         {
 121                                 SOFTCLIP(p->sample[0]);
 122                         }
 123                 }
 124 #undef SOFTCLIP
 125         }
 126 }
 127
 128 static void S_ConvertPaintBuffer(portable_sampleframe_t *painted_ptr, void *rb_ptr, int nbframes, int width, int nchannels)
 129 {
 130         int i, val;
 131
 132         // FIXME: add 24bit and 32bit float formats
 133         // FIXME: optimize with SSE intrinsics?
 134         if (width == 2)  // 16bit
 135         {
 136                 short *snd_out = (short*)rb_ptr;
 137                 if (nchannels == 8)  // 7.1 surround
 138                 {
 139                         for (i = 0;i < nbframes;i++, painted_ptr++)
 140                         {
 141                                 val = (int)(painted_ptr->sample[0] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 142                                 val = (int)(painted_ptr->sample[1] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 143                                 val = (int)(painted_ptr->sample[2] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 144                                 val = (int)(painted_ptr->sample[3] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 145                                 val = (int)(painted_ptr->sample[4] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 146                                 val = (int)(painted_ptr->sample[5] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 147                                 val = (int)(painted_ptr->sample[6] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 148                                 val = (int)(painted_ptr->sample[7] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 149                         }
 150                 }
 151                 else if (nchannels == 6)  // 5.1 surround
 152                 {
 153                         for (i = 0; i < nbframes; i++, painted_ptr++)
 154                         {
 155                                 val = (int)(painted_ptr->sample[0] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 156                                 val = (int)(painted_ptr->sample[1] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 157                                 val = (int)(painted_ptr->sample[2] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 158                                 val = (int)(painted_ptr->sample[3] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 159                                 val = (int)(painted_ptr->sample[4] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 160                                 val = (int)(painted_ptr->sample[5] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 161                         }
 162                 }
 163                 else if (nchannels == 4)  // 4.0 surround
 164                 {
 165                         for (i = 0; i < nbframes; i++, painted_ptr++)
 166                         {
 167                                 val = (int)(painted_ptr->sample[0] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 168                                 val = (int)(painted_ptr->sample[1] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 169                                 val = (int)(painted_ptr->sample[2] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 170                                 val = (int)(painted_ptr->sample[3] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 171                         }
 172                 }
 173                 else if (nchannels == 2)  // 2.0 stereo
 174                 {
 175                         for (i = 0; i < nbframes; i++, painted_ptr++)
 176                         {
 177                                 val = (int)(painted_ptr->sample[0] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 178                                 val = (int)(painted_ptr->sample[1] * 32768.0f);*snd_out++ = bound(-32768, val, 32767);
 179                         }
 180                 }
 181                 else if (nchannels == 1)  // 1.0 mono
 182                 {
 183                         for (i = 0; i < nbframes; i++, painted_ptr++)
 184                         {
 185                                 val = (int)((painted_ptr->sample[0] + painted_ptr->sample[1]) * 16384.0f);*snd_out++ = bound(-32768, val, 32767);
 186                         }
 187                 }
 188
 189                 // noise is really really annoying
 190                 if (cls.timedemo)
 191                         memset(rb_ptr, 0, nbframes * nchannels * width);
 192         }
 193         else  // 8bit
 194         {
 195                 unsigned char *snd_out = (unsigned char*)rb_ptr;
 196                 if (nchannels == 8)  // 7.1 surround
 197                 {
 198                         for (i = 0; i < nbframes; i++, painted_ptr++)
 199                         {
 200                                 val = (int)(painted_ptr->sample[0] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 201                                 val = (int)(painted_ptr->sample[1] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 202                                 val = (int)(painted_ptr->sample[2] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 203                                 val = (int)(painted_ptr->sample[3] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 204                                 val = (int)(painted_ptr->sample[4] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 205                                 val = (int)(painted_ptr->sample[5] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 206                                 val = (int)(painted_ptr->sample[6] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 207                                 val = (int)(painted_ptr->sample[7] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 208                         }
 209                 }
 210                 else if (nchannels == 6)  // 5.1 surround
 211                 {
 212                         for (i = 0; i < nbframes; i++, painted_ptr++)
 213                         {
 214                                 val = (int)(painted_ptr->sample[0] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 215                                 val = (int)(painted_ptr->sample[1] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 216                                 val = (int)(painted_ptr->sample[2] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 217                                 val = (int)(painted_ptr->sample[3] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 218                                 val = (int)(painted_ptr->sample[4] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 219                                 val = (int)(painted_ptr->sample[5] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 220                         }
 221                 }
 222                 else if (nchannels == 4)  // 4.0 surround
 223                 {
 224                         for (i = 0; i < nbframes; i++, painted_ptr++)
 225                         {
 226                                 val = (int)(painted_ptr->sample[0] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 227                                 val = (int)(painted_ptr->sample[1] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 228                                 val = (int)(painted_ptr->sample[2] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 229                                 val = (int)(painted_ptr->sample[3] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 230                         }
 231                 }
 232                 else if (nchannels == 2)  // 2.0 stereo
 233                 {
 234                         for (i = 0; i < nbframes; i++, painted_ptr++)
 235                         {
 236                                 val = (int)(painted_ptr->sample[0] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 237                                 val = (int)(painted_ptr->sample[1] * 128.0f) + 128; *snd_out++ = bound(0, val, 255);
 238                         }
 239                 }
 240                 else if (nchannels == 1)  // 1.0 mono
 241                 {
 242                         for (i = 0;i < nbframes;i++, painted_ptr++)
 243                         {
 244                                 val = (int)((painted_ptr->sample[0] + painted_ptr->sample[1]) * 64.0f) + 128; *snd_out++ = bound(0, val, 255);
 245                         }
 246                 }
 247
 248                 // noise is really really annoying
 249                 if (cls.timedemo)
 250                         memset(rb_ptr, 128, nbframes * nchannels);
 251         }
 252 }
 253
 254
 255 /*
 256 ===============================================================================
 257
 258 CHANNEL MIXING
 259
 260 ===============================================================================
 261 */
 262
 263 void S_MixToBuffer(void *stream, unsigned int bufferframes)
 264 {
 265         int channelindex;
 266         channel_t *ch;
 267         int totalmixframes;
 268         unsigned char *outbytes = (unsigned char *) stream;
 269         sfx_t *sfx;
 270         portable_sampleframe_t *paint;
 271         int wantframes;
 272         int i;
 273         int count;
 274         int fetched;
 275         int fetch;
 276         int istartframe;
 277         int iendframe;
 278         int ilengthframes;
 279         int totallength;
 280         int loopstart;
 281         int indexfrac;
 282         int indexfracstep;
 283 #define S_FETCHBUFFERSIZE 4096
 284         float fetchsampleframes[S_FETCHBUFFERSIZE*2];
 285         const float *fetchsampleframe;
 286         float vol[SND_LISTENERS];
 287         float lerp[2];
 288         float sample[3];
 289         double posd;
 290         double speedd;
 291         float maxvol;
 292         qboolean looping;
 293         qboolean silent;
 294
 295         // mix as many times as needed to fill the requested buffer
 296         while (bufferframes)
 297         {
 298                 // limit to the size of the paint buffer
 299                 totalmixframes = min(bufferframes, PAINTBUFFER_SIZE);
 300
 301                 // clear the paint buffer
 302                 memset(paintbuffer, 0, totalmixframes * sizeof(paintbuffer[0]));
 303
 304                 // paint in the channels.
 305                 // channels with zero volumes still advance in time but don't paint.
 306                 ch = channels; // cppcheck complains here but it is wrong, channels is a channel_t[MAX_CHANNELS] and not an int
 307                 for (channelindex = 0;channelindex < (int)total_channels;channelindex++, ch++)
 308                 {
 309                         sfx = ch->sfx;
 310                         if (sfx == NULL)
 311                                 continue;
 312                         if (!S_LoadSound (sfx, true))
 313                                 continue;
 314                         if (ch->flags & CHANNELFLAG_PAUSED)
 315                                 continue;
 316                         if (!sfx->total_length)
 317                                 continue;
 318
 319                         // copy the channel information to the stack for reference, otherwise the
 320                         // values might change during a mix if the spatializer is updating them
 321                         // (note: this still may get some old and some new values!)
 322                         posd = ch->position;
 323                         speedd = ch->mixspeed * sfx->format.speed / snd_renderbuffer->format.speed;
 324                         for (i = 0;i < SND_LISTENERS;i++)
 325                                 vol[i] = ch->volume[i];
 326
 327                         // check total volume level, because we can skip some code on silent sounds but other code must still run (position updates mainly)
 328                         maxvol = 0;
 329                         for (i = 0;i < SND_LISTENERS;i++)
 330                                 if(vol[i] > maxvol)
 331                                         maxvol = vol[i];
 332                         switch(snd_renderbuffer->format.width)
 333                         {
 334                                 case 1: // 8bpp
 335                                         silent = maxvol < (1.0f / (256.0f));
 336                                         // so silent it has zero effect
 337                                         break;
 338                                 case 2: // 16bpp
 339                                         silent = maxvol < (1.0f / (65536.0f));
 340                                         // so silent it has zero effect
 341                                         break;
 342                                 default: // floating point
 343                                         silent = maxvol < 1.0e-13f;
 344                                         // 130 dB is difference between hearing
 345                                         // threshold and a jackhammer from
 346                                         // working distance.
 347                                         // therefore, anyone who turns up
 348                                         // volume so much they notice this
 349                                         // cutoff, likely already has their
 350                                         // ear-drums blown out anyway.
 351                                         break;
 352                         }
 353
 354                         // when doing prologic mixing, some channels invert one side
 355                         if (ch->prologic_invert == -1)
 356                                 vol[1] *= -1.0f;
 357
 358                         // get some sfx info in a consistent form
 359                         totallength = sfx->total_length;
 360                         loopstart = (int)sfx->loopstart < totallength ? (int)sfx->loopstart : ((ch->flags & CHANNELFLAG_FORCELOOP) ? 0 : totallength);
 361                         looping = loopstart < totallength;
 362
 363                         // do the actual paint now (may skip work if silent)
 364                         paint = paintbuffer;
 365                         istartframe = 0;
 366                         for (wantframes = totalmixframes;wantframes > 0;posd += count * speedd, wantframes -= count)
 367                         {
 368                                 // check if this is a delayed sound
 369                                 if (posd < 0)
 370                                 {
 371                                         // for a delayed sound we have to eat into the delay first
 372                                         count = (int)floor(-posd / speedd) + 1;
 373                                         count = bound(1, count, wantframes);
 374                                         // let the for loop iterator apply the skip
 375                                         continue;
 376                                 }
 377
 378                                 // compute a fetch size that won't overflow our buffer
 379                                 count = wantframes;
 380                                 for (;;)
 381                                 {
 382                                         istartframe = (int)floor(posd);
 383                                         iendframe = (int)floor(posd + (count-1) * speedd);
 384                                         ilengthframes = count > 1 ? (iendframe - istartframe + 2) : 2;
 385                                         if (ilengthframes <= S_FETCHBUFFERSIZE)
 386                                                 break;
 387                                         // reduce count by 25% and try again
 388                                         count -= count >> 2;
 389                                 }
 390
 391                                 // zero whole fetch buffer for safety
 392                                 // (floating point noise from uninitialized memory = HORRIBLE)
 393                                 // otherwise we would only need to clear the excess
 394                                 if (!silent)
 395                                         memset(fetchsampleframes, 0, ilengthframes*sfx->format.channels*sizeof(fetchsampleframes[0]));
 396
 397                                 // if looping, do multiple fetches
 398                                 fetched = 0;
 399                                 for (;;)
 400                                 {
 401                                         fetch = min(ilengthframes - fetched, totallength - istartframe);
 402                                         if (fetch > 0)
 403                                         {
 404                                                 if (!silent)
 405                                                         sfx->fetcher->getsamplesfloat(ch, sfx, istartframe, fetch, fetchsampleframes + fetched*sfx->format.channels);
 406                                                 istartframe += fetch;
 407                                                 fetched += fetch;
 408                                         }
 409                                         if (istartframe == totallength && looping && fetched < ilengthframes)
 410                                         {
 411                                                 // loop and fetch some more
 412                                                 posd += loopstart - totallength;
 413                                                 istartframe = loopstart;
 414                                         }
 415                                         else
 416                                         {
 417                                                 break;
 418                                         }
 419                                 }
 420
 421                                 // set up our fixedpoint resampling variables (float to int conversions are expensive so do not do one per sampleframe)
 422                                 fetchsampleframe = fetchsampleframes;
 423                                 indexfrac = (int)floor((posd - floor(posd)) * 65536.0);
 424                                 indexfracstep = (int)floor(speedd * 65536.0);
 425                                 if (!silent)
 426                                 {
 427                                         if (sfx->format.channels == 2)
 428                                         {
 429                                                 // music is stereo
 430 #if SND_LISTENERS != 8
 431 #error the following code only supports up to 8 channels, update it
 432 #endif
 433                                                 if (snd_speakerlayout.channels > 2)
 434                                                 {
 435                                                         // surround mixing
 436                                                         for (i = 0;i < count;i++, paint++)
 437                                                         {
 438                                                                 lerp[1] = indexfrac * (1.0f / 65536.0f);
 439                                                                 lerp[0] = 1.0f - lerp[1];
 440                                                                 sample[0] = fetchsampleframe[0] * lerp[0] + fetchsampleframe[2] * lerp[1];
 441                                                                 sample[1] = fetchsampleframe[1] * lerp[0] + fetchsampleframe[3] * lerp[1];
 442                                                                 sample[2] = (sample[0] + sample[1]) * 0.5f;
 443                                                                 paint->sample[0] += sample[0] * vol[0];
 444                                                                 paint->sample[1] += sample[1] * vol[1];
 445                                                                 paint->sample[2] += sample[0] * vol[2];
 446                                                                 paint->sample[3] += sample[1] * vol[3];
 447                                                                 paint->sample[4] += sample[2] * vol[4];
 448                                                                 paint->sample[5] += sample[2] * vol[5];
 449                                                                 paint->sample[6] += sample[0] * vol[6];
 450                                                                 paint->sample[7] += sample[1] * vol[7];
 451                                                                 indexfrac += indexfracstep;
 452                                                                 fetchsampleframe += 2 * (indexfrac >> 16);
 453                                                                 indexfrac &= 0xFFFF;
 454                                                         }
 455                                                 }
 456                                                 else
 457                                                 {
 458                                                         // stereo mixing
 459                                                         for (i = 0;i < count;i++, paint++)
 460                                                         {
 461                                                                 lerp[1] = indexfrac * (1.0f / 65536.0f);
 462                                                                 lerp[0] = 1.0f - lerp[1];
 463                                                                 sample[0] = fetchsampleframe[0] * lerp[0] + fetchsampleframe[2] * lerp[1];
 464                                                                 sample[1] = fetchsampleframe[1] * lerp[0] + fetchsampleframe[3] * lerp[1];
 465                                                                 paint->sample[0] += sample[0] * vol[0];
 466                                                                 paint->sample[1] += sample[1] * vol[1];
 467                                                                 indexfrac += indexfracstep;
 468                                                                 fetchsampleframe += 2 * (indexfrac >> 16);
 469                                                                 indexfrac &= 0xFFFF;
 470                                                         }
 471                                                 }
 472                                         }
 473                                         else if (sfx->format.channels == 1)
 474                                         {
 475                                                 // most sounds are mono
 476 #if SND_LISTENERS != 8
 477 #error the following code only supports up to 8 channels, update it
 478 #endif
 479                                                 if (snd_speakerlayout.channels > 2)
 480                                                 {
 481                                                         // surround mixing
 482                                                         for (i = 0;i < count;i++, paint++)
 483                                                         {
 484                                                                 lerp[1] = indexfrac * (1.0f / 65536.0f);
 485                                                                 lerp[0] = 1.0f - lerp[1];
 486                                                                 sample[0] = fetchsampleframe[0] * lerp[0] + fetchsampleframe[1] * lerp[1];
 487                                                                 paint->sample[0] += sample[0] * vol[0];
 488                                                                 paint->sample[1] += sample[0] * vol[1];
 489                                                                 paint->sample[2] += sample[0] * vol[2];
 490                                                                 paint->sample[3] += sample[0] * vol[3];
 491                                                                 paint->sample[4] += sample[0] * vol[4];
 492                                                                 paint->sample[5] += sample[0] * vol[5];
 493                                                                 paint->sample[6] += sample[0] * vol[6];
 494                                                                 paint->sample[7] += sample[0] * vol[7];
 495                                                                 indexfrac += indexfracstep;
 496                                                                 fetchsampleframe += (indexfrac >> 16);
 497                                                                 indexfrac &= 0xFFFF;
 498                                                         }
 499                                                 }
 500                                                 else
 501                                                 {
 502                                                         // stereo mixing
 503                                                         for (i = 0;i < count;i++, paint++)
 504                                                         {
 505                                                                 lerp[1] = indexfrac * (1.0f / 65536.0f);
 506                                                                 lerp[0] = 1.0f - lerp[1];
 507                                                                 sample[0] = fetchsampleframe[0] * lerp[0] + fetchsampleframe[1] * lerp[1];
 508                                                                 paint->sample[0] += sample[0] * vol[0];
 509                                                                 paint->sample[1] += sample[0] * vol[1];
 510                                                                 indexfrac += indexfracstep;
 511                                                                 fetchsampleframe += (indexfrac >> 16);
 512                                                                 indexfrac &= 0xFFFF;
 513                                                         }
 514                                                 }
 515                                         }
 516                                 }
 517                         }
 518                         ch->position = posd;
 519                         if (!looping && istartframe == totallength)
 520                                 S_StopChannel(ch - channels, false, false);
 521                 }
 522
 523                 S_SoftClipPaintBuffer(paintbuffer, totalmixframes, snd_renderbuffer->format.width, snd_renderbuffer->format.channels);
 524
 525 #ifdef CONFIG_VIDEO_CAPTURE
 526                 if (!snd_usethreadedmixing)
 527                         S_CaptureAVISound(paintbuffer, totalmixframes);
 528 #endif
 529
 530                 S_ConvertPaintBuffer(paintbuffer, outbytes, totalmixframes, snd_renderbuffer->format.width, snd_renderbuffer->format.channels);
 531
 532                 // advance the output pointer
 533                 outbytes += totalmixframes * snd_renderbuffer->format.width * snd_renderbuffer->format.channels;
 534                 bufferframes -= totalmixframes;
 535         }
 536 }