ss_output.c

   1 /*
   2
   3     Ann Hell Ex Machina - Music Software
   4     Copyright (C) 2003/2006 Angel Ortega <angel@triptico.com>
   5
   6     ss_output.c - Softsynth output interface
   7
   8     This program is free software; you can redistribute it and/or
   9     modify it under the terms of the GNU General Public License
  10     as published by the Free Software Foundation; either version 2
  11     of the License, or (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21
  22     http://www.triptico.com
  23
  24 */
  25
  26 #include "config.h"
  27
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <unistd.h>
  31 #include <string.h>
  32 #include <math.h>
  33
  34 #include <signal.h>
  35
  36 #include "ahxm.h"
  37
  38 /*******************
  39         Data
  40 ********************/
  41
  42 /* master output volume */
  43 sample_t ss_master_volume = 0.5;
  44
  45 /* output accounting */
  46 int ss_output_clipped = 0;
  47 sample_t ss_max = 0.0;
  48
  49 /* optimal output volume */
  50 sample_t ss_optimal_volume;
  51
  52 /* driver data */
  53 static void * outdev;
  54
  55 /*
  56         usual channel mapping:
  57
  58         mono: all
  59         stereo: left | right
  60         3 channel: left | right | center
  61         quad: front left | front right | rear left | rear right
  62         4 channel: left | center | right | surround
  63         6 channel: left center | left | center | right center | right | surround
  64         home cinema 5.1: front l | center | front r | real l | rear r | subwoofer
  65
  66         Converting from wav to 5.1 ac3:
  67
  68         ffmpeg -ac 6 -ab 192 -ar 44100 -i input.wav output.ac3
  69 */
  70
  71 /* a copy of the output file name */
  72 static char * ss_output_file_name = NULL;
  73
  74 /* cue file name and track */
  75 char * ss_cue_file_name = NULL;
  76 static int ss_cue_file_track = -1;
  77
  78 /*******************
  79         Code
  80 ********************/
  81
  82 void * ss_outdev_open(char * drvname, char * file, int freq, int n_channels);
  83 void ss_outdev_write(void * drv, short int * frame);
  84 void * ss_outdev_close(void * drv);
  85
  86
  87 static void close_on_signal(int sig_num)
  88 /* SIGINT (and other) signal handler */
  89 {
  90         /* close output device */
  91         outdev = ss_outdev_close(outdev);
  92
  93         /* exit */
  94         exit(0);
  95 }
  96
  97
  98 /**
  99  * ss_output_open - Opens an output device.
 100  * @name: name of the driver
 101  * @filename: name of the file or device
 102  *
 103  * Opens an output device. @name contains the name of the driver
 104  * (i.e. "oss" or "wav"), @filename contains the (optional) name
 105  * of the output file or device (i.e. a filename
 106  * "wav" or "/dev/dsp" for a direct audio device like "oss").
 107  * @Name can be the special pseudo-driver "default"
 108  * to select the most appropriate (usually a platform-specific
 109  * direct output device, or "wav" if no one exists).
 110  * @filename can also be NULL; in that case, a driver dependent,
 111  * default value is used.
 112  *
 113  * Returns zero if the output device was correctly open, or
 114  * nonzero otherwise.
 115  */
 116 int ss_output_open(char * drvname, char * filename)
 117 {
 118         if(strcmp(drvname, "default") == 0)
 119                 drvname = NULL;
 120
 121         /* reset accounting */
 122         ss_output_clipped = 0;
 123         ss_max = 0.0;
 124
 125         /* close the device on unexpected signals */
 126         signal(SIGINT, close_on_signal);
 127
 128         /* store a copy of the filename */
 129         ss_output_file_name = filename;
 130
 131         return((outdev = ss_outdev_open(drvname,
 132                 filename, ss_frequency, ss_nchannels)) == NULL);
 133 }
 134
 135
 136 /**
 137  * ss_output_init_frame - Inits a frame
 138  * @frame: the frame
 139  *
 140  * Inits a frame, setting all samples to zero.
 141  */
 142 void ss_output_init_frame(sample_t frame[])
 143 {
 144         memset(frame, '\0', sizeof(sample_t) * SS_MAX_CHANNELS);
 145 }
 146
 147
 148 /**
 149  * ss_output_write - Outputs a frame of samples.
 150  * @frame: the frame of samples
 151  *
 152  * Outputs a frame of samples. Applies master volume, tests for
 153  * maximum amplitudes and clips all saturating ones.
 154  *
 155  * Returns a negative value in case of error, or 0 otherwise.
 156  */
 157 int ss_output_write(sample_t frame[])
 158 {
 159         int n, ret = 0;
 160         sample_t s;
 161         short int is[SS_MAX_CHANNELS];
 162
 163         /* final corrections */
 164         for(n = 0;n < ss_nchannels;n++)
 165         {
 166                 s = frame[n];
 167
 168                 /* test maximum amplitudes, apply master
 169                    volume and clipping */
 170                 if(s < 0)
 171                 {
 172                         if(s < -ss_max) ss_max = -s;
 173                         s *= ss_master_volume;
 174                         if(s < -1) { s = -1; ss_output_clipped++; }
 175                 }
 176                 else
 177                 {
 178                         if(s > ss_max) ss_max = s;
 179                         s *= ss_master_volume;
 180                         if(s > 1) { s = 1; ss_output_clipped++; }
 181                 }
 182
 183                 /* convert to 16 bit signed */
 184                 s *= 32767.0;
 185
 186                 /* store in buffer */
 187                 is[n] = (short int) s;
 188         }
 189
 190         /* finally write */
 191         ss_outdev_write(outdev, is);
 192
 193         return(ret);
 194 }
 195
 196
 197 /**
 198  * ss_output_close - Closes the output device.
 199  *
 200  * Closes the output driver.
 201  */
 202 void ss_output_close(void)
 203 {
 204         /* back to default signal behaviour */
 205         signal(SIGINT, SIG_DFL);
 206
 207         /* close the device */
 208         outdev = ss_outdev_close(outdev);
 209
 210         /* calculate optimal master volume for zero saturation */
 211         if(ss_max)
 212                 ss_optimal_volume = 1 / ss_max;
 213 }
 214
 215
 216 static int cue_file_init(void)
 217 /* inits the cue file, writing the first line */
 218 {
 219         FILE * f;
 220
 221         if(ss_output_file_name == NULL ||
 222                 (f = fopen(ss_cue_file_name, "w")) == NULL)
 223                 return(-2);
 224
 225         /* write first line */
 226         fprintf(f, "FILE \"%s\" WAVE\n", ss_output_file_name);
 227         fclose(f);
 228
 229         ss_cue_file_track = 0;
 230
 231         return(0);
 232 }
 233
 234
 235 int cue_file_song_info(int frame, char * author, char * name)
 236 {
 237         int s;
 238         FILE * f;
 239
 240         if(ss_cue_file_name == NULL)
 241                 return(0);
 242
 243         /* init if it's the first time */
 244         if(ss_cue_file_track == -1)
 245         {
 246                 /* can't open? fail */
 247                 if(cue_file_init() < 0)
 248                 {
 249                         ss_cue_file_name = NULL;
 250                         return(-1);
 251                 }
 252         }
 253
 254         /* open or fail */
 255         if((f = fopen(ss_cue_file_name, "a")) == NULL)
 256                 return(-1);
 257
 258         s = frame / ss_frequency;
 259
 260         fprintf(f, "TRACK %02d AUDIO\n", ss_cue_file_track++);
 261         fprintf(f, "  PERFORMER \"%s\"\n",      author);
 262         fprintf(f, "  TITLE \"%s\"\n", name);
 263         fprintf(f, "  INDEX 01 %02d:%02d:00\n", s / 60, s % 60);
 264
 265         fclose(f);
 266         return(0);
 267 }