jack_meter.c

   1 /*
   2
   3         jackmeter.c
   4         Simple console based Digital Peak Meter for JACK
   5         Copyright (C) 2005  Nicholas J. Humfrey
   6
   7         This program is free software; you can redistribute it and/or
   8         modify it under the terms of the GNU General Public License
   9         as published by the Free Software Foundation; either version 2
  10         of the License, or (at your option) any later version.
  11
  12         This program is distributed in the hope that it will be useful,
  13         but WITHOUT ANY WARRANTY; without even the implied warranty of
  14         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15         GNU General Public License for more details.
  16
  17         You should have received a copy of the GNU General Public License
  18         along with this program; if not, write to the Free Software
  19         Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  20
  21 */
  22
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25 #include <math.h>
  26 #include <string.h>
  27 #include <sys/types.h>
  28 #include <unistd.h>
  29
  30 #include <jack/jack.h>
  31 #include <getopt.h>
  32 #include "config.h"
  33
  34
  35 float bias = 1.0f;
  36 float peak = 0.0f;
  37
  38 int dpeak = 0;
  39 int dtime = 0;
  40 int decay_len;
  41
  42 jack_port_t *input_port = NULL;
  43 jack_client_t *client = NULL;
  44
  45
  46
  47 /* Read and reset the recent peak sample */
  48 static float read_peak()
  49 {
  50         float tmp = peak;
  51         peak = 0.0f;
  52
  53         return tmp;
  54 }
  55
  56
  57 /* Callback called by JACK when audio is available.
  58    Stores value of peak sample */
  59 static int process_peak(jack_nframes_t nframes, void *arg)
  60 {
  61         jack_default_audio_sample_t *in;
  62         unsigned int i;
  63
  64
  65         /* just incase the port isn't registered yet */
  66         if (input_port == NULL) {
  67                 return 0;
  68         }
  69
  70
  71         /* get the audio samples, and find the peak sample */
  72         in = (jack_default_audio_sample_t *) jack_port_get_buffer(input_port, nframes);
  73         for (i = 0; i < nframes; i++) {
  74                 const float s = fabs(in[i]);
  75                 if (s > peak) {
  76                         peak = s;
  77                 }
  78         }
  79
  80
  81         return 0;
  82 }
  83
  84
  85 /*
  86         db: the signal stength in db
  87         width: the size of the meter
  88 */
  89 static int iec_scale(float db, int size) {
  90         float def = 0.0f; /* Meter deflection %age */
  91
  92         if (db < -70.0f) {
  93                 def = 0.0f;
  94         } else if (db < -60.0f) {
  95                 def = (db + 70.0f) * 0.25f;
  96         } else if (db < -50.0f) {
  97                 def = (db + 60.0f) * 0.5f + 2.5f;
  98         } else if (db < -40.0f) {
  99                 def = (db + 50.0f) * 0.75f + 7.5;
 100         } else if (db < -30.0f) {
 101                 def = (db + 40.0f) * 1.5f + 15.0f;
 102         } else if (db < -20.0f) {
 103                 def = (db + 30.0f) * 2.0f + 30.0f;
 104         } else if (db < 0.0f) {
 105                 def = (db + 20.0f) * 2.5f + 50.0f;
 106         } else {
 107                 def = 100.0f;
 108         }
 109
 110         return (int)( (def / 100.0f) * ((float) size) );
 111 }
 112
 113
 114 /* Close down JACK when exiting */
 115 static void cleanup()
 116 {
 117         const char **all_ports;
 118         unsigned int i;
 119
 120         fprintf(stderr,"cleanup()\n");
 121
 122         if (input_port != NULL ) {
 123
 124                 all_ports = jack_port_get_all_connections(client, input_port);
 125
 126                 for (i=0; all_ports && all_ports[i]; i++) {
 127                         jack_disconnect(client, all_ports[i], jack_port_name(input_port));
 128                 }
 129         }
 130
 131         /* Leave the jack graph */
 132         jack_client_close(client);
 133
 134 }
 135
 136
 137 /* Connect the chosen port to ours */
 138 static void connect_port(jack_client_t *client, char *port_name)
 139 {
 140         jack_port_t *port;
 141
 142         // Get the port we are connecting to
 143         port = jack_port_by_name(client, port_name);
 144         if (port == NULL) {
 145                 fprintf(stderr, "Can't find port '%s'\n", port_name);
 146                 exit(1);
 147         }
 148
 149         // Connect the port to our input port
 150         printf("Connecting '%s' to '%s'...\n", jack_port_name(port), jack_port_name(input_port));
 151         if (jack_connect(client, jack_port_name(port), jack_port_name(input_port))) {
 152                 fprintf(stderr, "Cannot connect port '%s' to '%s'\n", jack_port_name(port), jack_port_name(input_port));
 153                 exit(1);
 154         }
 155 }
 156
 157
 158 /* Sleep for a fraction of a second */
 159 static int fsleep( float secs )
 160 {
 161
 162 //#ifdef HAVE_USLEEP
 163         return usleep( secs * 1000000 );
 164 //#endif
 165 }
 166
 167
 168 /* Display how to use this program */
 169 static int usage( const char * progname )
 170 {
 171         fprintf(stderr, "jackmeter version %s\n\n", VERSION);
 172         fprintf(stderr, "Usage %s [-f freqency] [-r ref-level] [-w width] [<port>]\n\n", progname);
 173         fprintf(stderr, "where  freqency is how often to update the meter per second [8]\n");
 174         fprintf(stderr, "       ref-level is the reference signal level for 0dB on the meter\n");
 175         fprintf(stderr, "       width is how wide to make the meter [79]\n");
 176         fprintf(stderr, "       port is the JACK port to monitor\n");
 177         exit(1);
 178 }
 179
 180
 181 void display_scale( int width )
 182 {
 183         int i=0;
 184         const int marks[11] = { 0, -5, -10, -15, -20, -25, -30, -35, -40, -50, -60 };
 185         char *scale = malloc( width+1 );
 186         char *line = malloc( width+1 );
 187
 188
 189         // Initialise the scale
 190         for(i=0; i<width; i++) { scale[i] = ' '; line[i]='_'; }
 191         scale[width] = 0;
 192         line[width] = 0;
 193
 194
 195         // 'draw' on each of the db marks
 196         for(i=0; i < 11; i++) {
 197                 char mark[5];
 198                 int pos = iec_scale( marks[i], width )-1;
 199                 int spos, slen;
 200
 201                 // Create string of the db value
 202                 snprintf(mark, 4, "%d", marks[i]);
 203
 204                 // Position the label string
 205                 slen = strlen(mark);
 206                 spos = pos-(slen/2);
 207                 if (spos<0) spos=0;
 208                 if (spos+strlen(mark)>width) spos=width-slen;
 209                 memcpy( scale+spos, mark, slen );
 210
 211                 // Position little marker
 212                 line[pos] = '|';
 213         }
 214
 215         // Print it to screen
 216         printf("%s\n", scale);
 217         printf("%s\n", line);
 218         free(scale);
 219         free(line);
 220 }
 221
 222
 223 void display_meter( float peak, int width )
 224 {
 225         float db = 20.0f * log10f(peak * bias);
 226         int size = iec_scale( db, width );
 227         int i;
 228
 229         if (size > dpeak) {
 230                 dpeak = size;
 231                 dtime = 0;
 232         } else if (dtime++ > decay_len) {
 233                 dpeak = size;
 234         }
 235
 236         printf("\r");
 237
 238         for(i=0; i<size-1; i++) { printf("#"); }
 239
 240         if (dpeak==size) {
 241                 printf("I");
 242         } else {
 243                 printf("#");
 244                 for(i=0; i<dpeak-size-1; i++) { printf(" "); }
 245                 printf("I");
 246         }
 247
 248         for(i=0; i<width-dpeak; i++) { printf(" "); }
 249 }
 250
 251
 252 int main(int argc, char *argv[])
 253 {
 254         int console_width = 79;
 255         char client_name[255];
 256         int running = 1;
 257         float ref_lev;
 258         int rate = 8;
 259         int opt;
 260
 261         // Make STDOUT unbuffered
 262         setbuf(stdout, NULL);
 263
 264         while ((opt = getopt(argc, argv, "w:f:r:h")) != -1) {
 265                 switch (opt) {
 266                         case 'r':
 267                                 ref_lev = atof(optarg);
 268                                 printf("Reference level: %.1fdB\n", ref_lev);
 269                                 bias = powf(10.0f, ref_lev * -0.05f);
 270                                 break;
 271                         case 'f':
 272                                 rate = atoi(optarg);
 273                                 printf("Updates per second: %d\n", rate);
 274                                 break;
 275                         case 'w':
 276                                 console_width = atoi(optarg);
 277                                 printf("Console Width: %d\n", console_width);
 278                                 break;
 279                         case 'h':
 280                                 /* Force help to be shown */
 281                                 usage( argv[0] );
 282                                 break;
 283                         default:
 284                                 usage( argv[0] );
 285                                 break;
 286                 }
 287         }
 288
 289
 290
 291         // Register with Jack
 292         snprintf(client_name, 255, "meter-%d", getpid());
 293         if ((client = jack_client_new(client_name)) == 0) {
 294                 fprintf(stderr, "JACK server not running?\n");
 295                 exit(1);
 296         }
 297         printf("Registering as %s.\n", client_name);
 298
 299         // Create our input port
 300         if (!(input_port = jack_port_register(client, "meter", JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput, 0))) {
 301                 fprintf(stderr, "Cannot register input port 'meter'.\n");
 302                 exit(1);
 303         }
 304
 305         // Register the cleanup function to be called when program exits
 306         atexit( cleanup );
 307
 308         // Register the peak signal callback
 309         jack_set_process_callback(client, process_peak, 0);
 310
 311
 312         if (jack_activate(client)) {
 313                 fprintf(stderr, "Cannot activate client.\n");
 314                 exit(1);
 315         }
 316
 317
 318         // Connect our port to specified port
 319         if (argc > optind) {
 320                 connect_port( client, argv[ optind ] );
 321         } else {
 322                 printf("Meter is not connected to a port.\n");
 323         }
 324
 325         // Calculate the decay length (should be 1600ms)
 326         decay_len = (int)(1.6f / (1.0f/rate));
 327
 328
 329         // Display the scale
 330         display_scale( console_width );
 331
 332         while (running) {
 333                 display_meter( read_peak(), console_width );
 334                 fsleep( 1.0f/rate );
 335         }
 336
 337         return 0;
 338 }
 339