sys/v4l2/v4l2_calls.c

   1 /* G-Streamer generic V4L2 element - generic V4L2 calls handling
   2  * Copyright (C) 2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library 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.  See the GNU
  12  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #include <config.h>
  22 #endif
  23
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <fcntl.h>
  27 #include <sys/ioctl.h>
  28 #include <sys/mman.h>
  29 #include <string.h>
  30 #include <errno.h>
  31 #include <unistd.h>
  32 #include "v4l2_calls.h"
  33 #include "gstv4l2tuner.h"
  34 #include "gstv4l2xoverlay.h"
  35 #include "gstv4l2colorbalance.h"
  36
  37 #include "gstv4l2src.h"
  38
  39 #define DEBUG(format, args...) \
  40         GST_DEBUG_OBJECT (\
  41                 GST_ELEMENT(v4l2element), \
  42                 "V4L2: " format, ##args)
  43
  44
  45 /******************************************************
  46  * gst_v4l2_get_capabilities():
  47  *   get the device's capturing capabilities
  48  * return value: TRUE on success, FALSE on error
  49  ******************************************************/
  50
  51 static gboolean
  52 gst_v4l2_get_capabilities (GstV4l2Element *v4l2element)
  53 {
  54         DEBUG("getting capabilities");
  55         GST_V4L2_CHECK_OPEN(v4l2element);
  56
  57         if (ioctl(v4l2element->video_fd, VIDIOC_QUERYCAP, &(v4l2element->vcap)) < 0) {
  58                 gst_element_error(GST_ELEMENT(v4l2element),
  59                         "Error getting %s capabilities: %s",
  60                         v4l2element->device, g_strerror(errno));
  61                 return FALSE;
  62         }
  63
  64         return TRUE;
  65 }
  66
  67
  68 /******************************************************
  69  * gst_v4l2_empty_lists() and gst_v4l2_fill_lists():
  70  *   fill/empty the lists of enumerations
  71  * return value: TRUE on success, FALSE on error
  72  ******************************************************/
  73
  74 static gboolean
  75 gst_v4l2_fill_lists (GstV4l2Element *v4l2element)
  76 {
  77         gint n;
  78         const GList *pads =
  79                 gst_element_get_pad_list (GST_ELEMENT (v4l2element));
  80         GstPadDirection dir = GST_PAD_UNKNOWN;
  81
  82         DEBUG("getting enumerations");
  83         GST_V4L2_CHECK_OPEN(v4l2element);
  84
  85         /* sinks have outputs, all others have inputs */
  86         if (pads && g_list_length ((GList *) pads) == 1)
  87                 dir = GST_PAD_DIRECTION (GST_PAD (pads->data));
  88
  89         if (dir != GST_PAD_SINK) {
  90         /* and now, the inputs */
  91                 for (n=0;;n++) {
  92                         struct v4l2_input input;
  93                         GstV4l2TunerChannel *v4l2channel;
  94                         GstTunerChannel *channel;
  95
  96                         input.index = n;
  97                         if (ioctl(v4l2element->video_fd, VIDIOC_ENUMINPUT,
  98                                   &input) < 0) {
  99                                 if (errno == EINVAL)
 100                                         break; /* end of enumeration */
 101                                 else {
 102                                         gst_element_error(GST_ELEMENT(v4l2element),
 103                                                 "Failed to get no. %d in input enumeration for %s: %s",
 104                                                 n, v4l2element->device,
 105                                                 g_strerror(errno));
 106                                         return FALSE;
 107                                 }
 108                         }
 109
 110                         v4l2channel =
 111                                 g_object_new(GST_TYPE_V4L2_TUNER_CHANNEL, NULL);
 112                         channel = GST_TUNER_CHANNEL(v4l2channel);
 113                         channel->label = g_strdup(input.name);
 114                         channel->flags = GST_TUNER_CHANNEL_INPUT;
 115                         v4l2channel->index = n;
 116                         if (input.type == V4L2_INPUT_TYPE_TUNER) {
 117                                 struct v4l2_tuner vtun;
 118
 119                                 v4l2channel->tuner = input.tuner;
 120                                 channel->flags |= GST_TUNER_CHANNEL_FREQUENCY;
 121
 122                                 vtun.index = input.tuner;
 123                                 if (ioctl(v4l2element->video_fd, VIDIOC_G_TUNER,
 124                                           &vtun) < 0) {
 125                                         gst_element_error(GST_ELEMENT(v4l2element),
 126                                                 "Failed to get tuner %d settings on %s: %s",
 127                                                 input.tuner,
 128                                                 v4l2element->device,
 129                                                 g_strerror(errno));
 130                                         g_object_unref(G_OBJECT(channel));
 131                                         return FALSE;
 132                                 }
 133                                 channel->min_frequency = vtun.rangelow;
 134                                 channel->max_frequency = vtun.rangehigh;
 135                                 channel->min_signal = 0;
 136                                 channel->max_signal = 0xffff;
 137                         }
 138                         if (input.audioset) {
 139                                 /* we take the first. We don't care for
 140                                  * the others for now */
 141                                 while (!(input.audioset &
 142                                          (1<<v4l2channel->audio)))
 143                                         v4l2channel->audio++;
 144                                 channel->flags |= GST_TUNER_CHANNEL_AUDIO;
 145                         }
 146
 147                         v4l2element->channels =
 148                                 g_list_append(v4l2element->channels,
 149                                               (gpointer) channel);
 150                 }
 151         } else {
 152                 /* outputs */
 153                 for (n=0;;n++) {
 154                         struct v4l2_output output;
 155                         GstV4l2TunerChannel *v4l2channel;
 156                         GstTunerChannel *channel;
 157
 158                         output.index = n;
 159                         if (ioctl(v4l2element->video_fd, VIDIOC_ENUMOUTPUT,
 160                                   &output) < 0) {
 161                                 if (errno == EINVAL)
 162                                         break; /* end of enumeration */
 163                                 else {
 164                                         gst_element_error(GST_ELEMENT(v4l2element),
 165                                                 "Failed to get no. %d in output enumeration for %s: %s",
 166                                                 n, v4l2element->device,
 167                                                 g_strerror(errno));
 168                                         return FALSE;
 169                                 }
 170                         }
 171
 172                         v4l2channel = g_object_new(GST_TYPE_V4L2_TUNER_CHANNEL, NULL);
 173                         channel = GST_TUNER_CHANNEL(v4l2channel);
 174                         channel->label = g_strdup(output.name);
 175                         channel->flags = GST_TUNER_CHANNEL_OUTPUT;
 176                         v4l2channel->index = n;
 177                         if (output.audioset) {
 178                                 /* we take the first. We don't care for
 179                                  * the others for now */
 180                                 while (!(output.audioset &
 181                                          (1<<v4l2channel->audio)))
 182                                         v4l2channel->audio++;
 183                                 channel->flags |= GST_TUNER_CHANNEL_AUDIO;
 184                         }
 185
 186                         v4l2element->channels =
 187                                 g_list_append(v4l2element->channels,
 188                                               (gpointer) channel);
 189                 }
 190         }
 191
 192         /* norms... */
 193         for (n=0;;n++) {
 194                 struct v4l2_standard standard;
 195                 GstV4l2TunerNorm *v4l2norm;
 196                 GstTunerNorm *norm;
 197
 198                 standard.index = n;
 199                 if (ioctl(v4l2element->video_fd, VIDIOC_ENUMSTD, &standard) < 0) {
 200                         if (errno == EINVAL)
 201                                 break; /* end of enumeration */
 202                         else {
 203                                 gst_element_error(GST_ELEMENT(v4l2element),
 204                                         "Failed to get no. %d in norm enumeration for %s: %s",
 205                                         n, v4l2element->device, g_strerror(errno));
 206                                 return FALSE;
 207                         }
 208                 }
 209
 210                 v4l2norm = g_object_new(GST_TYPE_V4L2_TUNER_NORM, NULL);
 211                 norm = GST_TUNER_NORM (v4l2norm);
 212                 norm->label = g_strdup(standard.name);
 213                 norm->fps = (gfloat) standard.frameperiod.denominator /
 214                                 standard.frameperiod.numerator;
 215                 v4l2norm->index = standard.id;
 216
 217                 v4l2element->norms = g_list_append(v4l2element->norms,
 218                                                    (gpointer) norm);
 219         }
 220
 221         /* and lastly, controls+menus (if appropriate) */
 222         for (n=V4L2_CID_BASE;;n++) {
 223                 struct v4l2_queryctrl control;
 224                 GstV4l2ColorBalanceChannel *v4l2channel;
 225                 GstColorBalanceChannel *channel;
 226
 227                 /* hacky... */
 228                 if (n == V4L2_CID_LASTP1)
 229                         n = V4L2_CID_PRIVATE_BASE;
 230
 231                 control.id = n;
 232                 if (ioctl(v4l2element->video_fd, VIDIOC_QUERYCTRL, &control) < 0) {
 233                         if (errno == EINVAL) {
 234                                 if (n < V4L2_CID_PRIVATE_BASE)
 235                                         continue;
 236                                 else
 237                                         break;
 238                         } else {
 239                                 gst_element_error(GST_ELEMENT(v4l2element),
 240                                         "Failed to get no. %d in control enumeration for %s: %s",
 241                                         n, v4l2element->device, g_strerror(errno));
 242                                 return FALSE;
 243                         }
 244                 }
 245                 if (control.flags & V4L2_CTRL_FLAG_DISABLED)
 246                         continue;
 247
 248                 switch (n) {
 249                         case V4L2_CID_BRIGHTNESS:
 250                         case V4L2_CID_CONTRAST:
 251                         case V4L2_CID_SATURATION:
 252                         case V4L2_CID_HUE:
 253                         case V4L2_CID_BLACK_LEVEL:
 254                         case V4L2_CID_AUTO_WHITE_BALANCE:
 255                         case V4L2_CID_DO_WHITE_BALANCE:
 256                         case V4L2_CID_RED_BALANCE:
 257                         case V4L2_CID_BLUE_BALANCE:
 258                         case V4L2_CID_GAMMA:
 259                         case V4L2_CID_EXPOSURE:
 260                         case V4L2_CID_AUTOGAIN:
 261                         case V4L2_CID_GAIN:
 262                                 /* we only handle these for now */
 263                                 break;
 264                         default:
 265                                 DEBUG("ControlID %s (%d) unhandled, FIXME",
 266                                       control.name, n);
 267                                 control.id++;
 268                                 break;
 269                 }
 270                 if (n != control.id)
 271                         continue;
 272
 273                 v4l2channel = g_object_new(GST_TYPE_V4L2_COLOR_BALANCE_CHANNEL,
 274                                            NULL);
 275                 channel = GST_COLOR_BALANCE_CHANNEL(v4l2channel);
 276                 channel->label = g_strdup(control.name);
 277                 v4l2channel->index = n;
 278
 279 #if 0
 280                 if (control.type == V4L2_CTRL_TYPE_MENU) {
 281                         struct v4l2_querymenu menu, *mptr;
 282                         int i;
 283                         menu.id = n;
 284                         for (i=0;;i++) {
 285                                 menu.index = i;
 286                                 if (ioctl(v4l2element->video_fd, VIDIOC_QUERYMENU, &menu) < 0) {
 287                                         if (errno == EINVAL)
 288                                                 break; /* end of enumeration */
 289                                         else {
 290                                                 gst_element_error(GST_ELEMENT(v4l2element),
 291                                                         "Failed to get no. %d in menu %d enumeration for %s: %s",
 292                                                         i, n, v4l2element->device, g_strerror(errno));
 293                                                 return FALSE;
 294                                         }
 295                                 }
 296                                 mptr = g_malloc(sizeof(menu));
 297                                 memcpy(mptr, &menu, sizeof(menu));
 298                                 menus = g_list_append(menus, mptr);
 299                         }
 300                 }
 301                 v4l2element->menus = g_list_append(v4l2element->menus, menus);
 302 #endif
 303
 304                 switch (control.type) {
 305                         case V4L2_CTRL_TYPE_INTEGER:
 306                                 channel->min_value = control.minimum;
 307                                 channel->max_value = control.maximum;
 308                                 break;
 309                         case V4L2_CTRL_TYPE_BOOLEAN:
 310                                 channel->min_value = FALSE;
 311                                 channel->max_value = TRUE;
 312                                 break;
 313                         default:
 314                                 channel->min_value =
 315                                         channel->max_value = 0;
 316                                 break;
 317                 }
 318
 319                 v4l2element->colors = g_list_append(v4l2element->colors,
 320                                                     (gpointer) channel);
 321         }
 322
 323         return TRUE;
 324 }
 325
 326
 327 static void
 328 gst_v4l2_empty_lists (GstV4l2Element *v4l2element)
 329 {
 330         DEBUG("deleting enumerations");
 331
 332         g_list_foreach (v4l2element->channels, (GFunc) g_object_unref, NULL);
 333         g_list_free (v4l2element->channels);
 334         v4l2element->channels = NULL;
 335
 336         g_list_foreach (v4l2element->norms, (GFunc) g_object_unref, NULL);
 337         g_list_free (v4l2element->norms);
 338         v4l2element->norms = NULL;
 339
 340         g_list_foreach (v4l2element->colors, (GFunc) g_object_unref, NULL);
 341         g_list_free (v4l2element->colors);
 342         v4l2element->colors = NULL;
 343 }
 344
 345
 346 /******************************************************
 347  * gst_v4l2_open():
 348  *   open the video device (v4l2element->device)
 349  * return value: TRUE on success, FALSE on error
 350  ******************************************************/
 351
 352 gboolean
 353 gst_v4l2_open (GstV4l2Element *v4l2element)
 354 {
 355         DEBUG("Trying to open device %s", v4l2element->device);
 356         GST_V4L2_CHECK_NOT_OPEN(v4l2element);
 357         GST_V4L2_CHECK_NOT_ACTIVE(v4l2element);
 358
 359         /* be sure we have a device */
 360         if (!v4l2element->device)
 361                 v4l2element->device = g_strdup("/dev/video");
 362
 363         /* open the device */
 364         v4l2element->video_fd = open(v4l2element->device, O_RDWR);
 365         if (!GST_V4L2_IS_OPEN(v4l2element)) {
 366                 gst_element_error(GST_ELEMENT(v4l2element),
 367                         "Failed to open device %s: %s",
 368                         v4l2element->device, g_strerror(errno));
 369                 goto error;
 370         }
 371
 372         /* get capabilities */
 373         if (!gst_v4l2_get_capabilities(v4l2element)) {
 374                 goto error;
 375         }
 376
 377         /* do we need to be a capture device? */
 378         if (GST_IS_V4L2SRC(v4l2element) &&
 379             !(v4l2element->vcap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
 380                 gst_element_error(GST_ELEMENT(v4l2element),
 381                                   "Not a capture device (0x%x)",
 382                                   v4l2element->vcap.capabilities);
 383                 goto error;
 384         }
 385
 386         /* create enumerations */
 387         if (!gst_v4l2_fill_lists(v4l2element))
 388                 goto error;
 389
 390         gst_info("Opened device '%s' (%s) successfully\n",
 391                 v4l2element->vcap.card, v4l2element->device);
 392
 393         return TRUE;
 394
 395 error:
 396         if (GST_V4L2_IS_OPEN(v4l2element)) {
 397                 /* close device */
 398                 close(v4l2element->video_fd);
 399                 v4l2element->video_fd = -1;
 400         }
 401         /* empty lists */
 402         gst_v4l2_empty_lists(v4l2element);
 403
 404         return FALSE;
 405 }
 406
 407
 408 /******************************************************
 409  * gst_v4l2_close():
 410  *   close the video device (v4l2element->video_fd)
 411  * return value: TRUE on success, FALSE on error
 412  ******************************************************/
 413
 414 gboolean
 415 gst_v4l2_close (GstV4l2Element *v4l2element)
 416 {
 417         DEBUG("Trying to close %s", v4l2element->device);
 418         GST_V4L2_CHECK_OPEN(v4l2element);
 419         GST_V4L2_CHECK_NOT_ACTIVE(v4l2element);
 420
 421         /* close device */
 422         close(v4l2element->video_fd);
 423         v4l2element->video_fd = -1;
 424
 425         /* empty lists */
 426         gst_v4l2_empty_lists(v4l2element);
 427
 428         return TRUE;
 429 }
 430
 431
 432 /******************************************************
 433  * gst_v4l2_get_norm()
 434  *   Get the norm of the current device
 435  * return value: TRUE on success, FALSE on error
 436  ******************************************************/
 437
 438 gboolean
 439 gst_v4l2_get_norm (GstV4l2Element *v4l2element,
 440                    v4l2_std_id    *norm)
 441 {
 442         DEBUG("getting norm");
 443         GST_V4L2_CHECK_OPEN(v4l2element);
 444
 445         if (ioctl(v4l2element->video_fd, VIDIOC_G_STD, norm) < 0) {
 446                 gst_element_error(GST_ELEMENT(v4l2element),
 447                         "Failed to get the current norm for device %s: %s",
 448                         v4l2element->device, g_strerror(errno));
 449                 return FALSE;
 450         }
 451
 452         return TRUE;
 453 }
 454
 455
 456 /******************************************************
 457  * gst_v4l2_set_norm()
 458  *   Set the norm of the current device
 459  * return value: TRUE on success, FALSE on error
 460  ******************************************************/
 461
 462 gboolean
 463 gst_v4l2_set_norm (GstV4l2Element *v4l2element,
 464                    v4l2_std_id     norm)
 465 {
 466         DEBUG("trying to set norm to %llx", norm);
 467         GST_V4L2_CHECK_OPEN(v4l2element);
 468         GST_V4L2_CHECK_NOT_ACTIVE(v4l2element);
 469
 470         if (ioctl(v4l2element->video_fd, VIDIOC_S_STD, &norm) < 0) {
 471                 gst_element_error(GST_ELEMENT(v4l2element),
 472                         "Failed to set norm 0x%llx for device %s: %s",
 473                         norm, v4l2element->device, g_strerror(errno));
 474                 return FALSE;
 475         }
 476
 477         return TRUE;
 478 }
 479
 480
 481 /******************************************************
 482  * gst_v4l2_get_input()
 483  *   Get the input of the current device
 484  * return value: TRUE on success, FALSE on error
 485  ******************************************************/
 486
 487 gboolean
 488 gst_v4l2_get_input (GstV4l2Element *v4l2element,
 489                     gint           *input)
 490 {
 491         gint n;
 492
 493         DEBUG("trying to get input");
 494         GST_V4L2_CHECK_OPEN(v4l2element);
 495
 496         if (ioctl(v4l2element->video_fd, VIDIOC_G_INPUT, &n) < 0) {
 497                 gst_element_error(GST_ELEMENT(v4l2element),
 498                         "Failed to get current input on device %s: %s",
 499                         v4l2element->device, g_strerror(errno));
 500                 return FALSE;
 501         }
 502
 503         *input = n;
 504
 505         return TRUE;
 506 }
 507
 508
 509 /******************************************************
 510  * gst_v4l2_set_input()
 511  *   Set the input of the current device
 512  * return value: TRUE on success, FALSE on error
 513  ******************************************************/
 514
 515 gboolean
 516 gst_v4l2_set_input (GstV4l2Element *v4l2element,
 517                     gint            input)
 518 {
 519         DEBUG("trying to set input to %d", input);
 520         GST_V4L2_CHECK_OPEN(v4l2element);
 521         GST_V4L2_CHECK_NOT_ACTIVE(v4l2element);
 522
 523         if (ioctl(v4l2element->video_fd, VIDIOC_S_INPUT, &input) < 0) {
 524                 gst_element_error(GST_ELEMENT(v4l2element),
 525                         "Failed to set input %d on device %s: %s",
 526                         input, v4l2element->device, g_strerror(errno));
 527                 return FALSE;
 528         }
 529
 530         return TRUE;
 531 }
 532
 533
 534 /******************************************************
 535  * gst_v4l2_get_output()
 536  *   Get the output of the current device
 537  * return value: TRUE on success, FALSE on error
 538  ******************************************************/
 539
 540 gboolean
 541 gst_v4l2_get_output (GstV4l2Element *v4l2element,
 542                      gint           *output)
 543 {
 544         gint n;
 545
 546         DEBUG("trying to get output");
 547         GST_V4L2_CHECK_OPEN(v4l2element);
 548
 549         if (ioctl(v4l2element->video_fd, VIDIOC_G_OUTPUT, &n) < 0) {
 550                 gst_element_error(GST_ELEMENT(v4l2element),
 551                         "Failed to get current output on device %s: %s",
 552                         v4l2element->device, g_strerror(errno));
 553                 return FALSE;
 554         }
 555
 556         *output = n;
 557
 558         return TRUE;
 559 }
 560
 561
 562 /******************************************************
 563  * gst_v4l2_set_output()
 564  *   Set the output of the current device
 565  * return value: TRUE on success, FALSE on error
 566  ******************************************************/
 567
 568 gboolean
 569 gst_v4l2_set_output (GstV4l2Element *v4l2element,
 570                      gint            output)
 571 {
 572         DEBUG("trying to set output to %d", output);
 573         GST_V4L2_CHECK_OPEN(v4l2element);
 574         GST_V4L2_CHECK_NOT_ACTIVE(v4l2element);
 575
 576         if (ioctl(v4l2element->video_fd, VIDIOC_S_OUTPUT, &output) < 0) {
 577                 gst_element_error(GST_ELEMENT(v4l2element),
 578                         "Failed to set output %d on device %s: %s",
 579                         output, v4l2element->device, g_strerror(errno));
 580                 return FALSE;
 581         }
 582
 583         return TRUE;
 584 }
 585
 586
 587 /******************************************************
 588  * gst_v4l2_get_frequency():
 589  *   get the current frequency
 590  * return value: TRUE on success, FALSE on error
 591  ******************************************************/
 592
 593 gboolean
 594 gst_v4l2_get_frequency (GstV4l2Element *v4l2element,
 595                         gint            tunernum,
 596                         gulong         *frequency)
 597 {
 598         struct v4l2_frequency freq;
 599
 600         DEBUG("getting current tuner frequency");
 601         GST_V4L2_CHECK_OPEN(v4l2element);
 602
 603         freq.tuner = tunernum;
 604         if (ioctl(v4l2element->video_fd, VIDIOC_G_FREQUENCY, &freq) < 0) {
 605                 gst_element_error(GST_ELEMENT(v4l2element),
 606                         "Failed to get current tuner frequency for device %s: %s",
 607                         v4l2element->device, g_strerror(errno));
 608                 return FALSE;
 609         }
 610
 611         *frequency = freq.frequency;
 612
 613         return TRUE;
 614 }
 615
 616
 617 /******************************************************
 618  * gst_v4l2_set_frequency():
 619  *   set frequency
 620  * return value: TRUE on success, FALSE on error
 621  ******************************************************/
 622
 623 gboolean
 624 gst_v4l2_set_frequency (GstV4l2Element *v4l2element,
 625                         gint            tunernum,
 626                         gulong          frequency)
 627 {
 628         struct v4l2_frequency freq;
 629
 630         DEBUG("setting current tuner frequency to %lu", frequency);
 631         GST_V4L2_CHECK_OPEN(v4l2element);
 632         GST_V4L2_CHECK_NOT_ACTIVE(v4l2element);
 633
 634         freq.tuner = tunernum;
 635         /* fill in type - ignore error */
 636         ioctl(v4l2element->video_fd, VIDIOC_G_FREQUENCY, &freq);
 637         freq.frequency = frequency;
 638
 639         if (ioctl(v4l2element->video_fd, VIDIOC_S_FREQUENCY, &freq) < 0) {
 640                 gst_element_error(GST_ELEMENT(v4l2element),
 641                         "Failed to set tuner frequency to %lu for device %s: %s",
 642                         frequency, v4l2element->device, g_strerror(errno));
 643                 return FALSE;
 644         }
 645
 646         return TRUE;
 647 }
 648
 649
 650 /******************************************************
 651  * gst_v4l2_signal_strength():
 652  *   get the strength of the signal on the current input
 653  * return value: TRUE on success, FALSE on error
 654  ******************************************************/
 655
 656 gboolean
 657 gst_v4l2_signal_strength (GstV4l2Element *v4l2element,
 658                           gint            tunernum,
 659                           gulong         *signal_strength)
 660 {
 661         struct v4l2_tuner tuner;
 662
 663         DEBUG("trying to get signal strength");
 664         GST_V4L2_CHECK_OPEN(v4l2element);
 665
 666         tuner.index = tunernum;
 667         if (ioctl(v4l2element->video_fd, VIDIOC_G_TUNER, &tuner) < 0) {
 668                 gst_element_error(GST_ELEMENT(v4l2element),
 669                         "Failed to get signal strength for device %s: %s",
 670                         v4l2element->device, g_strerror(errno));
 671                 return FALSE;
 672         }
 673
 674         *signal_strength = tuner.signal;
 675
 676         return TRUE;
 677 }
 678
 679
 680 /******************************************************
 681  * gst_v4l2_get_attribute():
 682  *   try to get the value of one specific attribute
 683  * return value: TRUE on success, FALSE on error
 684  ******************************************************/
 685
 686 gboolean
 687 gst_v4l2_get_attribute  (GstV4l2Element *v4l2element,
 688                          int             attribute_num,
 689                          int            *value)
 690 {
 691         struct v4l2_control control;
 692
 693         GST_V4L2_CHECK_OPEN(v4l2element);
 694
 695         DEBUG("getting value of attribute %d", attribute_num);
 696
 697         control.id = attribute_num;
 698
 699         if (ioctl(v4l2element->video_fd, VIDIOC_G_CTRL, &control) < 0) {
 700                 gst_element_error(GST_ELEMENT(v4l2element),
 701                         "Failed to get value for control %d on device %s: %s",
 702                         attribute_num, v4l2element->device, g_strerror(errno));
 703                 return FALSE;
 704         }
 705
 706         *value = control.value;
 707
 708         return TRUE;
 709 }
 710
 711
 712 /******************************************************
 713  * gst_v4l2_set_attribute():
 714  *   try to set the value of one specific attribute
 715  * return value: TRUE on success, FALSE on error
 716  ******************************************************/
 717
 718 gboolean
 719 gst_v4l2_set_attribute  (GstV4l2Element *v4l2element,
 720                          int             attribute_num,
 721                          const int       value)
 722 {
 723         struct v4l2_control control;
 724
 725         GST_V4L2_CHECK_OPEN(v4l2element);
 726
 727         DEBUG("setting value of attribute %d to %d", attribute_num, value);
 728
 729         control.id = attribute_num;
 730         control.value = value;
 731
 732         if (ioctl(v4l2element->video_fd, VIDIOC_S_CTRL, &control) < 0) {
 733                 gst_element_error(GST_ELEMENT(v4l2element),
 734                         "Failed to set value %d for control %d on device %s: %s",
 735                         value, attribute_num, v4l2element->device, g_strerror(errno));
 736                 return FALSE;
 737         }
 738
 739         return TRUE;
 740 }
 741