source.c

/*
 * IceStreamer - A simple live audio streamer
 *
 * Copyright (C) 2017 George Kiagiadakis <gkiagia@tolabaki.gr>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "icestreamer.h"
#include <gst/audio/audio.h>

static GstElement *
icstr_source_add_capsfilter (GstElement *element, GKeyFile *keyfile)
{
  GstElement *bin = NULL;
  GstElement *capsfilter = NULL;
  GstPad *pad, *gpad;
  g_autoptr (GstCaps) caps = NULL;

  bin = gst_bin_new ("source_bin");
  capsfilter = gst_element_factory_make ("capsfilter", NULL);

  gst_bin_add_many (GST_BIN (bin), element, capsfilter, NULL);
  gst_element_link (element, capsfilter);

  caps = gst_caps_new_simple ("audio/x-raw", NULL);

  if (g_key_file_has_key (keyfile, "input", "format", NULL)) {
    gst_caps_set_simple (caps, "format", G_TYPE_STRING,
        g_key_file_get_value (keyfile, "input", "format", NULL), NULL);
  }
  if (g_key_file_has_key (keyfile, "input", "channels", NULL)) {
    int channels = g_key_file_get_integer (keyfile, "input", "channels", NULL);
    gst_caps_set_simple (caps,
        "channels", G_TYPE_INT, channels,
        "channel-mask", GST_TYPE_BITMASK,
           gst_audio_channel_get_fallback_mask (channels),
        NULL);
  }
  if (g_key_file_has_key (keyfile, "input", "rate", NULL)) {
    gst_caps_set_simple (caps, "rate", G_TYPE_INT,
        g_key_file_get_integer (keyfile, "input", "rate", NULL), NULL);
  }


  g_object_set (capsfilter, "caps", caps, NULL);

  pad = gst_element_get_static_pad (capsfilter, "src");
  gpad = gst_ghost_pad_new ("src", pad);
  gst_element_add_pad (bin, gpad);
  gst_object_unref (pad);

  return gst_object_ref_sink (bin);
}

GstElement *
icstr_construct_source (IceStreamer *self, GKeyFile *keyfile, GError **error)
{
  g_autoptr (GstElement) element = NULL;
  g_autofree gchar *value = NULL;
  const gchar *element_factory = NULL;
  g_autoptr (GError) internal_error = NULL;

  /* find out which element to construct and construct it */
  value = icstr_keyfile_get_string_with_fallback (keyfile, "input", "source",
                                                  "auto");
  if (g_str_equal (value, "auto"))
    element_factory = "autoaudiosrc";
  else if (g_str_equal (value, "jack"))
    element_factory = "jackaudiosrc";
  else if (g_str_equal (value, "alsa"))
    element_factory = "alsasrc";
  else if (g_str_equal (value, "pulse"))
    element_factory = "pulsesrc";
  else if (g_str_equal (value, "pipewire"))
    element_factory = "pipewiresrc";
  else if (g_str_equal (value, "test"))
    element_factory = "audiotestsrc";

  if (!element_factory) {
    g_set_error (error, ICSTR_ERROR, 0, "Unknown source: %s", value);
    return NULL;
  }

  GST_DEBUG ("Attempting to construct source element %s for input source %s",
             element_factory, value);

  element = gst_element_factory_make (element_factory, NULL);
  if (!element) {
    g_set_error (error, ICSTR_ERROR, 0,
                 "Failed to construct source element (source = %s, factory = %s)",
                 value, element_factory);
    return NULL;
  }

  /* claim ownership */
  gst_object_ref_sink (element);

  /* set its properties */
  if (!icstr_object_set_properties_from_keyfile (element, keyfile, "input",
                                                 &internal_error)) {
    /* group not found is ok - for anything else, bail out */
    if (internal_error->code != G_KEY_FILE_ERROR_GROUP_NOT_FOUND) {
      g_propagate_prefixed_error (error, g_steal_pointer (&internal_error),
                                  "Failed to read input properties:");
      return NULL;
    }
  }

  /* force audiotestsrc to behave like a live source */
  if (g_str_equal (element_factory, "audiotestsrc"))
    g_object_set (element, "is-live", TRUE, NULL);

  /* make sure it works */
  if (gst_element_set_state (element, GST_STATE_READY)
      != GST_STATE_CHANGE_SUCCESS) {
    g_set_error (error, ICSTR_ERROR, 0, "Failed to activate input element");
    return NULL;
  }

  /* bring back to NULL state, for the case where we have to dispose before going to PLAYING */
  gst_element_set_state (element, GST_STATE_NULL);

  /* wrap in a bin with a capsfilter */
  return icstr_source_add_capsfilter (element, keyfile);
}