gst_plugins_base/ext/alsa/gstalsamixer.c
branchRCL_3
changeset 29 567bb019e3e3
parent 6 9b2c3c7a1a9c
child 30 7e817e7e631c
--- a/gst_plugins_base/ext/alsa/gstalsamixer.c	Wed Mar 31 22:03:18 2010 +0300
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,887 +0,0 @@
-/* ALSA mixer implementation.
- * Copyright (C) 2003 Leif Johnson <leif@ambient.2y.net>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library 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
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
- */
-
-/**
- * SECTION:element-alsamixer
- * @short_description: control properties of an audio device
- * @see_also: alsasink, alsasrc
- *
- * <refsect2>
- * <para>
- * This element controls various aspects such as the volume and balance
- * of an audio device using the ALSA api.
- * </para>
- * <para>
- * The application should query and use the interfaces provided by this 
- * element to control the device.
- * </para>
- * </refsect2>
- *
- * Last reviewed on 2006-03-01 (0.10.4)
- */
-
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
-
-#include "gstalsamixer.h"
-
-static void gst_alsa_mixer_update_option (GstAlsaMixer * mixer,
-    GstAlsaMixerOptions * alsa_opts);
-static void gst_alsa_mixer_update_track (GstAlsaMixer * mixer,
-    GstAlsaMixerTrack * alsa_track);
-static int gst_alsa_mixer_handle_callback (snd_mixer_t * handle,
-    unsigned int mask, snd_mixer_elem_t * elem);
-
-/* First some utils, then the mixer implementation */
-static gboolean
-gst_alsa_mixer_open (GstAlsaMixer * mixer)
-{
-  gint err;
-  snd_ctl_t *ctl;
-  snd_ctl_card_info_t *card_info;
-
-  g_return_val_if_fail (mixer->handle == NULL, FALSE);
-
-  /* open and initialize the mixer device */
-  err = snd_mixer_open (&mixer->handle, 0);
-  if (err < 0 || mixer->handle == NULL)
-    goto open_failed;
-
-  if ((err = snd_mixer_attach (mixer->handle, mixer->device)) < 0) {
-    GST_WARNING ("Cannot open mixer for sound device '%s': %s", mixer->device,
-        snd_strerror (err));
-    goto error;
-  }
-
-  if ((err = snd_mixer_selem_register (mixer->handle, NULL, NULL)) < 0) {
-    GST_WARNING ("Cannot register mixer elements: %s", snd_strerror (err));
-    goto error;
-  }
-
-  if ((err = snd_mixer_load (mixer->handle)) < 0) {
-    GST_WARNING ("Cannot load mixer settings: %s", snd_strerror (err));
-    goto error;
-  }
-
-  snd_mixer_set_callback_private (mixer->handle, mixer);
-  snd_mixer_set_callback (mixer->handle, gst_alsa_mixer_handle_callback);
-
-  /* now get the device name, any of this is not fatal */
-  g_free (mixer->cardname);
-  if ((err = snd_ctl_open (&ctl, mixer->device, 0)) < 0) {
-    GST_WARNING ("Cannot open CTL: %s", snd_strerror (err));
-    goto no_card_name;
-  }
-
-  snd_ctl_card_info_malloc (&card_info);
-  if ((err = snd_ctl_card_info (ctl, card_info)) < 0) {
-    GST_WARNING ("Cannot get card info: %s", snd_strerror (err));
-    snd_ctl_close (ctl);
-    goto no_card_name;
-  }
-
-  mixer->cardname = g_strdup (snd_ctl_card_info_get_name (card_info));
-  GST_DEBUG ("Card name = %s", GST_STR_NULL (mixer->cardname));
-  snd_ctl_card_info_free (card_info);
-  snd_ctl_close (ctl);
-
-no_card_name:
-  if (mixer->cardname == NULL) {
-    mixer->cardname = g_strdup ("Unknown");
-    GST_DEBUG ("Cannot find card name");
-  }
-
-  GST_INFO ("Successfully opened mixer for device '%s'.", mixer->device);
-
-  return TRUE;
-
-  /* ERROR */
-open_failed:
-  {
-    GST_WARNING ("Cannot open mixer: %s", snd_strerror (err));
-    mixer->handle = NULL;
-    return FALSE;
-  }
-error:
-  {
-    snd_mixer_close (mixer->handle);
-    mixer->handle = NULL;
-    return FALSE;
-  }
-}
-
-static snd_mixer_elem_t *
-gst_alsa_mixer_find_master_mixer (GstAlsaMixer * mixer, snd_mixer_t * handle)
-{
-  snd_mixer_elem_t *element;
-  gint i, count;
-
-  count = snd_mixer_get_count (handle);
-
-  /* Check if we have a playback mixer labelled as 'Master' */
-  element = snd_mixer_first_elem (handle);
-  for (i = 0; i < count; i++) {
-    if (snd_mixer_selem_has_playback_volume (element) &&
-        strcmp (snd_mixer_selem_get_name (element), "Master") == 0) {
-      return element;
-    }
-    element = snd_mixer_elem_next (element);
-  }
-
-  /* If not, check if we have a playback mixer labelled as 'Front' */
-  element = snd_mixer_first_elem (handle);
-  for (i = 0; i < count; i++) {
-    if (snd_mixer_selem_has_playback_volume (element) &&
-        strcmp (snd_mixer_selem_get_name (element), "Front") == 0) {
-      return element;
-    }
-    element = snd_mixer_elem_next (element);
-  }
-
-  /* If not, check if we have a playback mixer labelled as 'PCM' */
-  element = snd_mixer_first_elem (handle);
-  for (i = 0; i < count; i++) {
-    if (snd_mixer_selem_has_playback_volume (element) &&
-        strcmp (snd_mixer_selem_get_name (element), "PCM") == 0) {
-      return element;
-    }
-    element = snd_mixer_elem_next (element);
-  }
-
-  /* If not, check if we have a playback mixer with both volume and switch */
-  element = snd_mixer_first_elem (handle);
-  for (i = 0; i < count; i++) {
-    if (snd_mixer_selem_has_playback_volume (element) &&
-        snd_mixer_selem_has_playback_switch (element)) {
-      return element;
-    }
-    element = snd_mixer_elem_next (element);
-  }
-
-  /* If not, take any playback mixer with a volume control */
-  element = snd_mixer_first_elem (handle);
-  for (i = 0; i < count; i++) {
-    if (snd_mixer_selem_has_playback_volume (element)) {
-      return element;
-    }
-    element = snd_mixer_elem_next (element);
-  }
-
-  /* Looks like we're out of luck ... */
-  return NULL;
-}
-
-static void
-gst_alsa_mixer_update (GstAlsaMixer * mixer, snd_mixer_elem_t * elem)
-{
-  GList *item;
-
-  g_return_if_fail (mixer != NULL);
-
-  g_static_rec_mutex_lock (mixer->rec_mutex);
-
-  for (item = mixer->tracklist; item != NULL; item = item->next) {
-    if (GST_IS_ALSA_MIXER_TRACK (item->data)) {
-      if (elem && (GST_ALSA_MIXER_TRACK (item->data)->element != elem))
-        continue;
-
-      gst_alsa_mixer_update_track (mixer, GST_ALSA_MIXER_TRACK (item->data));
-    } else if (GST_IS_ALSA_MIXER_OPTIONS (item->data)) {
-      if (elem && (GST_ALSA_MIXER_OPTIONS (item->data)->element != elem))
-        continue;
-
-      gst_alsa_mixer_update_option (mixer, GST_ALSA_MIXER_OPTIONS (item->data));
-    }
-  }
-
-  g_static_rec_mutex_unlock (mixer->rec_mutex);
-}
-
-static int
-gst_alsa_mixer_elem_handle_callback (snd_mixer_elem_t * elem, unsigned int mask)
-{
-  GstAlsaMixer *mixer =
-      (GstAlsaMixer *) snd_mixer_elem_get_callback_private (elem);
-
-  GST_LOG ("ALSA elem cb");
-
-  g_return_val_if_fail (mixer != NULL, 1);
-
-  gst_alsa_mixer_update (mixer, elem);
-
-  return 0;
-}
-
-static int
-gst_alsa_mixer_handle_callback (snd_mixer_t * handle, unsigned int mask,
-    snd_mixer_elem_t * elem)
-{
-  GstAlsaMixer *mixer =
-      (GstAlsaMixer *) snd_mixer_get_callback_private (handle);
-
-  GST_LOG ("ALSA cb");
-
-  g_return_val_if_fail (mixer != NULL, 1);
-
-  /* Hopefully won't be call recursively and will handle pending elem events */
-  snd_mixer_handle_events (mixer->handle);
-
-  gst_alsa_mixer_update (mixer, elem);
-
-  return 0;
-}
-
-static void
-gst_alsa_mixer_ensure_track_list (GstAlsaMixer * mixer)
-{
-  gint i, count;
-  snd_mixer_elem_t *element, *master;
-  GList *item;
-
-  g_return_if_fail (mixer->handle != NULL);
-
-  if (mixer->tracklist)
-    return;
-
-  g_static_rec_mutex_lock (mixer->rec_mutex);
-
-  master = gst_alsa_mixer_find_master_mixer (mixer, mixer->handle);
-
-  count = snd_mixer_get_count (mixer->handle);
-  element = snd_mixer_first_elem (mixer->handle);
-
-  /* build track list
-   *
-   * Some ALSA tracks may have playback and capture capabilities.
-   * Here we model them as two separate GStreamer tracks.
-   */
-
-  for (i = 0; i < count; i++) {
-    GstMixerTrack *play_track = NULL;
-    GstMixerTrack *cap_track = NULL;
-    const gchar *name;
-    GList *item;
-    gint samename = 0;
-
-    name = snd_mixer_selem_get_name (element);
-
-    /* prevent dup names */
-    for (item = mixer->tracklist; item != NULL; item = item->next) {
-      snd_mixer_elem_t *temp;
-
-      if (GST_IS_ALSA_MIXER_OPTIONS (item->data))
-        temp = GST_ALSA_MIXER_OPTIONS (item->data)->element;
-      else
-        temp = GST_ALSA_MIXER_TRACK (item->data)->element;
-
-      if (strcmp (name, snd_mixer_selem_get_name (temp)) == 0)
-        samename++;
-    }
-
-    GST_LOG ("[%s] probing element #%u, mixer->dir=%u", name, i, mixer->dir);
-
-    if (mixer->dir & GST_ALSA_MIXER_PLAYBACK) {
-      gboolean has_playback_switch, has_playback_volume;
-
-      has_playback_switch = snd_mixer_selem_has_playback_switch (element);
-      has_playback_volume = snd_mixer_selem_has_playback_volume (element);
-
-      GST_LOG ("[%s] PLAYBACK: has_playback_volume=%d, has_playback_switch=%d"
-          "%s", name, has_playback_volume, has_playback_switch,
-          (element == master) ? " MASTER" : "");
-
-      if (has_playback_volume) {
-        gint flags = GST_MIXER_TRACK_OUTPUT;
-
-        if (element == master)
-          flags |= GST_MIXER_TRACK_MASTER;
-
-        play_track = gst_alsa_mixer_track_new (element, samename, i,
-            flags, FALSE, NULL, FALSE);
-
-      } else if (has_playback_switch) {
-        /* simple mute switch */
-        play_track = gst_alsa_mixer_track_new (element, samename, i,
-            GST_MIXER_TRACK_OUTPUT, TRUE, NULL, FALSE);
-      }
-
-      if (snd_mixer_selem_is_enumerated (element)) {
-        GstMixerOptions *opts = gst_alsa_mixer_options_new (element, i);
-
-        GST_LOG ("[%s] is enumerated (%d)", name, i);
-        mixer->tracklist = g_list_append (mixer->tracklist, opts);
-      }
-    }
-
-    if (mixer->dir & GST_ALSA_MIXER_CAPTURE) {
-      gboolean has_capture_switch, has_common_switch;
-      gboolean has_capture_volume, has_common_volume;
-
-      has_capture_switch = snd_mixer_selem_has_capture_switch (element);
-      has_common_switch = snd_mixer_selem_has_common_switch (element);
-      has_capture_volume = snd_mixer_selem_has_capture_volume (element);
-      has_common_volume = snd_mixer_selem_has_common_volume (element);
-
-      GST_LOG ("[%s] CAPTURE: has_capture_volume=%d, has_common_volume=%d, "
-          "has_capture_switch=%d, has_common_switch=%d, play_track=%p", name,
-          has_capture_volume, has_common_volume, has_capture_switch,
-          has_common_switch, play_track);
-
-      if (has_capture_volume && !(play_track && has_common_volume)) {
-        cap_track = gst_alsa_mixer_track_new (element, samename, i,
-            GST_MIXER_TRACK_INPUT, FALSE, NULL, play_track != NULL);
-      } else if (has_capture_switch && !(play_track && has_common_switch)) {
-        cap_track = gst_alsa_mixer_track_new (element, samename, i,
-            GST_MIXER_TRACK_INPUT, TRUE, NULL, play_track != NULL);
-      }
-    }
-
-
-    if (play_track && cap_track) {
-      GST_ALSA_MIXER_TRACK (play_track)->shared_mute =
-          GST_ALSA_MIXER_TRACK (cap_track);
-      GST_ALSA_MIXER_TRACK (cap_track)->shared_mute =
-          GST_ALSA_MIXER_TRACK (play_track);
-    }
-
-    if (play_track)
-      mixer->tracklist = g_list_append (mixer->tracklist, play_track);
-
-    if (cap_track)
-      mixer->tracklist = g_list_append (mixer->tracklist, cap_track);
-
-    element = snd_mixer_elem_next (element);
-  }
-
-  for (item = mixer->tracklist; item != NULL; item = item->next) {
-    snd_mixer_elem_t *temp;
-
-    if (GST_IS_ALSA_MIXER_OPTIONS (item->data))
-      temp = GST_ALSA_MIXER_OPTIONS (item->data)->element;
-    else
-      temp = GST_ALSA_MIXER_TRACK (item->data)->element;
-
-    snd_mixer_elem_set_callback (temp, gst_alsa_mixer_elem_handle_callback);
-    snd_mixer_elem_set_callback_private (temp, mixer);
-  }
-
-  g_static_rec_mutex_unlock (mixer->rec_mutex);
-}
-
-static void
-task_monitor_alsa (gpointer data)
-{
-  struct pollfd *pfds;
-  unsigned int nfds, rnfds;
-  unsigned short revents;
-  GstAlsaMixer *mixer = (GstAlsaMixer *) data;
-
-  g_static_rec_mutex_lock (mixer->rec_mutex);
-
-  nfds = snd_mixer_poll_descriptors_count (mixer->handle);
-  if (nfds <= 0) {
-    GST_ERROR ("snd_mixer_poll_descriptors_count <= 0: %d", nfds);
-    /* FIXME: sleep ? stop monitoring ? */
-    return;
-  }
-
-  pfds = g_newa (struct pollfd, nfds + 1);
-  rnfds = snd_mixer_poll_descriptors (mixer->handle, pfds, nfds);
-  g_assert (rnfds <= nfds);
-
-  pfds[rnfds].fd = mixer->pfd[0];
-  pfds[rnfds].events = POLLIN | POLLPRI | POLLHUP | POLLERR;
-  pfds[rnfds].revents = 0;
-
-  g_static_rec_mutex_unlock (mixer->rec_mutex);
-
-  GST_LOG ("task loop");
-  poll (pfds, rnfds + 1, -1);
-
-  g_static_rec_mutex_lock (mixer->rec_mutex);
-
-  snd_mixer_poll_descriptors_revents (mixer->handle, pfds, nfds, &revents);
-  if (revents & POLLIN || revents & POLLPRI) {
-    GST_DEBUG ("Handling events");
-    snd_mixer_handle_events (mixer->handle);
-  }
-
-  g_static_rec_mutex_unlock (mixer->rec_mutex);
-}
-
-/* API */
-
-GstAlsaMixer *
-gst_alsa_mixer_new (const char *device, GstAlsaMixerDirection dir)
-{
-  GstAlsaMixer *ret = NULL;
-
-  g_return_val_if_fail (device != NULL, NULL);
-
-  ret = g_new0 (GstAlsaMixer, 1);
-
-  if (pipe (ret->pfd) == -1)
-    goto error;
-
-  ret->rec_mutex = g_new (GStaticRecMutex, 1);
-  g_static_rec_mutex_init (ret->rec_mutex);
-
-  ret->task_mutex = g_new (GStaticRecMutex, 1);
-  g_static_rec_mutex_init (ret->task_mutex);
-
-  ret->task = gst_task_create (task_monitor_alsa, ret);
-  gst_task_set_lock (ret->task, ret->task_mutex);
-
-  ret->device = g_strdup (device);
-  ret->dir = dir;
-
-  if (!gst_alsa_mixer_open (ret))
-    goto error;
-
-  if (gst_task_start (ret->task) == FALSE) {
-    GST_WARNING ("Could not start alsamixer task");
-  }
-
-  return ret;
-
-  /* ERRORS */
-error:
-  {
-    gst_alsa_mixer_free (ret);
-    return NULL;
-  }
-}
-
-void
-gst_alsa_mixer_free (GstAlsaMixer * mixer)
-{
-  g_return_if_fail (mixer != NULL);
-
-  if (mixer->task) {
-    if (write (mixer->pfd[1], "stop", 5) <= 0) {
-      GST_ERROR ("Cannot send " "stop" " to alsamixer task");
-      close (mixer->pfd[1]);
-      mixer->pfd[1] = -1;
-    }
-
-    if (gst_task_join (mixer->task) == FALSE) {
-      GST_ERROR ("Cannot join alsamixer task");
-    }
-
-    gst_object_unref (mixer->task);
-    mixer->task = NULL;
-  }
-
-  g_static_rec_mutex_free (mixer->task_mutex);
-  g_free (mixer->task_mutex);
-  mixer->task_mutex = NULL;
-
-  if (mixer->pfd[0] > 0) {
-    close (mixer->pfd[0]);
-    mixer->pfd[0] = -1;
-  }
-
-  if (mixer->pfd[1] > 0) {
-    close (mixer->pfd[1]);
-    mixer->pfd[1] = -1;
-  }
-
-  if (mixer->interface) {
-    g_object_unref (G_OBJECT (mixer->interface));
-    mixer->interface = NULL;
-  }
-
-  if (mixer->device) {
-    g_free (mixer->device);
-    mixer->device = NULL;
-  }
-
-  if (mixer->cardname) {
-    g_free (mixer->cardname);
-    mixer->cardname = NULL;
-  }
-
-  if (mixer->tracklist) {
-    g_list_foreach (mixer->tracklist, (GFunc) g_object_unref, NULL);
-    g_list_free (mixer->tracklist);
-    mixer->tracklist = NULL;
-  }
-
-  if (mixer->handle) {
-    snd_mixer_close (mixer->handle);
-    mixer->handle = NULL;
-  }
-
-  g_static_rec_mutex_free (mixer->rec_mutex);
-  g_free (mixer->rec_mutex);
-  mixer->rec_mutex = NULL;
-
-  g_free (mixer);
-}
-
-const GList *
-gst_alsa_mixer_list_tracks (GstAlsaMixer * mixer)
-{
-  g_return_val_if_fail (mixer->handle != NULL, NULL);
-
-  gst_alsa_mixer_ensure_track_list (mixer);
-
-  return (const GList *) mixer->tracklist;
-}
-
-void
-gst_alsa_mixer_get_volume (GstAlsaMixer * mixer, GstMixerTrack * track,
-    gint * volumes)
-{
-  gint i;
-  GstAlsaMixerTrack *alsa_track = GST_ALSA_MIXER_TRACK (track);
-
-  g_return_if_fail (mixer->handle != NULL);
-
-  gst_alsa_mixer_track_update (alsa_track);
-
-  if (track->flags & GST_MIXER_TRACK_OUTPUT) {  /* return playback volume */
-
-    /* Is emulated mute flag activated? */
-    if (track->flags & GST_MIXER_TRACK_MUTE &&
-        !(alsa_track->alsa_flags & GST_ALSA_MIXER_TRACK_PSWITCH)) {
-      for (i = 0; i < track->num_channels; i++)
-        volumes[i] = alsa_track->volumes[i];
-    } else {
-      for (i = 0; i < track->num_channels; i++) {
-        long tmp = 0;
-
-        snd_mixer_selem_get_playback_volume (alsa_track->element, i, &tmp);
-        alsa_track->volumes[i] = volumes[i] = (gint) tmp;
-      }
-    }
-
-  } else if (track->flags & GST_MIXER_TRACK_INPUT) {    /* return capture volume */
-
-    /* Is emulated record flag activated? */
-    if (alsa_track->alsa_flags & GST_ALSA_MIXER_TRACK_CSWITCH ||
-        track->flags & GST_MIXER_TRACK_RECORD) {
-      for (i = 0; i < track->num_channels; i++) {
-        long tmp = 0;
-
-        snd_mixer_selem_get_capture_volume (alsa_track->element, i, &tmp);
-        alsa_track->volumes[i] = volumes[i] = (gint) tmp;
-      }
-    } else {
-      for (i = 0; i < track->num_channels; i++)
-        volumes[i] = alsa_track->volumes[i];
-    }
-  }
-}
-
-static gboolean
-check_if_volumes_are_the_same (guint num_channels, gint * volumes)
-{
-  guint i;
-
-  if (num_channels <= 1)
-    return TRUE;
-
-  for (i = 1; i < num_channels; i++) {
-    if (volumes[i] != volumes[0])
-      return FALSE;
-  }
-
-  return TRUE;
-}
-
-void
-gst_alsa_mixer_set_volume (GstAlsaMixer * mixer, GstMixerTrack * track,
-    gint * volumes)
-{
-  GstAlsaMixerTrack *alsa_track = GST_ALSA_MIXER_TRACK (track);
-  gint i;
-
-  g_return_if_fail (mixer->handle != NULL);
-
-  gst_alsa_mixer_track_update (alsa_track);
-
-  if (track->flags & GST_MIXER_TRACK_OUTPUT) {
-
-    /* Is emulated mute flag activated? */
-    if (track->flags & GST_MIXER_TRACK_MUTE &&
-        !(alsa_track->alsa_flags & GST_ALSA_MIXER_TRACK_PSWITCH)) {
-      for (i = 0; i < track->num_channels; i++)
-        alsa_track->volumes[i] = volumes[i];
-    } else {
-      if (check_if_volumes_are_the_same (track->num_channels, volumes)) {
-        snd_mixer_selem_set_playback_volume_all (alsa_track->element,
-            volumes[0]);
-        for (i = 0; i < track->num_channels; i++)
-          alsa_track->volumes[i] = volumes[0];
-      } else {
-        for (i = 0; i < track->num_channels; i++) {
-          alsa_track->volumes[i] = volumes[i];
-          snd_mixer_selem_set_playback_volume (alsa_track->element, i,
-              volumes[i]);
-        }
-      }
-    }
-
-  } else if (track->flags & GST_MIXER_TRACK_INPUT) {
-
-    /* Is emulated record flag activated? */
-    if (track->flags & GST_MIXER_TRACK_RECORD ||
-        alsa_track->alsa_flags & GST_ALSA_MIXER_TRACK_CSWITCH) {
-      if (check_if_volumes_are_the_same (track->num_channels, volumes)) {
-        snd_mixer_selem_set_capture_volume_all (alsa_track->element,
-            volumes[0]);
-        for (i = 0; i < track->num_channels; i++)
-          alsa_track->volumes[i] = volumes[0];
-      } else {
-        for (i = 0; i < track->num_channels; i++) {
-          alsa_track->volumes[i] = volumes[i];
-          snd_mixer_selem_set_capture_volume (alsa_track->element, i,
-              volumes[i]);
-        }
-      }
-    } else {
-      for (i = 0; i < track->num_channels; i++)
-        alsa_track->volumes[i] = volumes[i];
-    }
-  }
-}
-
-void
-gst_alsa_mixer_set_mute (GstAlsaMixer * mixer, GstMixerTrack * track,
-    gboolean mute)
-{
-  GstAlsaMixerTrack *alsa_track = GST_ALSA_MIXER_TRACK (track);
-
-  g_return_if_fail (mixer->handle != NULL);
-
-  gst_alsa_mixer_track_update (alsa_track);
-
-  if (!!(mute) == !!(track->flags & GST_MIXER_TRACK_MUTE))
-    return;
-
-  if (mute) {
-    track->flags |= GST_MIXER_TRACK_MUTE;
-
-    if (alsa_track->shared_mute)
-      ((GstMixerTrack *) (alsa_track->shared_mute))->flags |=
-          GST_MIXER_TRACK_MUTE;
-  } else {
-    track->flags &= ~GST_MIXER_TRACK_MUTE;
-
-    if (alsa_track->shared_mute)
-      ((GstMixerTrack *) (alsa_track->shared_mute))->flags &=
-          ~GST_MIXER_TRACK_MUTE;
-  }
-
-  if (alsa_track->alsa_flags & GST_ALSA_MIXER_TRACK_PSWITCH) {
-    snd_mixer_selem_set_playback_switch_all (alsa_track->element, mute ? 0 : 1);
-  } else {
-    gint i;
-    GstAlsaMixerTrack *ctrl_track;
-
-    if ((track->flags & GST_MIXER_TRACK_INPUT)
-        && alsa_track->shared_mute != NULL)
-      ctrl_track = alsa_track->shared_mute;
-    else
-      ctrl_track = alsa_track;
-
-    for (i = 0; i < ((GstMixerTrack *) ctrl_track)->num_channels; i++) {
-      long vol =
-          mute ? ((GstMixerTrack *) ctrl_track)->min_volume : ctrl_track->
-          volumes[i];
-      snd_mixer_selem_set_playback_volume (ctrl_track->element, i, vol);
-    }
-  }
-}
-
-void
-gst_alsa_mixer_set_record (GstAlsaMixer * mixer,
-    GstMixerTrack * track, gboolean record)
-{
-  GstAlsaMixerTrack *alsa_track = GST_ALSA_MIXER_TRACK (track);
-
-  g_return_if_fail (mixer->handle != NULL);
-
-  gst_alsa_mixer_track_update (alsa_track);
-
-  if (!!(record) == !!(track->flags & GST_MIXER_TRACK_RECORD))
-    return;
-
-  if (record) {
-    track->flags |= GST_MIXER_TRACK_RECORD;
-  } else {
-    track->flags &= ~GST_MIXER_TRACK_RECORD;
-  }
-
-  if (alsa_track->alsa_flags & GST_ALSA_MIXER_TRACK_CSWITCH) {
-    snd_mixer_selem_set_capture_switch_all (alsa_track->element,
-        record ? 1 : 0);
-
-    /* update all tracks in same exlusive cswitch group */
-    if (alsa_track->alsa_flags & GST_ALSA_MIXER_TRACK_CSWITCH_EXCL) {
-      GList *item;
-
-      for (item = mixer->tracklist; item != NULL; item = item->next) {
-
-        if (GST_IS_ALSA_MIXER_TRACK (item->data)) {
-          GstAlsaMixerTrack *item_alsa_track =
-              GST_ALSA_MIXER_TRACK (item->data);
-
-          if (item_alsa_track->alsa_flags & GST_ALSA_MIXER_TRACK_CSWITCH_EXCL &&
-              item_alsa_track->capture_group == alsa_track->capture_group) {
-            gst_alsa_mixer_track_update (item_alsa_track);
-          }
-        }
-      }
-    }
-  } else {
-    gint i;
-
-    for (i = 0; i < track->num_channels; i++) {
-      long vol = record ? alsa_track->volumes[i] : track->min_volume;
-
-      snd_mixer_selem_set_capture_volume (alsa_track->element, i, vol);
-    }
-  }
-}
-
-void
-gst_alsa_mixer_set_option (GstAlsaMixer * mixer,
-    GstMixerOptions * opts, gchar * value)
-{
-  gint idx = -1, n = 0;
-  GList *item;
-  GstAlsaMixerOptions *alsa_opts = GST_ALSA_MIXER_OPTIONS (opts);
-
-  g_return_if_fail (mixer->handle != NULL);
-
-  for (item = opts->values; item != NULL; item = item->next, n++) {
-    if (!strcmp (item->data, value)) {
-      idx = n;
-      break;
-    }
-  }
-  if (idx == -1)
-    return;
-
-  snd_mixer_selem_set_enum_item (alsa_opts->element, 0, idx);
-}
-
-const gchar *
-gst_alsa_mixer_get_option (GstAlsaMixer * mixer, GstMixerOptions * opts)
-{
-  gint ret;
-  guint idx;
-  GstAlsaMixerOptions *alsa_opts = GST_ALSA_MIXER_OPTIONS (opts);
-
-  g_return_val_if_fail (mixer->handle != NULL, NULL);
-
-  ret = snd_mixer_selem_get_enum_item (alsa_opts->element, 0, &idx);
-  if (ret == 0)
-    return g_list_nth_data (opts->values, idx);
-  else
-    return snd_strerror (ret);  /* feeble attempt at error handling */
-}
-
-GstMixerFlags
-gst_alsa_mixer_get_mixer_flags (GstAlsaMixer * mixer)
-{
-  g_return_val_if_fail (mixer != NULL, GST_MIXER_FLAG_NONE);
-
-  return GST_MIXER_FLAG_AUTO_NOTIFICATIONS;
-}
-
-static void
-gst_alsa_mixer_update_option (GstAlsaMixer * mixer,
-    GstAlsaMixerOptions * alsa_opts)
-{
-  gint ret;
-  guint idx;
-  /* const */ gchar *option;
-
-  if (mixer->interface == NULL) {
-    GST_WARNING ("Cannot send update notifications, no GstMixer * given");
-    return;
-  }
-
-  ret = snd_mixer_selem_get_enum_item (alsa_opts->element, 0, &idx);
-  if (ret == 0) {
-    option = g_list_nth_data (GST_MIXER_OPTIONS (alsa_opts)->values, idx);
-    gst_mixer_option_changed (mixer->interface, GST_MIXER_OPTIONS (alsa_opts),
-        option);
-  }
-}
-
-static void
-gst_alsa_mixer_update_track (GstAlsaMixer * mixer,
-    GstAlsaMixerTrack * alsa_track)
-{
-  GstMixerTrack *track = (GstMixerTrack *) alsa_track;
-  gboolean old_mute;
-  gboolean old_record;
-  gint i, n_channels;
-  gint *old_volumes;
-
-  GST_DEBUG ("Updating track %" GST_PTR_FORMAT, alsa_track);
-
-  if (mixer->interface == NULL) {
-    GST_WARNING ("Cannot send update notifications, no GstMixer * given");
-    return;
-  }
-
-  old_mute = !!(GST_MIXER_TRACK_HAS_FLAG (track, GST_MIXER_TRACK_MUTE));
-  old_record = !!(GST_MIXER_TRACK_HAS_FLAG (track, GST_MIXER_TRACK_RECORD));
-  old_volumes = g_new (gint, track->num_channels);
-  n_channels = track->num_channels;
-  memcpy (old_volumes, alsa_track->volumes,
-      sizeof (gint) * track->num_channels);
-
-  gst_alsa_mixer_track_update (alsa_track);
-
-  if (old_record !=
-      !!(GST_MIXER_TRACK_HAS_FLAG (track, GST_MIXER_TRACK_RECORD))) {
-    gst_mixer_record_toggled (mixer->interface, track,
-        !!GST_MIXER_TRACK_HAS_FLAG (track, GST_MIXER_TRACK_RECORD));
-  }
-  if (old_mute != !!(GST_MIXER_TRACK_HAS_FLAG (track, GST_MIXER_TRACK_MUTE))) {
-    gst_mixer_mute_toggled (mixer->interface, track,
-        !!GST_MIXER_TRACK_HAS_FLAG (track, GST_MIXER_TRACK_MUTE));
-  }
-
-  n_channels = MIN (n_channels, track->num_channels);
-  for (i = 0; i < n_channels; i++) {
-    if (old_volumes[i] != alsa_track->volumes[i]) {
-      gst_mixer_volume_changed (mixer->interface, track, alsa_track->volumes);
-      break;
-    }
-  }
-  g_free (old_volumes);
-}
-
-/* utility function for gstalsamixerelement to set the interface */
-void
-_gst_alsa_mixer_set_interface (GstAlsaMixer * mixer, GstMixer * interface)
-{
-  g_return_if_fail (mixer != NULL && mixer->interface == NULL);
-  g_return_if_fail (interface != NULL);
-
-  mixer->interface = g_object_ref (G_OBJECT (interface));
-}