diff -r 567bb019e3e3 -r 7e817e7e631c gst_plugins_base/ext/alsa/gstalsa.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gst_plugins_base/ext/alsa/gstalsa.c	Wed Sep 01 12:16:41 2010 +0100
@@ -0,0 +1,556 @@
+/* Copyright (C) 2006 Tim-Philipp Müller <tim centricular 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "gstalsa.h"
+
+#include <gst/audio/multichannel.h>
+
+static GstCaps *
+gst_alsa_detect_rates (GstObject * obj, snd_pcm_hw_params_t * hw_params,
+    GstCaps * in_caps)
+{
+  GstCaps *caps;
+  guint min, max;
+  gint err, dir, min_rate, max_rate, i;
+
+  GST_LOG_OBJECT (obj, "probing sample rates ...");
+
+  if ((err = snd_pcm_hw_params_get_rate_min (hw_params, &min, &dir)) < 0)
+    goto min_rate_err;
+
+  if ((err = snd_pcm_hw_params_get_rate_max (hw_params, &max, &dir)) < 0)
+    goto max_rate_err;
+
+  min_rate = min;
+  max_rate = max;
+
+  if (min_rate < 4000)
+    min_rate = 4000;            /* random 'sensible minimum' */
+
+  if (max_rate <= 0)
+    max_rate = G_MAXINT;        /* or maybe just use 192400 or so? */
+  else if (max_rate > 0 && max_rate < 4000)
+    max_rate = MAX (4000, min_rate);
+
+  GST_DEBUG_OBJECT (obj, "Min. rate = %u (%d)", min_rate, min);
+  GST_DEBUG_OBJECT (obj, "Max. rate = %u (%d)", max_rate, max);
+
+  caps = gst_caps_make_writable (in_caps);
+
+  for (i = 0; i < gst_caps_get_size (caps); ++i) {
+    GstStructure *s;
+
+    s = gst_caps_get_structure (caps, i);
+    if (min_rate == max_rate) {
+      gst_structure_set (s, "rate", G_TYPE_INT, min_rate, NULL);
+    } else {
+      gst_structure_set (s, "rate", GST_TYPE_INT_RANGE,
+          min_rate, max_rate, NULL);
+    }
+  }
+
+  return caps;
+
+  /* ERRORS */
+min_rate_err:
+  {
+    GST_ERROR_OBJECT (obj, "failed to query minimum sample rate: %s",
+        snd_strerror (err));
+    gst_caps_unref (in_caps);
+    return NULL;
+  }
+max_rate_err:
+  {
+    GST_ERROR_OBJECT (obj, "failed to query maximum sample rate: %s",
+        snd_strerror (err));
+    gst_caps_unref (in_caps);
+    return NULL;
+  }
+}
+
+static const struct
+{
+  const int width;
+  const int depth;
+  const int sformat;
+  const int uformat;
+} pcmformats[] = {
+  {
+  8, 8, SND_PCM_FORMAT_S8, SND_PCM_FORMAT_U8}, {
+  16, 16, SND_PCM_FORMAT_S16, SND_PCM_FORMAT_U16}, {
+  32, 24, SND_PCM_FORMAT_S24, SND_PCM_FORMAT_U24}, {
+#if (G_BYTE_ORDER == G_LITTLE_ENDIAN)   /* no endian-unspecific enum available */
+  24, 24, SND_PCM_FORMAT_S24_3LE, SND_PCM_FORMAT_U24_3LE}, {
+#else
+  24, 24, SND_PCM_FORMAT_S24_3BE, SND_PCM_FORMAT_U24_3BE}, {
+#endif
+  32, 32, SND_PCM_FORMAT_S32, SND_PCM_FORMAT_U32}
+};
+
+static GstCaps *
+gst_alsa_detect_formats (GstObject * obj, snd_pcm_hw_params_t * hw_params,
+    GstCaps * in_caps)
+{
+  snd_pcm_format_mask_t *mask;
+  GstStructure *s;
+  GstCaps *caps;
+  gint i;
+
+  snd_pcm_format_mask_malloc (&mask);
+  snd_pcm_hw_params_get_format_mask (hw_params, mask);
+
+  caps = gst_caps_new_empty ();
+
+  for (i = 0; i < gst_caps_get_size (in_caps); ++i) {
+    GstStructure *scopy;
+    gint w, width = 0, depth = 0;
+
+    s = gst_caps_get_structure (in_caps, i);
+    if (!gst_structure_has_name (s, "audio/x-raw-int")) {
+      GST_WARNING_OBJECT (obj, "skipping non-int format");
+      continue;
+    }
+    if (!gst_structure_get_int (s, "width", &width) ||
+        !gst_structure_get_int (s, "depth", &depth))
+      continue;
+    if (width == 0 || (width % 8) != 0)
+      continue;                 /* Only full byte widths are valid */
+    for (w = 0; w < G_N_ELEMENTS (pcmformats); w++)
+      if (pcmformats[w].width == width && pcmformats[w].depth == depth)
+        break;
+    if (w == G_N_ELEMENTS (pcmformats))
+      continue;                 /* Unknown format */
+
+    if (snd_pcm_format_mask_test (mask, pcmformats[w].sformat) &&
+        snd_pcm_format_mask_test (mask, pcmformats[w].uformat)) {
+      /* template contains { true, false } or just one, leave it as it is */
+      scopy = gst_structure_copy (s);
+    } else if (snd_pcm_format_mask_test (mask, pcmformats[w].sformat)) {
+      scopy = gst_structure_copy (s);
+      gst_structure_set (scopy, "signed", G_TYPE_BOOLEAN, TRUE, NULL);
+    } else if (snd_pcm_format_mask_test (mask, pcmformats[w].uformat)) {
+      scopy = gst_structure_copy (s);
+      gst_structure_set (scopy, "signed", G_TYPE_BOOLEAN, FALSE, NULL);
+    } else {
+      scopy = NULL;
+    }
+    if (scopy) {
+      if (width > 8) {
+        /* TODO: proper endianness detection, for now it's CPU endianness only */
+        gst_structure_set (scopy, "endianness", G_TYPE_INT, G_BYTE_ORDER, NULL);
+      }
+      gst_caps_append_structure (caps, scopy);
+    }
+  }
+
+  snd_pcm_format_mask_free (mask);
+  gst_caps_unref (in_caps);
+  return caps;
+}
+
+/* we don't have channel mappings for more than this many channels */
+#define GST_ALSA_MAX_CHANNELS 8
+
+static GstStructure *
+get_channel_free_structure (const GstStructure * in_structure)
+{
+  GstStructure *s = gst_structure_copy (in_structure);
+
+  gst_structure_remove_field (s, "channels");
+  return s;
+}
+
+static void
+caps_add_channel_configuration (GstCaps * caps,
+    const GstStructure * in_structure, gint min_chans, gint max_chans)
+{
+  GstAudioChannelPosition pos[8] = {
+    GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
+    GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT,
+    GST_AUDIO_CHANNEL_POSITION_REAR_LEFT,
+    GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT,
+    GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER,
+    GST_AUDIO_CHANNEL_POSITION_LFE,
+    GST_AUDIO_CHANNEL_POSITION_SIDE_LEFT,
+    GST_AUDIO_CHANNEL_POSITION_SIDE_RIGHT
+  };
+  GstStructure *s = NULL;
+  gint c;
+
+  if (min_chans == max_chans && max_chans <= 2) {
+    s = get_channel_free_structure (in_structure);
+    gst_structure_set (s, "channels", G_TYPE_INT, max_chans, NULL);
+    gst_caps_append_structure (caps, s);
+    return;
+  }
+
+  g_assert (min_chans >= 1);
+
+  /* mono and stereo don't need channel configurations */
+  if (min_chans == 2) {
+    s = get_channel_free_structure (in_structure);
+    gst_structure_set (s, "channels", G_TYPE_INT, 2, NULL);
+    gst_caps_append_structure (caps, s);
+  } else if (min_chans == 1 && max_chans >= 2) {
+    s = get_channel_free_structure (in_structure);
+    gst_structure_set (s, "channels", GST_TYPE_INT_RANGE, 1, 2, NULL);
+    gst_caps_append_structure (caps, s);
+  }
+
+  /* don't know whether to use 2.1 or 3.0 here - but I suspect
+   * alsa might work around that/fix it somehow. Can we tell alsa
+   * what our channel layout is like? */
+  if (max_chans >= 3 && min_chans <= 3) {
+    GstAudioChannelPosition pos_21[3] = {
+      GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
+      GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT,
+      GST_AUDIO_CHANNEL_POSITION_LFE
+    };
+
+    s = get_channel_free_structure (in_structure);
+    gst_structure_set (s, "channels", G_TYPE_INT, 3, NULL);
+    gst_audio_set_channel_positions (s, pos_21);
+    gst_caps_append_structure (caps, s);
+  }
+
+  /* everything else (4, 6, 8 channels) needs a channel layout */
+  for (c = MAX (4, min_chans); c <= 8; c += 2) {
+    if (max_chans >= c) {
+      s = get_channel_free_structure (in_structure);
+      gst_structure_set (s, "channels", G_TYPE_INT, c, NULL);
+      gst_audio_set_channel_positions (s, pos);
+      gst_caps_append_structure (caps, s);
+    }
+  }
+
+  for (c = MAX (9, min_chans); c <= max_chans; ++c) {
+    GstAudioChannelPosition *ch_layout;
+    guint i;
+
+    ch_layout = g_new (GstAudioChannelPosition, c);
+    for (i = 0; i < c; ++i) {
+      ch_layout[i] = GST_AUDIO_CHANNEL_POSITION_NONE;
+    }
+    s = get_channel_free_structure (in_structure);
+    gst_structure_set (s, "channels", G_TYPE_INT, c, NULL);
+    gst_audio_set_channel_positions (s, ch_layout);
+    gst_caps_append_structure (caps, s);
+    g_free (ch_layout);
+  }
+}
+
+static GstCaps *
+gst_alsa_detect_channels (GstObject * obj, snd_pcm_hw_params_t * hw_params,
+    GstCaps * in_caps)
+{
+  GstCaps *caps;
+  guint min, max;
+  gint min_chans, max_chans;
+  gint err, i;
+
+  GST_LOG_OBJECT (obj, "probing channels ...");
+
+  if ((err = snd_pcm_hw_params_get_channels_min (hw_params, &min)) < 0)
+    goto min_chan_error;
+
+  if ((err = snd_pcm_hw_params_get_channels_max (hw_params, &max)) < 0)
+    goto max_chan_error;
+
+  /* note: the above functions may return (guint) -1 */
+  min_chans = min;
+  max_chans = max;
+
+  if (min_chans < 0) {
+    min_chans = 1;
+    max_chans = GST_ALSA_MAX_CHANNELS;
+  } else if (max_chans < 0) {
+    max_chans = GST_ALSA_MAX_CHANNELS;
+  }
+
+  if (min_chans > max_chans) {
+    gint temp;
+
+    GST_WARNING_OBJECT (obj, "minimum channels > maximum channels (%d > %d), "
+        "please fix your soundcard drivers", min, max);
+    temp = min_chans;
+    min_chans = max_chans;
+    max_chans = temp;
+  }
+
+  /* pro cards seem to return large numbers for min_channels */
+  if (min_chans > GST_ALSA_MAX_CHANNELS) {
+    GST_DEBUG_OBJECT (obj, "min_chans = %u, looks like a pro card", min_chans);
+    if (max_chans < min_chans) {
+      max_chans = min_chans;
+    } else {
+      /* only support [max_chans; max_chans] for these cards for now
+       * to avoid inflating the source caps with loads of structures ... */
+      min_chans = max_chans;
+    }
+  } else {
+    min_chans = MAX (min_chans, 1);
+    max_chans = MIN (GST_ALSA_MAX_CHANNELS, max_chans);
+  }
+
+  GST_DEBUG_OBJECT (obj, "Min. channels = %d (%d)", min_chans, min);
+  GST_DEBUG_OBJECT (obj, "Max. channels = %d (%d)", max_chans, max);
+
+  caps = gst_caps_new_empty ();
+
+  for (i = 0; i < gst_caps_get_size (in_caps); ++i) {
+    GstStructure *s;
+    GType field_type;
+    gint c_min = min_chans;
+    gint c_max = max_chans;
+
+    s = gst_caps_get_structure (in_caps, i);
+    /* the template caps might limit the number of channels (like alsasrc),
+     * in which case we don't want to return a superset, so hack around this
+     * for the two common cases where the channels are either a fixed number
+     * or a min/max range). Example: alsasrc template has channels = [1,2] and 
+     * the detection will claim to support 8 channels for device 'plughw:0' */
+    field_type = gst_structure_get_field_type (s, "channels");
+    if (field_type == G_TYPE_INT) {
+      gst_structure_get_int (s, "channels", &c_min);
+      gst_structure_get_int (s, "channels", &c_max);
+    } else if (field_type == GST_TYPE_INT_RANGE) {
+      const GValue *val;
+
+      val = gst_structure_get_value (s, "channels");
+      c_min = CLAMP (gst_value_get_int_range_min (val), min_chans, max_chans);
+      c_max = CLAMP (gst_value_get_int_range_max (val), min_chans, max_chans);
+    } else {
+      c_min = min_chans;
+      c_max = max_chans;
+    }
+
+    caps_add_channel_configuration (caps, s, c_min, c_max);
+  }
+
+  gst_caps_unref (in_caps);
+
+  return caps;
+
+  /* ERRORS */
+min_chan_error:
+  {
+    GST_ERROR_OBJECT (obj, "failed to query minimum channel count: %s",
+        snd_strerror (err));
+    return NULL;
+  }
+max_chan_error:
+  {
+    GST_ERROR_OBJECT (obj, "failed to query maximum channel count: %s",
+        snd_strerror (err));
+    return NULL;
+  }
+}
+
+snd_pcm_t *
+gst_alsa_open_iec958_pcm (GstObject * obj)
+{
+  char *iec958_pcm_name = NULL;
+  snd_pcm_t *pcm = NULL;
+  int res;
+  char devstr[256];             /* Storage for local 'default' device string */
+
+  /*
+   * Try and open our default iec958 device. Fall back to searching on card x
+   * if this fails, which should only happen on older alsa setups
+   */
+
+  /* The string will be one of these:
+   * SPDIF_CON: Non-audio flag not set:
+   *    spdif:{AES0 0x0 AES1 0x82 AES2 0x0 AES3 0x2}
+   * SPDIF_CON: Non-audio flag set:
+   *    spdif:{AES0 0x2 AES1 0x82 AES2 0x0 AES3 0x2}
+   */
+  sprintf (devstr,
+      "iec958:{AES0 0x%02x AES1 0x%02x AES2 0x%02x AES3 0x%02x}",
+      IEC958_AES0_CON_EMPHASIS_NONE | IEC958_AES0_NONAUDIO,
+      IEC958_AES1_CON_ORIGINAL | IEC958_AES1_CON_PCM_CODER,
+      0, IEC958_AES3_CON_FS_48000);
+
+  GST_DEBUG_OBJECT (obj, "Generated device string \"%s\"", devstr);
+  iec958_pcm_name = devstr;
+
+  res = snd_pcm_open (&pcm, iec958_pcm_name, SND_PCM_STREAM_PLAYBACK, 0);
+  if (G_UNLIKELY (res < 0)) {
+    GST_DEBUG_OBJECT (obj, "failed opening IEC958 device: %s",
+        snd_strerror (res));
+    pcm = NULL;
+  }
+
+  return pcm;
+}
+
+
+/*
+ * gst_alsa_probe_supported_formats:
+ *
+ * Takes the template caps and returns the subset which is actually
+ * supported by this device.
+ *
+ */
+
+GstCaps *
+gst_alsa_probe_supported_formats (GstObject * obj, snd_pcm_t * handle,
+    const GstCaps * template_caps)
+{
+  snd_pcm_hw_params_t *hw_params;
+  snd_pcm_stream_t stream_type;
+  GstCaps *caps;
+  gint err;
+
+  snd_pcm_hw_params_malloc (&hw_params);
+  if ((err = snd_pcm_hw_params_any (handle, hw_params)) < 0)
+    goto error;
+
+  stream_type = snd_pcm_stream (handle);
+
+  caps = gst_caps_copy (template_caps);
+
+  if (!(caps = gst_alsa_detect_formats (obj, hw_params, caps)))
+    goto subroutine_error;
+
+  if (!(caps = gst_alsa_detect_rates (obj, hw_params, caps)))
+    goto subroutine_error;
+
+  if (!(caps = gst_alsa_detect_channels (obj, hw_params, caps)))
+    goto subroutine_error;
+
+  /* Try opening IEC958 device to see if we can support that format (playback
+   * only for now but we could add SPDIF capture later) */
+  if (stream_type == SND_PCM_STREAM_PLAYBACK) {
+    snd_pcm_t *pcm = gst_alsa_open_iec958_pcm (obj);
+
+    if (G_LIKELY (pcm)) {
+      gst_caps_append (caps, gst_caps_new_simple ("audio/x-iec958", NULL));
+      snd_pcm_close (pcm);
+    }
+  }
+
+  snd_pcm_hw_params_free (hw_params);
+  return caps;
+
+  /* ERRORS */
+error:
+  {
+    GST_ERROR_OBJECT (obj, "failed to query formats: %s", snd_strerror (err));
+    snd_pcm_hw_params_free (hw_params);
+    return NULL;
+  }
+subroutine_error:
+  {
+    GST_ERROR_OBJECT (obj, "failed to query formats");
+    snd_pcm_hw_params_free (hw_params);
+    return NULL;
+  }
+}
+
+static gchar *
+gst_alsa_find_device_name_no_handle (GstObject * obj, const gchar * devcard,
+    gint device_num, snd_pcm_stream_t stream)
+{
+  snd_ctl_card_info_t *info = NULL;
+  snd_ctl_t *ctl = NULL;
+  gchar *ret = NULL;
+  gint dev = -1;
+
+  GST_LOG_OBJECT (obj, "[%s] device=%d", devcard, device_num);
+
+  if (snd_ctl_open (&ctl, devcard, 0) < 0)
+    return NULL;
+
+  snd_ctl_card_info_malloc (&info);
+  if (snd_ctl_card_info (ctl, info) < 0)
+    goto done;
+
+  while (snd_ctl_pcm_next_device (ctl, &dev) == 0 && dev >= 0) {
+    if (dev == device_num) {
+      snd_pcm_info_t *pcminfo;
+
+      snd_pcm_info_malloc (&pcminfo);
+      snd_pcm_info_set_device (pcminfo, dev);
+      snd_pcm_info_set_subdevice (pcminfo, 0);
+      snd_pcm_info_set_stream (pcminfo, stream);
+      if (snd_ctl_pcm_info (ctl, pcminfo) < 0) {
+        snd_pcm_info_free (pcminfo);
+        break;
+      }
+
+      ret = g_strdup (snd_pcm_info_get_name (pcminfo));
+      snd_pcm_info_free (pcminfo);
+      GST_LOG_OBJECT (obj, "name from pcminfo: %s", GST_STR_NULL (ret));
+    }
+  }
+
+  if (ret == NULL) {
+    char *name = NULL;
+    gint card;
+
+    GST_LOG_OBJECT (obj, "no luck so far, trying backup");
+    card = snd_ctl_card_info_get_card (info);
+    snd_card_get_name (card, &name);
+    ret = g_strdup (name);
+    free (name);
+  }
+
+done:
+  snd_ctl_card_info_free (info);
+  snd_ctl_close (ctl);
+
+  return ret;
+}
+
+gchar *
+gst_alsa_find_device_name (GstObject * obj, const gchar * device,
+    snd_pcm_t * handle, snd_pcm_stream_t stream)
+{
+  gchar *ret = NULL;
+
+  if (device != NULL) {
+    gchar *dev, *comma;
+    gint devnum;
+
+    GST_LOG_OBJECT (obj, "Trying to get device name from string '%s'", device);
+
+    /* only want name:card bit, but not devices and subdevices */
+    dev = g_strdup (device);
+    if ((comma = strchr (dev, ','))) {
+      *comma = '\0';
+      devnum = atoi (comma + 1);
+      ret = gst_alsa_find_device_name_no_handle (obj, dev, devnum, stream);
+    }
+    g_free (dev);
+  }
+
+  if (ret == NULL && handle != NULL) {
+    snd_pcm_info_t *info;
+
+    GST_LOG_OBJECT (obj, "Trying to get device name from open handle");
+    snd_pcm_info_malloc (&info);
+    snd_pcm_info (handle, info);
+    ret = g_strdup (snd_pcm_info_get_name (info));
+    snd_pcm_info_free (info);
+  }
+
+  GST_LOG_OBJECT (obj, "Device name for device '%s': %s",
+      GST_STR_NULL (device), GST_STR_NULL (ret));
+
+  return ret;
+}