/* GStreamer Multichannel-Audio helper functions * (c) 2004 Ronald Bultje * * 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. */ #ifdef HAVE_CONFIG_H #include #endif #include "multichannel.h" #define GST_AUDIO_CHANNEL_POSITIONS_PROPERTY_NAME "channel-positions" /* * This function checks if basic assumptions apply: * - does each position occur at most once? * - do conflicting positions occur? * + front_mono vs. front_left/right * + front_center vs. front_left/right_of_center * + rear_center vs. rear_left/right * It also adds some hacks that 0.8.x needs for compatibility: * - if channels == 1, are we really mono? * - if channels == 2, are we really stereo? */ static gboolean gst_audio_check_channel_positions (const GstAudioChannelPosition * pos, gint channels) { gint i, n; struct { GstAudioChannelPosition pos1[2]; GstAudioChannelPosition pos2[1]; } conf[] = { /* front: mono <-> stereo */ { { GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT, GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT}, { GST_AUDIO_CHANNEL_POSITION_FRONT_MONO}}, /* front center: 2 <-> 1 */ { { GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER, GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER}, { GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER}}, /* rear: 2 <-> 1 */ { { GST_AUDIO_CHANNEL_POSITION_REAR_LEFT, GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT}, { GST_AUDIO_CHANNEL_POSITION_REAR_CENTER}}, { { GST_AUDIO_CHANNEL_POSITION_INVALID}} }; /* check for invalid channel positions */ for (n = 0; n < channels; n++) { if (pos[n] == GST_AUDIO_CHANNEL_POSITION_INVALID) { g_warning ("Position %d is invalid, not allowed", n); return FALSE; } } /* check for multiple position occurrences */ for (i = GST_AUDIO_CHANNEL_POSITION_INVALID + 1; i < GST_AUDIO_CHANNEL_POSITION_NUM; i++) { gint count = 0; for (n = 0; n < channels; n++) { if (pos[n] == i) count++; } if (count > 1) { g_warning ("Channel position %d occurred %d times, not allowed", i, count); return FALSE; } } /* check for position conflicts */ for (i = 0; conf[i].pos1[0] != GST_AUDIO_CHANNEL_POSITION_INVALID; i++) { gboolean found1 = FALSE, found2 = FALSE; for (n = 0; n < channels; n++) { if (pos[n] == conf[i].pos1[0] || pos[n] == conf[i].pos1[1]) found1 = TRUE; else if (pos[n] == conf[i].pos2[0]) found2 = TRUE; } if (found1 && found2) { g_warning ("Found conflicting channel positions %d/%d and %d", conf[i].pos1[0], conf[i].pos1[1], conf[i].pos2[0]); return FALSE; } } /* 0.8.x evilry */ if ((channels == 1 && pos[0] != GST_AUDIO_CHANNEL_POSITION_FRONT_MONO) || (channels == 2 && (pos[0] != GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT || pos[1] != GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT))) { g_warning ("0.8.x: channels=1 implies mono; channels=2 implies stereo"); return FALSE; } return TRUE; } /** * gst_audio_get_channel_positions: * @str: A #GstStructure to retrieve channel positions from. * * Retrieves a number of (fixed!) audio channel positions from * the provided #GstStructure and returns it as a newly allocated * array. The caller should g_free () this array. The caller * should also check that the members in this #GstStructure are * indeed "fixed" before calling this function. * * Returns: a newly allocated array containing the channel * positions as provided in the given #GstStructure. Returns * NULL on error. */ GstAudioChannelPosition * gst_audio_get_channel_positions (GstStructure * str) { GstAudioChannelPosition *pos; gint channels, n; const GValue *pos_val_arr, *pos_val_entry; gboolean res; GType t; /* get number of channels, general type checkups */ g_return_val_if_fail (str != NULL, NULL); res = gst_structure_get_int (str, "channels", &channels); g_return_val_if_fail (res, NULL); g_return_val_if_fail (channels > 0, NULL); pos_val_arr = gst_structure_get_value (str, GST_AUDIO_CHANNEL_POSITIONS_PROPERTY_NAME); /* The following checks are here to retain compatibility for plugins not * implementing this property. They expect that channels=1 implies mono * and channels=2 implies stereo, so we follow that. * This might be removed during 0.9.x. */ if (!pos_val_arr && (channels == 1 || channels == 2)) { pos = g_new (GstAudioChannelPosition, channels); if (channels == 1) { pos[0] = GST_AUDIO_CHANNEL_POSITION_FRONT_MONO; } else { pos[0] = GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT; pos[1] = GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT; } return pos; } g_return_val_if_fail (pos_val_arr != NULL, NULL); g_return_val_if_fail (gst_value_list_get_size (pos_val_arr) == channels, NULL); for (n = 0; n < channels; n++) { t = G_VALUE_TYPE (gst_value_list_get_value (pos_val_arr, n)); g_return_val_if_fail (t == GST_TYPE_AUDIO_CHANNEL_POSITION, NULL); } /* ... and fill array */ pos = g_new (GstAudioChannelPosition, channels); for (n = 0; n < channels; n++) { pos_val_entry = gst_value_list_get_value (pos_val_arr, n); pos[n] = g_value_get_enum (pos_val_entry); } if (!gst_audio_check_channel_positions (pos, channels)) { g_free (pos); return NULL; } return pos; } /** * gst_audio_set_channel_positions: * @str: A #GstStructure to retrieve channel positions from. * @pos: an array of channel positions. The number of members * in this array should be equal to the (fixed!) number * of the "channels" property in the given #GstStructure. * * Adds a "channel-positions" property to the given #GstStructure, * which will represent the channel positions as given in the * provided #GstAudioChannelPosition array. */ void gst_audio_set_channel_positions (GstStructure * str, const GstAudioChannelPosition * pos) { GValue pos_val_arr = { 0 }, pos_val_entry = { 0}; gint channels, n; gboolean res; /* get number of channels, checkups */ g_return_if_fail (str != NULL); g_return_if_fail (pos != NULL); res = gst_structure_get_int (str, "channels", &channels); g_return_if_fail (res); g_return_if_fail (channels > 0); if (!gst_audio_check_channel_positions (pos, channels)) return; /* build gvaluearray from positions */ g_value_init (&pos_val_entry, GST_TYPE_AUDIO_CHANNEL_POSITION); g_value_init (&pos_val_arr, GST_TYPE_FIXED_LIST); for (n = 0; n < channels; n++) { g_value_set_enum (&pos_val_entry, pos[n]); gst_value_list_append_value (&pos_val_arr, &pos_val_entry); } g_value_unset (&pos_val_entry); /* add to structure */ gst_structure_set_value (str, GST_AUDIO_CHANNEL_POSITIONS_PROPERTY_NAME, &pos_val_arr); g_value_unset (&pos_val_arr); } /** * gst_audio_set_structure_channel_positions_list: * @str: #GstStructure to set the list of channel positions * on. * @pos: the array containing one or more possible audio * channel positions that we should add in each value * of the array in the given structure. * @num_positions: the number of values in pos. * * Sets a (possibly non-fixed) list of possible audio channel * positions (given in pos) on the given structure. The * structure, after this function has been called, will contain * a "channel-positions" property with an array of the size of * the "channels" property value in the given structure (note * that this means that the channels property in the provided * structure should be fixed!). Each value in the array will * contain each of the values given in the pos array. */ void gst_audio_set_structure_channel_positions_list (GstStructure * str, const GstAudioChannelPosition * pos, gint num_positions) { gint channels, n, c; GValue pos_val_arr = { 0 }, pos_val_list = { 0}, pos_val_entry = { 0}; gboolean res; /* get number of channels, general type checkups */ g_return_if_fail (str != NULL); g_return_if_fail (num_positions > 0); g_return_if_fail (pos != NULL); res = gst_structure_get_int (str, "channels", &channels); g_return_if_fail (res); g_return_if_fail (channels > 0); /* 0.8.x: channels=1 or channels=2 is mono/stereo, no positions needed * there (we discard them anyway) */ if (channels == 1 || channels == 2) return; /* create the array of lists */ g_value_init (&pos_val_arr, GST_TYPE_FIXED_LIST); g_value_init (&pos_val_entry, GST_TYPE_AUDIO_CHANNEL_POSITION); for (n = 0; n < channels; n++) { g_value_init (&pos_val_list, GST_TYPE_LIST); for (c = 0; c < num_positions; c++) { g_value_set_enum (&pos_val_entry, pos[c]); gst_value_list_append_value (&pos_val_list, &pos_val_entry); } gst_value_list_append_value (&pos_val_arr, &pos_val_list); g_value_unset (&pos_val_list); } g_value_unset (&pos_val_entry); gst_structure_set_value (str, GST_AUDIO_CHANNEL_POSITIONS_PROPERTY_NAME, &pos_val_arr); g_value_unset (&pos_val_arr); } /* * Helper function for below. The structure will be conserved, * but might be cut down. Any additional structures that were * created will be stored in the returned caps. */ static GstCaps * add_list_to_struct (GstStructure * str, const GstAudioChannelPosition * pos, gint num_positions) { GstCaps *caps = gst_caps_new_empty (); const GValue *chan_val; chan_val = gst_structure_get_value (str, "channels"); if (G_VALUE_TYPE (chan_val) == G_TYPE_INT) { gst_audio_set_structure_channel_positions_list (str, pos, num_positions); } else if (G_VALUE_TYPE (chan_val) == GST_TYPE_LIST) { gint size; const GValue *sub_val; size = gst_value_list_get_size (chan_val); sub_val = gst_value_list_get_value (chan_val, 0); gst_structure_set_value (str, "channels", sub_val); gst_caps_append (caps, add_list_to_struct (str, pos, num_positions)); while (--size > 0) { str = gst_structure_copy (str); sub_val = gst_value_list_get_value (chan_val, size); gst_structure_set_value (str, "channels", sub_val); gst_caps_append (caps, add_list_to_struct (str, pos, num_positions)); gst_caps_append_structure (caps, str); } } else if (G_VALUE_TYPE (chan_val) == GST_TYPE_INT_RANGE) { gint min, max; min = gst_value_get_int_range_min (chan_val); max = gst_value_get_int_range_max (chan_val); gst_structure_set (str, "channels", G_TYPE_INT, min, NULL); gst_audio_set_structure_channel_positions_list (str, pos, num_positions); for (++min; min < max; min++) { str = gst_structure_copy (str); gst_structure_set (str, "channels", G_TYPE_INT, min, NULL); gst_audio_set_structure_channel_positions_list (str, pos, num_positions); gst_caps_append_structure (caps, str); } } else { g_warning ("Unknown value type for channels property"); } return caps; } /** * gst_audio_set_caps_channel_positions_list: * @caps: #GstCaps to set the list of channel positions on. * @pos: the array containing one or more possible audio * channel positions that we should add in each value * of the array in the given structure. * @num_positions: the number of values in pos. * * Sets a (possibly non-fixed) list of possible audio channel * positions (given in pos) on the given caps. Each of the * structures of the caps, after this function has been called, * will contain a "channel-positions" property with an array. * Each value in the array will contain each of the values given * in the pos array. Note that the size of the caps might be * increased by this, since each structure with a "channel- * positions" property needs to have a fixed "channels" property. * The input caps is not required to have this. */ void gst_audio_set_caps_channel_positions_list (GstCaps * caps, const GstAudioChannelPosition * pos, gint num_positions) { gint size, n; /* get number of channels, general type checkups */ g_return_if_fail (caps != NULL); g_return_if_fail (num_positions > 0); g_return_if_fail (pos != NULL); size = gst_caps_get_size (caps); for (n = 0; n < size; n++) { gst_caps_append (caps, add_list_to_struct (gst_caps_get_structure (caps, n), pos, num_positions)); } } /** * gst_audio_fixate_channel_positions: * @str: a #GstStructure containing a (possibly unfixed) * "channel-positions" property. * * Custom fixate function. Elements that implement some sort of * channel conversion algorhithm should use this function for * fixating on GstAudioChannelPosition properties. It will take * care of equal channel positioning (left/right). Caller g_free()s * the return value. The input properties may be (and are supposed * to be) unfixed. * Note that this function is mostly a hack because we currently * have no way to add default fixation functions for new GTypes. * * Returns: fixed values that the caller could use as a fixed * set of #GstAudioChannelPosition values. */ GstAudioChannelPosition * gst_audio_fixate_channel_positions (GstStructure * str) { GstAudioChannelPosition *pos; gint channels, n, num_unfixed = 0, i, c; const GValue *pos_val_arr, *pos_val_entry, *pos_val; gboolean res, is_stereo = TRUE; GType t; /* * We're going to do this cluelessly. We'll make an array of values that * conflict with each other and, for each iteration in this array, pick * either one until all unknown values are filled. This might not work in * corner cases but should work OK for the general case. */ struct { GstAudioChannelPosition pos1[2]; GstAudioChannelPosition pos2[1]; } conf[] = { /* front: mono <-> stereo */ { { GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT, GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT}, { GST_AUDIO_CHANNEL_POSITION_FRONT_MONO}}, /* front center: 2 <-> 1 */ { { GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER, GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER}, { GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER}}, /* rear: 2 <-> 1 */ { { GST_AUDIO_CHANNEL_POSITION_REAR_LEFT, GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT}, { GST_AUDIO_CHANNEL_POSITION_REAR_CENTER}}, { { GST_AUDIO_CHANNEL_POSITION_INVALID, GST_AUDIO_CHANNEL_POSITION_INVALID}, { GST_AUDIO_CHANNEL_POSITION_LFE}}, { { GST_AUDIO_CHANNEL_POSITION_SIDE_LEFT, GST_AUDIO_CHANNEL_POSITION_SIDE_RIGHT}, { GST_AUDIO_CHANNEL_POSITION_INVALID}}, { { GST_AUDIO_CHANNEL_POSITION_INVALID, GST_AUDIO_CHANNEL_POSITION_INVALID}, { GST_AUDIO_CHANNEL_POSITION_INVALID}} }; struct { gint num_opt[3]; guint num_opts[3]; gboolean is_fixed[3]; gint choice; /* -1 is none, 0 is the two, 1 is the one */ } opt; /* get number of channels, general type checkups */ g_return_val_if_fail (str != NULL, NULL); res = gst_structure_get_int (str, "channels", &channels); g_return_val_if_fail (res, NULL); g_return_val_if_fail (channels > 0, NULL); /* 0.8.x mono/stereo checks */ pos_val_arr = gst_structure_get_value (str, GST_AUDIO_CHANNEL_POSITIONS_PROPERTY_NAME); if (!pos_val_arr && (channels == 1 || channels == 2)) { pos = g_new (GstAudioChannelPosition, channels); if (channels == 1) { pos[0] = GST_AUDIO_CHANNEL_POSITION_FRONT_MONO; } else { pos[0] = GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT; pos[1] = GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT; } return pos; } g_return_val_if_fail (pos_val_arr != NULL, NULL); g_return_val_if_fail (gst_value_list_get_size (pos_val_arr) == channels, NULL); for (n = 0; n < channels; n++) { t = G_VALUE_TYPE (gst_value_list_get_value (pos_val_arr, n)); g_return_val_if_fail (t == GST_TYPE_LIST || t == GST_TYPE_AUDIO_CHANNEL_POSITION, NULL); } /* all unknown, to start with */ pos = g_new (GstAudioChannelPosition, channels); for (n = 0; n < channels; n++) pos[n] = GST_AUDIO_CHANNEL_POSITION_INVALID; num_unfixed = channels; /* Iterate the array of conflicting values */ for (i = 0; conf[i].pos1[0] != GST_AUDIO_CHANNEL_POSITION_INVALID || conf[i].pos2[0] != GST_AUDIO_CHANNEL_POSITION_INVALID; i++) { /* front/center only important if not mono (obviously) */ if (conf[i].pos1[0] == GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER && !is_stereo) continue; /* init values */ for (n = 0; n < 3; n++) { opt.num_opt[n] = -1; opt.num_opts[n] = -1; opt.is_fixed[n] = FALSE; } /* Now, we'll see for each channel if it allows for any of the values in * the set of conflicting audio channel positions and keep scores. */ for (n = 0; n < channels; n++) { /* if the channel is already taken, don't bother */ if (pos[n] != GST_AUDIO_CHANNEL_POSITION_INVALID) continue; pos_val_entry = gst_value_list_get_value (pos_val_arr, n); t = G_VALUE_TYPE (pos_val_entry); if (t == GST_TYPE_LIST) { /* This algorhythm is suboptimal. */ for (c = 0; c < gst_value_list_get_size (pos_val_entry); c++) { pos_val = gst_value_list_get_value (pos_val_entry, c); if (g_value_get_enum (pos_val) == conf[i].pos1[0] && opt.num_opts[0] > gst_value_list_get_size (pos_val_entry) && !opt.is_fixed[0]) { /* Now test if the old position of num_opt[0] also allows for * the other channel (which was skipped previously). If so, * keep score. */ if (opt.num_opt[0] != -1) { gint c1; pos_val_entry = gst_value_list_get_value (pos_val_arr, opt.num_opt[0]); if (G_VALUE_TYPE (pos_val_entry) == GST_TYPE_LIST) { for (c1 = 0; c1 < gst_value_list_get_size (pos_val_entry); c1++) { pos_val = gst_value_list_get_value (pos_val_entry, c1); if (g_value_get_enum (pos_val) == conf[i].pos1[1] && opt.num_opts[1] > opt.num_opts[0] && !opt.is_fixed[1]) { opt.num_opts[1] = opt.num_opts[0]; opt.num_opt[1] = opt.num_opt[0]; } } pos_val = gst_value_list_get_value (pos_val_entry, c); } pos_val_entry = gst_value_list_get_value (pos_val_arr, n); } /* and save values */ opt.num_opts[0] = gst_value_list_get_size (pos_val_entry); opt.num_opt[0] = n; } else if (g_value_get_enum (pos_val) == conf[i].pos1[1] && opt.num_opts[1] > gst_value_list_get_size (pos_val_entry) && !opt.is_fixed[1] && n != opt.num_opt[0]) { opt.num_opts[1] = gst_value_list_get_size (pos_val_entry); opt.num_opt[1] = n; } /* 2 goes separately, because 0/1 vs. 2 are separate */ if (g_value_get_enum (pos_val) == conf[i].pos2[0] && opt.num_opts[2] > gst_value_list_get_size (pos_val_entry) && !opt.is_fixed[2]) { opt.num_opts[2] = gst_value_list_get_size (pos_val_entry); opt.num_opt[2] = n; } } } else { if (g_value_get_enum (pos_val_entry) == conf[i].pos1[0]) { opt.num_opt[0] = n; opt.is_fixed[0] = TRUE; } else if (g_value_get_enum (pos_val_entry) == conf[i].pos1[1]) { opt.num_opt[1] = n; opt.is_fixed[1] = TRUE; } else if (g_value_get_enum (pos_val_entry) == conf[i].pos2[0]) { opt.num_opt[2] = n; opt.is_fixed[2] = TRUE; } } } /* check our results and choose either one */ if ((opt.is_fixed[0] || opt.is_fixed[1]) && opt.is_fixed[2]) { g_warning ("Pre-fixated on both %d/%d and %d - conflict!", conf[i].pos1[0], conf[i].pos1[1], conf[i].pos2[0]); g_free (pos); return NULL; } else if ((opt.is_fixed[0] && opt.num_opt[1] == -1) || (opt.is_fixed[1] && opt.num_opt[0] == -1)) { g_warning ("Pre-fixated one side, but other side n/a of %d/%d", conf[i].pos1[0], conf[i].pos1[1]); g_free (pos); return NULL; } else if (opt.is_fixed[0] || opt.is_fixed[1]) { opt.choice = 0; } else if (opt.is_fixed[2]) { opt.choice = 1; } else if (opt.num_opt[0] != -1 && opt.num_opt[1] != -1) { opt.choice = 0; } else if (opt.num_opt[2] != -1) { opt.choice = 1; } else { opt.choice = -1; } /* stereo? Note that we keep is_stereo to TRUE if we didn't decide on * any arrangement. The mono/stereo channels might be handled elsewhere * which is clearly outside the scope of this element, so we cannot * know and expect the application to handle that then. */ if (conf[i].pos2[0] == GST_AUDIO_CHANNEL_POSITION_FRONT_MONO && opt.choice == 1) { is_stereo = FALSE; } /* now actually decide what we'll do and fixate on that */ if (opt.choice == 0) { g_assert (conf[i].pos1[0] != GST_AUDIO_CHANNEL_POSITION_INVALID && conf[i].pos1[1] != GST_AUDIO_CHANNEL_POSITION_INVALID); pos[opt.num_opt[0]] = conf[i].pos1[0]; pos[opt.num_opt[1]] = conf[i].pos1[1]; num_unfixed -= 2; } else if (opt.choice == 1) { g_assert (conf[i].pos2[0] != GST_AUDIO_CHANNEL_POSITION_INVALID); pos[opt.num_opt[2]] = conf[i].pos2[0]; num_unfixed--; } } /* safety check */ if (num_unfixed > 0) { g_warning ("%d unfixed channel positions left after fixation!", num_unfixed); g_free (pos); return NULL; } if (!gst_audio_check_channel_positions (pos, channels)) { g_free (pos); return NULL; } return pos; }