/* GStreamer * Copyright (C) <2008> Wim Taymans <wim.taymans@gmail.com> * * 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., 51 Franklin St, Fifth Floor, * Boston, MA 02110-1301, USA. */ #include <string.h> #include <stdlib.h> #include "gstrtpchannels.h" /* * RTP channel positions as discussed in RFC 3551 and also RFC 3555 * * We can't really represent the described channel positions in GStreamer but we * implement a (very rough) approximation here. */ static gboolean check_channels (const GstRTPChannelOrder * order, const GstAudioChannelPosition * pos) { gint i, j; gboolean res = TRUE; for (i = 0; i < order->channels; i++) { for (j = 0; j < order->channels; j++) { if (order->pos[j] == pos[i]) break; } if (j == order->channels) return FALSE; } return res; } /** * gst_rtp_channels_get_by_pos: * @channels: the amount of channels * @pos: a channel layout * * Return a description of the channel layout. * * Returns: a #GstRTPChannelOrder with the channel information or NULL when @pos * is not a valid layout. */ const GstRTPChannelOrder * gst_rtp_channels_get_by_pos (gint channels, const GstAudioChannelPosition * pos) { gint i; const GstRTPChannelOrder *res = NULL; g_return_val_if_fail (pos != NULL, NULL); for (i = 0; channel_orders[i].pos; i++) { if (channel_orders[i].channels != channels) continue; if (check_channels (&channel_orders[i], pos)) { res = &channel_orders[i]; break; } } return res; } /** * gst_rtp_channels_create_default: * @channels: the amount of channels * @order: a channel order * * Get the channel order info the @order and @channels. * * Returns: a #GstRTPChannelOrder with the channel information or NULL when * @order is not a know layout for @channels. */ const GstRTPChannelOrder * gst_rtp_channels_get_by_order (gint channels, const gchar * order) { gint i; const GstRTPChannelOrder *res = NULL; for (i = 0; channel_orders[i].pos; i++) { if (channel_orders[i].channels != channels) continue; /* no name but channels match, continue */ if (!channel_orders[i].name || !order) { res = &channel_orders[i]; break; } /* compare names */ if (g_ascii_strcasecmp (channel_orders[i].name, order)) { res = &channel_orders[i]; break; } } return res; } /** * gst_rtp_channels_get_by_index: * @channels: the amount of channels * @idx: the channel index to retrieve * * Get the allowed channel order descriptions for @channels. @idx can be used to * retrieve the desired index. * * Returns: a #GstRTPChannelOrder at @idx, NULL when there are no valid channel * orders. */ const GstRTPChannelOrder * gst_rtp_channels_get_by_index (gint channels, guint idx) { gint i; const GstRTPChannelOrder *res = NULL; for (i = 0; channel_orders[i].pos; i++) { if (channel_orders[i].channels != channels) continue; if (idx == 0) { res = &channel_orders[i]; break; } idx--; } return res; } /** * gst_rtp_channels_create_default: * @channels: the amount of channels * * Create a default none channel mapping for @channels. * * Returns: a #GstAudioChannelPosition with all the channel position info set to * #GST_AUDIO_CHANNEL_POSITION_NONE. */ void gst_rtp_channels_create_default (gint channels, GstAudioChannelPosition * posn) { gint i; g_return_if_fail (channels > 0); for (i = 0; i < channels; i++) posn[i] = GST_AUDIO_CHANNEL_POSITION_NONE; }