+/*
+ * This file is part of DisOrder.
+ * Copyright (C) 2007 Richard Kettlewell
+ *
+ * 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 2 of the License, or
+ * (at your option) 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ * USA
+ */
+/** @file clients/playrtp.h
+ * @brief RTP player
+ */
+
+#ifndef PLAYRTP_H
+#define PLAYRTP_H
+
+/** @brief Maximum samples per packet we'll support
+ *
+ * NB that two channels = two samples in this program.
+ */
+#define MAXSAMPLES 2048
+
+/** @brief Number of samples to infill by in one go
+ *
+ * This is an upper bound - in practice we expect the underlying audio API to
+ * only ask for a much smaller number of samples in any one go.
+ */
+#define INFILL_SAMPLES (44100 * 2) /* 1s */
+
+/** @brief Received packet
+ *
+ * Received packets are kept in a binary heap (see @ref pheap) ordered by
+ * timestamp.
+ */
+struct packet {
+ /** @brief Next packet in @ref next_free_packet or @ref received_packets */
+ struct packet *next;
+
+ /** @brief Number of samples in this packet */
+ uint32_t nsamples;
+
+ /** @brief Timestamp from RTP packet
+ *
+ * NB that "timestamps" are really sample counters. Use lt() or lt_packet()
+ * to compare timestamps.
+ */
+ uint32_t timestamp;
+
+ /** @brief Flags
+ *
+ * Valid values are:
+ * - @ref IDLE - the idle bit was set in the RTP packet
+ */
+ unsigned flags;
+/** @brief idle bit set in RTP packet*/
+#define IDLE 0x0001
+
+ /** @brief Raw sample data
+ *
+ * Only the first @p nsamples samples are defined; the rest is uninitialized
+ * data.
+ */
+ uint16_t samples_raw[MAXSAMPLES];
+};
+
+/** @brief Structure of free packet list */
+union free_packet {
+ struct packet p;
+ union free_packet *next;
+};
+
+/** @brief Return true iff \f$a < b\f$ in sequence-space arithmetic
+ *
+ * Specifically it returns true if \f$(a-b) mod 2^{32} < 2^{31}\f$.
+ *
+ * See also lt_packet().
+ */
+static inline int lt(uint32_t a, uint32_t b) {
+ return (uint32_t)(a - b) & 0x80000000;
+}
+
+/** @brief Return true iff a >= b in sequence-space arithmetic */
+static inline int ge(uint32_t a, uint32_t b) {
+ return !lt(a, b);
+}
+
+/** @brief Return true iff a > b in sequence-space arithmetic */
+static inline int gt(uint32_t a, uint32_t b) {
+ return lt(b, a);
+}
+
+/** @brief Return true iff a <= b in sequence-space arithmetic */
+static inline int le(uint32_t a, uint32_t b) {
+ return !lt(b, a);
+}
+
+/** @brief Ordering for packets, used by @ref pheap */
+static inline int lt_packet(const struct packet *a, const struct packet *b) {
+ return lt(a->timestamp, b->timestamp);
+}
+
+/** @struct pheap
+ * @brief Binary heap of packets ordered by timestamp */
+HEAP_TYPE(pheap, struct packet *, lt_packet);
+
+struct packet *new_packet(void);
+void free_packet(struct packet *p);
+
+extern const char *device;
+extern struct packet *received_packets;
+extern struct packet **received_tail;
+extern pthread_mutex_t receive_lock;
+extern pthread_cond_t receive_cond;
+extern uint32_t nreceived;
+extern struct pheap packets;
+extern volatile uint32_t nsamples;
+extern uint32_t next_timestamp;
+extern int active;
+extern pthread_mutex_t lock;
+extern pthread_cond_t cond;
+
+
+#endif /* PLAYRTP_H */
+
+/*
+Local Variables:
+c-basic-offset:2
+comment-column:40
+fill-column:79
+indent-tabs-mode:nil
+End:
+*/
~mdw / disorder / commitdiff