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	1	/*
	2	* This file is part of DisOrder.
	3	* Copyright (C) 2007 Richard Kettlewell
	4	*
	5	* This program is free software: you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation, either version 3 of the License, or
	8	* (at your option) any later version.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	17	*/
	18	/** @file clients/playrtp.h
	19	* @brief RTP player
	20	*/
	21
	22	#ifndef PLAYRTP_H
	23	#define PLAYRTP_H
	24
	25	/** @brief Maximum samples per packet we'll support
	26	*
	27	* NB that two channels = two samples in this program.
	28	*/
	29	#define MAXSAMPLES 2048
	30
	31	/** @brief Number of samples to infill by in one go
	32	*
	33	* This is an upper bound - in practice we expect the underlying audio API to
	34	* only ask for a much smaller number of samples in any one go.
	35	*/
	36	#define INFILL_SAMPLES (44100 * 2) /* 1s */
	37
	38	/** @brief Received packet
	39	*
	40	* Received packets are kept in a binary heap (see @ref pheap) ordered by
	41	* timestamp.
	42	*/
	43	struct packet {
	44	/** @brief Next packet in @ref next_free_packet or @ref received_packets */
	45	struct packet *next;
	46
	47	/** @brief Number of samples in this packet */
	48	uint32_t nsamples;
	49
	50	/** @brief Timestamp from RTP packet
	51	*
	52	* NB that "timestamps" are really sample counters. Use lt() or lt_packet()
	53	* to compare timestamps.
	54	*/
	55	uint32_t timestamp;
	56
	57	/** @brief Flags
	58	*
	59	* Valid values are:
	60	* - @ref IDLE - the idle bit was set in the RTP packet
	61	* - @ref SILENT - packet is entirely silent
	62	*/
	63	unsigned flags;
	64	/** @brief idle bit set in RTP packet*/
	65	#define IDLE 0x0001
	66
	67	/** @brief RTP packet is entirely silent */
	68	#define SILENT 0x0002
	69
	70	/** @brief Raw sample data
	71	*
	72	* Only the first @p nsamples samples are defined; the rest is uninitialized
	73	* data.
	74	*/
	75	uint16_t samples_raw[MAXSAMPLES];
	76	};
	77
	78	/** @brief Structure of free packet list */
	79	union free_packet {
	80	struct packet p;
	81	union free_packet *next;
	82	};
	83
	84	/** @brief Return true iff \f$a < b\f$ in sequence-space arithmetic
	85	*
	86	* Specifically it returns true if \f$(a-b) mod 2^{32} < 2^{31}\f$.
	87	*
	88	* See also lt_packet().
	89	*/
	90	static inline int lt(uint32_t a, uint32_t b) {
	91	return (uint32_t)(a - b) & 0x80000000;
	92	}
	93
	94	/** @brief Return true iff a >= b in sequence-space arithmetic */
	95	static inline int ge(uint32_t a, uint32_t b) {
	96	return !lt(a, b);
	97	}
	98
	99	/** @brief Return true iff a > b in sequence-space arithmetic */
	100	static inline int gt(uint32_t a, uint32_t b) {
	101	return lt(b, a);
	102	}
	103
	104	/** @brief Return true iff a <= b in sequence-space arithmetic */
	105	static inline int le(uint32_t a, uint32_t b) {
	106	return !lt(b, a);
	107	}
	108
	109	/** @brief Ordering for packets, used by @ref pheap */
	110	static inline int lt_packet(const struct packet a, const struct packet b) {
	111	return lt(a->timestamp, b->timestamp);
	112	}
	113
	114	/** @brief Return true if @p p contains @p timestamp
	115	*
	116	* Containment implies that a sample @p timestamp exists within the packet.
	117	*/
	118	static inline int contains(const struct packet *p, uint32_t timestamp) {
	119	const uint32_t packet_start = p->timestamp;
	120	const uint32_t packet_end = p->timestamp + p->nsamples;
	121
	122	return (ge(timestamp, packet_start)
	123	&& lt(timestamp, packet_end));
	124	}
	125
	126	/** @struct pheap
	127	* @brief Binary heap of packets ordered by timestamp */
	128	HEAP_TYPE(pheap, struct packet *, lt_packet);
	129
	130	struct packet *playrtp_new_packet(void);
	131	void playrtp_free_packet(struct packet *p);
	132	void playrtp_fill_buffer(void);
	133	struct packet *playrtp_next_packet(void);
	134
	135	extern struct packet *received_packets;
	136	extern struct packet **received_tail;
	137	extern pthread_mutex_t receive_lock;
	138	extern pthread_cond_t receive_cond;
	139	extern uint32_t nreceived;
	140	extern struct pheap packets;
	141	extern volatile uint32_t nsamples;
	142	extern uint32_t next_timestamp;
	143	extern int active;
	144	extern pthread_mutex_t lock;
	145	extern pthread_cond_t cond;
	146	extern unsigned minbuffer;
	147
	148	extern int16_t *dump_buffer;
	149	extern size_t dump_index;
	150	extern size_t dump_size;
	151
	152	void playrtp_oss(void), playrtp_alsa(void), playrtp_coreaudio(void);
	153
	154	#endif /* PLAYRTP_H */
	155
	156	/*
	157	Local Variables:
	158	c-basic-offset:2
	159	comment-column:40
	160	fill-column:79
	161	indent-tabs-mode:nil
	162	End:
	163	*/