* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*/
+/** @file clients/playrtp.c
+ * @brief RTP player
+ *
+ * This RTP player supports Linux (ALSA) and Darwin (Core Audio) systems.
+ */
#include <config.h>
#include "types.h"
#include <netdb.h>
#include <pthread.h>
#include <locale.h>
+#include <sys/uio.h>
+#include <string.h>
#include "log.h"
#include "mem.h"
#include "syscalls.h"
#include "rtp.h"
#include "defs.h"
+#include "vector.h"
+#include "heap.h"
#if HAVE_COREAUDIO_AUDIOHARDWARE_H
# include <CoreAudio/AudioHardware.h>
/** @brief RTP socket */
static int rtpfd;
+/** @brief Log output */
+static FILE *logfp;
+
/** @brief Output device */
static const char *device;
* We'll stop reading from the network if we have this many samples. */
static unsigned maxbuffer;
-/** @brief Number of samples to infill by in one go */
+/** @brief Number of samples to infill by in one go
+ *
+ * This is an upper bound - in practice we expxect 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
*
- * Packets are recorded in an ordered linked list. */
+ * Received packets are kept in a binary heap (see @ref pheap) ordered by
+ * timestamp.
+ */
struct packet {
- /** @brief Pointer to next packet
- * The next packet might not be immediately next: if packets are dropped
- * or mis-ordered there may be gaps at any given moment. */
- 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.*/
+ * NB that "timestamps" are really sample counters. Use lt() or lt_packet()
+ * to compare timestamps.
+ */
uint32_t timestamp;
-#if HAVE_COREAUDIO_AUDIOHARDWARE_H
- /** @brief Converted sample data */
- float samples_float[MAXSAMPLES];
-#else
- /** @brief Raw sample data */
+ /** @brief Raw sample data
+ *
+ * Only the first @p nsamples samples are defined; the rest is uninitialized
+ * data.
+ */
unsigned char samples_raw[MAXSAMPLES * MAXSAMPLESIZE];
-#endif
};
+/** @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);
+
+/** @brief Binary heap of received packets */
+static struct pheap packets;
+
/** @brief Total number of samples available */
static unsigned long nsamples;
-/** @brief Linked list of packets
- *
- * In ascending order of timestamp. Really this should be a heap for more
- * efficient access. */
-static struct packet *packets;
-
/** @brief Timestamp of next packet to play.
*
* This is set to the timestamp of the last packet, plus the number of
* This is true when playing and false when just buffering. */
static int active;
-/** @brief Lock protecting @ref packets */
+/** @brief Structure of free packet list */
+union free_packet {
+ struct packet p;
+ union free_packet *next;
+};
+
+/** @brief Linked list of free packets
+ *
+ * This is a linked list of formerly used packets. For preference we re-use
+ * packets that have already been used rather than unused ones, to limit the
+ * size of the program's working set. If there are no free packets in the list
+ * we try @ref next_free_packet instead.
+ *
+ * Must hold @ref lock when accessing this.
+ */
+static union free_packet *free_packets;
+
+/** @brief Array of new free packets
+ *
+ * There are @ref count_free_packets ready to use at this address. If there
+ * are none left we allocate more memory.
+ *
+ * Must hold @ref lock when accessing this.
+ */
+static union free_packet *next_free_packet;
+
+/** @brief Count of new free packets at @ref next_free_packet
+ *
+ * Must hold @ref lock when accessing this.
+ */
+static size_t count_free_packets;
+
+/** @brief Lock protecting @ref packets
+ *
+ * This also protects the packet memory allocation infrastructure, @ref
+ * free_packets and @ref next_free_packet. */
static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
/** @brief Condition variable signalled whenever @ref packets is changed */
{ 0, 0, 0, 0 }
};
-/** @brief Return true iff a < b in sequence-space arithmetic */
-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 a new packet
+ *
+ * Assumes that @ref lock is held. */
+static struct packet *new_packet(void) {
+ struct packet *p;
+
+ if(free_packets) {
+ p = &free_packets->p;
+ free_packets = free_packets->next;
+ } else {
+ if(!count_free_packets) {
+ next_free_packet = xcalloc(1024, sizeof (union free_packet));
+ count_free_packets = 1024;
+ }
+ p = &(next_free_packet++)->p;
+ --count_free_packets;
+ }
+ return p;
}
-/** @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 Free a packet
+ *
+ * Assumes that @ref lock is held. */
+static void free_packet(struct packet *p) {
+ union free_packet *u = (union free_packet *)p;
+ u->next = free_packets;
+ free_packets = u;
}
-/** @brief Drop the packet at the head of the queue */
+/** @brief Drop the first packet
+ *
+ * Assumes that @ref lock is held.
+ */
static void drop_first_packet(void) {
- struct packet *const p = packets;
- packets = p->next;
- nsamples -= p->nsamples;
- free(p);
- pthread_cond_broadcast(&cond);
+ if(pheap_count(&packets)) {
+ struct packet *const p = pheap_remove(&packets);
+ nsamples -= p->nsamples;
+ free_packet(p);
+ pthread_cond_broadcast(&cond);
+ }
}
/** @brief Background thread collecting samples
* This function collects samples, perhaps converts them to the target format,
* and adds them to the packet list. */
static void *listen_thread(void attribute((unused)) *arg) {
- struct packet *p = 0, **pp;
+ struct packet *p = 0;
int n;
- union {
- struct rtp_header header;
- uint8_t bytes[sizeof(uint16_t) * MAXSAMPLES + sizeof (struct rtp_header)];
- } packet;
- const uint16_t *const samples = (uint16_t *)(packet.bytes
- + sizeof (struct rtp_header));
+ struct rtp_header header;
+ uint16_t seq;
+ uint32_t timestamp;
+ struct iovec iov[2];
for(;;) {
- if(!p)
- p = xmalloc(sizeof *p);
- n = read(rtpfd, packet.bytes, sizeof packet.bytes);
+ if(!p) {
+ pthread_mutex_lock(&lock);
+ p = new_packet();
+ pthread_mutex_unlock(&lock);
+ }
+ iov[0].iov_base = &header;
+ iov[0].iov_len = sizeof header;
+ iov[1].iov_base = p->samples_raw;
+ iov[1].iov_len = sizeof p->samples_raw;
+ n = readv(rtpfd, iov, 2);
if(n < 0) {
switch(errno) {
case EINTR:
}
}
/* Ignore too-short packets */
- if((size_t)n <= sizeof (struct rtp_header))
+ if((size_t)n <= sizeof (struct rtp_header)) {
+ info("ignored a short packet");
continue;
- p->timestamp = ntohl(packet.header.timestamp);
+ }
+ timestamp = htonl(header.timestamp);
+ seq = htons(header.seq);
/* Ignore packets in the past */
- if(active && lt(p->timestamp, next_timestamp)) {
+ if(active && lt(timestamp, next_timestamp)) {
info("dropping old packet, timestamp=%"PRIx32" < %"PRIx32,
- p->timestamp, next_timestamp);
+ timestamp, next_timestamp);
continue;
}
+ pthread_mutex_lock(&lock);
+ p = new_packet();
+ p->timestamp = timestamp;
/* Convert to target format */
- switch(packet.header.mpt & 0x7F) {
+ switch(header.mpt & 0x7F) {
case 10:
- p->nsamples = (n - sizeof (struct rtp_header)) / sizeof(uint16_t);
-#if HAVE_COREAUDIO_AUDIOHARDWARE_H
- /* Convert to what Core Audio expects */
- {
- size_t i;
-
- for(i = 0; i < p->nsamples; ++n)
- p->samples_float[i] = (int16_t)ntohs(samples[i]) * (0.5f / 32767);
- }
-#else
+ p->nsamples = (n - sizeof header) / sizeof(uint16_t);
/* ALSA can do any necessary conversion itself (though it might be better
* to do any necessary conversion in the background) */
- memcpy(p->samples_raw, samples, n - sizeof (struct rtp_header));
-#endif
+ /* TODO we could readv into the buffer */
break;
/* TODO support other RFC3551 media types (when the speaker does) */
default:
fatal(0, "unsupported RTP payload type %d",
- packet.header.mpt & 0x7F);
+ header.mpt & 0x7F);
}
- pthread_mutex_lock(&lock);
+ if(logfp)
+ fprintf(logfp, "sequence %u timestamp %"PRIx32" length %"PRIx32" end %"PRIx32"\n",
+ seq, timestamp, p->nsamples, timestamp + p->nsamples);
/* Stop reading if we've reached the maximum.
*
* This is rather unsatisfactory: it means that if packets get heavily
* out of order then we guarantee dropouts. But for now... */
- while(nsamples >= maxbuffer)
- pthread_cond_wait(&cond, &lock);
- for(pp = &packets;
- *pp && lt((*pp)->timestamp, p->timestamp);
- pp = &(*pp)->next)
- ;
- /* So now either !*pp or *pp >= p */
- if(*pp && p->timestamp == (*pp)->timestamp) {
- /* *pp == p; a duplicate. Ideally we avoid the translation step here,
- * but we'll worry about that another time. */
- info("dropped a duplicated");
- } else {
- if(*pp)
- info("receiving packets out of order");
- p->next = *pp;
- *pp = p;
- nsamples += p->nsamples;
- pthread_cond_broadcast(&cond);
- p = 0; /* we've consumed this packet */
+ if(nsamples >= maxbuffer) {
+ info("buffer full");
+ while(nsamples >= maxbuffer)
+ pthread_cond_wait(&cond, &lock);
}
+ /* Add the packet to the heap */
+ pheap_insert(&packets, p);
+ nsamples += p->nsamples;
+ pthread_cond_broadcast(&cond);
pthread_mutex_unlock(&lock);
}
}
+/** @brief Return true if @p p contains @p timestamp */
+static inline int contains(const struct packet *p, uint32_t timestamp) {
+ const uint32_t packet_start = p->timestamp;
+ const uint32_t packet_end = p->timestamp + p->nsamples;
+
+ return (ge(timestamp, packet_start)
+ && lt(timestamp, packet_end));
+}
+
#if HAVE_COREAUDIO_AUDIOHARDWARE_H
/** @brief Callback from Core Audio */
static OSStatus adioproc
void attribute((unused)) *inClientData) {
UInt32 nbuffers = outOutputData->mNumberBuffers;
AudioBuffer *ab = outOutputData->mBuffers;
+ const struct packet *p;
+ uint32_t samples_available;
pthread_mutex_lock(&lock);
while(nbuffers > 0) {
float *samplesOut = ab->mData;
size_t samplesOutLeft = ab->mDataByteSize / sizeof (float);
-
+
while(samplesOutLeft > 0) {
- if(packets) {
- /* There's a packet */
- const uint32_t packet_start = packets->timestamp;
- const uint32_t packet_end = packets->timestamp + packets->nsamples;
-
- if(le(packet_end, next_timestamp)) {
- /* This packet is in the past */
- info("dropping buffered past packet %"PRIx32" < %"PRIx32,
- packets->timestamp, next_timestamp);
- continue;
- }
- if(ge(next_timestamp, packet_start)
- && lt(next_timestamp, packet_end)) {
- /* This packet is suitable */
- const uint32_t offset = next_timestamp - packets->timestamp;
- uint32_t samples_available = packet_end - next_timestamp;
- if(samples_available > samplesOutLeft)
- samples_available = samplesOutLeft;
- memcpy(samplesOut,
- packets->samples_float + offset,
- samples_available * sizeof(float));
- samplesOut += samples_available;
- next_timestamp += samples_available;
- if(ge(next_timestamp, packet_end))
- drop_first_packet();
- continue;
- }
+ /* Look for a suitable packet, dropping any unsuitable ones along the
+ * way. Unsuitable packets are ones that are in the past. */
+ while(pheap_count(&packets)) {
+ p = pheap_first(&packets);
+ if(le(p->timestamp + p->nsamples, next_timestamp))
+ /* This packet is in the past. Drop it and try another one. */
+ drop_first_packet();
+ else
+ /* This packet is NOT in the past. (It might be in the future
+ * however.) */
+ break;
}
- /* We didn't find a suitable packet (though there might still be
- * unsuitable ones). We infill with 0s. */
- if(packets) {
- /* There is a next packet, only infill up to that point */
- uint32_t samples_available = packets->timestamp - next_timestamp;
-
+ p = pheap_count(&packets) ? pheap_first(&packets) : 0;
+ if(p && contains(p, next_timestamp)) {
+ /* This packet is ready to play */
+ const uint32_t packet_end = p->timestamp + p->nsamples;
+ const uint32_t offset = next_timestamp - p->timestamp;
+ const uint16_t *ptr =
+ (void *)(p->samples_raw + offset * sizeof (uint16_t));
+
+ samples_available = packet_end - next_timestamp;
if(samples_available > samplesOutLeft)
samples_available = samplesOutLeft;
- /* Convniently the buffer is 0 to start with */
next_timestamp += samples_available;
- samplesOut += samples_available;
samplesOutLeft -= samples_available;
- /* TODO log infill */
+ while(samples_available-- > 0)
+ *samplesOut++ = (int16_t)ntohs(*ptr++) * (0.5 / 32767);
+ /* We don't bother junking the packet - that'll be dealt with next time
+ * round */
} else {
- /* There's no next packet at all */
- next_timestamp += samplesOutLeft;
- samplesOut += samplesOutLeft;
- samplesOutLeft = 0;
- /* TODO log infill */
+ /* No packet is ready to play (and there might be no packet at all) */
+ samples_available = p ? p->timestamp - next_timestamp
+ : samplesOutLeft;
+ if(samples_available > samplesOutLeft)
+ samples_available = samplesOutLeft;
+ info("infill by %"PRIu32, samples_available);
+ /* Conveniently the buffer is 0 to start with */
+ next_timestamp += samples_available;
+ samplesOut += samples_available;
+ samplesOutLeft -= samples_available;
}
}
++ab;
fatal(0, "error calling snd_pcm_prepare: %d", err);
prepared = 1;
}
- /* Start at the first available packet */
- next_timestamp = packets->timestamp;
active = 1;
infilling = 0;
escape = 0;
pthread_mutex_lock(&lock);
for(;;) {
/* Wait for the buffer to fill up a bit */
+ info("Buffering...");
while(nsamples < readahead)
pthread_cond_wait(&cond, &lock);
/* Start playing now */
+ info("Playing...");
+ next_timestamp = pheap_first(&packets)->timestamp;
+ active = 1;
status = AudioDeviceStart(adid, adioproc);
if(status)
fatal(0, "AudioDeviceStart: %d", (int)status);
status = AudioDeviceStop(adid, adioproc);
if(status)
fatal(0, "AudioDeviceStop: %d", (int)status);
+ active = 0;
/* Go back round */
}
}
mem_init();
if(!setlocale(LC_CTYPE, "")) fatal(errno, "error calling setlocale");
- while((n = getopt_long(argc, argv, "hVdD:m:b:x:", options, 0)) >= 0) {
+ while((n = getopt_long(argc, argv, "hVdD:m:b:x:L:", options, 0)) >= 0) {
switch(n) {
case 'h': help();
case 'V': version();
case 'm': minbuffer = 2 * atol(optarg); break;
case 'b': readahead = 2 * atol(optarg); break;
case 'x': maxbuffer = 2 * atol(optarg); break;
+ case 'L': logfp = fopen(optarg, "w"); break;
default: fatal(0, "invalid option");
}
}
~mdw / disorder / blobdiff