2 * This file is part of DisOrder.
3 * Copyright (C) 2007, 2008 Richard Kettlewell
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.
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.
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/>.
18 /** @file clients/playrtp.c
21 * This player supports Linux (<a href="http://www.alsa-project.org/">ALSA</a>)
23 * href="http://developer.apple.com/audio/coreaudio.html">Core Audio</a>)
24 * systems. There is no support for Microsoft Windows yet, and that will in
25 * fact probably an entirely separate program.
27 * The program runs (at least) three threads. listen_thread() is responsible
28 * for reading RTP packets off the wire and adding them to the linked list @ref
29 * received_packets, assuming they are basically sound. queue_thread() takes
30 * packets off this linked list and adds them to @ref packets (an operation
31 * which might be much slower due to contention for @ref lock).
33 * The main thread is responsible for actually playing audio. In ALSA this
34 * means it waits until ALSA says it's ready for more audio which it then
35 * plays. See @ref clients/playrtp-alsa.c.
37 * In Core Audio the main thread is only responsible for starting and stopping
38 * play: the system does the actual playback in its own private thread, and
39 * calls adioproc() to fetch the audio data. See @ref
40 * clients/playrtp-coreaudio.c.
42 * Sometimes it happens that there is no audio available to play. This may
43 * because the server went away, or a packet was dropped, or the server
44 * deliberately did not send any sound because it encountered a silence.
47 * - it is safe to read uint32_t values without a lock protecting them
53 #include <sys/socket.h>
54 #include <sys/types.h>
55 #include <sys/socket.h>
61 #include <netinet/in.h>
70 #include "configuration.h"
80 #include "inputline.h"
84 #define readahead linux_headers_are_borked
86 /** @brief Obsolete synonym */
87 #ifndef IPV6_JOIN_GROUP
88 # define IPV6_JOIN_GROUP IPV6_ADD_MEMBERSHIP
91 /** @brief RTP socket */
94 /** @brief Log output */
97 /** @brief Output device */
99 /** @brief Minimum low watermark
101 * We'll stop playing if there's only this many samples in the buffer. */
102 unsigned minbuffer = 2 * 44100 / 10; /* 0.2 seconds */
104 /** @brief Buffer high watermark
106 * We'll only start playing when this many samples are available. */
107 static unsigned readahead = 2 * 2 * 44100;
109 /** @brief Maximum buffer size
111 * We'll stop reading from the network if we have this many samples. */
112 static unsigned maxbuffer;
114 /** @brief Received packets
115 * Protected by @ref receive_lock
117 * Received packets are added to this list, and queue_thread() picks them off
118 * it and adds them to @ref packets. Whenever a packet is added to it, @ref
119 * receive_cond is signalled.
121 struct packet *received_packets;
123 /** @brief Tail of @ref received_packets
124 * Protected by @ref receive_lock
126 struct packet **received_tail = &received_packets;
128 /** @brief Lock protecting @ref received_packets
130 * Only listen_thread() and queue_thread() ever hold this lock. It is vital
131 * that queue_thread() not hold it any longer than it strictly has to. */
132 pthread_mutex_t receive_lock = PTHREAD_MUTEX_INITIALIZER;
134 /** @brief Condition variable signalled when @ref received_packets is updated
136 * Used by listen_thread() to notify queue_thread() that it has added another
137 * packet to @ref received_packets. */
138 pthread_cond_t receive_cond = PTHREAD_COND_INITIALIZER;
140 /** @brief Length of @ref received_packets */
143 /** @brief Binary heap of received packets */
144 struct pheap packets;
146 /** @brief Total number of samples available
148 * We make this volatile because we inspect it without a protecting lock,
149 * so the usual pthread_* guarantees aren't available.
151 volatile uint32_t nsamples;
153 /** @brief Timestamp of next packet to play.
155 * This is set to the timestamp of the last packet, plus the number of
156 * samples it contained. Only valid if @ref active is nonzero.
158 uint32_t next_timestamp;
160 /** @brief True if actively playing
162 * This is true when playing and false when just buffering. */
165 /** @brief Lock protecting @ref packets */
166 pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
168 /** @brief Condition variable signalled whenever @ref packets is changed */
169 pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
171 /** @brief Backend to play with */
172 static const struct uaudio *backend;
174 HEAP_DEFINE(pheap, struct packet *, lt_packet);
176 /** @brief Control socket or NULL */
177 const char *control_socket;
179 /** @brief Buffer for debugging dump
181 * The debug dump is enabled by the @c --dump option. It records the last 20s
182 * of audio to the specified file (which will be about 3.5Mbytes). The file is
183 * written as as ring buffer, so the start point will progress through it.
185 * Use clients/dump2wav to convert this to a WAV file, which can then be loaded
186 * into (e.g.) Audacity for further inspection.
188 * All three backends (ALSA, OSS, Core Audio) now support this option.
190 * The idea is to allow the user a few seconds to react to an audible artefact.
192 int16_t *dump_buffer;
194 /** @brief Current index within debugging dump */
197 /** @brief Size of debugging dump in samples */
198 size_t dump_size = 44100/*Hz*/ * 2/*channels*/ * 20/*seconds*/;
200 static const struct option options[] = {
201 { "help", no_argument, 0, 'h' },
202 { "version", no_argument, 0, 'V' },
203 { "debug", no_argument, 0, 'd' },
204 { "device", required_argument, 0, 'D' },
205 { "min", required_argument, 0, 'm' },
206 { "max", required_argument, 0, 'x' },
207 { "buffer", required_argument, 0, 'b' },
208 { "rcvbuf", required_argument, 0, 'R' },
209 #if HAVE_SYS_SOUNDCARD_H || EMPEG_HOST
210 { "oss", no_argument, 0, 'o' },
212 #if HAVE_ALSA_ASOUNDLIB_H
213 { "alsa", no_argument, 0, 'a' },
215 #if HAVE_COREAUDIO_AUDIOHARDWARE_H
216 { "core-audio", no_argument, 0, 'c' },
218 { "dump", required_argument, 0, 'r' },
219 { "command", required_argument, 0, 'e' },
220 { "socket", required_argument, 0, 's' },
221 { "config", required_argument, 0, 'C' },
225 /** @brief Control thread
227 * This thread is responsible for accepting control commands from Disobedience
228 * (or other controllers) over an AF_UNIX stream socket with a path specified
229 * by the @c --socket option. The protocol uses simple string commands and
232 * - @c stop will shut the player down
233 * - @c query will send back the reply @c running
234 * - anything else is ignored
236 * Commands and response strings terminated by shutting down the connection or
237 * by a newline. No attempt is made to multiplex multiple clients so it is
238 * important that the command be sent as soon as the connection is made - it is
239 * assumed that both parties to the protocol are entirely cooperating with one
242 static void *control_thread(void attribute((unused)) *arg) {
243 struct sockaddr_un sa;
249 assert(control_socket);
250 unlink(control_socket);
251 memset(&sa, 0, sizeof sa);
252 sa.sun_family = AF_UNIX;
253 strcpy(sa.sun_path, control_socket);
254 sfd = xsocket(PF_UNIX, SOCK_STREAM, 0);
255 if(bind(sfd, (const struct sockaddr *)&sa, sizeof sa) < 0)
256 fatal(errno, "error binding to %s", control_socket);
257 if(listen(sfd, 128) < 0)
258 fatal(errno, "error calling listen on %s", control_socket);
259 info("listening on %s", control_socket);
262 cfd = accept(sfd, (struct sockaddr *)&sa, &salen);
269 fatal(errno, "error calling accept on %s", control_socket);
272 if(!(fp = fdopen(cfd, "r+"))) {
273 error(errno, "error calling fdopen for %s connection", control_socket);
277 if(!inputline(control_socket, fp, &line, '\n')) {
278 if(!strcmp(line, "stop")) {
279 info("stopped via %s", control_socket);
280 exit(0); /* terminate immediately */
282 if(!strcmp(line, "query"))
283 fprintf(fp, "running");
287 error(errno, "error closing %s connection", control_socket);
291 /** @brief Drop the first packet
293 * Assumes that @ref lock is held.
295 static void drop_first_packet(void) {
296 if(pheap_count(&packets)) {
297 struct packet *const p = pheap_remove(&packets);
298 nsamples -= p->nsamples;
299 playrtp_free_packet(p);
300 pthread_cond_broadcast(&cond);
304 /** @brief Background thread adding packets to heap
306 * This just transfers packets from @ref received_packets to @ref packets. It
307 * is important that it holds @ref receive_lock for as little time as possible,
308 * in order to minimize the interval between calls to read() in
311 static void *queue_thread(void attribute((unused)) *arg) {
315 /* Get the next packet */
316 pthread_mutex_lock(&receive_lock);
317 while(!received_packets) {
318 pthread_cond_wait(&receive_cond, &receive_lock);
320 p = received_packets;
321 received_packets = p->next;
322 if(!received_packets)
323 received_tail = &received_packets;
325 pthread_mutex_unlock(&receive_lock);
326 /* Add it to the heap */
327 pthread_mutex_lock(&lock);
328 pheap_insert(&packets, p);
329 nsamples += p->nsamples;
330 pthread_cond_broadcast(&cond);
331 pthread_mutex_unlock(&lock);
335 /** @brief Background thread collecting samples
337 * This function collects samples, perhaps converts them to the target format,
338 * and adds them to the packet list.
340 * It is crucial that the gap between successive calls to read() is as small as
341 * possible: otherwise packets will be dropped.
343 * We use a binary heap to ensure that the unavoidable effort is at worst
344 * logarithmic in the total number of packets - in fact if packets are mostly
345 * received in order then we will largely do constant work per packet since the
346 * newest packet will always be last.
348 * Of more concern is that we must acquire the lock on the heap to add a packet
349 * to it. If this proves a problem in practice then the answer would be
350 * (probably doubly) linked list with new packets added the end and a second
351 * thread which reads packets off the list and adds them to the heap.
353 * We keep memory allocation (mostly) very fast by keeping pre-allocated
354 * packets around; see @ref playrtp_new_packet().
356 static void *listen_thread(void attribute((unused)) *arg) {
357 struct packet *p = 0;
359 struct rtp_header header;
366 p = playrtp_new_packet();
367 iov[0].iov_base = &header;
368 iov[0].iov_len = sizeof header;
369 iov[1].iov_base = p->samples_raw;
370 iov[1].iov_len = sizeof p->samples_raw / sizeof *p->samples_raw;
371 n = readv(rtpfd, iov, 2);
377 fatal(errno, "error reading from socket");
380 /* Ignore too-short packets */
381 if((size_t)n <= sizeof (struct rtp_header)) {
382 info("ignored a short packet");
385 timestamp = htonl(header.timestamp);
386 seq = htons(header.seq);
387 /* Ignore packets in the past */
388 if(active && lt(timestamp, next_timestamp)) {
389 info("dropping old packet, timestamp=%"PRIx32" < %"PRIx32,
390 timestamp, next_timestamp);
393 /* Ignore packets with the extension bit set. */
394 if(header.vpxcc & 0x10)
398 p->timestamp = timestamp;
399 /* Convert to target format */
400 if(header.mpt & 0x80)
402 switch(header.mpt & 0x7F) {
404 p->nsamples = (n - sizeof header) / sizeof(uint16_t);
406 /* TODO support other RFC3551 media types (when the speaker does) */
408 fatal(0, "unsupported RTP payload type %d",
412 fprintf(logfp, "sequence %u timestamp %"PRIx32" length %"PRIx32" end %"PRIx32"\n",
413 seq, timestamp, p->nsamples, timestamp + p->nsamples);
414 /* Stop reading if we've reached the maximum.
416 * This is rather unsatisfactory: it means that if packets get heavily
417 * out of order then we guarantee dropouts. But for now... */
418 if(nsamples >= maxbuffer) {
419 pthread_mutex_lock(&lock);
420 while(nsamples >= maxbuffer) {
421 pthread_cond_wait(&cond, &lock);
423 pthread_mutex_unlock(&lock);
425 /* Add the packet to the receive queue */
426 pthread_mutex_lock(&receive_lock);
428 received_tail = &p->next;
430 pthread_cond_signal(&receive_cond);
431 pthread_mutex_unlock(&receive_lock);
432 /* We'll need a new packet */
437 /** @brief Wait until the buffer is adequately full
439 * Must be called with @ref lock held.
441 void playrtp_fill_buffer(void) {
444 info("Buffering...");
445 while(nsamples < readahead) {
446 pthread_cond_wait(&cond, &lock);
448 next_timestamp = pheap_first(&packets)->timestamp;
452 /** @brief Find next packet
453 * @return Packet to play or NULL if none found
455 * The return packet is merely guaranteed not to be in the past: it might be
456 * the first packet in the future rather than one that is actually suitable to
459 * Must be called with @ref lock held.
461 struct packet *playrtp_next_packet(void) {
462 while(pheap_count(&packets)) {
463 struct packet *const p = pheap_first(&packets);
464 if(le(p->timestamp + p->nsamples, next_timestamp)) {
465 /* This packet is in the past. Drop it and try another one. */
468 /* This packet is NOT in the past. (It might be in the future
475 /* display usage message and terminate */
476 static void help(void) {
478 " disorder-playrtp [OPTIONS] [[ADDRESS] PORT]\n"
480 " --device, -D DEVICE Output device\n"
481 " --min, -m FRAMES Buffer low water mark\n"
482 " --buffer, -b FRAMES Buffer high water mark\n"
483 " --max, -x FRAMES Buffer maximum size\n"
484 " --rcvbuf, -R BYTES Socket receive buffer size\n"
485 " --config, -C PATH Set configuration file\n"
486 #if HAVE_ALSA_ASOUNDLIB_H
487 " --alsa, -a Use ALSA to play audio\n"
489 #if HAVE_SYS_SOUNDCARD_H || EMPEG_HOST
490 " --oss, -o Use OSS to play audio\n"
492 #if HAVE_COREAUDIO_AUDIOHARDWARE_H
493 " --core-audio, -c Use Core Audio to play audio\n"
495 " --command, -e COMMAND Pipe audio to command\n"
496 " --help, -h Display usage message\n"
497 " --version, -V Display version number\n"
503 static size_t playrtp_callback(void *buffer,
505 void attribute((unused)) *userdata) {
508 pthread_mutex_lock(&lock);
509 /* Get the next packet, junking any that are now in the past */
510 const struct packet *p = playrtp_next_packet();
511 if(p && contains(p, next_timestamp)) {
512 /* This packet is ready to play; the desired next timestamp points
513 * somewhere into it. */
515 /* Timestamp of end of packet */
516 const uint32_t packet_end = p->timestamp + p->nsamples;
518 /* Offset of desired next timestamp into current packet */
519 const uint32_t offset = next_timestamp - p->timestamp;
521 /* Pointer to audio data */
522 const uint16_t *ptr = (void *)(p->samples_raw + offset);
524 /* Compute number of samples left in packet, limited to output buffer
526 samples = packet_end - next_timestamp;
527 if(samples > max_samples)
528 samples = max_samples;
530 /* Copy into buffer, converting to native endianness */
532 int16_t *bufptr = buffer;
534 *bufptr++ = (int16_t)ntohs(*ptr++);
537 /* We don't junk the packet here; a subsequent call to
538 * playrtp_next_packet() will dispose of it (if it's actually done with). */
540 /* There is no suitable packet. We introduce 0s up to the next packet, or
541 * to fill the buffer if there's no next packet or that's too many. The
542 * comparison with max_samples deals with the otherwise troubling overflow
544 samples = p ? p->timestamp - next_timestamp : max_samples;
545 if(samples > max_samples)
546 samples = max_samples;
547 //info("infill by %zu", samples);
548 memset(buffer, 0, samples * uaudio_sample_size);
552 for(size_t i = 0; i < samples; ++i) {
553 dump_buffer[dump_index++] = ((int16_t *)buffer)[i];
554 dump_index %= dump_size;
557 /* Advance timestamp */
558 next_timestamp += samples;
559 pthread_mutex_unlock(&lock);
563 int main(int argc, char **argv) {
565 struct addrinfo *res;
566 struct stringlist sl;
568 int rcvbuf, target_rcvbuf = 131072;
571 struct ipv6_mreq mreq6;
573 char *address, *port;
577 struct sockaddr_in in;
578 struct sockaddr_in6 in6;
580 union any_sockaddr mgroup;
581 const char *dumpfile = 0;
584 static const struct addrinfo prefs = {
585 .ai_flags = AI_PASSIVE,
586 .ai_family = PF_INET,
587 .ai_socktype = SOCK_DGRAM,
588 .ai_protocol = IPPROTO_UDP
592 if(!setlocale(LC_CTYPE, "")) fatal(errno, "error calling setlocale");
593 backend = uaudio_apis[0];
594 while((n = getopt_long(argc, argv, "hVdD:m:b:x:L:R:M:aocC:re:", options, 0)) >= 0) {
597 case 'V': version("disorder-playrtp");
598 case 'd': debugging = 1; break;
599 case 'D': uaudio_set("device", optarg); break;
600 case 'm': minbuffer = 2 * atol(optarg); break;
601 case 'b': readahead = 2 * atol(optarg); break;
602 case 'x': maxbuffer = 2 * atol(optarg); break;
603 case 'L': logfp = fopen(optarg, "w"); break;
604 case 'R': target_rcvbuf = atoi(optarg); break;
605 #if HAVE_ALSA_ASOUNDLIB_H
606 case 'a': backend = &uaudio_alsa; break;
608 #if HAVE_SYS_SOUNDCARD_H || EMPEG_HOST
609 case 'o': backend = &uaudio_oss; break;
611 #if HAVE_COREAUDIO_AUDIOHARDWARE_H
612 case 'c': backend = &uaudio_coreaudio; break;
614 case 'C': configfile = optarg; break;
615 case 's': control_socket = optarg; break;
616 case 'r': dumpfile = optarg; break;
617 case 'e': backend = &uaudio_command; uaudio_set("command", optarg); break;
618 default: fatal(0, "invalid option");
621 if(config_read(0)) fatal(0, "cannot read configuration");
623 maxbuffer = 4 * readahead;
628 /* Get configuration from server */
629 if(!(c = disorder_new(1))) exit(EXIT_FAILURE);
630 if(disorder_connect(c)) exit(EXIT_FAILURE);
631 if(disorder_rtp_address(c, &address, &port)) exit(EXIT_FAILURE);
633 sl.s = xcalloc(2, sizeof *sl.s);
639 /* Use command-line ADDRESS+PORT or just PORT */
644 fatal(0, "usage: disorder-playrtp [OPTIONS] [[ADDRESS] PORT]");
646 /* Look up address and port */
647 if(!(res = get_address(&sl, &prefs, &sockname)))
649 /* Create the socket */
650 if((rtpfd = socket(res->ai_family,
652 res->ai_protocol)) < 0)
653 fatal(errno, "error creating socket");
654 /* Stash the multicast group address */
655 if((is_multicast = multicast(res->ai_addr))) {
656 memcpy(&mgroup, res->ai_addr, res->ai_addrlen);
657 switch(res->ai_addr->sa_family) {
659 mgroup.in.sin_port = 0;
662 mgroup.in6.sin6_port = 0;
667 switch(res->ai_addr->sa_family) {
669 memset(&((struct sockaddr_in *)res->ai_addr)->sin_addr, 0,
670 sizeof (struct in_addr));
673 memset(&((struct sockaddr_in6 *)res->ai_addr)->sin6_addr, 0,
674 sizeof (struct in6_addr));
677 fatal(0, "unsupported family %d", (int)res->ai_addr->sa_family);
679 if(bind(rtpfd, res->ai_addr, res->ai_addrlen) < 0)
680 fatal(errno, "error binding socket to %s", sockname);
682 switch(mgroup.sa.sa_family) {
684 mreq.imr_multiaddr = mgroup.in.sin_addr;
685 mreq.imr_interface.s_addr = 0; /* use primary interface */
686 if(setsockopt(rtpfd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
687 &mreq, sizeof mreq) < 0)
688 fatal(errno, "error calling setsockopt IP_ADD_MEMBERSHIP");
691 mreq6.ipv6mr_multiaddr = mgroup.in6.sin6_addr;
692 memset(&mreq6.ipv6mr_interface, 0, sizeof mreq6.ipv6mr_interface);
693 if(setsockopt(rtpfd, IPPROTO_IPV6, IPV6_JOIN_GROUP,
694 &mreq6, sizeof mreq6) < 0)
695 fatal(errno, "error calling setsockopt IPV6_JOIN_GROUP");
698 fatal(0, "unsupported address family %d", res->ai_family);
700 info("listening on %s multicast group %s",
701 format_sockaddr(res->ai_addr), format_sockaddr(&mgroup.sa));
703 info("listening on %s", format_sockaddr(res->ai_addr));
705 if(getsockopt(rtpfd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, &len) < 0)
706 fatal(errno, "error calling getsockopt SO_RCVBUF");
707 if(target_rcvbuf > rcvbuf) {
708 if(setsockopt(rtpfd, SOL_SOCKET, SO_RCVBUF,
709 &target_rcvbuf, sizeof target_rcvbuf) < 0)
710 error(errno, "error calling setsockopt SO_RCVBUF %d",
712 /* We try to carry on anyway */
714 info("changed socket receive buffer from %d to %d",
715 rcvbuf, target_rcvbuf);
717 info("default socket receive buffer %d", rcvbuf);
719 info("WARNING: -L option can impact performance");
723 if((err = pthread_create(&tid, 0, control_thread, 0)))
724 fatal(err, "pthread_create control_thread");
728 unsigned char buffer[65536];
731 if((fd = open(dumpfile, O_RDWR|O_TRUNC|O_CREAT, 0666)) < 0)
732 fatal(errno, "opening %s", dumpfile);
733 /* Fill with 0s to a suitable size */
734 memset(buffer, 0, sizeof buffer);
735 for(written = 0; written < dump_size * sizeof(int16_t);
736 written += sizeof buffer) {
737 if(write(fd, buffer, sizeof buffer) < 0)
738 fatal(errno, "clearing %s", dumpfile);
740 /* Map the buffer into memory for convenience */
741 dump_buffer = mmap(0, dump_size * sizeof(int16_t), PROT_READ|PROT_WRITE,
743 if(dump_buffer == (void *)-1)
744 fatal(errno, "mapping %s", dumpfile);
745 info("dumping to %s", dumpfile);
747 /* Set up output. Currently we only support L16 so there's no harm setting
748 * the format before we know what it is! */
749 uaudio_set_format(44100/*Hz*/, 2/*channels*/,
750 16/*bits/channel*/, 1/*signed*/);
751 backend->start(playrtp_callback, NULL);
752 /* We receive and convert audio data in a background thread */
753 if((err = pthread_create(<id, 0, listen_thread, 0)))
754 fatal(err, "pthread_create listen_thread");
755 /* We have a second thread to add received packets to the queue */
756 if((err = pthread_create(<id, 0, queue_thread, 0)))
757 fatal(err, "pthread_create queue_thread");
758 pthread_mutex_lock(&lock);
760 /* Wait for the buffer to fill up a bit */
761 playrtp_fill_buffer();
762 /* Start playing now */
764 next_timestamp = pheap_first(&packets)->timestamp;
767 /* Wait until the buffer empties out */
768 while(nsamples >= minbuffer
770 && contains(pheap_first(&packets), next_timestamp))) {
771 pthread_cond_wait(&cond, &lock);
773 /* Stop playing for a bit until the buffer re-fills */
774 backend->deactivate();