#include <alsa/asoundlib.h>
#endif
+#define readahead linux_headers_are_borked
+
/** @brief RTP socket */
static int rtpfd;
+/** @brief Log output */
+static FILE *logfp;
+
/** @brief Output device */
static const char *device;
*/
#define MAXSAMPLES 2048
-/** @brief Minimum buffer size
+/** @brief Minimum low watermark
*
* We'll stop playing if there's only this many samples in the buffer. */
-#define MINBUFFER 8820
+static unsigned minbuffer = 2 * 44100 / 10; /* 0.2 seconds */
/** @brief Maximum sample size
*
* The maximum supported size (in bytes) of one sample. */
#define MAXSAMPLESIZE 2
-#define READAHEAD 88200 /* how far to read ahead */
+/** @brief Buffer high watermark
+ *
+ * We'll only start playing when this many samples are available. */
+static unsigned readahead = 2 * 2 * 44100;
+
+/** @brief Maximum buffer size
+ *
+ * We'll stop reading from the network if we have this many samples. */
+static unsigned maxbuffer;
-#define MAXBUFFER (3 * 88200) /* maximum buffer contents */
+/** @brief Number of samples to infill by in one go */
+#define INFILL_SAMPLES (44100 * 2) /* 1s */
/** @brief Received packet
*
* or mis-ordered there may be gaps at any given moment. */
struct packet *next;
/** @brief Number of samples in this packet */
- int nsamples;
- /** @brief Number of samples used from this packet */
- int nused;
+ uint32_t nsamples;
/** @brief Timestamp from RTP packet
*
* NB that "timestamps" are really sample counters.*/
/** @brief Linked list of packets
*
- * In ascending order of timestamp. */
+ * 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
- * samples it contained.
+ * samples it contained. Only valid if @ref active is nonzero.
*/
static uint32_t next_timestamp;
+/** @brief True if actively playing
+ *
+ * This is true when playing and false when just buffering. */
+static int active;
+
/** @brief Lock protecting @ref packets */
static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
{ "version", no_argument, 0, 'V' },
{ "debug", no_argument, 0, 'd' },
{ "device", required_argument, 0, 'D' },
+ { "min", required_argument, 0, 'm' },
+ { "max", required_argument, 0, 'x' },
+ { "buffer", required_argument, 0, 'b' },
{ 0, 0, 0, 0 }
};
/** @brief Return true iff a < b in sequence-space arithmetic */
-static inline int lt(const struct packet *a, const struct packet *b) {
- return (uint32_t)(a->timestamp - b->timestamp) & 0x80000000;
+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 Drop the packet at the head of the queue */
+static void drop_first_packet(void) {
+ struct packet *const p = packets;
+ packets = p->next;
+ nsamples -= p->nsamples;
+ free(p);
+ pthread_cond_broadcast(&cond);
}
-/** Background thread collecting samples
+/** @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 *f = 0, **ff;
+ struct packet *p = 0, **pp;
int n;
union {
struct rtp_header header;
+ sizeof (struct rtp_header));
for(;;) {
- if(!f)
- f = xmalloc(sizeof *f);
+ if(!p)
+ p = xmalloc(sizeof *p);
n = read(rtpfd, packet.bytes, sizeof packet.bytes);
if(n < 0) {
switch(errno) {
}
}
/* 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);
+ /* Ignore packets in the past */
+ if(active && lt(p->timestamp, next_timestamp)) {
+ info("dropping old packet, timestamp=%"PRIx32" < %"PRIx32,
+ p->timestamp, next_timestamp);
+ continue;
+ }
/* Convert to target format */
switch(packet.header.mpt & 0x7F) {
case 10:
- f->nsamples = (n - sizeof (struct rtp_header)) / sizeof(uint16_t);
+ p->nsamples = (n - sizeof (struct rtp_header)) / sizeof(uint16_t);
#if HAVE_COREAUDIO_AUDIOHARDWARE_H
/* Convert to what Core Audio expects */
- for(n = 0; n < f->nsamples; ++n)
- f->samples_float[n] = (int16_t)ntohs(samples[n]) * (0.5f / 32767);
+ {
+ size_t i;
+
+ for(i = 0; i < p->nsamples; ++i)
+ p->samples_float[i] = (int16_t)ntohs(samples[i]) * (0.5f / 32767);
+ }
#else
/* ALSA can do any necessary conversion itself (though it might be better
* to do any necessary conversion in the background) */
- memcpy(f->samples_raw, samples, n - sizeof (struct rtp_header));
+ memcpy(p->samples_raw, samples, n - sizeof (struct rtp_header));
#endif
break;
/* TODO support other RFC3551 media types (when the speaker does) */
fatal(0, "unsupported RTP payload type %d",
packet.header.mpt & 0x7F);
}
- f->nused = 0;
- f->timestamp = ntohl(packet.header.timestamp);
+ if(logfp)
+ fprintf(logfp, "sequence %u timestamp %"PRIx32" length %"PRIx32" end %"PRIx32"\n",
+ ntohs(packet.header.seq),
+ p->timestamp, p->nsamples, p->timestamp + p->nsamples);
pthread_mutex_lock(&lock);
/* 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(ff = &packets; *ff && lt(*ff, f); ff = &(*ff)->next)
+ if(nsamples >= maxbuffer) {
+ info("buffer full");
+ while(nsamples >= maxbuffer)
+ pthread_cond_wait(&cond, &lock);
+ }
+ for(pp = &packets;
+ *pp && lt((*pp)->timestamp, p->timestamp);
+ pp = &(*pp)->next)
;
- /* So now either !*ff or *ff >= f */
- if(*ff && f->timestamp == (*ff)->timestamp) {
- /* *ff == f; a duplicate. Ideally we avoid the translation step here,
+ /* 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. */
- free(f);
+ info("dropped a duplicated");
} else {
- f->next = *ff;
- *ff = f;
- nsamples += f->nsamples;
+ 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 */
}
pthread_mutex_unlock(&lock);
- f = 0;
}
}
#if HAVE_COREAUDIO_AUDIOHARDWARE_H
-static OSStatus adioproc(AudioDeviceID inDevice,
- const AudioTimeStamp *inNow,
- const AudioBufferList *inInputData,
- const AudioTimeStamp *inInputTime,
- AudioBufferList *outOutputData,
- const AudioTimeStamp *inOutputTime,
- void *inClientData) {
+/** @brief Callback from Core Audio */
+static OSStatus adioproc
+ (AudioDeviceID attribute((unused)) inDevice,
+ const AudioTimeStamp attribute((unused)) *inNow,
+ const AudioBufferList attribute((unused)) *inInputData,
+ const AudioTimeStamp attribute((unused)) *inInputTime,
+ AudioBufferList *outOutputData,
+ const AudioTimeStamp attribute((unused)) *inOutputTime,
+ void attribute((unused)) *inClientData) {
UInt32 nbuffers = outOutputData->mNumberBuffers;
AudioBuffer *ab = outOutputData->mBuffers;
- float *samplesOut; /* where to write samples to */
- size_t samplesOutLeft; /* space left */
- size_t samplesInLeft;
- size_t samplesToCopy;
pthread_mutex_lock(&lock);
- samplesOut = ab->data;
- samplesOutLeft = ab->mDataByteSize / sizeof (float);
- while(packets && nbuffers > 0) {
- if(packets->used == packets->nsamples) {
- /* TODO if we dropped a packet then we should introduce a gap here */
- struct packet *const f = packets;
- packets = f->next;
- free(f);
- pthread_cond_broadcast(&cond);
- continue;
- }
- if(samplesOutLeft == 0) {
- --nbuffers;
- ++ab;
- samplesOut = ab->data;
- samplesOutLeft = ab->mDataByteSize / sizeof (float);
- continue;
+ 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,
+ packet_start, next_timestamp);
+ drop_first_packet();
+ continue;
+ }
+ if(ge(next_timestamp, packet_start)
+ && lt(next_timestamp, packet_end)) {
+ /* This packet is suitable */
+ const uint32_t offset = next_timestamp - packet_start;
+ 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;
+ samplesOutLeft -= samples_available;
+ if(ge(next_timestamp, packet_end))
+ drop_first_packet();
+ continue;
+ }
+ }
+ /* 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;
+
+ if(samples_available > samplesOutLeft)
+ samples_available = samplesOutLeft;
+ info("infill by %"PRIu32, samples_available);
+ /* Convniently the buffer is 0 to start with */
+ next_timestamp += samples_available;
+ samplesOut += samples_available;
+ samplesOutLeft -= samples_available;
+ } else {
+ /* There's no next packet at all */
+ info("infilled by %zu", samplesOutLeft);
+ next_timestamp += samplesOutLeft;
+ samplesOut += samplesOutLeft;
+ samplesOutLeft = 0;
+ }
}
- /* Now: (1) there is some data left to read
- * (2) there is some space to put it */
- samplesInLeft = packets->nsamples - packets->used;
- samplesToCopy = (samplesInLeft < samplesOutLeft
- ? samplesInLeft : samplesOutLeft);
- memcpy(samplesOut, packet->samples + packets->used, samplesToCopy);
- packets->used += samplesToCopy;
- samplesOut += samplesToCopy;
- samesOutLeft -= samplesToCopy;
+ ++ab;
+ --nbuffers;
}
pthread_mutex_unlock(&lock);
return 0;
}
#endif
+/** @brief Play an RTP stream
+ *
+ * This is the guts of the program. It is responsible for:
+ * - starting the listening thread
+ * - opening the audio device
+ * - reading ahead to build up a buffer
+ * - arranging for audio to be played
+ * - detecting when the buffer has got too small and re-buffering
+ */
static void play_rtp(void) {
pthread_t ltid;
size_t samples_written;
int prepared = 1;
int err;
+ int infilling = 0, escape = 0;
+ time_t logged, now;
+ uint32_t packet_start, packet_end;
/* Open ALSA */
if((err = snd_pcm_open(&pcm,
/* Ready to go */
+ time(&logged);
pthread_mutex_lock(&lock);
for(;;) {
/* Wait for the buffer to fill up a bit */
- while(nsamples < READAHEAD)
+ logged = now;
+ info("%lu samples in buffer (%lus)", nsamples,
+ nsamples / (44100 * 2));
+ info("Buffering...");
+ while(nsamples < readahead)
pthread_cond_wait(&cond, &lock);
if(!prepared) {
if((err = snd_pcm_prepare(pcm)))
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;
+ logged = now;
+ info("%lu samples in buffer (%lus)", nsamples,
+ nsamples / (44100 * 2));
+ info("Playing...");
/* Wait until the buffer empties out */
- while(nsamples >= MINBUFFER) {
+ while(nsamples >= minbuffer && !escape) {
+ time(&now);
+ if(now > logged + 10) {
+ logged = now;
+ info("%lu samples in buffer (%lus)", nsamples,
+ nsamples / (44100 * 2));
+ }
+ if(packets
+ && ge(next_timestamp, packets->timestamp + packets->nsamples)) {
+ info("dropping buffered past packet %"PRIx32" < %"PRIx32,
+ packets->timestamp, next_timestamp);
+ drop_first_packet();
+ continue;
+ }
/* Wait for ALSA to ask us for more data */
pthread_mutex_unlock(&lock);
- snd_pcm_wait(pcm, -1);
+ write(2, ".", 1); /* TODO remove me sometime */
+ switch(err = snd_pcm_wait(pcm, -1)) {
+ case 0:
+ info("snd_pcm_wait timed out");
+ break;
+ case 1:
+ break;
+ default:
+ fatal(0, "snd_pcm_wait returned %d", err);
+ }
pthread_mutex_lock(&lock);
- /* ALSA wants more data */
- if(packets && packets->timestamp + packets->nused == next_timestamp) {
- /* Hooray, we have a packet we can play */
- const size_t samples_available = packets->nsamples - packets->nused;
+ /* ALSA is ready for more data */
+ packet_start = packets->timestamp;
+ packet_end = packets->timestamp + packets->nsamples;
+ if(ge(next_timestamp, packet_start)
+ && lt(next_timestamp, packet_end)) {
+ /* The target timestamp is somewhere in this packet */
+ const uint32_t offset = next_timestamp - packets->timestamp;
+ const uint32_t samples_available = (packets->timestamp + packets->nsamples) - next_timestamp;
const size_t frames_available = samples_available / 2;
frames_written = snd_pcm_writei(pcm,
- packets->samples_raw + packets->nused,
+ packets->samples_raw + offset,
frames_available);
- if(frames_written < 0)
- fatal(0, "error calling snd_pcm_writei: %d", err);
- samples_written = frames_written * 2;
- packets->nused += samples_written;
- next_timestamp += samples_written;
- if(packets->nused == packets->nsamples) {
- struct packet *f = packets;
-
- packets = f->next;
- nsamples -= f->nsamples;
- free(f);
- pthread_cond_broadcast(&cond);
+ if(frames_written < 0) {
+ switch(frames_written) {
+ case -EAGAIN:
+ info("snd_pcm_wait() returned but we got -EAGAIN!");
+ break;
+ case -EPIPE:
+ error(0, "error calling snd_pcm_writei: %ld",
+ (long)frames_written);
+ escape = 1;
+ break;
+ default:
+ fatal(0, "error calling snd_pcm_writei: %ld",
+ (long)frames_written);
+ }
+ } else {
+ samples_written = frames_written * 2;
+ next_timestamp += samples_written;
+ if(ge(next_timestamp, packet_end))
+ drop_first_packet();
+ infilling = 0;
}
} else {
/* We don't have anything to play! We'd better play some 0s. */
- static const uint16_t zeros[1024];
- size_t samples_available = 1024, frames_available;
- if(packets && next_timestamp + samples_available > packets->timestamp)
+ static const uint16_t zeros[INFILL_SAMPLES];
+ size_t samples_available = INFILL_SAMPLES, frames_available;
+
+ /* If the maximum infill would take us past the start of the next
+ * packet then we truncate the infill to the right amount. */
+ if(lt(packets->timestamp,
+ next_timestamp + samples_available))
samples_available = packets->timestamp - next_timestamp;
+ if((int)samples_available < 0) {
+ info("packets->timestamp: %"PRIx32" next_timestamp: %"PRIx32" next+max: %"PRIx32" available: %"PRIx32,
+ packets->timestamp, next_timestamp,
+ next_timestamp + INFILL_SAMPLES, samples_available);
+ }
frames_available = samples_available / 2;
+ if(!infilling) {
+ info("Infilling %d samples, next=%"PRIx32" packet=[%"PRIx32",%"PRIx32"]",
+ samples_available, next_timestamp,
+ packets->timestamp, packets->timestamp + packets->nsamples);
+ //infilling++;
+ }
frames_written = snd_pcm_writei(pcm,
zeros,
frames_available);
- if(frames_written < 0)
- fatal(0, "error calling snd_pcm_writei: %d", err);
- next_timestamp += samples_written;
+ if(frames_written < 0) {
+ switch(frames_written) {
+ case -EAGAIN:
+ info("snd_pcm_wait() returned but we got -EAGAIN!");
+ break;
+ case -EPIPE:
+ error(0, "error calling snd_pcm_writei: %ld",
+ (long)frames_written);
+ escape = 1;
+ break;
+ default:
+ fatal(0, "error calling snd_pcm_writei: %ld",
+ (long)frames_written);
+ }
+ } else {
+ samples_written = frames_written * 2;
+ next_timestamp += samples_written;
+ }
}
}
+ active = 0;
/* We stop playing for a bit until the buffer re-fills */
pthread_mutex_unlock(&lock);
- if((err = snd_pcm_drain(pcm)))
- fatal(0, "error calling snd_pcm_drain: %d", err);
+ if((err = snd_pcm_nonblock(pcm, 0)))
+ fatal(0, "error calling snd_pcm_nonblock: %d", err);
+ if(escape) {
+ if((err = snd_pcm_drop(pcm)))
+ fatal(0, "error calling snd_pcm_drop: %d", err);
+ escape = 0;
+ } else
+ if((err = snd_pcm_drain(pcm)))
+ fatal(0, "error calling snd_pcm_drain: %d", err);
+ if((err = snd_pcm_nonblock(pcm, 1)))
+ fatal(0, "error calling snd_pcm_nonblock: %d", err);
prepared = 0;
pthread_mutex_lock(&lock);
}
if(status)
fatal(0, "AudioHardwareGetProperty: %d", (int)status);
D(("mSampleRate %f", asbd.mSampleRate));
- D(("mFormatID %08"PRIx32, asbd.mFormatID));
- D(("mFormatFlags %08"PRIx32, asbd.mFormatFlags));
- D(("mBytesPerPacket %08"PRIx32, asbd.mBytesPerPacket));
- D(("mFramesPerPacket %08"PRIx32, asbd.mFramesPerPacket));
- D(("mBytesPerFrame %08"PRIx32, asbd.mBytesPerFrame));
- D(("mChannelsPerFrame %08"PRIx32, asbd.mChannelsPerFrame));
- D(("mBitsPerChannel %08"PRIx32, asbd.mBitsPerChannel));
- D(("mReserved %08"PRIx32, asbd.mReserved));
+ D(("mFormatID %08lx", asbd.mFormatID));
+ D(("mFormatFlags %08lx", asbd.mFormatFlags));
+ D(("mBytesPerPacket %08lx", asbd.mBytesPerPacket));
+ D(("mFramesPerPacket %08lx", asbd.mFramesPerPacket));
+ D(("mBytesPerFrame %08lx", asbd.mBytesPerFrame));
+ D(("mChannelsPerFrame %08lx", asbd.mChannelsPerFrame));
+ D(("mBitsPerChannel %08lx", asbd.mBitsPerChannel));
+ D(("mReserved %08lx", asbd.mReserved));
if(asbd.mFormatID != kAudioFormatLinearPCM)
fatal(0, "audio device does not support kAudioFormatLinearPCM");
status = AudioDeviceAddIOProc(adid, adioproc, 0);
pthread_mutex_lock(&lock);
for(;;) {
/* Wait for the buffer to fill up a bit */
- while(nsamples < READAHEAD)
+ info("Buffering...");
+ while(nsamples < readahead)
pthread_cond_wait(&cond, &lock);
/* Start playing now */
+ info("Playing...");
+ next_timestamp = packets->timestamp;
+ active = 1;
status = AudioDeviceStart(adid, adioproc);
if(status)
fatal(0, "AudioDeviceStart: %d", (int)status);
/* Wait until the buffer empties out */
- while(nsamples >= MINBUFFER)
+ while(nsamples >= minbuffer)
pthread_cond_wait(&cond, &lock);
/* Stop playing for a bit until the buffer re-fills */
status = AudioDeviceStop(adid, adioproc);
if(status)
fatal(0, "AudioDeviceStop: %d", (int)status);
+ active = 0;
/* Go back round */
}
}
xprintf("Usage:\n"
" disorder-playrtp [OPTIONS] ADDRESS [PORT]\n"
"Options:\n"
+ " --device, -D DEVICE Output device\n"
+ " --min, -m FRAMES Buffer low water mark\n"
+ " --buffer, -b FRAMES Buffer high water mark\n"
+ " --max, -x FRAMES Buffer maximum size\n"
" --help, -h Display usage message\n"
" --version, -V Display version number\n"
- " --debug, -d Turn on debugging\n"
- " --device, -D DEVICE Output device\n");
+ );
xfclose(stdout);
exit(0);
}
mem_init();
if(!setlocale(LC_CTYPE, "")) fatal(errno, "error calling setlocale");
- while((n = getopt_long(argc, argv, "hVdD", 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 'd': debugging = 1; break;
case 'D': device = optarg; break;
+ 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");
}
}
+ if(!maxbuffer)
+ maxbuffer = 4 * readahead;
argc -= optind;
argv += optind;
if(argc < 1 || argc > 2)
~mdw / disorder / blobdiff