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master
Mark Hills 13 years ago
commit
8d8040f5a6
  1. 6
      .gitignore
  2. 24
      Makefile
  3. 14
      defaults.h
  4. 78
      device.c
  5. 10
      device.h
  6. 130
      jitter.c
  7. 34
      jitter.h
  8. 263
      rx.c
  9. 32
      sched.c
  10. 6
      sched.h
  11. 34
      test-jitter.c
  12. 235
      tx.c

6
.gitignore

@ -0,0 +1,6 @@
.config
*.o
*.d
tx
rx
test-jitter

24
Makefile

@ -0,0 +1,24 @@
-include .config
CFLAGS+=-MMD -Wall
.PHONY: all clean
all: rx tx
rx: rx.o device.o jitter.o sched.o
rx: LDLIBS+=-lcelt -lasound
tx: tx.o device.o sched.o
tx: LDLIBS+=-lcelt -lasound
test-jitter: test-jitter.o jitter.o
clean:
rm -f *.o
rm -f *.d
rm -f tx
rm -f rx
rm -f test-jitter
-include *.d

14
defaults.h

@ -0,0 +1,14 @@
#ifndef DEFAULTS_H
#define DEFAULTS_H
#define DEFAULT_DEVICE "default"
#define DEFAULT_BUFFER 16
#define DEFAULT_SERVICE "1350"
#define DEFAULT_FRAME 96
#define DEFAULT_RATE 44100
#define DEFAULT_CHANNELS 2
#define DEFAULT_BITRATE 128
#endif

78
device.c

@ -0,0 +1,78 @@
#include <stdio.h>
#include <alsa/asoundlib.h>
#define CHK(call, r) { \
if (r < 0) { \
aerror(call, r); \
return -1; \
} \
}
void aerror(const char *msg, int r)
{
fputs(msg, stderr);
fputs(": ", stderr);
fputs(snd_strerror(r), stderr);
fputc('\n', stderr);
}
int set_alsa_hw(snd_pcm_t *pcm,
unsigned int rate, unsigned int channels,
unsigned int buffer)
{
int r, dir;
snd_pcm_hw_params_t *hw;
snd_pcm_hw_params_alloca(&hw);
r = snd_pcm_hw_params_any(pcm, hw);
CHK("snd_pcm_hw_params_any", r);
r = snd_pcm_hw_params_set_rate_resample(pcm, hw, 1);
CHK("snd_pcm_hw_params_set_rate_resample", r);
r = snd_pcm_hw_params_set_access(pcm, hw, SND_PCM_ACCESS_RW_INTERLEAVED);
CHK("snd_pcm_hw_params_set_access", r);
r = snd_pcm_hw_params_set_format(pcm, hw, SND_PCM_FORMAT_FLOAT);
CHK("snd_pcm_hw_params_set_format", r);
r = snd_pcm_hw_params_set_rate(pcm, hw, rate, 0);
CHK("snd_pcm_hw_params_set_rate", r);
r = snd_pcm_hw_params_set_channels(pcm, hw, channels);
CHK("snd_pcm_hw_params_set_channels", r);
dir = 0;
r = snd_pcm_hw_params_set_buffer_time_near(pcm, hw, &buffer, &dir);
CHK("snd_pcm_hw_params_set_buffer_time_near", r);
r = snd_pcm_hw_params(pcm, hw);
CHK("hw_params", r);
return 0;
}
int set_alsa_sw(snd_pcm_t *pcm)
{
int r;
snd_pcm_sw_params_t *sw;
snd_pcm_uframes_t boundary;
snd_pcm_sw_params_alloca(&sw);
r = snd_pcm_sw_params_current(pcm, sw);
CHK("snd_pcm_sw_params_current", r);
r = snd_pcm_sw_params_get_boundary(sw, &boundary);
CHK("snd_pcm_sw_params_get_boundary", r);
r = snd_pcm_sw_params_set_stop_threshold(pcm, sw, boundary);
CHK("snd_pcm_sw_params_set_stop_threshold", r);
r = snd_pcm_sw_params(pcm, sw);
CHK("snd_pcm_sw_params", r);
return 0;
}

10
device.h

@ -0,0 +1,10 @@
#ifndef DEVICE_H
#define DEVICE_H
void aerror(const char *msg, int r);
int set_alsa_hw(snd_pcm_t *pcm,
unsigned int rate, unsigned int channels,
unsigned int buffer);
int set_alsa_sw(snd_pcm_t *pcm);
#endif

130
jitter.c

@ -0,0 +1,130 @@
#include <assert.h>
#include <stdlib.h>
#include "jitter.h"
void jitbuf_init(struct jitbuf_t *jb)
{
size_t n;
for (n = 0; n < JITBUF_MAX; n++)
jb->buf[n] = NULL;
jb->base = 0;
jb->out = 0;
jb->entries = 0;
}
void jitbuf_clear(struct jitbuf_t *jb)
{
}
/*
* Push an entry into the buffer, with the given sequence number
*
* Pre: data is not NULL
*/
int jitbuf_push(struct jitbuf_t *jb, seq_t t, void *data)
{
void **entry;
assert(data != NULL);
if (jb->entries == 0 && t != jb->base) {
fprintf(stderr, "Restarting (%d)\n", t);
jb->base = t;
} else {
if (t < jb->base) {
fprintf(stderr, "Late (%d)\n", t);
return -1;
}
if (t >= jb->base + JITBUF_MAX) {
fprintf(stderr, "Early (%d)\n", t);
return -1;
}
}
entry = &jb->buf[(t - jb->base + jb->out) % JITBUF_MAX];
if (*entry != NULL) {
fprintf(stderr, "Dup (%d)\n", t);
return -1;
}
*entry = data;
jb->entries++;
return 0;
}
/*
* Get the entry at the front of the buffer, in sequence number order
*
* Return: NULL if no entry, otherwise entry next in sequence
*/
void* jitbuf_front(const struct jitbuf_t *jb)
{
return jb->buf[jb->out];
}
/*
* Pop the next entry in the buffer
*/
void jitbuf_pop(struct jitbuf_t *jb)
{
void **entry;
entry = &jb->buf[jb->out];
if (*entry != NULL) {
jb->entries--;
*entry = NULL;
}
jb->base++;
jb->out++;
if (jb->out >= JITBUF_MAX)
jb->out = 0;
}
/*
* Return true if this buffer has enough data flow to be declared ready
*/
bool jitbuf_ready(const struct jitbuf_t *jb, seq_t count)
{
size_t n;
assert(count <= JITBUF_MAX);
for (n = 0; n < count; n++) {
if (jb->buf[(jb->out + n) % JITBUF_MAX] == NULL)
return false;
}
return true;
}
bool jitbuf_empty(const struct jitbuf_t *jb)
{
if (jb->entries > 0)
return false;
else
return true;
}
void jitbuf_debug(struct jitbuf_t *jb, FILE *fd)
{
seq_t n;
fprintf(fd, "% 3d ", jb->entries);
for (n = 0; n < JITBUF_MAX; n++) {
if (jb->buf[(jb->out + n) % JITBUF_MAX] != NULL) {
fputc('#', fd);
} else {
fputc(' ', fd);
}
}
fputc('\n', fd);
}

34
jitter.h

@ -0,0 +1,34 @@
#ifndef JITTER_H
#define JITTER_H
#include <stdbool.h>
#include <stdio.h>
#include <sys/types.h>
#define JITBUF_MAX 64
typedef unsigned int seq_t;
/*
* De-jitter buffer
*/
struct jitbuf_t {
seq_t base;
size_t out, entries, contiguous;
void *buf[JITBUF_MAX];
};
void jitbuf_init(struct jitbuf_t *jb);
void jitbuf_clear(struct jitbuf_t *jb);
int jitbuf_push(struct jitbuf_t *jb, seq_t t, void *data);
void* jitbuf_front(const struct jitbuf_t *jb);
void jitbuf_pop(struct jitbuf_t *jb);
bool jitbuf_ready(const struct jitbuf_t *jb, seq_t count);
bool jitbuf_empty(const struct jitbuf_t *jb);
void jitbuf_debug(struct jitbuf_t *jb, FILE *fd);
#endif

263
rx.c

@ -0,0 +1,263 @@
#include <netdb.h>
#include <string.h>
#include <alsa/asoundlib.h>
#include <celt/celt.h>
#include <sys/socket.h>
#include <sys/types.h>
#include "defaults.h"
#include "device.h"
#include "jitter.h"
#include "sched.h"
#define ENCODED_BYTES 128
/*
* Bind to a network socket for receiving packets on the given port
*/
static int listen_on_network(const char *service)
{
int r, sd;
struct addrinfo hints, *servinfo, *p;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_flags = AI_PASSIVE; /* use my IP */
r = getaddrinfo(NULL, service, &hints, &servinfo);
if (r != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(r));
return -1;
}
/* Bind to the first one we can */
for (p = servinfo; p != NULL; p = p->ai_next) {
sd = socket(p->ai_family, p->ai_socktype | SOCK_NONBLOCK,
p->ai_protocol);
if (sd == -1) {
perror("socket");
continue;
}
if (bind(sd, p->ai_addr, p->ai_addrlen) == -1) {
if (close(sd) == -1)
abort();
perror("bind");
continue;
}
break;
}
freeaddrinfo(servinfo);
if (p == NULL) {
fputs("Failed to bind socket\n", stderr);
return -1;
} else {
return sd;
}
}
/*
* Playback audio from the buffer to the audio device
*/
static int play_audio(struct jitbuf_t *jb, CELTDecoder *decoder,
snd_pcm_t *snd)
{
int r;
void *data;
float *pcm;
snd_pcm_sframes_t f;
pcm = alloca(sizeof(float) * DEFAULT_FRAME * DEFAULT_CHANNELS);
data = jitbuf_front(jb);
if (data == NULL) {
r = celt_decode_float(decoder, NULL, 0, pcm);
} else {
r = celt_decode_float(decoder, data, ENCODED_BYTES, pcm);
}
if (r != 0) {
fputs("Error in celt_decode\n", stderr);
return -1;
}
f = snd_pcm_writei(snd, pcm, DEFAULT_FRAME);
if (f < 0) {
aerror("snd_pcm_writei", f);
return -1;
}
if (f < DEFAULT_FRAME)
fprintf(stderr, "Short write %ld\n", f);
jitbuf_pop(jb);
free(data);
return 0;
}
/*
* Read from the network into the buffer
*/
static int read_from_network(int sd, struct jitbuf_t *jb)
{
size_t z;
char buf[32768];
void *data;
seq_t seq;
z = recvfrom(sd, buf, sizeof(buf), 0, NULL, NULL);
if (z == -1) {
if (errno == EAGAIN)
return -EAGAIN;
perror("recvfrom");
return -1;
}
if (z != sizeof(uint32_t) + ENCODED_BYTES) {
fputs("small packet", stderr);
return -1;
}
/* First 32-bits is sequence number, rest is data */
seq = ntohl(*(uint32_t*)buf);
z -= sizeof(uint32_t);
assert(z >= 0);
data = malloc(z);
memcpy(data, buf + sizeof(uint32_t), z);
if (jitbuf_push(jb, seq, data) == -1)
free(data);
return 0;
}
/*
* The main loop of receiving audio and playing it back
*/
static int run_rx(int sd, CELTDecoder *decoder, snd_pcm_t *snd)
{
int r;
struct jitbuf_t jb;
jitbuf_init(&jb);
for (;;) {
for (;;) {
r = read_from_network(sd, &jb);
if (r == -EAGAIN)
break;
if (r != 0)
return -1;
}
jitbuf_debug(&jb, stderr);
if (play_audio(&jb, decoder, snd) == -1)
return -1;
}
jitbuf_clear(&jb);
}
static void usage(FILE *fd)
{
fprintf(fd, "Usage: rx [<parameters>]\n");
fprintf(fd, "\nAudio device (ALSA) parameters:\n");
fprintf(fd, " -d <device> Device name (default '%s')\n",
DEFAULT_DEVICE);
fprintf(fd, " -m <ms> Buffer time (milliseconds, default %d)\n",
DEFAULT_BUFFER);
fprintf(fd, "\nNetwork parameters:\n");
fprintf(fd, " -p <port> UDP port number or name (default %s)\n",
DEFAULT_SERVICE);
}
int main(int argc, char *argv[])
{
int sd, r;
snd_pcm_t *snd;
CELTMode *mode;
CELTDecoder *decoder;
/* command-line options */
const char *device = DEFAULT_DEVICE,
*service = DEFAULT_SERVICE;
unsigned int buffer = DEFAULT_BUFFER;
for (;;) {
int c;
c = getopt(argc, argv, "d:m:p:");
if (c == -1)
break;
switch (c) {
case 'd':
device = optarg;
break;
case 'm':
buffer = atoi(optarg);
break;
case 'p':
service = optarg;
break;
default:
usage(stderr);
return -1;
}
}
mode = celt_mode_create(DEFAULT_RATE, DEFAULT_CHANNELS, DEFAULT_FRAME,
NULL);
if (mode == NULL) {
fputs("celt_mode_create failed\n", stderr);
return -1;
}
decoder = celt_decoder_create(mode);
if (decoder == NULL) {
fputs("celt_decoder_create failed\n", stderr);
return -1;
}
sd = listen_on_network(service);
if (sd == -1)
return -1;
r = snd_pcm_open(&snd, device, SND_PCM_STREAM_PLAYBACK, 0);
if (r < 0) {
aerror("snd_pcm_open", r);
return -1;
}
if (set_alsa_hw(snd, DEFAULT_RATE, DEFAULT_CHANNELS,
buffer * 1000) == -1)
{
return -1;
}
if (set_alsa_sw(snd) == -1)
return -1;
if (go_realtime() != 0)
return -1;
r = run_rx(sd, decoder, snd);
if (snd_pcm_close(snd) < 0)
abort();
celt_decoder_destroy(decoder);
celt_mode_destroy(mode);
if (close(sd) == -1)
abort();
return r;
}

32
sched.c

@ -0,0 +1,32 @@
#include <sched.h>
#include <stdio.h>
#include "sched.h"
#define REALTIME_PRIORITY 80
int go_realtime(void)
{
int max_pri;
struct sched_param sp;
if (sched_getparam(0, &sp)) {
perror("sched_getparam");
return -1;
}
max_pri = sched_get_priority_max(SCHED_FIFO);
sp.sched_priority = REALTIME_PRIORITY;
if (sp.sched_priority > max_pri) {
fprintf(stderr, "Invalid priority (maximum %d)\n", max_pri);
return -1;
}
if (sched_setscheduler(0, SCHED_FIFO, &sp)) {
perror("sched_setscheduler");
return -1;
}
return 0;
}

6
sched.h

@ -0,0 +1,6 @@
#ifndef MISC_H
#define MISC_H
int go_realtime(void);
#endif

34
test-jitter.c

@ -0,0 +1,34 @@
#include <stdio.h>
#include <stdlib.h>
#include "jitter.h"
int main(int argc, char *argv[])
{
int n;
struct jitbuf_t jb;
const char *test = "abcdefghijklmnopqrstuvwxyz1234567890";
jitbuf_init(&jb);
for (n = 0; n < strlen(test); n++) {
int m;
char *out;
size_t pos;
out = jitbuf_front(&jb);
if (out != NULL)
fputc(*out, stdout);
else
fputc('#', stdout);
jitbuf_pop(&jb);
for (m = 0; m < 8; m++) {
pos = n + rand() % (strlen(test) - n);
jitbuf_push(&jb, pos, (void*)&test[pos]);
}
}
fputc('\n', stdout);
jitbuf_clear(&jb);
}

235
tx.c

@ -0,0 +1,235 @@
#include <netdb.h>
#include <string.h>
#include <alsa/asoundlib.h>
#include <celt/celt.h>
#include <sys/socket.h>
#include <sys/types.h>
#include "defaults.h"
#include "device.h"
#include "sched.h"
#define ENCODED_BYTES 128
typedef int seq_t;
/*
* Bind to network socket, for sending to the given host and port
*/
static int bind_to_network(const char *host, const char *service,
struct addrinfo **servinfo, struct addrinfo **theirs)
{
int r, sd;
struct addrinfo hints, *p;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
r = getaddrinfo(host, service, &hints, servinfo);
if (r != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(r));
return -1;
}
for (p = *servinfo; p != NULL; p = p->ai_next) {
sd = socket(p->ai_family, p->ai_socktype, p->ai_protocol);
if (sd == -1) {
perror("socket");
continue;
}
break;
}
if (p == NULL) {
fputs("Failed to bind socket\n", stderr);
return -1;
} else {
*theirs = p;
return sd;
}
}
/*
* Encode a frame of audio and send it over the network
*/
static int send_audio(snd_pcm_t *snd, CELTEncoder *encoder,
int sd, struct addrinfo *theirs, seq_t *seq)
{
float *pcm;
void *packet, *encoded;
ssize_t z;
snd_pcm_sframes_t f;
pcm = alloca(sizeof(float) * DEFAULT_FRAME * DEFAULT_CHANNELS);
packet = alloca(ENCODED_BYTES + sizeof(uint32_t));
encoded = packet + sizeof(uint32_t);
f = snd_pcm_readi(snd, pcm, DEFAULT_FRAME);
if (f < 0) {
aerror("snd_pcm_readi", f);
return -1;
}
if (f < DEFAULT_FRAME)
fprintf(stderr, "Short read, %ld\n", f);
z = celt_encode_float(encoder, pcm, NULL, encoded, ENCODED_BYTES);
if (z < 0) {
fputs("celt_encode_float failed\n", stderr);
return -1;
}
*(uint32_t*)packet = htonl(*seq);
(*seq)++;
z = sendto(sd, packet, sizeof(uint32_t) + ENCODED_BYTES, 0,
theirs->ai_addr, theirs->ai_addrlen);
if (z == -1) {
perror("sendto");
return -1;
}
fputc('>', stderr);
return 0;
}
static int run_tx(snd_pcm_t *snd, CELTEncoder *encoder,
int sd, struct addrinfo *theirs)
{
seq_t seq = 0;
for (;;) {
int r;
r = send_audio(snd, encoder, sd, theirs, &seq);
if (r == -1)
return -1;
}
}
static void usage(FILE *fd)
{
fprintf(fd, "Usage: tx [<parameters>] <host>\n");
fprintf(fd, "\nAudio device (ALSA) parameters:\n");
fprintf(fd, " -d <device> Device name (default '%s')\n",
DEFAULT_DEVICE);
fprintf(fd, " -m <ms> Buffer time (milliseconds, default %d)\n",
DEFAULT_BUFFER);
fprintf(fd, "\nNetwork parameters:\n");
fprintf(fd, " -p <port> UDP port number or name (default %s)\n",
DEFAULT_SERVICE);
fprintf(fd, " -f <bytes> Frame size (default %d)\n",
DEFAULT_FRAME);
fprintf(fd, "\nEncoding parameters:\n");
fprintf(fd, " -r <rate> Sample rate (default %d)\n",
DEFAULT_RATE);
fprintf(fd, " -c <n> Number of channels (default %d)\n",
DEFAULT_CHANNELS);
fprintf(fd, " -b <bitrate> Bitrate (kbps, approx., default %d)\n",
DEFAULT_BITRATE);
}
int main(int argc, char *argv[])
{
int sd, r;
struct addrinfo *servinfo, *theirs;
snd_pcm_t *snd;
CELTMode *mode;
CELTEncoder *encoder;
/* command-line options */
const char *device = DEFAULT_DEVICE,
*service = DEFAULT_SERVICE,
*host;
unsigned int buffer = DEFAULT_BUFFER,
rate = DEFAULT_RATE,
channels = DEFAULT_CHANNELS;
size_t frame = DEFAULT_FRAME;
for (;;) {
int c;
c = getopt(argc, argv, "c:d:f:m:p:r:");
if (c == -1)
break;
switch (c) {
case 'c':
channels = atoi(optarg);
break;
case 'd':
device = optarg;
break;
case 'f':
frame = atol(optarg);
break;
case 'm':
buffer = atoi(optarg);
break;
case 'p':
service = optarg;
break;
case 'r':
rate = atoi(optarg);
break;
default:
usage(stderr);
return -1;
}
}
if (argv[optind] == NULL) {
usage(stderr);
return -1;
}
host = argv[optind];
mode = celt_mode_create(rate, channels, frame, NULL);
if (mode == NULL) {
fputs("celt_mode_create failed\n", stderr);
return -1;
}
encoder = celt_encoder_create(mode);
if (encoder == NULL) {
fputs("celt_encoder_create failed\n", stderr);
return -1;
}
sd = bind_to_network(host, service, &servinfo, &theirs);
if (sd == -1)
return -1;
r = snd_pcm_open(&snd, device, SND_PCM_STREAM_CAPTURE, 0);
if (r < 0) {
aerror("snd_pcm_open", r);
return -1;
}
if (set_alsa_hw(snd, rate, channels, buffer * 1000) == -1)
return -1;
if (set_alsa_sw(snd) == -1)
return -1;
if (go_realtime() != 0)
return -1;
r = run_tx(snd, encoder, sd, theirs);
freeaddrinfo(servinfo);
if (snd_pcm_close(snd) < 0)
abort();
celt_encoder_destroy(encoder);
celt_mode_destroy(mode);
if (close(sd) == -1)
abort();
return r;
}
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