Libav
jack_audio.c
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1 /*
2  * JACK Audio Connection Kit input device
3  * Copyright (c) 2009 Samalyse
4  * Author: Olivier Guilyardi <olivier samalyse com>
5  *
6  * This file is part of Libav.
7  *
8  * Libav is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * Libav is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with Libav; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "config.h"
24 #include <semaphore.h>
25 #include <jack/jack.h>
26 
27 #include "libavutil/log.h"
28 #include "libavutil/fifo.h"
29 #include "libavutil/opt.h"
30 #include "libavutil/time.h"
31 #include "libavcodec/avcodec.h"
32 #include "libavformat/avformat.h"
33 #include "libavformat/internal.h"
34 #include "timefilter.h"
35 
39 #define FIFO_PACKETS_NUM 16
40 
41 typedef struct {
42  AVClass *class;
43  jack_client_t * client;
44  int activated;
45  sem_t packet_count;
46  jack_nframes_t sample_rate;
47  jack_nframes_t buffer_size;
48  jack_port_t ** ports;
49  int nports;
53  int pkt_xrun;
54  int jack_xrun;
55 } JackData;
56 
57 static int process_callback(jack_nframes_t nframes, void *arg)
58 {
59  /* Warning: this function runs in realtime. One mustn't allocate memory here
60  * or do any other thing that could block. */
61 
62  int i, j;
63  JackData *self = arg;
64  float * buffer;
65  jack_nframes_t latency, cycle_delay;
66  AVPacket pkt;
67  float *pkt_data;
68  double cycle_time;
69 
70  if (!self->client)
71  return 0;
72 
73  /* The approximate delay since the hardware interrupt as a number of frames */
74  cycle_delay = jack_frames_since_cycle_start(self->client);
75 
76  /* Retrieve filtered cycle time */
77  cycle_time = ff_timefilter_update(self->timefilter,
78  av_gettime() / 1000000.0 - (double) cycle_delay / self->sample_rate,
79  self->buffer_size);
80 
81  /* Check if an empty packet is available, and if there's enough space to send it back once filled */
82  if ((av_fifo_size(self->new_pkts) < sizeof(pkt)) || (av_fifo_space(self->filled_pkts) < sizeof(pkt))) {
83  self->pkt_xrun = 1;
84  return 0;
85  }
86 
87  /* Retrieve empty (but allocated) packet */
88  av_fifo_generic_read(self->new_pkts, &pkt, sizeof(pkt), NULL);
89 
90  pkt_data = (float *) pkt.data;
91  latency = 0;
92 
93  /* Copy and interleave audio data from the JACK buffer into the packet */
94  for (i = 0; i < self->nports; i++) {
95  #if HAVE_JACK_PORT_GET_LATENCY_RANGE
96  jack_latency_range_t range;
97  jack_port_get_latency_range(self->ports[i], JackCaptureLatency, &range);
98  latency += range.max;
99  #else
100  latency += jack_port_get_total_latency(self->client, self->ports[i]);
101  #endif
102  buffer = jack_port_get_buffer(self->ports[i], self->buffer_size);
103  for (j = 0; j < self->buffer_size; j++)
104  pkt_data[j * self->nports + i] = buffer[j];
105  }
106 
107  /* Timestamp the packet with the cycle start time minus the average latency */
108  pkt.pts = (cycle_time - (double) latency / (self->nports * self->sample_rate)) * 1000000.0;
109 
110  /* Send the now filled packet back, and increase packet counter */
111  av_fifo_generic_write(self->filled_pkts, &pkt, sizeof(pkt), NULL);
112  sem_post(&self->packet_count);
113 
114  return 0;
115 }
116 
117 static void shutdown_callback(void *arg)
118 {
119  JackData *self = arg;
120  self->client = NULL;
121 }
122 
123 static int xrun_callback(void *arg)
124 {
125  JackData *self = arg;
126  self->jack_xrun = 1;
127  ff_timefilter_reset(self->timefilter);
128  return 0;
129 }
130 
131 static int supply_new_packets(JackData *self, AVFormatContext *context)
132 {
133  AVPacket pkt;
134  int test, pkt_size = self->buffer_size * self->nports * sizeof(float);
135 
136  /* Supply the process callback with new empty packets, by filling the new
137  * packets FIFO buffer with as many packets as possible. process_callback()
138  * can't do this by itself, because it can't allocate memory in realtime. */
139  while (av_fifo_space(self->new_pkts) >= sizeof(pkt)) {
140  if ((test = av_new_packet(&pkt, pkt_size)) < 0) {
141  av_log(context, AV_LOG_ERROR, "Could not create packet of size %d\n", pkt_size);
142  return test;
143  }
144  av_fifo_generic_write(self->new_pkts, &pkt, sizeof(pkt), NULL);
145  }
146  return 0;
147 }
148 
149 static int start_jack(AVFormatContext *context)
150 {
151  JackData *self = context->priv_data;
152  jack_status_t status;
153  int i, test;
154  double o, period;
155 
156  /* Register as a JACK client, using the context filename as client name. */
157  self->client = jack_client_open(context->filename, JackNullOption, &status);
158  if (!self->client) {
159  av_log(context, AV_LOG_ERROR, "Unable to register as a JACK client\n");
160  return AVERROR(EIO);
161  }
162 
163  sem_init(&self->packet_count, 0, 0);
164 
165  self->sample_rate = jack_get_sample_rate(self->client);
166  self->ports = av_malloc(self->nports * sizeof(*self->ports));
167  self->buffer_size = jack_get_buffer_size(self->client);
168 
169  /* Register JACK ports */
170  for (i = 0; i < self->nports; i++) {
171  char str[16];
172  snprintf(str, sizeof(str), "input_%d", i + 1);
173  self->ports[i] = jack_port_register(self->client, str,
174  JACK_DEFAULT_AUDIO_TYPE,
175  JackPortIsInput, 0);
176  if (!self->ports[i]) {
177  av_log(context, AV_LOG_ERROR, "Unable to register port %s:%s\n",
178  context->filename, str);
179  jack_client_close(self->client);
180  return AVERROR(EIO);
181  }
182  }
183 
184  /* Register JACK callbacks */
185  jack_set_process_callback(self->client, process_callback, self);
186  jack_on_shutdown(self->client, shutdown_callback, self);
187  jack_set_xrun_callback(self->client, xrun_callback, self);
188 
189  /* Create time filter */
190  period = (double) self->buffer_size / self->sample_rate;
191  o = 2 * M_PI * 1.5 * period;
192  self->timefilter = ff_timefilter_new (1.0 / self->sample_rate, sqrt(2 * o), o * o);
193  if (!self->timefilter) {
194  jack_client_close(self->client);
195  return AVERROR(ENOMEM);
196  }
197 
198  /* Create FIFO buffers */
199  self->filled_pkts = av_fifo_alloc(FIFO_PACKETS_NUM * sizeof(AVPacket));
200  /* New packets FIFO with one extra packet for safety against underruns */
201  self->new_pkts = av_fifo_alloc((FIFO_PACKETS_NUM + 1) * sizeof(AVPacket));
202  if ((test = supply_new_packets(self, context))) {
203  jack_client_close(self->client);
204  return test;
205  }
206 
207  return 0;
208 
209 }
210 
211 static void free_pkt_fifo(AVFifoBuffer *fifo)
212 {
213  AVPacket pkt;
214  while (av_fifo_size(fifo)) {
215  av_fifo_generic_read(fifo, &pkt, sizeof(pkt), NULL);
216  av_free_packet(&pkt);
217  }
218  av_fifo_free(fifo);
219 }
220 
221 static void stop_jack(JackData *self)
222 {
223  if (self->client) {
224  if (self->activated)
225  jack_deactivate(self->client);
226  jack_client_close(self->client);
227  }
228  sem_destroy(&self->packet_count);
229  free_pkt_fifo(self->new_pkts);
230  free_pkt_fifo(self->filled_pkts);
231  av_freep(&self->ports);
232  ff_timefilter_destroy(self->timefilter);
233 }
234 
235 static int audio_read_header(AVFormatContext *context)
236 {
237  JackData *self = context->priv_data;
238  AVStream *stream;
239  int test;
240 
241  if ((test = start_jack(context)))
242  return test;
243 
244  stream = avformat_new_stream(context, NULL);
245  if (!stream) {
246  stop_jack(self);
247  return AVERROR(ENOMEM);
248  }
249 
251 #if HAVE_BIGENDIAN
253 #else
255 #endif
256  stream->codec->sample_rate = self->sample_rate;
257  stream->codec->channels = self->nports;
258 
259  avpriv_set_pts_info(stream, 64, 1, 1000000); /* 64 bits pts in us */
260  return 0;
261 }
262 
263 static int audio_read_packet(AVFormatContext *context, AVPacket *pkt)
264 {
265  JackData *self = context->priv_data;
266  struct timespec timeout = {0, 0};
267  int test;
268 
269  /* Activate the JACK client on first packet read. Activating the JACK client
270  * means that process_callback() starts to get called at regular interval.
271  * If we activate it in audio_read_header(), we're actually reading audio data
272  * from the device before instructed to, and that may result in an overrun. */
273  if (!self->activated) {
274  if (!jack_activate(self->client)) {
275  self->activated = 1;
276  av_log(context, AV_LOG_INFO,
277  "JACK client registered and activated (rate=%dHz, buffer_size=%d frames)\n",
278  self->sample_rate, self->buffer_size);
279  } else {
280  av_log(context, AV_LOG_ERROR, "Unable to activate JACK client\n");
281  return AVERROR(EIO);
282  }
283  }
284 
285  /* Wait for a packet coming back from process_callback(), if one isn't available yet */
286  timeout.tv_sec = av_gettime() / 1000000 + 2;
287  if (sem_timedwait(&self->packet_count, &timeout)) {
288  if (errno == ETIMEDOUT) {
289  av_log(context, AV_LOG_ERROR,
290  "Input error: timed out when waiting for JACK process callback output\n");
291  } else {
292  av_log(context, AV_LOG_ERROR, "Error while waiting for audio packet: %s\n",
293  strerror(errno));
294  }
295  if (!self->client)
296  av_log(context, AV_LOG_ERROR, "Input error: JACK server is gone\n");
297 
298  return AVERROR(EIO);
299  }
300 
301  if (self->pkt_xrun) {
302  av_log(context, AV_LOG_WARNING, "Audio packet xrun\n");
303  self->pkt_xrun = 0;
304  }
305 
306  if (self->jack_xrun) {
307  av_log(context, AV_LOG_WARNING, "JACK xrun\n");
308  self->jack_xrun = 0;
309  }
310 
311  /* Retrieve the packet filled with audio data by process_callback() */
312  av_fifo_generic_read(self->filled_pkts, pkt, sizeof(*pkt), NULL);
313 
314  if ((test = supply_new_packets(self, context)))
315  return test;
316 
317  return 0;
318 }
319 
320 static int audio_read_close(AVFormatContext *context)
321 {
322  JackData *self = context->priv_data;
323  stop_jack(self);
324  return 0;
325 }
326 
327 #define OFFSET(x) offsetof(JackData, x)
328 static const AVOption options[] = {
329  { "channels", "Number of audio channels.", OFFSET(nports), AV_OPT_TYPE_INT, { .i64 = 2 }, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
330  { NULL },
331 };
332 
333 static const AVClass jack_indev_class = {
334  .class_name = "JACK indev",
335  .item_name = av_default_item_name,
336  .option = options,
337  .version = LIBAVUTIL_VERSION_INT,
338 };
339 
341  .name = "jack",
342  .long_name = NULL_IF_CONFIG_SMALL("JACK Audio Connection Kit"),
343  .priv_data_size = sizeof(JackData),
347  .flags = AVFMT_NOFILE,
348  .priv_class = &jack_indev_class,
349 };