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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 FFmpeg.
7  *
8  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 #include "avdevice.h"
36 
37 /**
38  * Size of the internal FIFO buffers as a number of audio packets
39  */
40 #define FIFO_PACKETS_NUM 16
41 
42 typedef struct {
43  AVClass *class;
44  jack_client_t * client;
45  int activated;
46  sem_t packet_count;
47  jack_nframes_t sample_rate;
48  jack_nframes_t buffer_size;
49  jack_port_t ** ports;
50  int nports;
54  int pkt_xrun;
55  int jack_xrun;
56 } JackData;
57 
58 static int process_callback(jack_nframes_t nframes, void *arg)
59 {
60  /* Warning: this function runs in realtime. One mustn't allocate memory here
61  * or do any other thing that could block. */
62 
63  int i, j;
64  JackData *self = arg;
65  float * buffer;
66  jack_nframes_t latency, cycle_delay;
67  AVPacket pkt;
68  float *pkt_data;
69  double cycle_time;
70 
71  if (!self->client)
72  return 0;
73 
74  /* The approximate delay since the hardware interrupt as a number of frames */
75  cycle_delay = jack_frames_since_cycle_start(self->client);
76 
77  /* Retrieve filtered cycle time */
78  cycle_time = ff_timefilter_update(self->timefilter,
79  av_gettime() / 1000000.0 - (double) cycle_delay / self->sample_rate,
80  self->buffer_size);
81 
82  /* Check if an empty packet is available, and if there's enough space to send it back once filled */
83  if ((av_fifo_size(self->new_pkts) < sizeof(pkt)) || (av_fifo_space(self->filled_pkts) < sizeof(pkt))) {
84  self->pkt_xrun = 1;
85  return 0;
86  }
87 
88  /* Retrieve empty (but allocated) packet */
89  av_fifo_generic_read(self->new_pkts, &pkt, sizeof(pkt), NULL);
90 
91  pkt_data = (float *) pkt.data;
92  latency = 0;
93 
94  /* Copy and interleave audio data from the JACK buffer into the packet */
95  for (i = 0; i < self->nports; i++) {
96  #if HAVE_JACK_PORT_GET_LATENCY_RANGE
97  jack_latency_range_t range;
98  jack_port_get_latency_range(self->ports[i], JackCaptureLatency, &range);
99  latency += range.max;
100  #else
101  latency += jack_port_get_total_latency(self->client, self->ports[i]);
102  #endif
103  buffer = jack_port_get_buffer(self->ports[i], self->buffer_size);
104  for (j = 0; j < self->buffer_size; j++)
105  pkt_data[j * self->nports + i] = buffer[j];
106  }
107 
108  /* Timestamp the packet with the cycle start time minus the average latency */
109  pkt.pts = (cycle_time - (double) latency / (self->nports * self->sample_rate)) * 1000000.0;
110 
111  /* Send the now filled packet back, and increase packet counter */
112  av_fifo_generic_write(self->filled_pkts, &pkt, sizeof(pkt), NULL);
113  sem_post(&self->packet_count);
114 
115  return 0;
116 }
117 
118 static void shutdown_callback(void *arg)
119 {
120  JackData *self = arg;
121  self->client = NULL;
122 }
123 
124 static int xrun_callback(void *arg)
125 {
126  JackData *self = arg;
127  self->jack_xrun = 1;
128  ff_timefilter_reset(self->timefilter);
129  return 0;
130 }
131 
132 static int supply_new_packets(JackData *self, AVFormatContext *context)
133 {
134  AVPacket pkt;
135  int test, pkt_size = self->buffer_size * self->nports * sizeof(float);
136 
137  /* Supply the process callback with new empty packets, by filling the new
138  * packets FIFO buffer with as many packets as possible. process_callback()
139  * can't do this by itself, because it can't allocate memory in realtime. */
140  while (av_fifo_space(self->new_pkts) >= sizeof(pkt)) {
141  if ((test = av_new_packet(&pkt, pkt_size)) < 0) {
142  av_log(context, AV_LOG_ERROR, "Could not create packet of size %d\n", pkt_size);
143  return test;
144  }
145  av_fifo_generic_write(self->new_pkts, &pkt, sizeof(pkt), NULL);
146  }
147  return 0;
148 }
149 
150 static int start_jack(AVFormatContext *context)
151 {
152  JackData *self = context->priv_data;
153  jack_status_t status;
154  int i, test;
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  self->timefilter = ff_timefilter_new (1.0 / self->sample_rate, self->buffer_size, 1.5);
191 
192  /* Create FIFO buffers */
193  self->filled_pkts = av_fifo_alloc(FIFO_PACKETS_NUM * sizeof(AVPacket));
194  /* New packets FIFO with one extra packet for safety against underruns */
195  self->new_pkts = av_fifo_alloc((FIFO_PACKETS_NUM + 1) * sizeof(AVPacket));
196  if ((test = supply_new_packets(self, context))) {
197  jack_client_close(self->client);
198  return test;
199  }
200 
201  return 0;
202 
203 }
204 
205 static void free_pkt_fifo(AVFifoBuffer *fifo)
206 {
207  AVPacket pkt;
208  while (av_fifo_size(fifo)) {
209  av_fifo_generic_read(fifo, &pkt, sizeof(pkt), NULL);
210  av_free_packet(&pkt);
211  }
212  av_fifo_free(fifo);
213 }
214 
215 static void stop_jack(JackData *self)
216 {
217  if (self->client) {
218  if (self->activated)
219  jack_deactivate(self->client);
220  jack_client_close(self->client);
221  }
222  sem_destroy(&self->packet_count);
223  free_pkt_fifo(self->new_pkts);
224  free_pkt_fifo(self->filled_pkts);
225  av_freep(&self->ports);
226  ff_timefilter_destroy(self->timefilter);
227 }
228 
229 static int audio_read_header(AVFormatContext *context)
230 {
231  JackData *self = context->priv_data;
232  AVStream *stream;
233  int test;
234 
235  if ((test = start_jack(context)))
236  return test;
237 
238  stream = avformat_new_stream(context, NULL);
239  if (!stream) {
240  stop_jack(self);
241  return AVERROR(ENOMEM);
242  }
243 
245 #if HAVE_BIGENDIAN
247 #else
249 #endif
250  stream->codec->sample_rate = self->sample_rate;
251  stream->codec->channels = self->nports;
252 
253  avpriv_set_pts_info(stream, 64, 1, 1000000); /* 64 bits pts in us */
254  return 0;
255 }
256 
258 {
259  JackData *self = context->priv_data;
260  struct timespec timeout = {0, 0};
261  int test;
262 
263  /* Activate the JACK client on first packet read. Activating the JACK client
264  * means that process_callback() starts to get called at regular interval.
265  * If we activate it in audio_read_header(), we're actually reading audio data
266  * from the device before instructed to, and that may result in an overrun. */
267  if (!self->activated) {
268  if (!jack_activate(self->client)) {
269  self->activated = 1;
270  av_log(context, AV_LOG_INFO,
271  "JACK client registered and activated (rate=%dHz, buffer_size=%d frames)\n",
272  self->sample_rate, self->buffer_size);
273  } else {
274  av_log(context, AV_LOG_ERROR, "Unable to activate JACK client\n");
275  return AVERROR(EIO);
276  }
277  }
278 
279  /* Wait for a packet coming back from process_callback(), if one isn't available yet */
280  timeout.tv_sec = av_gettime() / 1000000 + 2;
281  if (sem_timedwait(&self->packet_count, &timeout)) {
282  if (errno == ETIMEDOUT) {
283  av_log(context, AV_LOG_ERROR,
284  "Input error: timed out when waiting for JACK process callback output\n");
285  } else {
286  av_log(context, AV_LOG_ERROR, "Error while waiting for audio packet: %s\n",
287  strerror(errno));
288  }
289  if (!self->client)
290  av_log(context, AV_LOG_ERROR, "Input error: JACK server is gone\n");
291 
292  return AVERROR(EIO);
293  }
294 
295  if (self->pkt_xrun) {
296  av_log(context, AV_LOG_WARNING, "Audio packet xrun\n");
297  self->pkt_xrun = 0;
298  }
299 
300  if (self->jack_xrun) {
301  av_log(context, AV_LOG_WARNING, "JACK xrun\n");
302  self->jack_xrun = 0;
303  }
304 
305  /* Retrieve the packet filled with audio data by process_callback() */
306  av_fifo_generic_read(self->filled_pkts, pkt, sizeof(*pkt), NULL);
307 
308  if ((test = supply_new_packets(self, context)))
309  return test;
310 
311  return 0;
312 }
313 
314 static int audio_read_close(AVFormatContext *context)
315 {
316  JackData *self = context->priv_data;
317  stop_jack(self);
318  return 0;
319 }
320 
321 #define OFFSET(x) offsetof(JackData, x)
322 static const AVOption options[] = {
323  { "channels", "Number of audio channels.", OFFSET(nports), AV_OPT_TYPE_INT, { .i64 = 2 }, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
324  { NULL },
325 };
326 
327 static const AVClass jack_indev_class = {
328  .class_name = "JACK indev",
329  .item_name = av_default_item_name,
330  .option = options,
331  .version = LIBAVUTIL_VERSION_INT,
332 };
333 
335  .name = "jack",
336  .long_name = NULL_IF_CONFIG_SMALL("JACK Audio Connection Kit"),
337  .priv_data_size = sizeof(JackData),
341  .flags = AVFMT_NOFILE,
342  .priv_class = &jack_indev_class,
343 };