2 * JACK Audio Connection Kit input device
3 * Copyright (c) 2009 Samalyse
4 * Author: Olivier Guilyardi <olivier samalyse com>
6 * This file is part of FFmpeg.
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.
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.
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
24 #include <semaphore.h>
25 #include <jack/jack.h>
27 #include "libavutil/log.h"
28 #include "libavutil/fifo.h"
29 #include "libavutil/opt.h"
30 #include "libavcodec/avcodec.h"
31 #include "libavformat/avformat.h"
32 #include "timefilter.h"
36 * Size of the internal FIFO buffers as a number of audio packets
38 #define FIFO_PACKETS_NUM 16
42 jack_client_t * client;
45 jack_nframes_t sample_rate;
46 jack_nframes_t buffer_size;
49 TimeFilter * timefilter;
50 AVFifoBuffer * new_pkts;
51 AVFifoBuffer * filled_pkts;
56 static int process_callback(jack_nframes_t nframes, void *arg)
58 /* Warning: this function runs in realtime. One mustn't allocate memory here
59 * or do any other thing that could block. */
64 jack_nframes_t latency, cycle_delay;
72 /* The approximate delay since the hardware interrupt as a number of frames */
73 cycle_delay = jack_frames_since_cycle_start(self->client);
75 /* Retrieve filtered cycle time */
76 cycle_time = ff_timefilter_update(self->timefilter,
77 av_gettime() / 1000000.0 - (double) cycle_delay / self->sample_rate,
80 /* Check if an empty packet is available, and if there's enough space to send it back once filled */
81 if ((av_fifo_size(self->new_pkts) < sizeof(pkt)) || (av_fifo_space(self->filled_pkts) < sizeof(pkt))) {
86 /* Retrieve empty (but allocated) packet */
87 av_fifo_generic_read(self->new_pkts, &pkt, sizeof(pkt), NULL);
89 pkt_data = (float *) pkt.data;
92 /* Copy and interleave audio data from the JACK buffer into the packet */
93 for (i = 0; i < self->nports; i++) {
94 latency += jack_port_get_total_latency(self->client, self->ports[i]);
95 buffer = jack_port_get_buffer(self->ports[i], self->buffer_size);
96 for (j = 0; j < self->buffer_size; j++)
97 pkt_data[j * self->nports + i] = buffer[j];
100 /* Timestamp the packet with the cycle start time minus the average latency */
101 pkt.pts = (cycle_time - (double) latency / (self->nports * self->sample_rate)) * 1000000.0;
103 /* Send the now filled packet back, and increase packet counter */
104 av_fifo_generic_write(self->filled_pkts, &pkt, sizeof(pkt), NULL);
105 sem_post(&self->packet_count);
110 static void shutdown_callback(void *arg)
112 JackData *self = arg;
116 static int xrun_callback(void *arg)
118 JackData *self = arg;
120 ff_timefilter_reset(self->timefilter);
124 static int supply_new_packets(JackData *self, AVFormatContext *context)
127 int test, pkt_size = self->buffer_size * self->nports * sizeof(float);
129 /* Supply the process callback with new empty packets, by filling the new
130 * packets FIFO buffer with as many packets as possible. process_callback()
131 * can't do this by itself, because it can't allocate memory in realtime. */
132 while (av_fifo_space(self->new_pkts) >= sizeof(pkt)) {
133 if ((test = av_new_packet(&pkt, pkt_size)) < 0) {
134 av_log(context, AV_LOG_ERROR, "Could not create packet of size %d\n", pkt_size);
137 av_fifo_generic_write(self->new_pkts, &pkt, sizeof(pkt), NULL);
142 static int start_jack(AVFormatContext *context)
144 JackData *self = context->priv_data;
145 jack_status_t status;
149 /* Register as a JACK client, using the context filename as client name. */
150 self->client = jack_client_open(context->filename, JackNullOption, &status);
152 av_log(context, AV_LOG_ERROR, "Unable to register as a JACK client\n");
156 sem_init(&self->packet_count, 0, 0);
158 self->sample_rate = jack_get_sample_rate(self->client);
159 self->ports = av_malloc(self->nports * sizeof(*self->ports));
160 self->buffer_size = jack_get_buffer_size(self->client);
162 /* Register JACK ports */
163 for (i = 0; i < self->nports; i++) {
165 snprintf(str, sizeof(str), "input_%d", i + 1);
166 self->ports[i] = jack_port_register(self->client, str,
167 JACK_DEFAULT_AUDIO_TYPE,
169 if (!self->ports[i]) {
170 av_log(context, AV_LOG_ERROR, "Unable to register port %s:%s\n",
171 context->filename, str);
172 jack_client_close(self->client);
177 /* Register JACK callbacks */
178 jack_set_process_callback(self->client, process_callback, self);
179 jack_on_shutdown(self->client, shutdown_callback, self);
180 jack_set_xrun_callback(self->client, xrun_callback, self);
182 /* Create time filter */
183 period = (double) self->buffer_size / self->sample_rate;
184 o = 2 * M_PI * 1.5 * period; /// bandwidth: 1.5Hz
185 self->timefilter = ff_timefilter_new (1.0 / self->sample_rate, sqrt(2 * o), o * o);
187 /* Create FIFO buffers */
188 self->filled_pkts = av_fifo_alloc(FIFO_PACKETS_NUM * sizeof(AVPacket));
189 /* New packets FIFO with one extra packet for safety against underruns */
190 self->new_pkts = av_fifo_alloc((FIFO_PACKETS_NUM + 1) * sizeof(AVPacket));
191 if ((test = supply_new_packets(self, context))) {
192 jack_client_close(self->client);
200 static void free_pkt_fifo(AVFifoBuffer *fifo)
203 while (av_fifo_size(fifo)) {
204 av_fifo_generic_read(fifo, &pkt, sizeof(pkt), NULL);
205 av_free_packet(&pkt);
210 static void stop_jack(JackData *self)
214 jack_deactivate(self->client);
215 jack_client_close(self->client);
217 sem_destroy(&self->packet_count);
218 free_pkt_fifo(self->new_pkts);
219 free_pkt_fifo(self->filled_pkts);
220 av_freep(&self->ports);
221 ff_timefilter_destroy(self->timefilter);
224 static int audio_read_header(AVFormatContext *context, AVFormatParameters *params)
226 JackData *self = context->priv_data;
230 if ((test = start_jack(context)))
233 stream = avformat_new_stream(context, NULL);
236 return AVERROR(ENOMEM);
239 stream->codec->codec_type = AVMEDIA_TYPE_AUDIO;
241 stream->codec->codec_id = CODEC_ID_PCM_F32BE;
243 stream->codec->codec_id = CODEC_ID_PCM_F32LE;
245 stream->codec->sample_rate = self->sample_rate;
246 stream->codec->channels = self->nports;
248 av_set_pts_info(stream, 64, 1, 1000000); /* 64 bits pts in us */
252 static int audio_read_packet(AVFormatContext *context, AVPacket *pkt)
254 JackData *self = context->priv_data;
255 struct timespec timeout = {0, 0};
258 /* Activate the JACK client on first packet read. Activating the JACK client
259 * means that process_callback() starts to get called at regular interval.
260 * If we activate it in audio_read_header(), we're actually reading audio data
261 * from the device before instructed to, and that may result in an overrun. */
262 if (!self->activated) {
263 if (!jack_activate(self->client)) {
265 av_log(context, AV_LOG_INFO,
266 "JACK client registered and activated (rate=%dHz, buffer_size=%d frames)\n",
267 self->sample_rate, self->buffer_size);
269 av_log(context, AV_LOG_ERROR, "Unable to activate JACK client\n");
274 /* Wait for a packet comming back from process_callback(), if one isn't available yet */
275 timeout.tv_sec = av_gettime() / 1000000 + 2;
276 if (sem_timedwait(&self->packet_count, &timeout)) {
277 if (errno == ETIMEDOUT) {
278 av_log(context, AV_LOG_ERROR,
279 "Input error: timed out when waiting for JACK process callback output\n");
281 av_log(context, AV_LOG_ERROR, "Error while waiting for audio packet: %s\n",
285 av_log(context, AV_LOG_ERROR, "Input error: JACK server is gone\n");
290 if (self->pkt_xrun) {
291 av_log(context, AV_LOG_WARNING, "Audio packet xrun\n");
295 if (self->jack_xrun) {
296 av_log(context, AV_LOG_WARNING, "JACK xrun\n");
300 /* Retrieve the packet filled with audio data by process_callback() */
301 av_fifo_generic_read(self->filled_pkts, pkt, sizeof(*pkt), NULL);
303 if ((test = supply_new_packets(self, context)))
309 static int audio_read_close(AVFormatContext *context)
311 JackData *self = context->priv_data;
316 #define OFFSET(x) offsetof(JackData, x)
317 static const AVOption options[] = {
318 { "channels", "Number of audio channels.", OFFSET(nports), AV_OPT_TYPE_INT, { 2 }, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
322 static const AVClass jack_indev_class = {
323 .class_name = "JACK indev",
324 .item_name = av_default_item_name,
326 .version = LIBAVUTIL_VERSION_INT,
329 AVInputFormat ff_jack_demuxer = {
331 .long_name = NULL_IF_CONFIG_SMALL("JACK Audio Connection Kit"),
332 .priv_data_size = sizeof(JackData),
333 .read_header = audio_read_header,
334 .read_packet = audio_read_packet,
335 .read_close = audio_read_close,
336 .flags = AVFMT_NOFILE,
337 .priv_class = &jack_indev_class,