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/timefilter.h"
35 * Size of the internal FIFO buffers as a number of audio packets
37 #define FIFO_PACKETS_NUM 16
41 jack_client_t * client;
44 jack_nframes_t sample_rate;
45 jack_nframes_t buffer_size;
48 TimeFilter * timefilter;
49 AVFifoBuffer * new_pkts;
50 AVFifoBuffer * filled_pkts;
55 static int process_callback(jack_nframes_t nframes, void *arg)
57 /* Warning: this function runs in realtime. One mustn't allocate memory here
58 * or do any other thing that could block. */
63 jack_nframes_t latency, cycle_delay;
71 /* The approximate delay since the hardware interrupt as a number of frames */
72 cycle_delay = jack_frames_since_cycle_start(self->client);
74 /* Retrieve filtered cycle time */
75 cycle_time = ff_timefilter_update(self->timefilter,
76 av_gettime() / 1000000.0 - (double) cycle_delay / self->sample_rate,
79 /* Check if an empty packet is available, and if there's enough space to send it back once filled */
80 if ((av_fifo_size(self->new_pkts) < sizeof(pkt)) || (av_fifo_space(self->filled_pkts) < sizeof(pkt))) {
85 /* Retrieve empty (but allocated) packet */
86 av_fifo_generic_read(self->new_pkts, &pkt, sizeof(pkt), NULL);
88 pkt_data = (float *) pkt.data;
91 /* Copy and interleave audio data from the JACK buffer into the packet */
92 for (i = 0; i < self->nports; i++) {
93 latency += jack_port_get_total_latency(self->client, self->ports[i]);
94 buffer = jack_port_get_buffer(self->ports[i], self->buffer_size);
95 for (j = 0; j < self->buffer_size; j++)
96 pkt_data[j * self->nports + i] = buffer[j];
99 /* Timestamp the packet with the cycle start time minus the average latency */
100 pkt.pts = (cycle_time - (double) latency / (self->nports * self->sample_rate)) * 1000000.0;
102 /* Send the now filled packet back, and increase packet counter */
103 av_fifo_generic_write(self->filled_pkts, &pkt, sizeof(pkt), NULL);
104 sem_post(&self->packet_count);
109 static void shutdown_callback(void *arg)
111 JackData *self = arg;
115 static int xrun_callback(void *arg)
117 JackData *self = arg;
119 ff_timefilter_reset(self->timefilter);
123 static int supply_new_packets(JackData *self, AVFormatContext *context)
126 int test, pkt_size = self->buffer_size * self->nports * sizeof(float);
128 /* Supply the process callback with new empty packets, by filling the new
129 * packets FIFO buffer with as many packets as possible. process_callback()
130 * can't do this by itself, because it can't allocate memory in realtime. */
131 while (av_fifo_space(self->new_pkts) >= sizeof(pkt)) {
132 if ((test = av_new_packet(&pkt, pkt_size)) < 0) {
133 av_log(context, AV_LOG_ERROR, "Could not create packet of size %d\n", pkt_size);
136 av_fifo_generic_write(self->new_pkts, &pkt, sizeof(pkt), NULL);
141 static int start_jack(AVFormatContext *context)
143 JackData *self = context->priv_data;
144 jack_status_t status;
148 /* Register as a JACK client, using the context filename as client name. */
149 self->client = jack_client_open(context->filename, JackNullOption, &status);
151 av_log(context, AV_LOG_ERROR, "Unable to register as a JACK client\n");
155 sem_init(&self->packet_count, 0, 0);
157 self->sample_rate = jack_get_sample_rate(self->client);
158 self->ports = av_malloc(self->nports * sizeof(*self->ports));
159 self->buffer_size = jack_get_buffer_size(self->client);
161 /* Register JACK ports */
162 for (i = 0; i < self->nports; i++) {
164 snprintf(str, sizeof(str), "input_%d", i + 1);
165 self->ports[i] = jack_port_register(self->client, str,
166 JACK_DEFAULT_AUDIO_TYPE,
168 if (!self->ports[i]) {
169 av_log(context, AV_LOG_ERROR, "Unable to register port %s:%s\n",
170 context->filename, str);
171 jack_client_close(self->client);
176 /* Register JACK callbacks */
177 jack_set_process_callback(self->client, process_callback, self);
178 jack_on_shutdown(self->client, shutdown_callback, self);
179 jack_set_xrun_callback(self->client, xrun_callback, self);
181 /* Create time filter */
182 period = (double) self->buffer_size / self->sample_rate;
183 o = 2 * M_PI * 1.5 * period; /// bandwidth: 1.5Hz
184 self->timefilter = ff_timefilter_new (1.0 / self->sample_rate, sqrt(2 * o), o * o);
186 /* Create FIFO buffers */
187 self->filled_pkts = av_fifo_alloc(FIFO_PACKETS_NUM * sizeof(AVPacket));
188 /* New packets FIFO with one extra packet for safety against underruns */
189 self->new_pkts = av_fifo_alloc((FIFO_PACKETS_NUM + 1) * sizeof(AVPacket));
190 if ((test = supply_new_packets(self, context))) {
191 jack_client_close(self->client);
199 static void free_pkt_fifo(AVFifoBuffer *fifo)
202 while (av_fifo_size(fifo)) {
203 av_fifo_generic_read(fifo, &pkt, sizeof(pkt), NULL);
204 av_free_packet(&pkt);
209 static void stop_jack(JackData *self)
213 jack_deactivate(self->client);
214 jack_client_close(self->client);
216 sem_destroy(&self->packet_count);
217 free_pkt_fifo(self->new_pkts);
218 free_pkt_fifo(self->filled_pkts);
219 av_freep(&self->ports);
220 ff_timefilter_destroy(self->timefilter);
223 static int audio_read_header(AVFormatContext *context, AVFormatParameters *params)
225 JackData *self = context->priv_data;
229 if ((test = start_jack(context)))
232 stream = av_new_stream(context, 0);
235 return AVERROR(ENOMEM);
238 stream->codec->codec_type = AVMEDIA_TYPE_AUDIO;
240 stream->codec->codec_id = CODEC_ID_PCM_F32BE;
242 stream->codec->codec_id = CODEC_ID_PCM_F32LE;
244 stream->codec->sample_rate = self->sample_rate;
245 stream->codec->channels = self->nports;
247 av_set_pts_info(stream, 64, 1, 1000000); /* 64 bits pts in us */
251 static int audio_read_packet(AVFormatContext *context, AVPacket *pkt)
253 JackData *self = context->priv_data;
254 struct timespec timeout = {0, 0};
257 /* Activate the JACK client on first packet read. Activating the JACK client
258 * means that process_callback() starts to get called at regular interval.
259 * If we activate it in audio_read_header(), we're actually reading audio data
260 * from the device before instructed to, and that may result in an overrun. */
261 if (!self->activated) {
262 if (!jack_activate(self->client)) {
264 av_log(context, AV_LOG_INFO,
265 "JACK client registered and activated (rate=%dHz, buffer_size=%d frames)\n",
266 self->sample_rate, self->buffer_size);
268 av_log(context, AV_LOG_ERROR, "Unable to activate JACK client\n");
273 /* Wait for a packet comming back from process_callback(), if one isn't available yet */
274 timeout.tv_sec = av_gettime() / 1000000 + 2;
275 if (sem_timedwait(&self->packet_count, &timeout)) {
276 if (errno == ETIMEDOUT) {
277 av_log(context, AV_LOG_ERROR,
278 "Input error: timed out when waiting for JACK process callback output\n");
280 av_log(context, AV_LOG_ERROR, "Error while waiting for audio packet: %s\n",
284 av_log(context, AV_LOG_ERROR, "Input error: JACK server is gone\n");
289 if (self->pkt_xrun) {
290 av_log(context, AV_LOG_WARNING, "Audio packet xrun\n");
294 if (self->jack_xrun) {
295 av_log(context, AV_LOG_WARNING, "JACK xrun\n");
299 /* Retrieve the packet filled with audio data by process_callback() */
300 av_fifo_generic_read(self->filled_pkts, pkt, sizeof(*pkt), NULL);
302 if ((test = supply_new_packets(self, context)))
308 static int audio_read_close(AVFormatContext *context)
310 JackData *self = context->priv_data;
315 #define OFFSET(x) offsetof(JackData, x)
316 static const AVOption options[] = {
317 { "channels", "Number of audio channels.", OFFSET(nports), FF_OPT_TYPE_INT, { 2 }, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
321 static const AVClass jack_indev_class = {
322 .class_name = "JACK indev",
323 .item_name = av_default_item_name,
325 .version = LIBAVUTIL_VERSION_INT,
328 AVInputFormat ff_jack_demuxer = {
330 NULL_IF_CONFIG_SMALL("JACK Audio Connection Kit"),
336 .flags = AVFMT_NOFILE,
337 .priv_class = &jack_indev_class,