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 "libavcodec/avcodec.h"
30 #include "libavformat/avformat.h"
31 #include "libavformat/timefilter.h"
34 * Size of the internal FIFO buffers as a number of audio packets
36 #define FIFO_PACKETS_NUM 16
39 jack_client_t * client;
42 jack_nframes_t sample_rate;
43 jack_nframes_t buffer_size;
46 TimeFilter * timefilter;
47 AVFifoBuffer * new_pkts;
48 AVFifoBuffer * filled_pkts;
53 static int process_callback(jack_nframes_t nframes, void *arg)
55 /* Warning: this function runs in realtime. One mustn't allocate memory here
56 * or do any other thing that could block. */
61 jack_nframes_t latency, cycle_delay;
69 /* The approximate delay since the hardware interrupt as a number of frames */
70 cycle_delay = jack_frames_since_cycle_start(self->client);
72 /* Retrieve filtered cycle time */
73 cycle_time = ff_timefilter_update(self->timefilter,
74 av_gettime() / 1000000.0 - (double) cycle_delay / self->sample_rate,
77 /* Check if an empty packet is available, and if there's enough space to send it back once filled */
78 if ((av_fifo_size(self->new_pkts) < sizeof(pkt)) || (av_fifo_space(self->filled_pkts) < sizeof(pkt))) {
83 /* Retrieve empty (but allocated) packet */
84 av_fifo_generic_read(self->new_pkts, &pkt, sizeof(pkt), NULL);
86 pkt_data = (float *) pkt.data;
89 /* Copy and interleave audio data from the JACK buffer into the packet */
90 for (i = 0; i < self->nports; i++) {
91 latency += jack_port_get_total_latency(self->client, self->ports[i]);
92 buffer = jack_port_get_buffer(self->ports[i], self->buffer_size);
93 for (j = 0; j < self->buffer_size; j++)
94 pkt_data[j * self->nports + i] = buffer[j];
97 /* Timestamp the packet with the cycle start time minus the average latency */
98 pkt.pts = (cycle_time - (double) latency / (self->nports * self->sample_rate)) * 1000000.0;
100 /* Send the now filled packet back, and increase packet counter */
101 av_fifo_generic_write(self->filled_pkts, &pkt, sizeof(pkt), NULL);
102 sem_post(&self->packet_count);
107 static void shutdown_callback(void *arg)
109 JackData *self = arg;
113 static int xrun_callback(void *arg)
115 JackData *self = arg;
117 ff_timefilter_reset(self->timefilter);
121 static int supply_new_packets(JackData *self, AVFormatContext *context)
124 int test, pkt_size = self->buffer_size * self->nports * sizeof(float);
126 /* Supply the process callback with new empty packets, by filling the new
127 * packets FIFO buffer with as many packets as possible. process_callback()
128 * can't do this by itself, because it can't allocate memory in realtime. */
129 while (av_fifo_space(self->new_pkts) >= sizeof(pkt)) {
130 if ((test = av_new_packet(&pkt, pkt_size)) < 0) {
131 av_log(context, AV_LOG_ERROR, "Could not create packet of size %d\n", pkt_size);
134 av_fifo_generic_write(self->new_pkts, &pkt, sizeof(pkt), NULL);
139 static int start_jack(AVFormatContext *context, AVFormatParameters *params)
141 JackData *self = context->priv_data;
142 jack_status_t status;
146 /* Register as a JACK client, using the context filename as client name. */
147 self->client = jack_client_open(context->filename, JackNullOption, &status);
149 av_log(context, AV_LOG_ERROR, "Unable to register as a JACK client\n");
153 sem_init(&self->packet_count, 0, 0);
155 self->sample_rate = jack_get_sample_rate(self->client);
156 self->nports = params->channels;
157 self->ports = av_malloc(self->nports * sizeof(*self->ports));
158 self->buffer_size = jack_get_buffer_size(self->client);
160 /* Register JACK ports */
161 for (i = 0; i < self->nports; i++) {
163 snprintf(str, sizeof(str), "input_%d", i + 1);
164 self->ports[i] = jack_port_register(self->client, str,
165 JACK_DEFAULT_AUDIO_TYPE,
167 if (!self->ports[i]) {
168 av_log(context, AV_LOG_ERROR, "Unable to register port %s:%s\n",
169 context->filename, str);
170 jack_client_close(self->client);
175 /* Register JACK callbacks */
176 jack_set_process_callback(self->client, process_callback, self);
177 jack_on_shutdown(self->client, shutdown_callback, self);
178 jack_set_xrun_callback(self->client, xrun_callback, self);
180 /* Create time filter */
181 period = (double) self->buffer_size / self->sample_rate;
182 o = 2 * M_PI * 1.5 * period; /// bandwidth: 1.5Hz
183 self->timefilter = ff_timefilter_new (1.0 / self->sample_rate, sqrt(2 * o), o * o);
185 /* Create FIFO buffers */
186 self->filled_pkts = av_fifo_alloc(FIFO_PACKETS_NUM * sizeof(AVPacket));
187 /* New packets FIFO with one extra packet for safety against underruns */
188 self->new_pkts = av_fifo_alloc((FIFO_PACKETS_NUM + 1) * sizeof(AVPacket));
189 if ((test = supply_new_packets(self, context))) {
190 jack_client_close(self->client);
198 static void free_pkt_fifo(AVFifoBuffer *fifo)
201 while (av_fifo_size(fifo)) {
202 av_fifo_generic_read(fifo, &pkt, sizeof(pkt), NULL);
203 av_free_packet(&pkt);
208 static void stop_jack(JackData *self)
212 jack_deactivate(self->client);
213 jack_client_close(self->client);
215 sem_destroy(&self->packet_count);
216 free_pkt_fifo(self->new_pkts);
217 free_pkt_fifo(self->filled_pkts);
218 av_freep(&self->ports);
219 ff_timefilter_destroy(self->timefilter);
222 static int audio_read_header(AVFormatContext *context, AVFormatParameters *params)
224 JackData *self = context->priv_data;
228 if (params->sample_rate <= 0 || params->channels <= 0)
231 if ((test = start_jack(context, params)))
234 stream = av_new_stream(context, 0);
237 return AVERROR(ENOMEM);
240 stream->codec->codec_type = AVMEDIA_TYPE_AUDIO;
242 stream->codec->codec_id = CODEC_ID_PCM_F32BE;
244 stream->codec->codec_id = CODEC_ID_PCM_F32LE;
246 stream->codec->sample_rate = self->sample_rate;
247 stream->codec->channels = self->nports;
249 av_set_pts_info(stream, 64, 1, 1000000); /* 64 bits pts in us */
253 static int audio_read_packet(AVFormatContext *context, AVPacket *pkt)
255 JackData *self = context->priv_data;
256 struct timespec timeout = {0, 0};
259 /* Activate the JACK client on first packet read. Activating the JACK client
260 * means that process_callback() starts to get called at regular interval.
261 * If we activate it in audio_read_header(), we're actually reading audio data
262 * from the device before instructed to, and that may result in an overrun. */
263 if (!self->activated) {
264 if (!jack_activate(self->client)) {
266 av_log(context, AV_LOG_INFO,
267 "JACK client registered and activated (rate=%dHz, buffer_size=%d frames)\n",
268 self->sample_rate, self->buffer_size);
270 av_log(context, AV_LOG_ERROR, "Unable to activate JACK client\n");
275 /* Wait for a packet comming back from process_callback(), if one isn't available yet */
276 timeout.tv_sec = av_gettime() / 1000000 + 2;
277 if (sem_timedwait(&self->packet_count, &timeout)) {
278 if (errno == ETIMEDOUT) {
279 av_log(context, AV_LOG_ERROR,
280 "Input error: timed out when waiting for JACK process callback output\n");
282 av_log(context, AV_LOG_ERROR, "Error while waiting for audio packet: %s\n",
286 av_log(context, AV_LOG_ERROR, "Input error: JACK server is gone\n");
291 if (self->pkt_xrun) {
292 av_log(context, AV_LOG_WARNING, "Audio packet xrun\n");
296 if (self->jack_xrun) {
297 av_log(context, AV_LOG_WARNING, "JACK xrun\n");
301 /* Retrieve the packet filled with audio data by process_callback() */
302 av_fifo_generic_read(self->filled_pkts, pkt, sizeof(*pkt), NULL);
304 if ((test = supply_new_packets(self, context)))
310 static int audio_read_close(AVFormatContext *context)
312 JackData *self = context->priv_data;
317 AVInputFormat ff_jack_demuxer = {
319 NULL_IF_CONFIG_SMALL("JACK Audio Connection Kit"),
325 .flags = AVFMT_NOFILE,