libavdevice/jack_audio.c
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00001 /*
00002  * JACK Audio Connection Kit input device
00003  * Copyright (c) 2009 Samalyse
00004  * Author: Olivier Guilyardi <olivier samalyse com>
00005  *
00006  * This file is part of Libav.
00007  *
00008  * Libav is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * Libav is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with Libav; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00023 #include "config.h"
00024 #include <semaphore.h>
00025 #include <jack/jack.h>
00026 
00027 #include "libavutil/log.h"
00028 #include "libavutil/fifo.h"
00029 #include "libavutil/opt.h"
00030 #include "libavcodec/avcodec.h"
00031 #include "libavformat/avformat.h"
00032 #include "libavformat/internal.h"
00033 #include "timefilter.h"
00034 
00038 #define FIFO_PACKETS_NUM 16
00039 
00040 typedef struct {
00041     AVClass        *class;
00042     jack_client_t * client;
00043     int             activated;
00044     sem_t           packet_count;
00045     jack_nframes_t  sample_rate;
00046     jack_nframes_t  buffer_size;
00047     jack_port_t **  ports;
00048     int             nports;
00049     TimeFilter *    timefilter;
00050     AVFifoBuffer *  new_pkts;
00051     AVFifoBuffer *  filled_pkts;
00052     int             pkt_xrun;
00053     int             jack_xrun;
00054 } JackData;
00055 
00056 static int process_callback(jack_nframes_t nframes, void *arg)
00057 {
00058     /* Warning: this function runs in realtime. One mustn't allocate memory here
00059      * or do any other thing that could block. */
00060 
00061     int i, j;
00062     JackData *self = arg;
00063     float * buffer;
00064     jack_nframes_t latency, cycle_delay;
00065     AVPacket pkt;
00066     float *pkt_data;
00067     double cycle_time;
00068 
00069     if (!self->client)
00070         return 0;
00071 
00072     /* The approximate delay since the hardware interrupt as a number of frames */
00073     cycle_delay = jack_frames_since_cycle_start(self->client);
00074 
00075     /* Retrieve filtered cycle time */
00076     cycle_time = ff_timefilter_update(self->timefilter,
00077                                       av_gettime() / 1000000.0 - (double) cycle_delay / self->sample_rate,
00078                                       self->buffer_size);
00079 
00080     /* Check if an empty packet is available, and if there's enough space to send it back once filled */
00081     if ((av_fifo_size(self->new_pkts) < sizeof(pkt)) || (av_fifo_space(self->filled_pkts) < sizeof(pkt))) {
00082         self->pkt_xrun = 1;
00083         return 0;
00084     }
00085 
00086     /* Retrieve empty (but allocated) packet */
00087     av_fifo_generic_read(self->new_pkts, &pkt, sizeof(pkt), NULL);
00088 
00089     pkt_data  = (float *) pkt.data;
00090     latency   = 0;
00091 
00092     /* Copy and interleave audio data from the JACK buffer into the packet */
00093     for (i = 0; i < self->nports; i++) {
00094         latency += jack_port_get_total_latency(self->client, self->ports[i]);
00095         buffer = jack_port_get_buffer(self->ports[i], self->buffer_size);
00096         for (j = 0; j < self->buffer_size; j++)
00097             pkt_data[j * self->nports + i] = buffer[j];
00098     }
00099 
00100     /* Timestamp the packet with the cycle start time minus the average latency */
00101     pkt.pts = (cycle_time - (double) latency / (self->nports * self->sample_rate)) * 1000000.0;
00102 
00103     /* Send the now filled packet back, and increase packet counter */
00104     av_fifo_generic_write(self->filled_pkts, &pkt, sizeof(pkt), NULL);
00105     sem_post(&self->packet_count);
00106 
00107     return 0;
00108 }
00109 
00110 static void shutdown_callback(void *arg)
00111 {
00112     JackData *self = arg;
00113     self->client = NULL;
00114 }
00115 
00116 static int xrun_callback(void *arg)
00117 {
00118     JackData *self = arg;
00119     self->jack_xrun = 1;
00120     ff_timefilter_reset(self->timefilter);
00121     return 0;
00122 }
00123 
00124 static int supply_new_packets(JackData *self, AVFormatContext *context)
00125 {
00126     AVPacket pkt;
00127     int test, pkt_size = self->buffer_size * self->nports * sizeof(float);
00128 
00129     /* Supply the process callback with new empty packets, by filling the new
00130      * packets FIFO buffer with as many packets as possible. process_callback()
00131      * can't do this by itself, because it can't allocate memory in realtime. */
00132     while (av_fifo_space(self->new_pkts) >= sizeof(pkt)) {
00133         if ((test = av_new_packet(&pkt, pkt_size)) < 0) {
00134             av_log(context, AV_LOG_ERROR, "Could not create packet of size %d\n", pkt_size);
00135             return test;
00136         }
00137         av_fifo_generic_write(self->new_pkts, &pkt, sizeof(pkt), NULL);
00138     }
00139     return 0;
00140 }
00141 
00142 static int start_jack(AVFormatContext *context)
00143 {
00144     JackData *self = context->priv_data;
00145     jack_status_t status;
00146     int i, test;
00147     double o, period;
00148 
00149     /* Register as a JACK client, using the context filename as client name. */
00150     self->client = jack_client_open(context->filename, JackNullOption, &status);
00151     if (!self->client) {
00152         av_log(context, AV_LOG_ERROR, "Unable to register as a JACK client\n");
00153         return AVERROR(EIO);
00154     }
00155 
00156     sem_init(&self->packet_count, 0, 0);
00157 
00158     self->sample_rate = jack_get_sample_rate(self->client);
00159     self->ports       = av_malloc(self->nports * sizeof(*self->ports));
00160     self->buffer_size = jack_get_buffer_size(self->client);
00161 
00162     /* Register JACK ports */
00163     for (i = 0; i < self->nports; i++) {
00164         char str[16];
00165         snprintf(str, sizeof(str), "input_%d", i + 1);
00166         self->ports[i] = jack_port_register(self->client, str,
00167                                             JACK_DEFAULT_AUDIO_TYPE,
00168                                             JackPortIsInput, 0);
00169         if (!self->ports[i]) {
00170             av_log(context, AV_LOG_ERROR, "Unable to register port %s:%s\n",
00171                    context->filename, str);
00172             jack_client_close(self->client);
00173             return AVERROR(EIO);
00174         }
00175     }
00176 
00177     /* Register JACK callbacks */
00178     jack_set_process_callback(self->client, process_callback, self);
00179     jack_on_shutdown(self->client, shutdown_callback, self);
00180     jack_set_xrun_callback(self->client, xrun_callback, self);
00181 
00182     /* Create time filter */
00183     period            = (double) self->buffer_size / self->sample_rate;
00184     o                 = 2 * M_PI * 1.5 * period; 
00185     self->timefilter  = ff_timefilter_new (1.0 / self->sample_rate, sqrt(2 * o), o * o);
00186 
00187     /* Create FIFO buffers */
00188     self->filled_pkts = av_fifo_alloc(FIFO_PACKETS_NUM * sizeof(AVPacket));
00189     /* New packets FIFO with one extra packet for safety against underruns */
00190     self->new_pkts    = av_fifo_alloc((FIFO_PACKETS_NUM + 1) * sizeof(AVPacket));
00191     if ((test = supply_new_packets(self, context))) {
00192         jack_client_close(self->client);
00193         return test;
00194     }
00195 
00196     return 0;
00197 
00198 }
00199 
00200 static void free_pkt_fifo(AVFifoBuffer *fifo)
00201 {
00202     AVPacket pkt;
00203     while (av_fifo_size(fifo)) {
00204         av_fifo_generic_read(fifo, &pkt, sizeof(pkt), NULL);
00205         av_free_packet(&pkt);
00206     }
00207     av_fifo_free(fifo);
00208 }
00209 
00210 static void stop_jack(JackData *self)
00211 {
00212     if (self->client) {
00213         if (self->activated)
00214             jack_deactivate(self->client);
00215         jack_client_close(self->client);
00216     }
00217     sem_destroy(&self->packet_count);
00218     free_pkt_fifo(self->new_pkts);
00219     free_pkt_fifo(self->filled_pkts);
00220     av_freep(&self->ports);
00221     ff_timefilter_destroy(self->timefilter);
00222 }
00223 
00224 static int audio_read_header(AVFormatContext *context, AVFormatParameters *params)
00225 {
00226     JackData *self = context->priv_data;
00227     AVStream *stream;
00228     int test;
00229 
00230     if ((test = start_jack(context)))
00231         return test;
00232 
00233     stream = avformat_new_stream(context, NULL);
00234     if (!stream) {
00235         stop_jack(self);
00236         return AVERROR(ENOMEM);
00237     }
00238 
00239     stream->codec->codec_type   = AVMEDIA_TYPE_AUDIO;
00240 #if HAVE_BIGENDIAN
00241     stream->codec->codec_id     = CODEC_ID_PCM_F32BE;
00242 #else
00243     stream->codec->codec_id     = CODEC_ID_PCM_F32LE;
00244 #endif
00245     stream->codec->sample_rate  = self->sample_rate;
00246     stream->codec->channels     = self->nports;
00247 
00248     avpriv_set_pts_info(stream, 64, 1, 1000000);  /* 64 bits pts in us */
00249     return 0;
00250 }
00251 
00252 static int audio_read_packet(AVFormatContext *context, AVPacket *pkt)
00253 {
00254     JackData *self = context->priv_data;
00255     struct timespec timeout = {0, 0};
00256     int test;
00257 
00258     /* Activate the JACK client on first packet read. Activating the JACK client
00259      * means that process_callback() starts to get called at regular interval.
00260      * If we activate it in audio_read_header(), we're actually reading audio data
00261      * from the device before instructed to, and that may result in an overrun. */
00262     if (!self->activated) {
00263         if (!jack_activate(self->client)) {
00264             self->activated = 1;
00265             av_log(context, AV_LOG_INFO,
00266                    "JACK client registered and activated (rate=%dHz, buffer_size=%d frames)\n",
00267                    self->sample_rate, self->buffer_size);
00268         } else {
00269             av_log(context, AV_LOG_ERROR, "Unable to activate JACK client\n");
00270             return AVERROR(EIO);
00271         }
00272     }
00273 
00274     /* Wait for a packet coming back from process_callback(), if one isn't available yet */
00275     timeout.tv_sec = av_gettime() / 1000000 + 2;
00276     if (sem_timedwait(&self->packet_count, &timeout)) {
00277         if (errno == ETIMEDOUT) {
00278             av_log(context, AV_LOG_ERROR,
00279                    "Input error: timed out when waiting for JACK process callback output\n");
00280         } else {
00281             av_log(context, AV_LOG_ERROR, "Error while waiting for audio packet: %s\n",
00282                    strerror(errno));
00283         }
00284         if (!self->client)
00285             av_log(context, AV_LOG_ERROR, "Input error: JACK server is gone\n");
00286 
00287         return AVERROR(EIO);
00288     }
00289 
00290     if (self->pkt_xrun) {
00291         av_log(context, AV_LOG_WARNING, "Audio packet xrun\n");
00292         self->pkt_xrun = 0;
00293     }
00294 
00295     if (self->jack_xrun) {
00296         av_log(context, AV_LOG_WARNING, "JACK xrun\n");
00297         self->jack_xrun = 0;
00298     }
00299 
00300     /* Retrieve the packet filled with audio data by process_callback() */
00301     av_fifo_generic_read(self->filled_pkts, pkt, sizeof(*pkt), NULL);
00302 
00303     if ((test = supply_new_packets(self, context)))
00304         return test;
00305 
00306     return 0;
00307 }
00308 
00309 static int audio_read_close(AVFormatContext *context)
00310 {
00311     JackData *self = context->priv_data;
00312     stop_jack(self);
00313     return 0;
00314 }
00315 
00316 #define OFFSET(x) offsetof(JackData, x)
00317 static const AVOption options[] = {
00318     { "channels", "Number of audio channels.", OFFSET(nports), AV_OPT_TYPE_INT, { 2 }, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
00319     { NULL },
00320 };
00321 
00322 static const AVClass jack_indev_class = {
00323     .class_name     = "JACK indev",
00324     .item_name      = av_default_item_name,
00325     .option         = options,
00326     .version        = LIBAVUTIL_VERSION_INT,
00327 };
00328 
00329 AVInputFormat ff_jack_demuxer = {
00330     .name           = "jack",
00331     .long_name      = NULL_IF_CONFIG_SMALL("JACK Audio Connection Kit"),
00332     .priv_data_size = sizeof(JackData),
00333     .read_header    = audio_read_header,
00334     .read_packet    = audio_read_packet,
00335     .read_close     = audio_read_close,
00336     .flags          = AVFMT_NOFILE,
00337     .priv_class     = &jack_indev_class,
00338 };