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 FFmpeg.
00007  *
00008  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 #include "avdevice.h"
00035 
00039 #define FIFO_PACKETS_NUM 16
00040 
00041 typedef struct {
00042     AVClass        *class;
00043     jack_client_t * client;
00044     int             activated;
00045     sem_t           packet_count;
00046     jack_nframes_t  sample_rate;
00047     jack_nframes_t  buffer_size;
00048     jack_port_t **  ports;
00049     int             nports;
00050     TimeFilter *    timefilter;
00051     AVFifoBuffer *  new_pkts;
00052     AVFifoBuffer *  filled_pkts;
00053     int             pkt_xrun;
00054     int             jack_xrun;
00055 } JackData;
00056 
00057 static int process_callback(jack_nframes_t nframes, void *arg)
00058 {
00059     /* Warning: this function runs in realtime. One mustn't allocate memory here
00060      * or do any other thing that could block. */
00061 
00062     int i, j;
00063     JackData *self = arg;
00064     float * buffer;
00065     jack_nframes_t latency, cycle_delay;
00066     AVPacket pkt;
00067     float *pkt_data;
00068     double cycle_time;
00069 
00070     if (!self->client)
00071         return 0;
00072 
00073     /* The approximate delay since the hardware interrupt as a number of frames */
00074     cycle_delay = jack_frames_since_cycle_start(self->client);
00075 
00076     /* Retrieve filtered cycle time */
00077     cycle_time = ff_timefilter_update(self->timefilter,
00078                                       av_gettime() / 1000000.0 - (double) cycle_delay / self->sample_rate,
00079                                       self->buffer_size);
00080 
00081     /* Check if an empty packet is available, and if there's enough space to send it back once filled */
00082     if ((av_fifo_size(self->new_pkts) < sizeof(pkt)) || (av_fifo_space(self->filled_pkts) < sizeof(pkt))) {
00083         self->pkt_xrun = 1;
00084         return 0;
00085     }
00086 
00087     /* Retrieve empty (but allocated) packet */
00088     av_fifo_generic_read(self->new_pkts, &pkt, sizeof(pkt), NULL);
00089 
00090     pkt_data  = (float *) pkt.data;
00091     latency   = 0;
00092 
00093     /* Copy and interleave audio data from the JACK buffer into the packet */
00094     for (i = 0; i < self->nports; i++) {
00095         latency += jack_port_get_total_latency(self->client, self->ports[i]);
00096         buffer = jack_port_get_buffer(self->ports[i], self->buffer_size);
00097         for (j = 0; j < self->buffer_size; j++)
00098             pkt_data[j * self->nports + i] = buffer[j];
00099     }
00100 
00101     /* Timestamp the packet with the cycle start time minus the average latency */
00102     pkt.pts = (cycle_time - (double) latency / (self->nports * self->sample_rate)) * 1000000.0;
00103 
00104     /* Send the now filled packet back, and increase packet counter */
00105     av_fifo_generic_write(self->filled_pkts, &pkt, sizeof(pkt), NULL);
00106     sem_post(&self->packet_count);
00107 
00108     return 0;
00109 }
00110 
00111 static void shutdown_callback(void *arg)
00112 {
00113     JackData *self = arg;
00114     self->client = NULL;
00115 }
00116 
00117 static int xrun_callback(void *arg)
00118 {
00119     JackData *self = arg;
00120     self->jack_xrun = 1;
00121     ff_timefilter_reset(self->timefilter);
00122     return 0;
00123 }
00124 
00125 static int supply_new_packets(JackData *self, AVFormatContext *context)
00126 {
00127     AVPacket pkt;
00128     int test, pkt_size = self->buffer_size * self->nports * sizeof(float);
00129 
00130     /* Supply the process callback with new empty packets, by filling the new
00131      * packets FIFO buffer with as many packets as possible. process_callback()
00132      * can't do this by itself, because it can't allocate memory in realtime. */
00133     while (av_fifo_space(self->new_pkts) >= sizeof(pkt)) {
00134         if ((test = av_new_packet(&pkt, pkt_size)) < 0) {
00135             av_log(context, AV_LOG_ERROR, "Could not create packet of size %d\n", pkt_size);
00136             return test;
00137         }
00138         av_fifo_generic_write(self->new_pkts, &pkt, sizeof(pkt), NULL);
00139     }
00140     return 0;
00141 }
00142 
00143 static int start_jack(AVFormatContext *context)
00144 {
00145     JackData *self = context->priv_data;
00146     jack_status_t status;
00147     int i, test;
00148     double o, period;
00149 
00150     /* Register as a JACK client, using the context filename as client name. */
00151     self->client = jack_client_open(context->filename, JackNullOption, &status);
00152     if (!self->client) {
00153         av_log(context, AV_LOG_ERROR, "Unable to register as a JACK client\n");
00154         return AVERROR(EIO);
00155     }
00156 
00157     sem_init(&self->packet_count, 0, 0);
00158 
00159     self->sample_rate = jack_get_sample_rate(self->client);
00160     self->ports       = av_malloc(self->nports * sizeof(*self->ports));
00161     self->buffer_size = jack_get_buffer_size(self->client);
00162 
00163     /* Register JACK ports */
00164     for (i = 0; i < self->nports; i++) {
00165         char str[16];
00166         snprintf(str, sizeof(str), "input_%d", i + 1);
00167         self->ports[i] = jack_port_register(self->client, str,
00168                                             JACK_DEFAULT_AUDIO_TYPE,
00169                                             JackPortIsInput, 0);
00170         if (!self->ports[i]) {
00171             av_log(context, AV_LOG_ERROR, "Unable to register port %s:%s\n",
00172                    context->filename, str);
00173             jack_client_close(self->client);
00174             return AVERROR(EIO);
00175         }
00176     }
00177 
00178     /* Register JACK callbacks */
00179     jack_set_process_callback(self->client, process_callback, self);
00180     jack_on_shutdown(self->client, shutdown_callback, self);
00181     jack_set_xrun_callback(self->client, xrun_callback, self);
00182 
00183     /* Create time filter */
00184     period            = (double) self->buffer_size / self->sample_rate;
00185     o                 = 2 * M_PI * 1.5 * period; 
00186     self->timefilter  = ff_timefilter_new (1.0 / self->sample_rate, sqrt(2 * o), o * o);
00187 
00188     /* Create FIFO buffers */
00189     self->filled_pkts = av_fifo_alloc(FIFO_PACKETS_NUM * sizeof(AVPacket));
00190     /* New packets FIFO with one extra packet for safety against underruns */
00191     self->new_pkts    = av_fifo_alloc((FIFO_PACKETS_NUM + 1) * sizeof(AVPacket));
00192     if ((test = supply_new_packets(self, context))) {
00193         jack_client_close(self->client);
00194         return test;
00195     }
00196 
00197     return 0;
00198 
00199 }
00200 
00201 static void free_pkt_fifo(AVFifoBuffer *fifo)
00202 {
00203     AVPacket pkt;
00204     while (av_fifo_size(fifo)) {
00205         av_fifo_generic_read(fifo, &pkt, sizeof(pkt), NULL);
00206         av_free_packet(&pkt);
00207     }
00208     av_fifo_free(fifo);
00209 }
00210 
00211 static void stop_jack(JackData *self)
00212 {
00213     if (self->client) {
00214         if (self->activated)
00215             jack_deactivate(self->client);
00216         jack_client_close(self->client);
00217     }
00218     sem_destroy(&self->packet_count);
00219     free_pkt_fifo(self->new_pkts);
00220     free_pkt_fifo(self->filled_pkts);
00221     av_freep(&self->ports);
00222     ff_timefilter_destroy(self->timefilter);
00223 }
00224 
00225 static int audio_read_header(AVFormatContext *context, AVFormatParameters *params)
00226 {
00227     JackData *self = context->priv_data;
00228     AVStream *stream;
00229     int test;
00230 
00231     if ((test = start_jack(context)))
00232         return test;
00233 
00234     stream = avformat_new_stream(context, NULL);
00235     if (!stream) {
00236         stop_jack(self);
00237         return AVERROR(ENOMEM);
00238     }
00239 
00240     stream->codec->codec_type   = AVMEDIA_TYPE_AUDIO;
00241 #if HAVE_BIGENDIAN
00242     stream->codec->codec_id     = CODEC_ID_PCM_F32BE;
00243 #else
00244     stream->codec->codec_id     = CODEC_ID_PCM_F32LE;
00245 #endif
00246     stream->codec->sample_rate  = self->sample_rate;
00247     stream->codec->channels     = self->nports;
00248 
00249     avpriv_set_pts_info(stream, 64, 1, 1000000);  /* 64 bits pts in us */
00250     return 0;
00251 }
00252 
00253 static int audio_read_packet(AVFormatContext *context, AVPacket *pkt)
00254 {
00255     JackData *self = context->priv_data;
00256     struct timespec timeout = {0, 0};
00257     int test;
00258 
00259     /* Activate the JACK client on first packet read. Activating the JACK client
00260      * means that process_callback() starts to get called at regular interval.
00261      * If we activate it in audio_read_header(), we're actually reading audio data
00262      * from the device before instructed to, and that may result in an overrun. */
00263     if (!self->activated) {
00264         if (!jack_activate(self->client)) {
00265             self->activated = 1;
00266             av_log(context, AV_LOG_INFO,
00267                    "JACK client registered and activated (rate=%dHz, buffer_size=%d frames)\n",
00268                    self->sample_rate, self->buffer_size);
00269         } else {
00270             av_log(context, AV_LOG_ERROR, "Unable to activate JACK client\n");
00271             return AVERROR(EIO);
00272         }
00273     }
00274 
00275     /* Wait for a packet coming back from process_callback(), if one isn't available yet */
00276     timeout.tv_sec = av_gettime() / 1000000 + 2;
00277     if (sem_timedwait(&self->packet_count, &timeout)) {
00278         if (errno == ETIMEDOUT) {
00279             av_log(context, AV_LOG_ERROR,
00280                    "Input error: timed out when waiting for JACK process callback output\n");
00281         } else {
00282             av_log(context, AV_LOG_ERROR, "Error while waiting for audio packet: %s\n",
00283                    strerror(errno));
00284         }
00285         if (!self->client)
00286             av_log(context, AV_LOG_ERROR, "Input error: JACK server is gone\n");
00287 
00288         return AVERROR(EIO);
00289     }
00290 
00291     if (self->pkt_xrun) {
00292         av_log(context, AV_LOG_WARNING, "Audio packet xrun\n");
00293         self->pkt_xrun = 0;
00294     }
00295 
00296     if (self->jack_xrun) {
00297         av_log(context, AV_LOG_WARNING, "JACK xrun\n");
00298         self->jack_xrun = 0;
00299     }
00300 
00301     /* Retrieve the packet filled with audio data by process_callback() */
00302     av_fifo_generic_read(self->filled_pkts, pkt, sizeof(*pkt), NULL);
00303 
00304     if ((test = supply_new_packets(self, context)))
00305         return test;
00306 
00307     return 0;
00308 }
00309 
00310 static int audio_read_close(AVFormatContext *context)
00311 {
00312     JackData *self = context->priv_data;
00313     stop_jack(self);
00314     return 0;
00315 }
00316 
00317 #define OFFSET(x) offsetof(JackData, x)
00318 static const AVOption options[] = {
00319     { "channels", "Number of audio channels.", OFFSET(nports), AV_OPT_TYPE_INT, { 2 }, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
00320     { NULL },
00321 };
00322 
00323 static const AVClass jack_indev_class = {
00324     .class_name     = "JACK indev",
00325     .item_name      = av_default_item_name,
00326     .option         = options,
00327     .version        = LIBAVUTIL_VERSION_INT,
00328 };
00329 
00330 AVInputFormat ff_jack_demuxer = {
00331     .name           = "jack",
00332     .long_name      = NULL_IF_CONFIG_SMALL("JACK Audio Connection Kit"),
00333     .priv_data_size = sizeof(JackData),
00334     .read_header    = audio_read_header,
00335     .read_packet    = audio_read_packet,
00336     .read_close     = audio_read_close,
00337     .flags          = AVFMT_NOFILE,
00338     .priv_class     = &jack_indev_class,
00339 };