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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 "libavcodec/avcodec.h"
00030 #include "libavformat/avformat.h"
00031 #include "libavformat/timefilter.h"
00032 
00036 #define FIFO_PACKETS_NUM 16
00037 
00038 typedef struct {
00039     jack_client_t * client;
00040     int             activated;
00041     sem_t           packet_count;
00042     jack_nframes_t  sample_rate;
00043     jack_nframes_t  buffer_size;
00044     jack_port_t **  ports;
00045     int             nports;
00046     TimeFilter *    timefilter;
00047     AVFifoBuffer *  new_pkts;
00048     AVFifoBuffer *  filled_pkts;
00049     int             pkt_xrun;
00050     int             jack_xrun;
00051 } JackData;
00052 
00053 static int process_callback(jack_nframes_t nframes, void *arg)
00054 {
00055     /* Warning: this function runs in realtime. One mustn't allocate memory here
00056      * or do any other thing that could block. */
00057 
00058     int i, j;
00059     JackData *self = arg;
00060     float * buffer;
00061     jack_nframes_t latency, cycle_delay;
00062     AVPacket pkt;
00063     float *pkt_data;
00064     double cycle_time;
00065 
00066     if (!self->client)
00067         return 0;
00068 
00069     /* The approximate delay since the hardware interrupt as a number of frames */
00070     cycle_delay = jack_frames_since_cycle_start(self->client);
00071 
00072     /* Retrieve filtered cycle time */
00073     cycle_time = ff_timefilter_update(self->timefilter,
00074                                       av_gettime() / 1000000.0 - (double) cycle_delay / self->sample_rate,
00075                                       self->buffer_size);
00076 
00077     /* Check if an empty packet is available, and if there's enough space to send it back once filled */
00078     if ((av_fifo_size(self->new_pkts) < sizeof(pkt)) || (av_fifo_space(self->filled_pkts) < sizeof(pkt))) {
00079         self->pkt_xrun = 1;
00080         return 0;
00081     }
00082 
00083     /* Retrieve empty (but allocated) packet */
00084     av_fifo_generic_read(self->new_pkts, &pkt, sizeof(pkt), NULL);
00085 
00086     pkt_data  = (float *) pkt.data;
00087     latency   = 0;
00088 
00089     /* Copy and interleave audio data from the JACK buffer into the packet */
00090     for (i = 0; i < self->nports; i++) {
00091         latency += jack_port_get_total_latency(self->client, self->ports[i]);
00092         buffer = jack_port_get_buffer(self->ports[i], self->buffer_size);
00093         for (j = 0; j < self->buffer_size; j++)
00094             pkt_data[j * self->nports + i] = buffer[j];
00095     }
00096 
00097     /* Timestamp the packet with the cycle start time minus the average latency */
00098     pkt.pts = (cycle_time - (double) latency / (self->nports * self->sample_rate)) * 1000000.0;
00099 
00100     /* Send the now filled packet back, and increase packet counter */
00101     av_fifo_generic_write(self->filled_pkts, &pkt, sizeof(pkt), NULL);
00102     sem_post(&self->packet_count);
00103 
00104     return 0;
00105 }
00106 
00107 static void shutdown_callback(void *arg)
00108 {
00109     JackData *self = arg;
00110     self->client = NULL;
00111 }
00112 
00113 static int xrun_callback(void *arg)
00114 {
00115     JackData *self = arg;
00116     self->jack_xrun = 1;
00117     ff_timefilter_reset(self->timefilter);
00118     return 0;
00119 }
00120 
00121 static int supply_new_packets(JackData *self, AVFormatContext *context)
00122 {
00123     AVPacket pkt;
00124     int test, pkt_size = self->buffer_size * self->nports * sizeof(float);
00125 
00126     /* Supply the process callback with new empty packets, by filling the new
00127      * packets FIFO buffer with as many packets as possible. process_callback()
00128      * can't do this by itself, because it can't allocate memory in realtime. */
00129     while (av_fifo_space(self->new_pkts) >= sizeof(pkt)) {
00130         if ((test = av_new_packet(&pkt, pkt_size)) < 0) {
00131             av_log(context, AV_LOG_ERROR, "Could not create packet of size %d\n", pkt_size);
00132             return test;
00133         }
00134         av_fifo_generic_write(self->new_pkts, &pkt, sizeof(pkt), NULL);
00135     }
00136     return 0;
00137 }
00138 
00139 static int start_jack(AVFormatContext *context, AVFormatParameters *params)
00140 {
00141     JackData *self = context->priv_data;
00142     jack_status_t status;
00143     int i, test;
00144     double o, period;
00145 
00146     /* Register as a JACK client, using the context filename as client name. */
00147     self->client = jack_client_open(context->filename, JackNullOption, &status);
00148     if (!self->client) {
00149         av_log(context, AV_LOG_ERROR, "Unable to register as a JACK client\n");
00150         return AVERROR(EIO);
00151     }
00152 
00153     sem_init(&self->packet_count, 0, 0);
00154 
00155     self->sample_rate = jack_get_sample_rate(self->client);
00156     self->nports      = params->channels;
00157     self->ports       = av_malloc(self->nports * sizeof(*self->ports));
00158     self->buffer_size = jack_get_buffer_size(self->client);
00159 
00160     /* Register JACK ports */
00161     for (i = 0; i < self->nports; i++) {
00162         char str[16];
00163         snprintf(str, sizeof(str), "input_%d", i + 1);
00164         self->ports[i] = jack_port_register(self->client, str,
00165                                             JACK_DEFAULT_AUDIO_TYPE,
00166                                             JackPortIsInput, 0);
00167         if (!self->ports[i]) {
00168             av_log(context, AV_LOG_ERROR, "Unable to register port %s:%s\n",
00169                    context->filename, str);
00170             jack_client_close(self->client);
00171             return AVERROR(EIO);
00172         }
00173     }
00174 
00175     /* Register JACK callbacks */
00176     jack_set_process_callback(self->client, process_callback, self);
00177     jack_on_shutdown(self->client, shutdown_callback, self);
00178     jack_set_xrun_callback(self->client, xrun_callback, self);
00179 
00180     /* Create time filter */
00181     period            = (double) self->buffer_size / self->sample_rate;
00182     o                 = 2 * M_PI * 1.5 * period; 
00183     self->timefilter  = ff_timefilter_new (1.0 / self->sample_rate, sqrt(2 * o), o * o);
00184 
00185     /* Create FIFO buffers */
00186     self->filled_pkts = av_fifo_alloc(FIFO_PACKETS_NUM * sizeof(AVPacket));
00187     /* New packets FIFO with one extra packet for safety against underruns */
00188     self->new_pkts    = av_fifo_alloc((FIFO_PACKETS_NUM + 1) * sizeof(AVPacket));
00189     if ((test = supply_new_packets(self, context))) {
00190         jack_client_close(self->client);
00191         return test;
00192     }
00193 
00194     return 0;
00195 
00196 }
00197 
00198 static void free_pkt_fifo(AVFifoBuffer *fifo)
00199 {
00200     AVPacket pkt;
00201     while (av_fifo_size(fifo)) {
00202         av_fifo_generic_read(fifo, &pkt, sizeof(pkt), NULL);
00203         av_free_packet(&pkt);
00204     }
00205     av_fifo_free(fifo);
00206 }
00207 
00208 static void stop_jack(JackData *self)
00209 {
00210     if (self->client) {
00211         if (self->activated)
00212             jack_deactivate(self->client);
00213         jack_client_close(self->client);
00214     }
00215     sem_destroy(&self->packet_count);
00216     free_pkt_fifo(self->new_pkts);
00217     free_pkt_fifo(self->filled_pkts);
00218     av_freep(&self->ports);
00219     ff_timefilter_destroy(self->timefilter);
00220 }
00221 
00222 static int audio_read_header(AVFormatContext *context, AVFormatParameters *params)
00223 {
00224     JackData *self = context->priv_data;
00225     AVStream *stream;
00226     int test;
00227 
00228     if (params->sample_rate <= 0 || params->channels <= 0)
00229         return -1;
00230 
00231     if ((test = start_jack(context, params)))
00232         return test;
00233 
00234     stream = av_new_stream(context, 0);
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     av_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 comming 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 AVInputFormat jack_demuxer = {
00318     "jack",
00319     NULL_IF_CONFIG_SMALL("JACK Audio Connection Kit"),
00320     sizeof(JackData),
00321     NULL,
00322     audio_read_header,
00323     audio_read_packet,
00324     audio_read_close,
00325     .flags = AVFMT_NOFILE,
00326 };

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