Initial working implementation of jack out device

Signed-off-by: falkTX <falktx@falktx.com>

configure

@@ -3421,6 +3421,7 @@ gdigrab_indev_select="bmp_decoder"
 iec61883_indev_deps="libiec61883"
 jack_indev_deps="libjack"
 jack_indev_deps_any="sem_timedwait dispatch_dispatch_h"
+jack_outdev_deps="libjack"
 kmsgrab_indev_deps="libdrm"
 lavfi_indev_deps="avfilter"
 libcdio_indev_deps="libcdio"

libavdevice/Makefile

@@ -31,6 +31,7 @@ OBJS-$(CONFIG_FBDEV_OUTDEV)              += fbdev_enc.o \
 OBJS-$(CONFIG_GDIGRAB_INDEV)             += gdigrab.o
 OBJS-$(CONFIG_IEC61883_INDEV)            += iec61883.o
 OBJS-$(CONFIG_JACK_INDEV)                += jack.o timefilter.o
+OBJS-$(CONFIG_JACK_OUTDEV)               += jack_enc.o
 OBJS-$(CONFIG_KMSGRAB_INDEV)             += kmsgrab.o
 OBJS-$(CONFIG_LAVFI_INDEV)               += lavfi.o
 OBJS-$(CONFIG_OPENAL_INDEV)              += openal-dec.o

libavdevice/alldevices.c

@@ -39,6 +39,7 @@ extern AVOutputFormat ff_fbdev_muxer;
 extern AVInputFormat  ff_gdigrab_demuxer;
 extern AVInputFormat  ff_iec61883_demuxer;
 extern AVInputFormat  ff_jack_demuxer;
+extern AVOutputFormat ff_jack_muxer;
 extern AVInputFormat  ff_kmsgrab_demuxer;
 extern AVInputFormat  ff_lavfi_demuxer;
 extern AVInputFormat  ff_openal_demuxer;

libavdevice/jack_enc.c

@@ -0,0 +1,312 @@
+/*
+ * JACK Audio Connection Kit input device
+ * Copyright (c) 2021 falkTX
+ * Author: Filipe Coelho <falktx@falktx.com>
+ * Based on jack.c by Olivier Guilyardi <olivier samalyse com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "config.h"
+#include <semaphore.h>
+#include <jack/jack.h>
+#include <jack/ringbuffer.h>
+
+#include "libavutil/fifo.h"
+#include "libavutil/time.h"
+#include "libavformat/avformat.h"
+#include "libavformat/internal.h"
+#include "avdevice.h"
+
+/**
+ * Maximum number of "packets" of audio to queue in ringbuffer
+ */
+#define RINGBUFFER_NUM_PACKETS 8
+
+typedef struct JackData {
+    AVClass*           class;
+    jack_client_t*     client;
+    int                activated;
+    sem_t              packet_count;
+    jack_nframes_t     sample_rate;
+    jack_nframes_t     buffer_size;
+    jack_port_t **     ports;
+    int                nports;
+    AVFifoBuffer *     new_pkts;
+    int                pkt_xrun;
+    int                jack_xrun;
+    jack_nframes_t     audio_pkt_size;
+    float*             audio_pkt;
+    jack_ringbuffer_t* ringbuffer;
+} JackData;
+
+static int process_callback(jack_nframes_t nframes, void *arg)
+{
+    /* Warning: this function runs in realtime. One mustn't allocate memory here
+     * or do any other thing that could block. */
+
+    int i, j;
+    JackData *self = arg;
+    float* audio_pkt = self->audio_pkt;
+    float* buffer;
+
+    if (!self->client) {
+        return 0;
+    }
+
+    /* Check if audio is available */
+    if (jack_ringbuffer_read_space(self->ringbuffer) < self->audio_pkt_size) {
+        for (i = 0; i < self->nports; i++) {
+            buffer = jack_port_get_buffer(self->ports[i], nframes);
+            memset(buffer, 0, sizeof(float)*nframes);
+        }
+        self->pkt_xrun = 1;
+        return 0;
+    }
+
+    /* Retrieve audio */
+    jack_ringbuffer_read(self->ringbuffer, (char*)audio_pkt, self->audio_pkt_size);
+
+    /* Copy and interleave audio data from the packet into the JACK buffer */
+    for (i = 0; i < self->nports; i++) {
+        buffer = jack_port_get_buffer(self->ports[i], nframes);
+
+        for (j = 0; j < nframes; j++)
+            buffer[j] = audio_pkt[j * self->nports + i];
+    }
+
+    sem_post(&self->packet_count);
+    return 0;
+}
+
+static void shutdown_callback(void *arg)
+{
+    JackData *self = arg;
+    self->client = NULL;
+}
+
+static int xrun_callback(void *arg)
+{
+    JackData *self = arg;
+    self->jack_xrun = 1;
+    return 0;
+}
+
+static int start_jack(AVFormatContext *context)
+{
+    JackData *self = context->priv_data;
+    int i;
+
+    /* Register as a JACK client, using the context url as client name. */
+    self->client = jack_client_open(context->url, JackNullOption, NULL);
+    if (!self->client) {
+        av_log(context, AV_LOG_ERROR, "Unable to register as a JACK client\n");
+        return AVERROR(EIO);
+    }
+
+    self->ports = av_malloc_array(self->nports, sizeof(*self->ports));
+    if (!self->ports)
+        return AVERROR(ENOMEM);
+
+    self->sample_rate    = jack_get_sample_rate(self->client);
+    self->buffer_size    = jack_get_buffer_size(self->client);
+    self->audio_pkt_size = self->nports * self->buffer_size * sizeof(float);
+    self->ringbuffer     = jack_ringbuffer_create(self->audio_pkt_size * RINGBUFFER_NUM_PACKETS);
+
+    self->audio_pkt = av_malloc_array(self->audio_pkt_size, sizeof(float));
+    if (!self->audio_pkt) {
+        return AVERROR(ENOMEM);
+    }
+
+    sem_init(&self->packet_count, 0, 0);
+
+    /* Register JACK ports */
+    for (i = 0; i < self->nports; i++) {
+        char str[16];
+        snprintf(str, sizeof(str), "output_%d", i + 1);
+        self->ports[i] = jack_port_register(self->client, str,
+                                            JACK_DEFAULT_AUDIO_TYPE,
+                                            JackPortIsOutput, 0);
+        if (!self->ports[i]) {
+            av_log(context, AV_LOG_ERROR, "Unable to register port %s:%s\n",
+                   context->url, str);
+            jack_client_close(self->client);
+            return AVERROR(EIO);
+        }
+    }
+
+    /* Register JACK callbacks */
+    jack_set_process_callback(self->client, process_callback, self);
+    jack_on_shutdown(self->client, shutdown_callback, self);
+    jack_set_xrun_callback(self->client, xrun_callback, self);
+
+    return 0;
+}
+
+static void stop_jack(JackData *self)
+{
+    if (self->client) {
+        if (self->activated)
+            jack_deactivate(self->client);
+        jack_client_close(self->client);
+    }
+    sem_destroy(&self->packet_count);
+    av_freep(&self->audio_pkt);
+    av_freep(&self->ports);
+    jack_ringbuffer_free(self->ringbuffer);
+}
+
+static av_cold int audio_write_header(AVFormatContext *context)
+{
+    JackData *self = context->priv_data;
+    AVStream *stream = NULL;
+    int test;
+
+    if (context->nb_streams != 1 || context->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_AUDIO) {
+        av_log(stream, AV_LOG_ERROR, "Only a single audio stream is supported.\n");
+        return AVERROR(EINVAL);
+    }
+    stream = context->streams[0];
+
+    if ((test = start_jack(context)))
+        return test;
+
+    if (self->sample_rate != stream->codecpar->sample_rate) {
+        av_log(stream, AV_LOG_ERROR,
+               "sample rate %d not available, must use %d\n",
+               stream->codecpar->sample_rate, self->sample_rate);
+        stop_jack(self);
+        return AVERROR(EIO);
+    }
+
+    avpriv_set_pts_info(stream, 64, 1, 1000000);  /* 64 bits pts in us */
+    return 0;
+}
+
+static int audio_write_packet(AVFormatContext *context, AVPacket *pkt)
+{
+    JackData *self = context->priv_data;
+    struct timespec timeout = {0, 0};
+    int should_activate = 0;
+
+    /* Check packet size */
+    if (pkt->size > self->audio_pkt_size * (RINGBUFFER_NUM_PACKETS/2)) {
+        av_log(context, AV_LOG_ERROR, "Packet is too big! (%u)\n", pkt->size);
+        return AVERROR(EIO);
+    }
+
+    /* Check if there's enough space to send */
+    if (jack_ringbuffer_write_space(self->ringbuffer)+1 < pkt->size) {
+        av_log(context, AV_LOG_WARNING, "Audio source packet overrun, space left %lu\n",
+               jack_ringbuffer_write_space(self->ringbuffer));
+        if (!self->activated) {
+            should_activate = 1;
+        }
+    } else {
+        /* Write the packet to later be used by process_callback() */
+        jack_ringbuffer_write(self->ringbuffer, pkt->data, pkt->size);
+        if (!self->activated && jack_ringbuffer_write_space(self->ringbuffer)+1 >= pkt->size) {
+            should_activate = 1;
+        }
+    }
+
+    /* Activate the JACK client after a few packet writes. */
+    if (should_activate) {
+        if (!jack_activate(self->client)) {
+            self->activated = 1;
+            av_log(context, AV_LOG_INFO,
+                   "JACK client registered and activated (rate=%dHz, buffer_size=%d frames)\n",
+                   self->sample_rate, self->buffer_size);
+        } else {
+            av_log(context, AV_LOG_ERROR, "Unable to activate JACK client\n");
+            return AVERROR(EIO);
+        }
+    }
+
+    if (self->activated) {
+        timeout.tv_sec = av_gettime() / 1000000 + 2;
+
+        while (jack_ringbuffer_write_space(self->ringbuffer) < self->audio_pkt_size * (RINGBUFFER_NUM_PACKETS/2)) {
+            if (sem_timedwait(&self->packet_count, &timeout)) {
+                if (errno == ETIMEDOUT) {
+                    av_log(context, AV_LOG_ERROR,
+                           "Input error: timed out when waiting for JACK process callback input\n");
+                } else {
+                    char errbuf[128];
+                    int ret = AVERROR(errno);
+                    av_strerror(ret, errbuf, sizeof(errbuf));
+                    av_log(context, AV_LOG_ERROR, "Error while waiting for audio packet: %s\n",
+                           errbuf);
+                }
+                if (!self->client) {
+                    av_log(context, AV_LOG_ERROR, "Input error: JACK server is gone\n");
+                }
+
+                return AVERROR(EIO);
+            }
+        }
+    }
+
+    if (self->pkt_xrun) {
+        av_log(context, AV_LOG_WARNING, "Audio source packet underrun\n");
+        self->pkt_xrun = 0;
+    }
+
+    if (self->jack_xrun) {
+        av_log(context, AV_LOG_WARNING, "JACK output xrun\n");
+        self->jack_xrun = 0;
+    }
+
+    return 0;
+}
+
+static int audio_write_trailer(AVFormatContext *context)
+{
+    JackData *self = context->priv_data;
+    stop_jack(self);
+    return 0;
+}
+
+#define OFFSET(x) offsetof(JackData, x)
+static const AVOption options[] = {
+    { "channels", "Number of audio channels.", OFFSET(nports), AV_OPT_TYPE_INT, { .i64 = 2 }, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
+    { NULL },
+};
+
+static const AVClass jack_outdev_class = {
+    .class_name     = "JACK outdev",
+    .item_name      = av_default_item_name,
+    .option         = options,
+    .version        = LIBAVUTIL_VERSION_INT,
+    .category       = AV_CLASS_CATEGORY_DEVICE_AUDIO_OUTPUT,
+};
+
+AVOutputFormat ff_jack_muxer = {
+    .name           = "jack",
+    .long_name      = NULL_IF_CONFIG_SMALL("JACK audio output"),
+    .priv_data_size = sizeof(JackData),
+    /* XXX: we make the assumption that the soundcard accepts this format */
+    /* XXX: find better solution with "preinit" method, needed also in
+       other formats */
+    .audio_codec    = AV_NE(AV_CODEC_ID_PCM_F32BE, AV_CODEC_ID_PCM_F32LE),
+    .video_codec    = AV_CODEC_ID_NONE,
+    .write_header   = audio_write_header,
+    .write_packet   = audio_write_packet,
+    .write_trailer  = audio_write_trailer,
+    .flags          = AVFMT_NOFILE,
+    .priv_class     = &jack_outdev_class,
+};