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ffmpeg / libavdevice / jack_audio.c @ 72415b2a

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/*
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 * JACK Audio Connection Kit input device
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 * Copyright (c) 2009 Samalyse
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 * Author: Olivier Guilyardi <olivier samalyse com>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "config.h"
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#include <semaphore.h>
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#include <jack/jack.h>
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#include "libavutil/log.h"
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#include "libavutil/fifo.h"
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#include "libavcodec/avcodec.h"
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#include "libavformat/avformat.h"
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#include "libavformat/timefilter.h"
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/**
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 * Size of the internal FIFO buffers as a number of audio packets
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 */
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#define FIFO_PACKETS_NUM 16
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typedef struct {
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    jack_client_t * client;
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    int             activated;
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    sem_t           packet_count;
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    jack_nframes_t  sample_rate;
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    jack_nframes_t  buffer_size;
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    jack_port_t **  ports;
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    int             nports;
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    TimeFilter *    timefilter;
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    AVFifoBuffer *  new_pkts;
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    AVFifoBuffer *  filled_pkts;
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    int             pkt_xrun;
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    int             jack_xrun;
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} JackData;
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static int process_callback(jack_nframes_t nframes, void *arg)
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{
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    /* Warning: this function runs in realtime. One mustn't allocate memory here
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     * or do any other thing that could block. */
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    int i, j;
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    JackData *self = arg;
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    float * buffer;
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    jack_nframes_t latency, cycle_delay;
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    AVPacket pkt;
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    float *pkt_data;
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    double cycle_time;
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    if (!self->client)
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        return 0;
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    /* The approximate delay since the hardware interrupt as a number of frames */
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    cycle_delay = jack_frames_since_cycle_start(self->client);
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    /* Retrieve filtered cycle time */
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    cycle_time = ff_timefilter_update(self->timefilter,
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                                      av_gettime() / 1000000.0 - (double) cycle_delay / self->sample_rate,
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                                      self->buffer_size);
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    /* Check if an empty packet is available, and if there's enough space to send it back once filled */
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    if ((av_fifo_size(self->new_pkts) < sizeof(pkt)) || (av_fifo_space(self->filled_pkts) < sizeof(pkt))) {
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        self->pkt_xrun = 1;
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        return 0;
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    }
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    /* Retrieve empty (but allocated) packet */
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    av_fifo_generic_read(self->new_pkts, &pkt, sizeof(pkt), NULL);
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    pkt_data  = (float *) pkt.data;
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    latency   = 0;
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    /* Copy and interleave audio data from the JACK buffer into the packet */
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    for (i = 0; i < self->nports; i++) {
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        latency += jack_port_get_total_latency(self->client, self->ports[i]);
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        buffer = jack_port_get_buffer(self->ports[i], self->buffer_size);
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        for (j = 0; j < self->buffer_size; j++)
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            pkt_data[j * self->nports + i] = buffer[j];
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    }
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    /* Timestamp the packet with the cycle start time minus the average latency */
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    pkt.pts = (cycle_time - (double) latency / (self->nports * self->sample_rate)) * 1000000.0;
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    /* Send the now filled packet back, and increase packet counter */
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    av_fifo_generic_write(self->filled_pkts, &pkt, sizeof(pkt), NULL);
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    sem_post(&self->packet_count);
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    return 0;
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}
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static void shutdown_callback(void *arg)
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{
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    JackData *self = arg;
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    self->client = NULL;
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}
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static int xrun_callback(void *arg)
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{
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    JackData *self = arg;
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    self->jack_xrun = 1;
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    ff_timefilter_reset(self->timefilter);
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    return 0;
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}
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static int supply_new_packets(JackData *self, AVFormatContext *context)
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{
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    AVPacket pkt;
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    int test, pkt_size = self->buffer_size * self->nports * sizeof(float);
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    /* Supply the process callback with new empty packets, by filling the new
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     * packets FIFO buffer with as many packets as possible. process_callback()
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     * can't do this by itself, because it can't allocate memory in realtime. */
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    while (av_fifo_space(self->new_pkts) >= sizeof(pkt)) {
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        if ((test = av_new_packet(&pkt, pkt_size)) < 0) {
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            av_log(context, AV_LOG_ERROR, "Could not create packet of size %d\n", pkt_size);
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            return test;
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        }
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        av_fifo_generic_write(self->new_pkts, &pkt, sizeof(pkt), NULL);
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    }
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    return 0;
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}
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static int start_jack(AVFormatContext *context, AVFormatParameters *params)
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{
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    JackData *self = context->priv_data;
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    jack_status_t status;
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    int i, test;
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    double o, period;
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    /* Register as a JACK client, using the context filename as client name. */
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    self->client = jack_client_open(context->filename, JackNullOption, &status);
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    if (!self->client) {
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        av_log(context, AV_LOG_ERROR, "Unable to register as a JACK client\n");
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        return AVERROR(EIO);
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    }
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    sem_init(&self->packet_count, 0, 0);
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    self->sample_rate = jack_get_sample_rate(self->client);
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    self->nports      = params->channels;
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    self->ports       = av_malloc(self->nports * sizeof(*self->ports));
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    self->buffer_size = jack_get_buffer_size(self->client);
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    /* Register JACK ports */
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    for (i = 0; i < self->nports; i++) {
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        char str[16];
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        snprintf(str, sizeof(str), "input_%d", i + 1);
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        self->ports[i] = jack_port_register(self->client, str,
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                                            JACK_DEFAULT_AUDIO_TYPE,
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                                            JackPortIsInput, 0);
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        if (!self->ports[i]) {
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            av_log(context, AV_LOG_ERROR, "Unable to register port %s:%s\n",
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                   context->filename, str);
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            jack_client_close(self->client);
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            return AVERROR(EIO);
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        }
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    }
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    /* Register JACK callbacks */
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    jack_set_process_callback(self->client, process_callback, self);
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    jack_on_shutdown(self->client, shutdown_callback, self);
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    jack_set_xrun_callback(self->client, xrun_callback, self);
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    /* Create time filter */
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    period            = (double) self->buffer_size / self->sample_rate;
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    o                 = 2 * M_PI * 1.5 * period; /// bandwidth: 1.5Hz
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    self->timefilter  = ff_timefilter_new (1.0 / self->sample_rate, sqrt(2 * o), o * o);
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    /* Create FIFO buffers */
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    self->filled_pkts = av_fifo_alloc(FIFO_PACKETS_NUM * sizeof(AVPacket));
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    /* New packets FIFO with one extra packet for safety against underruns */
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    self->new_pkts    = av_fifo_alloc((FIFO_PACKETS_NUM + 1) * sizeof(AVPacket));
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    if ((test = supply_new_packets(self, context))) {
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        jack_client_close(self->client);
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        return test;
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    }
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    return 0;
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}
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static void free_pkt_fifo(AVFifoBuffer *fifo)
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{
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    AVPacket pkt;
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    while (av_fifo_size(fifo)) {
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        av_fifo_generic_read(fifo, &pkt, sizeof(pkt), NULL);
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        av_free_packet(&pkt);
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    }
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    av_fifo_free(fifo);
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}
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static void stop_jack(JackData *self)
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{
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    if (self->client) {
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        if (self->activated)
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            jack_deactivate(self->client);
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        jack_client_close(self->client);
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    }
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    sem_destroy(&self->packet_count);
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    free_pkt_fifo(self->new_pkts);
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    free_pkt_fifo(self->filled_pkts);
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    av_freep(&self->ports);
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    ff_timefilter_destroy(self->timefilter);
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}
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static int audio_read_header(AVFormatContext *context, AVFormatParameters *params)
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{
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    JackData *self = context->priv_data;
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    AVStream *stream;
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    int test;
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    if (params->sample_rate <= 0 || params->channels <= 0)
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        return -1;
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    if ((test = start_jack(context, params)))
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        return test;
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    stream = av_new_stream(context, 0);
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    if (!stream) {
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        stop_jack(self);
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        return AVERROR(ENOMEM);
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    }
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    stream->codec->codec_type   = AVMEDIA_TYPE_AUDIO;
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#if HAVE_BIGENDIAN
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    stream->codec->codec_id     = CODEC_ID_PCM_F32BE;
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#else
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    stream->codec->codec_id     = CODEC_ID_PCM_F32LE;
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#endif
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    stream->codec->sample_rate  = self->sample_rate;
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    stream->codec->channels     = self->nports;
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    av_set_pts_info(stream, 64, 1, 1000000);  /* 64 bits pts in us */
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    return 0;
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}
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static int audio_read_packet(AVFormatContext *context, AVPacket *pkt)
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{
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    JackData *self = context->priv_data;
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    struct timespec timeout = {0, 0};
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    int test;
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    /* Activate the JACK client on first packet read. Activating the JACK client
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     * means that process_callback() starts to get called at regular interval.
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     * If we activate it in audio_read_header(), we're actually reading audio data
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     * from the device before instructed to, and that may result in an overrun. */
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    if (!self->activated) {
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        if (!jack_activate(self->client)) {
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            self->activated = 1;
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            av_log(context, AV_LOG_INFO,
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                   "JACK client registered and activated (rate=%dHz, buffer_size=%d frames)\n",
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                   self->sample_rate, self->buffer_size);
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        } else {
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            av_log(context, AV_LOG_ERROR, "Unable to activate JACK client\n");
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            return AVERROR(EIO);
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        }
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    }
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    /* Wait for a packet comming back from process_callback(), if one isn't available yet */
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    timeout.tv_sec = av_gettime() / 1000000 + 2;
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    if (sem_timedwait(&self->packet_count, &timeout)) {
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        if (errno == ETIMEDOUT) {
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            av_log(context, AV_LOG_ERROR,
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                   "Input error: timed out when waiting for JACK process callback output\n");
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        } else {
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            av_log(context, AV_LOG_ERROR, "Error while waiting for audio packet: %s\n",
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                   strerror(errno));
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        }
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        if (!self->client)
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            av_log(context, AV_LOG_ERROR, "Input error: JACK server is gone\n");
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        return AVERROR(EIO);
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    }
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    if (self->pkt_xrun) {
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        av_log(context, AV_LOG_WARNING, "Audio packet xrun\n");
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        self->pkt_xrun = 0;
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    }
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    if (self->jack_xrun) {
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        av_log(context, AV_LOG_WARNING, "JACK xrun\n");
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        self->jack_xrun = 0;
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    }
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    /* Retrieve the packet filled with audio data by process_callback() */
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    av_fifo_generic_read(self->filled_pkts, pkt, sizeof(*pkt), NULL);
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    if ((test = supply_new_packets(self, context)))
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        return test;
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    return 0;
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}
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static int audio_read_close(AVFormatContext *context)
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{
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    JackData *self = context->priv_data;
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    stop_jack(self);
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    return 0;
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}
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AVInputFormat jack_demuxer = {
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    "jack",
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    NULL_IF_CONFIG_SMALL("JACK Audio Connection Kit"),
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    sizeof(JackData),
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    NULL,
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    audio_read_header,
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    audio_read_packet,
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    audio_read_close,
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    .flags = AVFMT_NOFILE,
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};