obs-studio/plugins/linux-jack/jack-wrapper.c

/*
Copyright (C) 2015 by Bernd Buschinski <b.buschinski@gmail.com>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.

This program 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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "jack-wrapper.h"

#include <util/threading.h>
#include <stdio.h>

#include <util/platform.h>

#define blog(level, msg, ...) blog(level, "jack-input: " msg, ##__VA_ARGS__)

/**
 * Get obs speaker layout from number of channels
 *
 * @param channels number of channels reported by jack
 *
 * @return obs speaker_layout id
 *
 * @note This *might* not work for some rather unusual setups, but should work
 *       fine for the majority of cases.
 */
static enum speaker_layout jack_channels_to_obs_speakers(uint_fast32_t channels)
{
	switch (channels) {
	case 1:
		return SPEAKERS_MONO;
	case 2:
		return SPEAKERS_STEREO;
	case 3:
		return SPEAKERS_2POINT1;
	case 4:
		return SPEAKERS_4POINT0;
	case 5:
		return SPEAKERS_4POINT1;
	case 6:
		return SPEAKERS_5POINT1;
	/* What should we do with 7 channels? */
	/* case 7: return SPEAKERS_...; */
	case 8:
		return SPEAKERS_7POINT1;
	}

	return SPEAKERS_UNKNOWN;
}

int jack_process_callback(jack_nframes_t nframes, void *arg)
{
	struct jack_data *data = (struct jack_data *)arg;
	jack_nframes_t current_frames;
	jack_time_t current_usecs, next_usecs;
	float period_usecs;

	uint64_t now = os_gettime_ns();

	if (data == 0)
		return 0;

	struct obs_source_audio out;
	out.speakers = jack_channels_to_obs_speakers(data->channels);
	out.samples_per_sec = jack_get_sample_rate(data->jack_client);
	/* format is always 32 bit float for jack */
	out.format = AUDIO_FORMAT_FLOAT_PLANAR;

	for (unsigned int i = 0; i < data->channels; ++i) {
		jack_default_audio_sample_t *jack_buffer =
			(jack_default_audio_sample_t *)jack_port_get_buffer(
				data->jack_ports[i], nframes);
		out.data[i] = (uint8_t *)jack_buffer;
	}

	out.frames = nframes;
	if (!jack_get_cycle_times(data->jack_client, &current_frames,
				  &current_usecs, &next_usecs, &period_usecs)) {
		out.timestamp = now - (int64_t)(period_usecs * 1000);
	} else {
		out.timestamp = now - util_mul_div64(nframes, 1000000000ULL,
						     data->samples_per_sec);
		blog(LOG_WARNING,
		     "jack_get_cycle_times error: guessing timestamp");
	}

	/* FIXME: this function is not realtime-safe, we should do something
	 * about this */
	obs_source_output_audio(data->source, &out);
	return 0;
}

int_fast32_t jack_init(struct jack_data *data)
{
	pthread_mutex_lock(&data->jack_mutex);

	if (data->jack_client != NULL)
		goto good;

	jack_options_t jack_option =
		data->start_jack_server ? JackNullOption : JackNoStartServer;

	data->jack_client = jack_client_open(data->device, jack_option, 0);
	if (data->jack_client == NULL) {
		blog(LOG_ERROR,
		     "jack_client_open Error:"
		     "Could not create JACK client! %s",
		     data->device);
		goto error;
	}

	data->jack_ports =
		(jack_port_t **)bzalloc(sizeof(jack_port_t *) * data->channels);
	for (unsigned int i = 0; i < data->channels; ++i) {
		char port_name[10] = {'\0'};
		snprintf(port_name, sizeof(port_name), "in_%u", i + 1);

		data->jack_ports[i] = jack_port_register(
			data->jack_client, port_name, JACK_DEFAULT_AUDIO_TYPE,
			JackPortIsInput | JackPortIsTerminal, 0);
		if (data->jack_ports[i] == NULL) {
			blog(LOG_ERROR,
			     "jack_port_register Error:"
			     "Could not create JACK port! %s",
			     port_name);
			goto error;
		}
	}

	if (jack_set_process_callback(data->jack_client, jack_process_callback,
				      data) != 0) {
		blog(LOG_ERROR, "jack_set_process_callback Error");
		goto error;
	}

	if (jack_activate(data->jack_client) != 0) {
		blog(LOG_ERROR, "jack_activate Error:"
				"Could not activate JACK client!");
		goto error;
	}

good:
	pthread_mutex_unlock(&data->jack_mutex);
	return 0;

error:
	pthread_mutex_unlock(&data->jack_mutex);
	return 1;
}

void deactivate_jack(struct jack_data *data)
{
	pthread_mutex_lock(&data->jack_mutex);

	if (data->jack_client) {
		jack_client_close(data->jack_client);
		if (data->jack_ports != NULL) {
			bfree(data->jack_ports);
			data->jack_ports = NULL;
		}
		data->jack_client = NULL;
	}
	pthread_mutex_unlock(&data->jack_mutex);
}