Add latency tools

tools/lset.c

@@ -0,0 +1,277 @@
+/*
+ *  lset - Correct latency reported by port
+ *
+ *  Copyright (C) 2016 Alba Mendez
+ *
+ *  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, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <signal.h>
+#include <assert.h>
+#include <getopt.h>
+#include <math.h>
+#include <jack/jack.h>
+#ifndef WIN32
+#include <unistd.h>
+#endif
+
+/* Represents an input/output port pair. */
+typedef struct port_pair {
+	jack_port_t *input;
+	jack_port_t *output;
+} port_pair;
+
+static int correct_capture = 0;
+static int correct_playback = 0;
+static int join_range = 0;
+static int absolute = 0;
+static float latency_coefficient = 0.5;
+static float amount = 1;
+
+static jack_client_t *client;
+static port_pair *pairs;
+static size_t pairs_count;
+
+void
+jack_latency(jack_latency_callback_mode_t mode, void *arg)
+{
+	size_t i;
+	for (i = 0; i < pairs_count; i++) {
+		jack_port_t *get, *set;
+		jack_latency_range_t range;
+
+		if (mode == JackCaptureLatency)
+			get = pairs[i].input, set = pairs[i].output;
+		else
+			get = pairs[i].output, set = pairs[i].input;
+
+		jack_port_get_latency_range(get, mode, &range);
+
+		if ((correct_capture && mode == JackCaptureLatency) ||
+		    (correct_playback && mode == JackPlaybackLatency)) {
+			/* Correct the latency. */
+			float latency = latency_coefficient * range.max + (1-latency_coefficient) * range.min;
+			float correction = amount - (absolute ? latency : 0);
+			range.min = roundf((join_range ? latency : range.min) + correction);
+			range.max = roundf((join_range ? latency : range.max) + correction);
+		}
+
+		jack_port_set_latency_range(set, mode, &range);
+	}
+}
+
+int
+jack_process(jack_nframes_t nframes, void *arg)
+{
+	size_t i;
+	for (i = 0; i < pairs_count; i++) {
+		jack_default_audio_sample_t *in = jack_port_get_buffer(pairs[i].input, nframes);
+		jack_default_audio_sample_t *out = jack_port_get_buffer(pairs[i].output, nframes);
+		memcpy(out, in, nframes * sizeof(jack_default_audio_sample_t));
+	}
+	return 0;
+}
+
+/* Option parsing, initialization and shutdown. */
+
+void
+signal_handler(int sig)
+{
+	jack_client_close(client);
+	exit(EXIT_SUCCESS);
+}
+
+void
+jack_shutdown(void *arg)
+{
+	exit(EXIT_FAILURE);
+}
+
+void
+show_usage()
+{
+	fprintf(stderr, "Usage: jack_lset [options] <amount>[ms|s]\n");
+	fprintf(stderr, "Passthrough client that corrects latency reported by another port.\n\n");
+	fprintf(stderr, "Options:\n");
+	fprintf(stderr, "      -a, --audio-ports <n>  Number of audio port pairs. Default: 1\n");
+	fprintf(stderr, "      -C, --capture          Correct capture latencies.\n");
+	fprintf(stderr, "      -P, --playback         Correct playback latencies (default).\n");
+	fprintf(stderr, "      -j, --join             Join minimum-maximum values into one.\n");
+	fprintf(stderr, "      -A, --absolute         Replace reported latency instead of adding.\n");
+	fprintf(stderr, "      -l, --coefficient <k>  Set the latency coefficient for -j or -A:\n"
+			"                             if 0, latencies will be aligned to their minimum;\n"
+			"                             if 1, to their maximum. Default: 0.5, to center\n");
+	fprintf(stderr, "      -n, --name <name>      Set the name of the JACK client to <name>.\n");
+	fprintf(stderr, "      -s, --server <name>    Connect to the JACK server named <name>.\n");
+	fprintf(stderr, "      -h, --help             Display this help message.\n");
+	fprintf(stderr, "\nFor more information see http://jackaudio.org/\n");
+}
+
+int
+main(int argc, char *argv[])
+{
+	jack_options_t options = 0;
+	jack_status_t status;
+	const char *name = "lset";
+	const char *server = NULL;
+	int c, audio_ports = 1;
+	unsigned int i, amount_len;
+	char *amount_str;
+
+	/* Parse command line options. */
+	struct option long_options[] = {
+		{ "audio-ports", 1, 0, 'a' },
+		{ "capture", 0, 0, 'C' },
+		{ "playback", 0, 0, 'P' },
+		{ "join", 0, 0, 'j' },
+		{ "absolute", 0, 0, 'A' },
+		{ "coefficient", 1, 0, 'l' },
+		{ "name", 1, 0, 'n' },
+		{ "server", 1, 0, 's' },
+		{ "help", 0, 0, 'h' },
+		{ 0, 0, 0, 0 }
+	};
+	while ((c = getopt_long(argc, argv, "a:CPjAl:n:s:h", long_options, NULL)) != -1) {
+		switch (c) {
+		case 'a':
+			audio_ports = atoi(optarg);
+			if (audio_ports < 0) {
+				show_usage();
+				return EXIT_FAILURE;
+			}
+			break;
+		case 'C':
+			correct_capture = 1;
+			break;
+		case 'P':
+			correct_playback = 1;
+			break;
+		case 'j':
+			join_range = 1;
+			break;
+		case 'A':
+			absolute = 1;
+			break;
+		case 'l':
+			latency_coefficient = atof(optarg);
+			break;
+		case 'h':
+			show_usage();
+			return EXIT_SUCCESS;
+		case 'n':
+			name = optarg;
+			options |= JackUseExactName;
+			break;
+		case 's':
+			server = optarg;
+			options |= JackServerName;
+			break;
+		default:
+			show_usage();
+			return EXIT_FAILURE;
+		}
+	}
+
+	pairs_count = audio_ports;
+	if (!correct_capture && !correct_playback)
+		correct_playback = 1;
+	if (optind + 1 != argc || pairs_count == 0) {
+		show_usage();
+		return EXIT_FAILURE;
+	}
+	amount_str = argv[optind];
+	amount_len = strlen(amount_str);
+
+	/* Open JACK client. */
+	client = jack_client_open(name, options, &status, server);
+	if (!client) {
+		fprintf(stderr, "jack_client_open() failed, status = %#2.0x\n", status);
+		return EXIT_FAILURE;
+	}
+
+	/* Set callbacks. */
+	if (jack_set_latency_callback(client, jack_latency, NULL) ||
+	    jack_set_process_callback(client, jack_process, NULL)) {
+		fprintf(stderr, "Could not set client callbacks\n");
+		jack_client_close(client);
+		return EXIT_FAILURE;
+	}
+
+	/* Setup port pairs. */
+	pairs = malloc(pairs_count * sizeof(port_pair));
+	assert(pairs);
+
+	for (i = 0; i < pairs_count; i++) {
+		char port_name [32];
+		const char* port_type = JACK_DEFAULT_AUDIO_TYPE;
+
+		snprintf(port_name, 32, "input_%u", i+1);
+		pairs[i].input = jack_port_register(client, port_name, port_type, JackPortIsInput, 0);
+
+		snprintf(port_name, 32, "output_%u", i+1);
+		pairs[i].output = jack_port_register(client, port_name, port_type, JackPortIsOutput, 0);
+
+		if (!pairs[i].output || !pairs[i].input) {
+			fprintf(stderr, "Failed to register ports\n");
+			jack_client_close(client);
+			return EXIT_FAILURE;
+		}
+	}
+
+	/* Calculate amount. */
+	if (amount_len >= 1 && amount_str[amount_len-1] == 's') {
+		amount_str[--amount_len] = 0;
+		amount *= jack_get_sample_rate(client);
+		if (amount_len >= 1 && amount_str[amount_len-1] == 'm') {
+			amount_str[--amount_len] = 0;
+			amount /= 1000;
+		}
+	}
+	if (amount_len == 0) {
+		show_usage();
+		jack_client_close(client);
+		return EXIT_FAILURE;
+	}
+	amount *= atof(amount_str);
+
+	/* Ensure safe shutdown. */
+	jack_on_shutdown(client, jack_shutdown, NULL);
+	signal(SIGINT, signal_handler);
+	signal(SIGTERM, signal_handler);
+#ifdef WIN32
+	signal(SIGABRT, signal_handler);
+#else
+	signal(SIGQUIT, signal_handler);
+	signal(SIGHUP, signal_handler);
+#endif
+
+	/* Start! */
+	if (jack_activate(client)) {
+		fprintf(stderr, "Could not activate client\n");
+		jack_client_close(client);
+		return EXIT_FAILURE;
+	}
+
+	while (1) {
+#ifdef WIN32
+		Sleep(1000);
+#else
+		sleep(1);
+#endif
+	}
+}