Files
ustreamer/janus/src/au.c
Maxim Devaev a6f111f7cf refactoring
2026-01-23 03:06:16 +02:00

152 lines
3.9 KiB
C

/*****************************************************************************
# #
# uStreamer - Lightweight and fast MJPEG-HTTP streamer. #
# #
# Copyright (C) 2018-2024 Maxim Devaev <mdevaev@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 3 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 <https://www.gnu.org/licenses/>. #
# #
*****************************************************************************/
#include "au.h"
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <sys/stat.h>
#include "uslibs/tools.h"
bool us_au_probe(const char *name) {
// This function is very limited. It takes something like:
// hw:0,0 or hw:tc358743,0 or plughw:UAC2Gadget,0
// parses card name (0, tc358743, UAC2Gadget) and checks
// the existence of it in /proc/asound/.
// It's enough for our case.
if (name == NULL) {
return false;
}
if (strchr(name, '/') || strchr(name, '.')) {
return false;
}
const char *begin = strchr(name, ':');
if (begin == NULL) {
return false;
}
begin += 1;
if (*begin == '\0') {
return false;
}
const char *end = strchr(begin, ',');
if (end == NULL) {
return false;
}
if (end - begin < 1) {
return false;
}
char *card = us_strdup(begin);
card[end - begin] = '\0';
bool numeric = true;
for (uz index = 0; card[index] != '\0'; ++index) {
if (!isdigit(card[index])) {
numeric = false;
break;
}
}
char *path;
if (numeric) {
US_ASPRINTF(path, "/proc/asound/card%s", card);
} else {
US_ASPRINTF(path, "/proc/asound/%s", card);
}
bool ok = false;
struct stat st;
if (lstat(path, &st) == 0) {
if (numeric && S_ISDIR(st.st_mode)) {
ok = true;
} else if (!numeric && S_ISLNK(st.st_mode)) {
ok = true;
}
}
free(path);
free(card);
return ok;
}
us_au_pcm_s *us_au_pcm_init(void) {
us_au_pcm_s *pcm;
US_CALLOC(pcm, 1);
return pcm;
}
void us_au_pcm_destroy(us_au_pcm_s *pcm) {
free(pcm);
}
void us_au_pcm_mix(us_au_pcm_s *dest, us_au_pcm_s *src) {
const uz size = src->frames * US_RTP_OPUS_CH * 2; // 2 for 16 bit
if (src->frames == 0) {
return;
} else if (dest->frames == 0) {
memcpy(dest->data, src->data, size);
dest->frames = src->frames;
} else if (dest->frames == src->frames) {
// https://stackoverflow.com/questions/12089662
for (uz index = 0; index < size; ++index) {
int a = dest->data[index];
int b = src->data[index];
int m;
a += 32768;
b += 32768;
if ((a < 32768) && (b < 32768)) {
m = a * b / 32768;
} else {
m = 2 * (a + b) - (a * b) / 32768 - 65536;
}
if (m == 65536) {
m = 65535;
}
m -= 32768;
dest->data[index] = m;
}
}
}
us_au_encoded_s *us_au_encoded_init(void) {
us_au_encoded_s *enc;
US_CALLOC(enc, 1);
return enc;
}
void us_au_encoded_destroy(us_au_encoded_s *enc) {
free(enc);
}