audio/filter: Add channel remap filter

src/audio/filter/channel_remap.cpp

@@ -0,0 +1,199 @@
+/**
+ * @file   channel_remap.cpp
+ * @author Martin Piatka     <[email protected]>
+ */
+/*
+ * Copyright (c) 2024 CESNET, z. s. p. o.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, is permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of CESNET nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#include "config_unix.h"
+#include "config_win32.h"
+#endif /* HAVE_CONFIG_H */
+
+#include <memory>
+#include <string_view>
+
+#include "debug.h"
+#include "module.h"
+#include "audio/audio_filter.h"
+#include "audio/types.h"
+#include "audio/utils.h"
+#include "lib_common.h"
+#include "utils/misc.h"
+#include "utils/string_view_utils.hpp"
+
+#define MOD_NAME "[Remap filter] "
+
+struct state_channel_remap{
+        state_channel_remap(struct module *mod) : mod(MODULE_CLASS_DATA, mod, this) {  }
+
+        module_raii mod;
+
+        int bps = 0;
+        int ch_count = 0;
+        int sample_rate = 0;
+
+        struct channel_map channel_map;
+
+        std::vector<char> out_buffer;
+        struct audio_frame out_frame = {};
+};
+
+static void usage(){
+        color_printf("Audio filter " TBOLD(
+            "channel_remap") " allows remapping audio channels.\n\n");
+        color_printf("Usage:\n");
+        color_printf("\t" TBOLD("--audio-filter channel_remap:[<src_ch>]:<dst_ch>[,[<src_ch>]:<dst_ch>]...\n\n"));
+        color_printf("(indexed from zero)\n");
+        color_printf("Maps source channels into destination channels.\n");
+        color_printf("If multiple source channels are mapped into the same destination channel, they are mixed together.\n");
+        color_printf("E.g. 0:0,1:0 means that the first and second channel are mixed to produce a single mono channel.\n");
+        color_printf("2:0,3:1 means that the third and fourth channel are mapped into first and second channel respectively.\n");
+}
+
+static af_result_code init(struct module *parent, const char *cfg, void **state){
+        auto s = std::make_unique<state_channel_remap>(parent);
+
+        if(strcmp(cfg, "help") == 0){
+                usage();
+                return AF_HELP_SHOWN;
+        }
+
+        if(!parse_channel_map_cfg(&s->channel_map, cfg)){
+                return AF_FAILURE;
+        }
+
+        assert(s->channel_map.size > 0);
+
+        *state = s.release();
+
+        return AF_OK;
+};
+
+static af_result_code configure(void *state,
+                        int in_bps, int in_ch_count, int in_sample_rate)
+{
+        auto s = static_cast<state_channel_remap *>(state);
+
+        s->bps = in_bps;
+        s->ch_count = in_ch_count;
+        s->sample_rate = in_sample_rate;
+
+        s->out_frame.bps = s->bps;
+        s->out_frame.sample_rate = s->sample_rate;
+
+        if(s->channel_map.size > in_ch_count){
+                log_msg(LOG_LEVEL_WARNING, MOD_NAME "Audio channel map references channels with idx higher than ch. count!\n");
+        }
+
+        return AF_OK;
+}
+
+static void done(void *state){
+        auto s = static_cast<state_channel_remap *>(state);
+
+        delete s;
+}
+
+static void get_configured_in(void *state,
+                        int *bps, int *ch_count, int *sample_rate)
+{
+        auto s = static_cast<state_channel_remap *>(state);
+
+        if(bps) *bps = s->bps;
+        if(ch_count) *ch_count = s->ch_count;
+        if(sample_rate) *sample_rate = s->sample_rate;
+}
+
+static void get_configured_out(void *state,
+                        int *bps, int *ch_count, int *sample_rate)
+{
+        auto s = static_cast<state_channel_remap *>(state);
+
+        if(bps) *bps = s->bps;
+        if(ch_count) *ch_count = s->channel_map.max_output + 1;
+        if(sample_rate) *sample_rate = s->sample_rate;
+}
+
+static af_result_code filter(void *state, struct audio_frame **frame){
+        auto s = static_cast<state_channel_remap *>(state);
+        auto f = *frame;
+
+        if(f->bps != s->bps || f->ch_count != s->ch_count){
+                if(configure(state, f->bps, f->ch_count, f->sample_rate) != AF_OK){
+                        return AF_MISCONFIGURED;
+                }
+        }
+
+        int frame_count = f->data_len / f->ch_count / f->bps;
+
+        s->out_frame.ch_count = s->channel_map.max_output + 1;
+        s->out_frame.data_len = frame_count * s->out_frame.bps * s->out_frame.ch_count;
+        if(s->out_frame.data_len > s->out_frame.max_size){
+                s->out_frame.max_size = s->out_frame.data_len;
+                s->out_buffer.resize(s->out_frame.max_size);
+                s->out_frame.data = s->out_buffer.data();
+        }
+
+        memset(s->out_frame.data, 0, s->out_frame.data_len);
+
+        int max_src_count = std::min(s->channel_map.size, f->ch_count);
+
+        for(int src_ch = 0; src_ch < max_src_count; src_ch++){
+                for(int dst_ch = 0; dst_ch < s->channel_map.sizes[src_ch]; dst_ch++){
+                        remux_and_mix_channel(s->out_frame.data, f->data,
+                                        s->bps, frame_count,
+                                        f->ch_count, s->out_frame.ch_count,
+                                        src_ch, s->channel_map.map[src_ch][dst_ch], 1.0);
+                }
+        }
+
+        s->out_frame.timestamp = f->timestamp;
+
+        *frame = &s->out_frame;
+
+        return AF_OK;
+}
+
+static const struct audio_filter_info audio_filter_channel_remap = {
+        .name = "channel_remap",
+        .init = init,
+        .done = done,
+        .configure = configure,
+        .get_configured_in = get_configured_in,
+        .get_configured_out = get_configured_out,
+        .filter = filter,
+};
+
+REGISTER_MODULE(channel_remap, &audio_filter_channel_remap, LIBRARY_CLASS_AUDIO_FILTER, AUDIO_FILTER_ABI_VERSION);