Split the enable-lfe-remixing setting into two

remixing-produce-lfe controls upmixing, and remixing-consume-lfe
controls downmixing. The motivation is that a user might want to
synthesize LFE while playing stereo audio on his/her 5.1 speakers,
but at the same time follow the industry recommendation to omit
the LFE channel when producting a stereo downmix (e.g. for headphones)
from 5.1 content. Or the other way round.

Fixes: #753.

man/pulse-daemon.conf.5.xml.in

@@ -147,13 +147,28 @@ License along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
     </option>
 
     <option>
-      <p><opt>enable-lfe-remixing=</opt> If disabled when upmixing or
+      <p><opt>enable-lfe-remixing=</opt> This is a way to set
-      downmixing ignore LFE channels. When this option is disabled the
+      <opt>remixing-produce-lfe</opt> and <opt>remixing-consume-lfe</opt>
-      output LFE channel will only get a signal when an input LFE
+      to the same value at once. This option only exists for backward
-      channel is available as well. If no input LFE channel is
+      compatibility and may be removed in a future version of PulseAudio.</p>
-      available the output LFE channel will always be 0. If no output
+    </option>
-      LFE channel is available the signal on the input LFE channel
+
-      will be ignored. Defaults to <opt>no</opt>.</p>
+    <option>
+      <p><opt>remixing-produce-lfe=</opt> If enabled, and the sink input
+      does not have the LFE channel, synthesize the output LFE channel
+      as a (lowpass-filtered, if <opt>lfe-crossover-freq</opt> is not 0)
+      average of all input channels. Also, when <opt>lfe-crossover-freq</opt>
+      is not 0, filter out low frequencies from other channels while
+      producing a synthetic LFE output. If disabled, the output LFE channel
+      will only get a signal when an input LFE channel is available as well.
+      Defaults to <opt>no</opt>.</p>
+    </option>
+
+    <option>
+      <p><opt>remixing-consume-lfe=</opt> If enabled, and the sink does not
+      have an LFE channel, redirect the input LFE channel (if any) to other
+      channels. If disabled, the input LFE channel will remain unused unless
+      the sink has the LFE channel as well. Defaults to <opt>no</opt>.</p>
     </option>
 
     <option>

src/daemon/daemon-conf.c

@@ -84,7 +84,8 @@ static const pa_daemon_conf default_conf = {
     .avoid_resampling = false,
     .disable_remixing = false,
     .remixing_use_all_sink_channels = true,
-    .disable_lfe_remixing = true,
+    .remixing_produce_lfe = false,
+    .remixing_consume_lfe = false,
     .lfe_crossover_freq = 0,
     .config_file = NULL,
     .use_pid_file = true,
@@ -496,6 +497,48 @@ static int parse_rtprio(pa_config_parser_state *state) {
     return 0;
 }
 
+static int parse_disable_lfe_remix(pa_config_parser_state *state) {
+    pa_daemon_conf *c;
+    int k;
+
+    pa_assert(state);
+    c = state->data;
+
+    if ((k = pa_parse_boolean(state->rvalue)) < 0) {
+        pa_log("[%s:%u] Failed to parse boolean value: %s", state->filename, state->lineno, state->rvalue);
+        return -1;
+    }
+
+    c->remixing_produce_lfe = c->remixing_consume_lfe = !k;
+
+    pa_log("[%s:%u] Deprecated option 'disable-lfe-remixing' found.", state->filename, state->lineno);
+    pa_log("[%s:%u] Please migrate to 'remixing-produce-lfe' and 'remixing-consume-lfe', set both to '%s'.",
+           state->filename, state->lineno, pa_yes_no(c->remixing_produce_lfe));
+
+    return 0;
+}
+
+static int parse_enable_lfe_remix(pa_config_parser_state *state) {
+    pa_daemon_conf *c;
+    int k;
+
+    pa_assert(state);
+    c = state->data;
+
+    if ((k = pa_parse_boolean(state->rvalue)) < 0) {
+        pa_log("[%s:%u] Failed to parse boolean value: %s", state->filename, state->lineno, state->rvalue);
+        return -1;
+    }
+
+    c->remixing_produce_lfe = c->remixing_consume_lfe = k;
+
+    pa_log("[%s:%u] Deprecated option 'enable-lfe-remixing' found.", state->filename, state->lineno);
+    pa_log("[%s:%u] Please migrate to 'remixing-produce-lfe' and 'remixing-consume-lfe', set both to '%s'.",
+           state->filename, state->lineno, pa_yes_no(c->remixing_produce_lfe));
+
+    return 0;
+}
+
 #ifdef HAVE_DBUS
 static int parse_server_type(pa_config_parser_state *state) {
     pa_daemon_conf *c;
@@ -565,8 +608,10 @@ int pa_daemon_conf_load(pa_daemon_conf *c, const char *filename) {
         { "enable-remixing",            pa_config_parse_not_bool, &c->disable_remixing, NULL },
         { "remixing-use-all-sink-channels",
                                         pa_config_parse_bool,     &c->remixing_use_all_sink_channels, NULL },
-        { "disable-lfe-remixing",       pa_config_parse_bool,     &c->disable_lfe_remixing, NULL },
+        { "disable-lfe-remixing",       parse_disable_lfe_remix,  c, NULL },
-        { "enable-lfe-remixing",        pa_config_parse_not_bool, &c->disable_lfe_remixing, NULL },
+        { "enable-lfe-remixing",        parse_enable_lfe_remix,   c, NULL },
+        { "remixing-produce-lfe",       pa_config_parse_bool,     &c->remixing_produce_lfe, NULL },
+        { "remixing-consume-lfe",       pa_config_parse_bool,     &c->remixing_consume_lfe, NULL },
         { "lfe-crossover-freq",         pa_config_parse_unsigned, &c->lfe_crossover_freq, NULL },
         { "load-default-script-file",   pa_config_parse_bool,     &c->load_default_script_file, NULL },
         { "shm-size-bytes",             pa_config_parse_size,     &c->shm_size, NULL },
@@ -761,7 +806,8 @@ char *pa_daemon_conf_dump(pa_daemon_conf *c) {
     pa_strbuf_printf(s, "avoid-resampling = %s\n", pa_yes_no(c->avoid_resampling));
     pa_strbuf_printf(s, "enable-remixing = %s\n", pa_yes_no(!c->disable_remixing));
     pa_strbuf_printf(s, "remixing-use-all-sink-channels = %s\n", pa_yes_no(c->remixing_use_all_sink_channels));
-    pa_strbuf_printf(s, "enable-lfe-remixing = %s\n", pa_yes_no(!c->disable_lfe_remixing));
+    pa_strbuf_printf(s, "remixing-produce-lfe = %s\n", pa_yes_no(c->remixing_produce_lfe));
+    pa_strbuf_printf(s, "remixing-consume-lfe = %s\n", pa_yes_no(c->remixing_consume_lfe));
     pa_strbuf_printf(s, "lfe-crossover-freq = %u\n", c->lfe_crossover_freq);
     pa_strbuf_printf(s, "default-sample-format = %s\n", pa_sample_format_to_string(c->default_sample_spec.format));
     pa_strbuf_printf(s, "default-sample-rate = %u\n", c->default_sample_spec.rate);

src/daemon/daemon-conf.h

@@ -70,7 +70,8 @@ typedef struct pa_daemon_conf {
         avoid_resampling,
         disable_remixing,
         remixing_use_all_sink_channels,
-        disable_lfe_remixing,
+        remixing_produce_lfe,
+        remixing_consume_lfe,
         load_default_script_file,
         disallow_exit,
         log_meta,

src/daemon/daemon.conf.in

@@ -57,7 +57,8 @@ ifelse(@HAVE_DBUS@, 1, [dnl
 ; avoid-resampling = false
 ; enable-remixing = yes
 ; remixing-use-all-sink-channels = yes
-; enable-lfe-remixing = no
+; remixing-produce-lfe = no
+; remixing-consume-lfe = no
 ; lfe-crossover-freq = 0
 
 ; flat-volumes = no

src/daemon/main.c

@@ -1056,7 +1056,8 @@ int main(int argc, char *argv[]) {
     c->avoid_resampling = conf->avoid_resampling;
     c->disable_remixing = conf->disable_remixing;
     c->remixing_use_all_sink_channels = conf->remixing_use_all_sink_channels;
-    c->disable_lfe_remixing = conf->disable_lfe_remixing;
+    c->remixing_produce_lfe = conf->remixing_produce_lfe;
+    c->remixing_consume_lfe = conf->remixing_consume_lfe;
     c->deferred_volume = conf->deferred_volume;
     c->running_as_daemon = conf->daemonize;
     c->disallow_exit = conf->disallow_exit;

src/pulsecore/core.c

@@ -144,7 +144,8 @@ pa_core* pa_core_new(pa_mainloop_api *m, bool shared, bool enable_memfd, size_t
     c->realtime_priority = 5;
     c->disable_remixing = false;
     c->remixing_use_all_sink_channels = true;
-    c->disable_lfe_remixing = true;
+    c->remixing_produce_lfe = false;
+    c->remixing_consume_lfe = false;
     c->lfe_crossover_freq = 0;
     c->deferred_volume = true;
     c->resample_method = PA_RESAMPLER_SPEEX_FLOAT_BASE + 1;

src/pulsecore/core.h

@@ -220,7 +220,8 @@ struct pa_core {
     bool avoid_resampling:1;
     bool disable_remixing:1;
     bool remixing_use_all_sink_channels:1;
-    bool disable_lfe_remixing:1;
+    bool remixing_produce_lfe:1;
+    bool remixing_consume_lfe:1;
     bool deferred_volume:1;
 
     pa_resample_method_t resample_method;

src/pulsecore/resampler.c

@@ -1099,7 +1099,7 @@ static void setup_remap(const pa_resampler *r, pa_remap_t *m, bool *lfe_remixed)
                      * right input channel. Something is really wrong in this
                      * case anyway. */
 
-                } else if (on_lfe(b) && !(r->flags & PA_RESAMPLER_NO_LFE)) {
+                } else if (on_lfe(b) && (r->flags & PA_RESAMPLER_PRODUCE_LFE)) {
 
                     /* We are not connected and an LFE. Let's average all
                      * channels for LFE. */
@@ -1150,7 +1150,7 @@ static void setup_remap(const pa_resampler *r, pa_remap_t *m, bool *lfe_remixed)
                     m->map_table_f[oc][ic] = (1.f/9.f) / (float) ic_unconnected_center;
                     ic_unconnected_center_mixed_in = true;
 
-                } else if (on_lfe(a) && !(r->flags & PA_RESAMPLER_NO_LFE))
+                } else if (on_lfe(a) && (r->flags & PA_RESAMPLER_CONSUME_LFE))
                     m->map_table_f[oc][ic] = .375f / (float) ic_unconnected_lfe;
             }
         }

src/pulsecore/resampler.h

@@ -68,8 +68,9 @@ typedef enum pa_resample_flags {
     PA_RESAMPLER_VARIABLE_RATE = 0x0001U,
     PA_RESAMPLER_NO_REMAP      = 0x0002U,  /* implies NO_REMIX */
     PA_RESAMPLER_NO_REMIX      = 0x0004U,
-    PA_RESAMPLER_NO_LFE        = 0x0008U,
     PA_RESAMPLER_NO_FILL_SINK  = 0x0010U,
+    PA_RESAMPLER_PRODUCE_LFE   = 0x0020U,
+    PA_RESAMPLER_CONSUME_LFE   = 0x0040U,
 } pa_resample_flags_t;
 
 struct pa_resampler {

src/pulsecore/sink-input.c

@@ -476,7 +476,8 @@ int pa_sink_input_new(
                           ((data->flags & PA_SINK_INPUT_NO_REMAP) ? PA_RESAMPLER_NO_REMAP : 0) |
                           (core->disable_remixing || (data->flags & PA_SINK_INPUT_NO_REMIX) ? PA_RESAMPLER_NO_REMIX : 0) |
                           (core->remixing_use_all_sink_channels ? 0 : PA_RESAMPLER_NO_FILL_SINK) |
-                          (core->disable_lfe_remixing ? PA_RESAMPLER_NO_LFE : 0)))) {
+                          (core->remixing_produce_lfe ? PA_RESAMPLER_PRODUCE_LFE : 0) |
+                          (core->remixing_consume_lfe ? PA_RESAMPLER_CONSUME_LFE : 0)))) {
                 pa_log_warn("Unsupported resampling operation.");
                 return -PA_ERR_NOTSUPPORTED;
             }
@@ -2313,7 +2314,8 @@ int pa_sink_input_update_resampler(pa_sink_input *i) {
                                      ((i->flags & PA_SINK_INPUT_NO_REMAP) ? PA_RESAMPLER_NO_REMAP : 0) |
                                      (i->core->disable_remixing || (i->flags & PA_SINK_INPUT_NO_REMIX) ? PA_RESAMPLER_NO_REMIX : 0) |
                                      (i->core->remixing_use_all_sink_channels ? 0 : PA_RESAMPLER_NO_FILL_SINK) |
-                                     (i->core->disable_lfe_remixing ? PA_RESAMPLER_NO_LFE : 0));
+                                     (i->core->remixing_produce_lfe ? PA_RESAMPLER_PRODUCE_LFE : 0) |
+                                     (i->core->remixing_consume_lfe ? PA_RESAMPLER_CONSUME_LFE : 0));
 
         if (!new_resampler) {
             pa_log_warn("Unsupported resampling operation.");

src/pulsecore/source-output.c

@@ -414,7 +414,8 @@ int pa_source_output_new(
                         ((data->flags & PA_SOURCE_OUTPUT_NO_REMAP) ? PA_RESAMPLER_NO_REMAP : 0) |
                         (core->disable_remixing || (data->flags & PA_SOURCE_OUTPUT_NO_REMIX) ? PA_RESAMPLER_NO_REMIX : 0) |
                         (core->remixing_use_all_sink_channels ? 0 : PA_RESAMPLER_NO_FILL_SINK) |
-                        (core->disable_lfe_remixing ? PA_RESAMPLER_NO_LFE : 0)))) {
+                        (core->remixing_produce_lfe ? PA_RESAMPLER_PRODUCE_LFE : 0) |
+                        (core->remixing_consume_lfe ? PA_RESAMPLER_CONSUME_LFE : 0)))) {
                 pa_log_warn("Unsupported resampling operation.");
                 return -PA_ERR_NOTSUPPORTED;
             }
@@ -1755,7 +1756,8 @@ int pa_source_output_update_resampler(pa_source_output *o) {
                                      ((o->flags & PA_SOURCE_OUTPUT_NO_REMAP) ? PA_RESAMPLER_NO_REMAP : 0) |
                                      (o->core->disable_remixing || (o->flags & PA_SOURCE_OUTPUT_NO_REMIX) ? PA_RESAMPLER_NO_REMIX : 0) |
                                      (o->core->remixing_use_all_sink_channels ? 0 : PA_RESAMPLER_NO_FILL_SINK) |
-                                     (o->core->disable_lfe_remixing ? PA_RESAMPLER_NO_LFE : 0));
+                                     (o->core->remixing_produce_lfe ? PA_RESAMPLER_PRODUCE_LFE : 0) |
+                                     (o->core->remixing_consume_lfe ? PA_RESAMPLER_CONSUME_LFE : 0));
 
         if (!new_resampler) {
             pa_log_warn("Unsupported resampling operation.");

src/tests/remix-test.c

@@ -33,7 +33,7 @@ struct resample_flags {
 };
 
 /* Call like this to get an initializer for struct resample_flags:
- *     RESAMPLE_FLAGS(PA_RESAMPLER_NO_LFE)
+ *     RESAMPLE_FLAGS(PA_RESAMPLER_PRODUCE_LFE)
  */
 #define RESAMPLE_FLAGS(flags) { .str = #flags, .value = (flags) }
 
@@ -60,9 +60,13 @@ int main(int argc, char *argv[]) {
         RESAMPLE_FLAGS(0),
         RESAMPLE_FLAGS(PA_RESAMPLER_NO_REMAP),
         RESAMPLE_FLAGS(PA_RESAMPLER_NO_REMIX),
-        RESAMPLE_FLAGS(PA_RESAMPLER_NO_LFE),
+        RESAMPLE_FLAGS(PA_RESAMPLER_PRODUCE_LFE),
         RESAMPLE_FLAGS(PA_RESAMPLER_NO_FILL_SINK),
-        RESAMPLE_FLAGS(PA_RESAMPLER_NO_LFE | PA_RESAMPLER_NO_FILL_SINK),
+        RESAMPLE_FLAGS(PA_RESAMPLER_PRODUCE_LFE | PA_RESAMPLER_NO_FILL_SINK),
+        RESAMPLE_FLAGS(PA_RESAMPLER_CONSUME_LFE),
+        RESAMPLE_FLAGS(PA_RESAMPLER_CONSUME_LFE | PA_RESAMPLER_NO_FILL_SINK),
+        RESAMPLE_FLAGS(PA_RESAMPLER_PRODUCE_LFE | PA_RESAMPLER_CONSUME_LFE),
+        RESAMPLE_FLAGS(PA_RESAMPLER_PRODUCE_LFE | PA_RESAMPLER_CONSUME_LFE | PA_RESAMPLER_NO_FILL_SINK),
         { .str = NULL, .value = 0 },
     };