ao_jack: allow more control about channel layouts

3 files changed, 37 insertions, 1 deletions

diff --git a/DOCS/man/en/ao.rst b/DOCS/man/en/ao.rst
index e86fa2cc2c..f8af559ee9 100644
--- a/DOCS/man/en/ao.rst
+++ b/DOCS/man/en/ao.rst
@@ -60,6 +60,21 @@ jack
         Automatically create connections to output ports (default: enabled).
         When enabled, the maximum number of output channels will be limited to
         the number of available output ports.
+    std-channel-layout=alsa|waveext|any
+        Select the standard channel layout (default: alsa). JACK itself has no
+        notion of channel layouts (i.e. assigning which speaker a given
+        channel is supposed to map to) - it just takes whatever the application
+        outputs, and reroutes it to whatever the user defines. This means the
+        user and the application is in charge of dealing with the channel
+        layout. ``alsa`` uses the old MPlayer layout, which is inspired by
+        ALSA's standard layouts. In this mode, ao_jack will refuse to play 3
+        or 7 channels (because these don't really have a defined meaning in
+        MPlayer). ``waveext`` uses WAVE_FORMAT_EXTENSIBLE order, which even
+        though it was defined by Microsoft, is the standard on many systems.
+        The value ``any`` makes JACK accept whatever comes from the audio
+        filter chain, regardless of channel layout and without reordering. This
+        mode is probably not very useful, other than debugging or when used
+        with fixed setups.
 
 coreaudio (Mac OS X only)
     native Mac OS X audio output driver
diff --git a/audio/chmap_sel.c b/audio/chmap_sel.c
index 8e5be5c86e..215ba5add8 100644
--- a/audio/chmap_sel.c
+++ b/audio/chmap_sel.c
@@ -70,6 +70,7 @@ void mp_chmap_sel_add_waveext(struct mp_chmap_sel *s)
     s->allow_waveext = true;
 }
 
+// Classic ALSA-based MPlayer layouts.
 void mp_chmap_sel_add_alsa_def(struct mp_chmap_sel *s)
 {
     for (int n = 0; n < MP_NUM_CHANNELS; n++) {
diff --git a/audio/out/ao_jack.c b/audio/out/ao_jack.c
index 9c38dcde97..964eb5bce6 100644
--- a/audio/out/ao_jack.c
+++ b/audio/out/ao_jack.c
@@ -188,6 +188,7 @@ static int init(struct ao *ao, char *params)
     const char **matching_ports = NULL;
     char *port_name = NULL;
     char *client_name = NULL;
+    char *stdlayout = NULL;
     int autostart = 0;
     int connect = 1;
     struct priv *p = talloc_zero(ao, struct priv);
@@ -197,6 +198,7 @@ static int init(struct ao *ao, char *params)
         {"estimate", OPT_ARG_BOOL, &p->estimate, NULL},
         {"autostart", OPT_ARG_BOOL, &autostart, NULL},
         {"connect", OPT_ARG_BOOL, &connect, NULL},
+        {"std-channel-layout", OPT_ARG_MSTRZ, &stdlayout, NULL},
         {NULL}
     };
     jack_options_t open_options = JackUseExactName;
@@ -210,7 +212,23 @@ static int init(struct ao *ao, char *params)
     }
 
     struct mp_chmap_sel sel = {0};
-    mp_chmap_sel_add_waveext(&sel);
+
+    if (stdlayout) {
+        if (strcmp(stdlayout, "waveext") == 0) {
+            mp_chmap_sel_add_waveext(&sel);
+        } else if (strcmp(stdlayout, "alsa") == 0) {
+            mp_chmap_sel_add_alsa_def(&sel);
+        } else if (strcmp(stdlayout, "any") == 0) {
+            mp_chmap_sel_add_any(&sel);
+        } else {
+            mp_msg(MSGT_AO, MSGL_FATAL, "[JACK] std-channel-layout suboption "
+                   "expects 'alsa' or 'waveext' as value.\n");
+            goto err_out;
+        }
+    } else {
+        mp_chmap_sel_add_waveext(&sel);
+    }
+
     if (!ao_chmap_sel_adjust(ao, &sel, &ao->channels))
         goto err_out;
 
@@ -286,12 +304,14 @@ static int init(struct ao *ao, char *params)
     free(matching_ports);
     free(port_name);
     free(client_name);
+    free(stdlayout);
     return 0;
 
 err_out:
     free(matching_ports);
     free(port_name);
     free(client_name);
+    free(stdlayout);
     if (p->client)
         jack_client_close(p->client);
     return -1;