diff --git a/src/pulsecore/sink.c b/src/pulsecore/sink.c
index 42a8eb3da..627769858 100644
--- a/src/pulsecore/sink.c
+++ b/src/pulsecore/sink.c
@@ -180,6 +180,7 @@ static void reset_callbacks(pa_sink *s) {
     s->update_requested_latency = NULL;
     s->set_port = NULL;
     s->get_formats = NULL;
+    s->set_formats = NULL;
 }
 
 /* Called from main context */
@@ -3428,6 +3429,21 @@ pa_idxset* pa_sink_get_formats(pa_sink *s) {
     return ret;
 }
 
+/* Called from the main thread */
+/* Allows an external source to set what formats a sink supports if the sink
+ * permits this. The function makes a copy of the formats on success. */
+pa_bool_t pa_sink_set_formats(pa_sink *s, pa_idxset *formats) {
+    pa_assert(s);
+    pa_assert(formats);
+
+    if (s->set_formats)
+        /* Sink supports setting formats -- let's give it a shot */
+        return s->set_formats(s, formats);
+    else
+        /* Sink doesn't support setting this -- bail out */
+        return FALSE;
+}
+
 /* Called from the main thread */
 /* Checks if the sink can accept this format */
 pa_bool_t pa_sink_check_format(pa_sink *s, pa_format_info *f)
diff --git a/src/pulsecore/sink.h b/src/pulsecore/sink.h
index 8aa04b867..0bd5e81eb 100644
--- a/src/pulsecore/sink.h
+++ b/src/pulsecore/sink.h
@@ -223,6 +223,12 @@ struct pa_sink {
      * in descending order of preference. */
     pa_idxset* (*get_formats)(pa_sink *s); /* ditto */
 
+    /* Called to set the list of formats supported by the sink. Can be
+     * NULL if the sink does not support this. Returns TRUE on success,
+     * FALSE otherwise (for example when an unsupportable format is
+     * set). Makes a copy of the formats passed in. */
+    pa_bool_t (*set_formats)(pa_sink *s, pa_idxset *formats); /* ditto */
+
     /* Contains copies of the above data so that the real-time worker
      * thread can work without access locking */
     struct {
@@ -434,6 +440,7 @@ void pa_sink_move_all_finish(pa_sink *s, pa_queue *q, pa_bool_t save);
 void pa_sink_move_all_fail(pa_queue *q);
 
 pa_idxset* pa_sink_get_formats(pa_sink *s);
+pa_bool_t pa_sink_set_formats(pa_sink *s, pa_idxset *formats);
 pa_bool_t pa_sink_check_format(pa_sink *s, pa_format_info *f);
 pa_idxset* pa_sink_check_formats(pa_sink *s, pa_idxset *in_formats);