diff --git a/src/map-file b/src/map-file
index 1acc6e987..8d683405a 100644
--- a/src/map-file
+++ b/src/map-file
@@ -163,6 +163,7 @@ pa_ext_stream_restore_test;
 pa_ext_stream_restore_write;
 pa_format_info_copy;
 pa_format_info_free;
+pa_format_info_is_compatible;
 pa_format_info_is_pcm;
 pa_format_info_new;
 pa_format_info_snprint;
diff --git a/src/pulse/format.c b/src/pulse/format.c
index e601d9025..a634b27b0 100644
--- a/src/pulse/format.c
+++ b/src/pulse/format.c
@@ -115,7 +115,7 @@ char *pa_format_info_snprint(char *s, size_t l, const pa_format_info *f) {
     return s;
 }
 
-pa_bool_t pa_format_info_is_compatible(pa_format_info *first, pa_format_info *second) {
+int pa_format_info_is_compatible(pa_format_info *first, pa_format_info *second) {
     const char *key;
     void *state = NULL;
 
diff --git a/src/pulse/format.h b/src/pulse/format.h
index bd32ba92b..b0efe502a 100644
--- a/src/pulse/format.h
+++ b/src/pulse/format.h
@@ -83,6 +83,15 @@ int pa_format_info_valid(const pa_format_info *f);
 /** Returns non-zero when the format info structure represents a PCM (i.e. uncompressed data) format */
 int pa_format_info_is_pcm(const pa_format_info *f);
 
+/** Returns non-zero if the format represented \a first is a subset of
+ * the format represented by \second. This means that \a second must
+ * have all the fields that \a first does, but the reverse need not
+ * be true. This is typically expected to be used to check if a
+ * stream's format is compatible with a given sink. In such a case,
+ * \a first would be the sink's format and \a second would be the
+ * stream's.*/
+int pa_format_info_is_compatible(pa_format_info *first, pa_format_info *second);
+
 /** Maximum required string length for
  * pa_format_info_snprint(). Please note that this value can change
  * with any release without warning and without being considered API
diff --git a/src/pulse/internal.h b/src/pulse/internal.h
index 351aeec92..a659576ae 100644
--- a/src/pulse/internal.h
+++ b/src/pulse/internal.h
@@ -297,7 +297,6 @@ void pa_ext_device_manager_command(pa_context *c, uint32_t tag, pa_tagstruct *t)
 void pa_ext_stream_restore_command(pa_context *c, uint32_t tag, pa_tagstruct *t);
 
 void pa_format_info_free2(pa_format_info *f, void *userdata);
-pa_bool_t pa_format_info_is_compatible(pa_format_info *first, pa_format_info *second);
 pa_format_info* pa_format_info_from_sample_spec(pa_sample_spec *ss, pa_channel_map *map);
 pa_bool_t pa_format_info_to_sample_spec(pa_format_info *f, pa_sample_spec *ss, pa_channel_map *map);
 pa_bool_t pa_format_info_to_sample_spec_fake(pa_format_info *f, pa_sample_spec *ss);