diff --git a/libavformat/demux.h b/libavformat/demux.h
index 209cd813ab..a008c3dba1 100644
--- a/libavformat/demux.h
+++ b/libavformat/demux.h
@@ -226,4 +226,10 @@ int ff_generate_avci_extradata(AVStream *st);
  */
 int ff_get_extradata(void *logctx, AVCodecParameters *par, AVIOContext *pb, int size);
 
+/**
+ * Find stream index based on format-specific stream ID
+ * @return stream index, or < 0 on error
+ */
+int ff_find_stream_index(const AVFormatContext *s, int id);
+
 #endif /* AVFORMAT_DEMUX_H */
diff --git a/libavformat/demux_utils.c b/libavformat/demux_utils.c
index a59476e0da..56cc6e15d8 100644
--- a/libavformat/demux_utils.c
+++ b/libavformat/demux_utils.c
@@ -367,3 +367,11 @@ int ff_get_extradata(void *logctx, AVCodecParameters *par, AVIOContext *pb, int
 
     return ret;
 }
+
+int ff_find_stream_index(const AVFormatContext *s, int id)
+{
+    for (unsigned i = 0; i < s->nb_streams; i++)
+        if (s->streams[i]->id == id)
+            return i;
+    return -1;
+}
diff --git a/libavformat/gxf.c b/libavformat/gxf.c
index e61291382a..f720521c1b 100644
--- a/libavformat/gxf.c
+++ b/libavformat/gxf.c
@@ -24,6 +24,7 @@
 #include "libavutil/channel_layout.h"
 #include "libavutil/common.h"
 #include "avformat.h"
+#include "demux.h"
 #include "internal.h"
 #include "gxf.h"
 
diff --git a/libavformat/internal.h b/libavformat/internal.h
index acda79821a..44516578b0 100644
--- a/libavformat/internal.h
+++ b/libavformat/internal.h
@@ -558,12 +558,6 @@ typedef void (*ff_parse_key_val_cb)(void *context, const char *key,
 void ff_parse_key_value(const char *str, ff_parse_key_val_cb callback_get_buf,
                         void *context);
 
-/**
- * Find stream index based on format-specific stream ID
- * @return stream index, or < 0 on error
- */
-int ff_find_stream_index(const AVFormatContext *s, int id);
-
 enum AVCodecID ff_guess_image2_codec(const char *filename);
 
 const AVCodec *ff_find_decoder(AVFormatContext *s, const AVStream *st,
diff --git a/libavformat/utils.c b/libavformat/utils.c
index c8d975ddcc..68ea1d1050 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -644,14 +644,6 @@ void ff_parse_key_value(const char *str, ff_parse_key_val_cb callback_get_buf,
     }
 }
 
-int ff_find_stream_index(const AVFormatContext *s, int id)
-{
-    for (unsigned i = 0; i < s->nb_streams; i++)
-        if (s->streams[i]->id == id)
-            return i;
-    return -1;
-}
-
 int avformat_network_init(void)
 {
 #if CONFIG_NETWORK