diff --git a/libavformat/matroska.c b/libavformat/matroska.c
index acfacc85dd..5878594e68 100644
--- a/libavformat/matroska.c
+++ b/libavformat/matroska.c
@@ -19,8 +19,6 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#include "libavutil/stereo3d.h"
-
 #include "matroska.h"
 
 /* If you add a tag here that is not in ff_codec_bmp_tags[]
@@ -145,59 +143,3 @@ const char * const ff_matroska_video_stereo_mode[MATROSKA_VIDEO_STEREOMODE_TYPE_
     "block_lr",
     "block_rl",
 };
-
-int ff_mkv_stereo3d_conv(AVStream *st, MatroskaVideoStereoModeType stereo_mode)
-{
-    AVStereo3D *stereo;
-    int ret;
-
-    stereo = av_stereo3d_alloc();
-    if (!stereo)
-        return AVERROR(ENOMEM);
-
-    // note: the missing breaks are intentional
-    switch (stereo_mode) {
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_MONO:
-        stereo->type = AV_STEREO3D_2D;
-        break;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_RIGHT_LEFT:
-        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_LEFT_RIGHT:
-        stereo->type = AV_STEREO3D_SIDEBYSIDE;
-        break;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_BOTTOM_TOP:
-        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_TOP_BOTTOM:
-        stereo->type = AV_STEREO3D_TOPBOTTOM;
-        break;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_CHECKERBOARD_RL:
-        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_CHECKERBOARD_LR:
-        stereo->type = AV_STEREO3D_CHECKERBOARD;
-        break;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_ROW_INTERLEAVED_RL:
-        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_ROW_INTERLEAVED_LR:
-        stereo->type = AV_STEREO3D_LINES;
-        break;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_COL_INTERLEAVED_RL:
-        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_COL_INTERLEAVED_LR:
-        stereo->type = AV_STEREO3D_COLUMNS;
-        break;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_BOTH_EYES_BLOCK_RL:
-        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_BOTH_EYES_BLOCK_LR:
-        stereo->type = AV_STEREO3D_FRAMESEQUENCE;
-        break;
-    }
-
-    ret = av_stream_add_side_data(st, AV_PKT_DATA_STEREO3D, (uint8_t *)stereo,
-                                  sizeof(*stereo));
-    if (ret < 0) {
-        av_freep(&stereo);
-        return ret;
-    }
-
-    return 0;
-}
diff --git a/libavformat/matroska.h b/libavformat/matroska.h
index 3a1ee740ce..719f2ef796 100644
--- a/libavformat/matroska.h
+++ b/libavformat/matroska.h
@@ -23,7 +23,6 @@
 #define AVFORMAT_MATROSKA_H
 
 #include "libavcodec/codec_id.h"
-#include "avformat.h"
 #include "metadata.h"
 
 /* EBML version supported */
@@ -437,8 +436,6 @@ extern const char * const ff_matroska_video_stereo_mode[MATROSKA_VIDEO_STEREOMOD
 #define TRACK_NUMBER "webm_dash_manifest_track_number"
 #define CODEC_PRIVATE_SIZE "webm_dash_manifest_codec_priv_size"
 
-int ff_mkv_stereo3d_conv(AVStream *st, MatroskaVideoStereoModeType stereo_mode);
-
 #define DVCC_DVVC_BLOCK_TYPE_NAME "Dolby Vision configuration"
 
 #endif /* AVFORMAT_MATROSKA_H */
diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index c6042eed2b..98695479c6 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -2163,6 +2163,62 @@ static void mkv_stereo_mode_display_mul(int stereo_mode,
     }
 }
 
+static int mkv_stereo3d_conv(AVStream *st, MatroskaVideoStereoModeType stereo_mode)
+{
+    AVStereo3D *stereo;
+    int ret;
+
+    stereo = av_stereo3d_alloc();
+    if (!stereo)
+        return AVERROR(ENOMEM);
+
+    // note: the missing breaks are intentional
+    switch (stereo_mode) {
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_MONO:
+        stereo->type = AV_STEREO3D_2D;
+        break;
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_RIGHT_LEFT:
+        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_LEFT_RIGHT:
+        stereo->type = AV_STEREO3D_SIDEBYSIDE;
+        break;
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_BOTTOM_TOP:
+        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_TOP_BOTTOM:
+        stereo->type = AV_STEREO3D_TOPBOTTOM;
+        break;
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_CHECKERBOARD_RL:
+        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_CHECKERBOARD_LR:
+        stereo->type = AV_STEREO3D_CHECKERBOARD;
+        break;
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_ROW_INTERLEAVED_RL:
+        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_ROW_INTERLEAVED_LR:
+        stereo->type = AV_STEREO3D_LINES;
+        break;
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_COL_INTERLEAVED_RL:
+        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_COL_INTERLEAVED_LR:
+        stereo->type = AV_STEREO3D_COLUMNS;
+        break;
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_BOTH_EYES_BLOCK_RL:
+        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
+    case MATROSKA_VIDEO_STEREOMODE_TYPE_BOTH_EYES_BLOCK_LR:
+        stereo->type = AV_STEREO3D_FRAMESEQUENCE;
+        break;
+    }
+
+    ret = av_stream_add_side_data(st, AV_PKT_DATA_STEREO3D, (uint8_t *)stereo,
+                                  sizeof(*stereo));
+    if (ret < 0) {
+        av_freep(&stereo);
+        return ret;
+    }
+
+    return 0;
+}
+
 static int mkv_parse_video_color(AVStream *st, const MatroskaTrack *track) {
     const MatroskaTrackVideoColor *color = track->video.color.elem;
     const MatroskaMasteringMeta *mastering_meta;
@@ -3008,7 +3064,7 @@ static int matroska_parse_tracks(AVFormatContext *s)
             // add stream level stereo3d side data if it is a supported format
             if (track->video.stereo_mode < MATROSKA_VIDEO_STEREOMODE_TYPE_NB &&
                 track->video.stereo_mode != 10 && track->video.stereo_mode != 12) {
-                int ret = ff_mkv_stereo3d_conv(st, track->video.stereo_mode);
+                int ret = mkv_stereo3d_conv(st, track->video.stereo_mode);
                 if (ret < 0)
                     return ret;
             }