diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 6f094c458c8d2d112041ab230ecb916ede72611b..dad6d6c93f1bd4cffa36068d9010b9a8e667f9b1 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -953,78 +953,79 @@ static int mkv_write_video_color(AVIOContext *pb, AVCodecParameters *par, AVStre
     return 0;
 }
 
-static int mkv_write_video_projection(AVFormatContext *s, AVIOContext *pb, AVStream *st)
+static int mkv_write_video_projection(AVFormatContext *s, AVIOContext *pb,
+                                      AVStream *st)
 {
+    AVIOContext b;
+    AVIOContext *dyn_cp;
     int side_data_size = 0;
+    int ret, projection_size;
+    uint8_t *projection_ptr;
+    uint8_t private[20];
+
     const AVSphericalMapping *spherical =
-        (const AVSphericalMapping*) av_stream_get_side_data(st, AV_PKT_DATA_SPHERICAL,
+        (const AVSphericalMapping *)av_stream_get_side_data(st, AV_PKT_DATA_SPHERICAL,
                                                             &side_data_size);
 
-    if (side_data_size) {
-        AVIOContext *dyn_cp;
-        uint8_t *projection_ptr;
-        int ret, projection_size;
+    if (!side_data_size)
+        return 0;
 
-        ret = avio_open_dyn_buf(&dyn_cp);
-        if (ret < 0)
-            return ret;
+    ret = avio_open_dyn_buf(&dyn_cp);
+    if (ret < 0)
+        return ret;
 
-        switch (spherical->projection) {
-        case AV_SPHERICAL_EQUIRECTANGULAR:
-            put_ebml_uint(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONTYPE,
-                          MATROSKA_VIDEO_PROJECTION_TYPE_EQUIRECTANGULAR);
-            break;
-        case AV_SPHERICAL_EQUIRECTANGULAR_TILE:
-        {
-            AVIOContext b;
-            uint8_t private[20];
-            ffio_init_context(&b, private, sizeof(private),
-                              1, NULL, NULL, NULL, NULL);
-            put_ebml_uint(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONTYPE,
-                          MATROSKA_VIDEO_PROJECTION_TYPE_EQUIRECTANGULAR);
-            avio_wb32(&b, 0); // version + flags
-            avio_wb32(&b, spherical->bound_top);
-            avio_wb32(&b, spherical->bound_bottom);
-            avio_wb32(&b, spherical->bound_left);
-            avio_wb32(&b, spherical->bound_right);
-            put_ebml_binary(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPRIVATE, private, sizeof(private));
-            break;
-        }
-        case AV_SPHERICAL_CUBEMAP:
-        {
-            AVIOContext b;
-            uint8_t private[12];
-            ffio_init_context(&b, private, sizeof(private),
-                              1, NULL, NULL, NULL, NULL);
-            put_ebml_uint(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONTYPE,
-                          MATROSKA_VIDEO_PROJECTION_TYPE_CUBEMAP);
-            avio_wb32(&b, 0); // version + flags
-            avio_wb32(&b, 0); // layout
-            avio_wb32(&b, spherical->padding);
-            put_ebml_binary(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPRIVATE, private, sizeof(private));
-            break;
-        }
-        default:
-            av_log(s, AV_LOG_WARNING, "Unknown projection type\n");
-            goto end;
-        }
+    switch (spherical->projection) {
+    case AV_SPHERICAL_EQUIRECTANGULAR:
+        put_ebml_uint(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONTYPE,
+                      MATROSKA_VIDEO_PROJECTION_TYPE_EQUIRECTANGULAR);
+        break;
+    case AV_SPHERICAL_EQUIRECTANGULAR_TILE:
+        ffio_init_context(&b, private, 20, 1, NULL, NULL, NULL, NULL);
+        put_ebml_uint(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONTYPE,
+                      MATROSKA_VIDEO_PROJECTION_TYPE_EQUIRECTANGULAR);
+        avio_wb32(&b, 0); // version + flags
+        avio_wb32(&b, spherical->bound_top);
+        avio_wb32(&b, spherical->bound_bottom);
+        avio_wb32(&b, spherical->bound_left);
+        avio_wb32(&b, spherical->bound_right);
+        put_ebml_binary(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPRIVATE,
+                        private, avio_tell(&b));
+        break;
+    case AV_SPHERICAL_CUBEMAP:
+        ffio_init_context(&b, private, 12, 1, NULL, NULL, NULL, NULL);
+        put_ebml_uint(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONTYPE,
+                      MATROSKA_VIDEO_PROJECTION_TYPE_CUBEMAP);
+        avio_wb32(&b, 0); // version + flags
+        avio_wb32(&b, 0); // layout
+        avio_wb32(&b, spherical->padding);
+        put_ebml_binary(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPRIVATE,
+                        private, avio_tell(&b));
+        break;
+    default:
+        av_log(s, AV_LOG_WARNING, "Unknown projection type\n");
+        goto end;
+    }
 
-        if (spherical->yaw)
-            put_ebml_float(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPOSEYAW,   (double)spherical->yaw   / (1 << 16));
-        if (spherical->pitch)
-            put_ebml_float(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPOSEPITCH, (double)spherical->pitch / (1 << 16));
-        if (spherical->roll)
-            put_ebml_float(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPOSEROLL,  (double)spherical->roll  / (1 << 16));
+    if (spherical->yaw)
+        put_ebml_float(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPOSEYAW,
+                       (double) spherical->yaw   / (1 << 16));
+    if (spherical->pitch)
+        put_ebml_float(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPOSEPITCH,
+                       (double) spherical->pitch / (1 << 16));
+    if (spherical->roll)
+        put_ebml_float(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPOSEROLL,
+                       (double) spherical->roll  / (1 << 16));
 
 end:
-        projection_size = avio_close_dyn_buf(dyn_cp, &projection_ptr);
-        if (projection_size) {
-            ebml_master projection = start_ebml_master(pb, MATROSKA_ID_VIDEOPROJECTION, projection_size);
-            avio_write(pb, projection_ptr, projection_size);
-            end_ebml_master(pb, projection);
-        }
-        av_freep(&projection_ptr);
-    }
+    projection_size = avio_close_dyn_buf(dyn_cp, &projection_ptr);
+    if (projection_size) {
+        ebml_master projection = start_ebml_master(pb,
+                                                   MATROSKA_ID_VIDEOPROJECTION,
+                                                   projection_size);
+        avio_write(pb, projection_ptr, projection_size);
+        end_ebml_master(pb, projection);
+    }
+    av_freep(&projection_ptr);
 
     return 0;
 }