diff --git a/libavformat/file.c b/libavformat/file.c
index e21148e2b464f0bee4418b055fc89800ef440e52..defe3165e2c73a8f294051a181ba248759c353ba 100644
--- a/libavformat/file.c
+++ b/libavformat/file.c
@@ -135,12 +135,17 @@ static int file_open(URLContext *h, const char *filename, int flags)
 static int64_t file_seek(URLContext *h, int64_t pos, int whence)
 {
     FileContext *c = h->priv_data;
+    int ret;
+
     if (whence == AVSEEK_SIZE) {
         struct stat st;
-        int ret = fstat(c->fd, &st);
+        ret = fstat(c->fd, &st);
         return ret < 0 ? AVERROR(errno) : (S_ISFIFO(st.st_mode) ? 0 : st.st_size);
     }
-    return lseek(c->fd, pos, whence);
+
+    ret = lseek(c->fd, pos, whence);
+
+    return ret < 0 ? AVERROR(errno) : ret;
 }
 
 static int file_close(URLContext *h)
diff --git a/libavformat/mov.c b/libavformat/mov.c
index 078bd3f8eabf5f369bb0f11014d52dfaef4357f2..0bcdb21b88592121ef50630be39ac9ab6453f230 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -1204,16 +1204,16 @@ int ff_mov_read_stsd_entries(MOVContext *c, AVIOContext *pb, int entries)
         int dref_id = 1;
         MOVAtom a = { AV_RL32("stsd") };
         int64_t start_pos = avio_tell(pb);
-        int size = avio_rb32(pb); /* size */
+        int64_t size = avio_rb32(pb); /* size */
         uint32_t format = avio_rl32(pb); /* data format */
 
         if (size >= 16) {
             avio_rb32(pb); /* reserved */
             avio_rb16(pb); /* reserved */
             dref_id = avio_rb16(pb);
-        }else if (size <= 0){
+        }else if (size <= 7){
             av_log(c->fc, AV_LOG_ERROR, "invalid size %d in stsd\n", size);
-            return -1;
+            return AVERROR_INVALIDDATA;
         }
 
         if (st->codec->codec_tag &&