diff --git a/libavformat/flvenc.c b/libavformat/flvenc.c
index a1b498d9e1..fb36f662b7 100644
--- a/libavformat/flvenc.c
+++ b/libavformat/flvenc.c
@@ -539,7 +539,7 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
 
     if (enc->codec_type == AVMEDIA_TYPE_DATA) {
         int data_size;
-        int metadata_size_pos = avio_tell(pb);
+        int64_t metadata_size_pos = avio_tell(pb);
         avio_w8(pb, AMF_DATA_TYPE_STRING);
         put_amf_string(pb, "onTextData");
         avio_w8(pb, AMF_DATA_TYPE_MIXEDARRAY);