diff --git a/libavformat/mov.c b/libavformat/mov.c
index 0601830a1441d5d23df5dec1fc7f6508780b4907..54930a4052a23df44e8dedab6de47db18bb8ee3f 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -1212,6 +1212,8 @@ static int mov_read_aclr(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     uint64_t original_size;
     if (c->fc->nb_streams >= 1) {
         AVCodecContext *codec = c->fc->streams[c->fc->nb_streams-1]->codec;
+        if (codec->codec_id == AV_CODEC_ID_H264)
+            return 0;
         if (atom.size == 16) {
             original_size = codec->extradata_size;
             ret = mov_realloc_extradata(codec, atom);