diff --git a/libavformat/wavdec.c b/libavformat/wavdec.c
index adf41ecd89..d5b3b9ef2f 100644
--- a/libavformat/wavdec.c
+++ b/libavformat/wavdec.c
@@ -54,6 +54,7 @@ typedef struct WAVDemuxContext {
     int spdif;
     int smv_cur_pt;
     int smv_given_first;
+    int unaligned; // e.g. if an odd number of bytes ID3 tag was prepended
 } WAVDemuxContext;
 
 #if CONFIG_WAV_DEMUXER
@@ -64,16 +65,16 @@ static int64_t next_tag(AVIOContext *pb, uint32_t *tag)
     return avio_rl32(pb);
 }
 
-/* RIFF chunks are always on a even offset. */
-static int64_t wav_seek_tag(AVIOContext *s, int64_t offset, int whence)
+/* RIFF chunks are always at even offsets relative to where they start. */
+static int64_t wav_seek_tag(WAVDemuxContext * wav, AVIOContext *s, int64_t offset, int whence)
 {
-    offset += offset < INT64_MAX && offset & 1;
+    offset += offset < INT64_MAX && offset + wav->unaligned & 1;
 
     return avio_seek(s, offset, whence);
 }
 
 /* return the size of the found tag */
-static int64_t find_tag(AVIOContext *pb, uint32_t tag1)
+static int64_t find_tag(WAVDemuxContext * wav, AVIOContext *pb, uint32_t tag1)
 {
     unsigned int tag;
     int64_t size;
@@ -84,7 +85,7 @@ static int64_t find_tag(AVIOContext *pb, uint32_t tag1)
         size = next_tag(pb, &tag);
         if (tag == tag1)
             break;
-        wav_seek_tag(pb, size, SEEK_CUR);
+        wav_seek_tag(wav, pb, size, SEEK_CUR);
     }
     return size;
 }
@@ -247,6 +248,8 @@ static int wav_read_header(AVFormatContext *s)
     int ret, got_fmt = 0;
     int64_t next_tag_ofs, data_ofs = -1;
 
+    wav->unaligned = avio_tell(s->pb) & 1;
+
     wav->smv_data_ofs = -1;
 
     /* check RIFF header */
@@ -383,7 +386,7 @@ static int wav_read_header(AVFormatContext *s)
 
         /* seek to next tag unless we know that we'll run into EOF */
         if ((avio_size(pb) > 0 && next_tag_ofs >= avio_size(pb)) ||
-            wav_seek_tag(pb, next_tag_ofs, SEEK_SET) < 0) {
+            wav_seek_tag(wav, pb, next_tag_ofs, SEEK_SET) < 0) {
             break;
         }
     }
@@ -511,7 +514,7 @@ smv_out:
         if (CONFIG_W64_DEMUXER && wav->w64)
             left = find_guid(s->pb, ff_w64_guid_data) - 24;
         else
-            left = find_tag(s->pb, MKTAG('d', 'a', 't', 'a'));
+            left = find_tag(wav, s->pb, MKTAG('d', 'a', 't', 'a'));
         if (left < 0) {
             wav->audio_eof = 1;
             if (wav->smv_data_ofs > 0 && !wav->smv_eof)