add seekpoint placeholder
diff --git a/src/libFLAC/format.c b/src/libFLAC/format.c
index 291581a..3fee5f4 100644
--- a/src/libFLAC/format.c
+++ b/src/libFLAC/format.c
@@ -40,9 +40,11 @@
 
 const unsigned FLAC__STREAM_METADATA_SEEKPOINT_SAMPLE_NUMBER_LEN = 64; /* bits */
 const unsigned FLAC__STREAM_METADATA_SEEKPOINT_STREAM_OFFSET_LEN = 64; /* bits */
-const unsigned FLAC__STREAM_METADATA_SEEKPOINT_BLOCK_OFFSET_LEN = 16; /* bits */
+const unsigned FLAC__STREAM_METADATA_SEEKPOINT_FRAME_SAMPLES_LEN = 16; /* bits */
 const unsigned FLAC__STREAM_METADATA_SEEKPOINT_LEN = 18; /* bytes */
 
+const uint64 FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER = 0xffffffffffffffff;
+
 const unsigned FLAC__STREAM_METADATA_IS_LAST_LEN = 1; /* bits */
 const unsigned FLAC__STREAM_METADATA_TYPE_LEN = 7; /* bits */
 const unsigned FLAC__STREAM_METADATA_LENGTH_LEN = 24; /* bits */