diff --git a/libavformat/matroska.h b/libavformat/matroska.h
index 8a7e10b64d..af662bea4d 100644
--- a/libavformat/matroska.h
+++ b/libavformat/matroska.h
@@ -195,6 +195,7 @@
 #define MATROSKA_ID_BLOCK      0xA1
 #define MATROSKA_ID_BLOCKDURATION 0x9B
 #define MATROSKA_ID_BLOCKREFERENCE 0xFB
+#define MATROSKA_ID_CODECSTATE 0xA4
 
 /* IDs in the attachments master */
 #define MATROSKA_ID_ATTACHEDFILE        0x61A7
diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 9aca99a1a3..b82f289e9f 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -564,6 +564,7 @@ static EbmlSyntax matroska_blockgroup[] = {
     { MATROSKA_ID_SIMPLEBLOCK,    EBML_BIN,  0, offsetof(MatroskaBlock,bin) },
     { MATROSKA_ID_BLOCKDURATION,  EBML_UINT, 0, offsetof(MatroskaBlock,duration) },
     { MATROSKA_ID_BLOCKREFERENCE, EBML_UINT, 0, offsetof(MatroskaBlock,reference) },
+    { MATROSKA_ID_CODECSTATE,     EBML_NONE },
     { 1,                          EBML_UINT, 0, offsetof(MatroskaBlock,non_simple), {.u=1} },
     { 0 }
 };
diff --git a/libavformat/smacker.c b/libavformat/smacker.c
index 84481e22a6..7f270b48b1 100644
--- a/libavformat/smacker.c
+++ b/libavformat/smacker.c
@@ -276,7 +276,7 @@ static int smacker_read_packet(AVFormatContext *s, AVPacket *pkt)
                 } else if(t & 0x40){ /* copy with offset */
                     off = avio_r8(s->pb);
                     j = (t & 0x3F) + 1;
-                    if (off + j - 1 > 0xff) {
+                    if (off + j > 0x100) {
                         av_log(s, AV_LOG_ERROR,
                                "Invalid palette update, offset=%d length=%d extends beyond palette size\n",
                                off, j);