diff --git a/src/oapv.c b/src/oapv.c
index 696be50..6d29453 100644
--- a/src/oapv.c
+++ b/src/oapv.c
@@ -797,7 +797,7 @@ static int enc_tile_comp(oapv_bs_t *bs, oapve_tile_t *tile, oapve_ctx_t *ctx, oa
                     ctx->fn_enc_blk(ctx, core, OAPV_LOG2_BLK_W, OAPV_LOG2_BLK_H, c);
                     oapve_vlc_dc_coef(bs, core->dc_diff, &core->kparam_dc[c]);
                     oapve_vlc_ac_coef(bs, core->coef, &core->kparam_ac[c]);
-                    DUMP_COEF(core->coef, OAPV_BLK_D, blk_x, blk_y, c);
+                    DUMP_COEF(core->dc_diff, core->coef + 1, OAPV_BLK_D - 1, blk_x, blk_y, c);
 
                     if(rec != NULL) {
                         r16 = (s16 *)((u8 *)rec + blk_y * s_rec) + blk_x;
@@ -1639,7 +1639,7 @@ static int dec_tile_comp(oapvd_tile_t *tile, oapvd_ctx_t *ctx, oapvd_core_t *cor
                     // parse AC coefficient
                     ret = oapvd_vlc_ac_coef(bs, core->coef, &core->kparam_ac[c]);
                     oapv_assert_rv(OAPV_SUCCEEDED(ret), ret);
-                    DUMP_COEF(core->coef, OAPV_BLK_D, blk_x, blk_y, c);
+                    DUMP_COEF(core->dc_diff, core->coef + 1, OAPV_BLK_D - 1, blk_x, blk_y, c);
 
                     // decode a block
                     ret = dec_block(ctx, core, OAPV_LOG2_BLK_W, OAPV_LOG2_BLK_H, c);
diff --git a/src/oapv_util.c b/src/oapv_util.c
index f6a0cec..eed3b6c 100644
--- a/src/oapv_util.c
+++ b/src/oapv_util.c
@@ -401,13 +401,14 @@ void oapv_dump_string0(int cond, const char *fmt, ...)
     va_end(args);
 }
 
-void oapv_dump_coef0(short *coef, int size, int x, int y, int c)
+void oapv_dump_coef0(int dc, short *coef, int size, int x, int y, int c)
 {
     if(!DUMP_ENABLE_COEF || !oapv_is_dump)
         return;
 
     fprintf(oapv_fp_dump, "x pos : % d y pos : % d comp : % d\n", x, y, c);
     fprintf(oapv_fp_dump, "coef:");
+    fprintf(oapv_fp_dump, " %d", dc);
     for(int i = 0; i < size; i++) {
         fprintf(oapv_fp_dump, " %d", coef[i]);
     }
diff --git a/src/oapv_util.h b/src/oapv_util.h
index 458ca45..834d0d4 100644
--- a/src/oapv_util.h
+++ b/src/oapv_util.h
@@ -171,7 +171,7 @@ extern FILE *oapv_fp_dump;
 extern int   oapv_is_dump;
 
 void oapv_dump_string0(int cond, const char *fmt, ...);
-void oapv_dump_coef0(short *coef, int size, int x, int y, int c);
+void oapv_dump_coef0(int dc, short *coef, int size, int x, int y, int c);
 void oapv_dump_create0(int is_enc);
 void oapv_dump_delete0();
 
@@ -181,8 +181,8 @@ void oapv_dump_delete0();
 #define DUMP_SET(val)       oapv_is_dump = val
 #define DUMP_HLS(name, val) \
     oapv_dump_string0(OAPV_DUMP_HLS, "%-34s: %12d\n", #name, val)
-#define DUMP_COEF(coef, size, x, y, c) \
-    oapv_dump_coef0(coef, size, x, y, c)
+#define DUMP_COEF(dc, coef, size, x, y, c) \
+    oapv_dump_coef0(dc, coef, size, x, y, c)
 #define DUMP_SAVE(id) long dump32u8i90432890_##id = ftell(oapv_fp_dump)
 #define DUMP_LOAD(id) fseek(oapv_fp_dump, dump32u8i90432890_##id, SEEK_SET)
 #else
@@ -190,7 +190,7 @@ void oapv_dump_delete0();
 #define DUMP_DELETE()
 #define DUMP_SET(val)
 #define DUMP_HLS(name, val)
-#define DUMP_COEF(coef, size, args, ...)
+#define DUMP_COEF(dc, coef, size, args, ...)
 #define DUMP_SAVE(id)
 #define DUMP_LOAD(id)
 #endif
diff --git a/src/oapv_vlc.c b/src/oapv_vlc.c
index 54cc783..d0ed8ae 100644
--- a/src/oapv_vlc.c
+++ b/src/oapv_vlc.c
@@ -450,6 +450,7 @@ int oapve_vlc_pbu_size(oapv_bs_t *bs, int pbu_size)
 
 int oapve_vlc_pbu_header(oapv_bs_t *bs, int pbu_type, int group_id)
 {
+    DUMP_HLS(pbu_size, 0);
     oapv_bsw_write(bs, pbu_type, 8);
     DUMP_HLS(pbu_type, pbu_type);
     oapv_bsw_write(bs, group_id, 16);
@@ -466,6 +467,8 @@ int oapve_vlc_metadata(oapv_md_t *md, oapv_bs_t *bs)
     bs_pos_md = oapv_bsw_sink(bs);
 
     oapv_bsw_write(bs, 0, 32); // raw bitstream byte size (skip)
+    DUMP_SAVE(0);
+    DUMP_HLS(metadata_size, 0);
 
     oapv_mdp_t *mdp = md->md_payload;
 
@@ -498,7 +501,10 @@ int oapve_vlc_metadata(oapv_md_t *md, oapv_bs_t *bs)
     }
     u32 md_size = (u32)((u8 *)oapv_bsw_sink(bs) - bs_pos_md) - 4;
     oapv_bsw_write_direct(bs_pos_md, md_size, 32);
+    DUMP_SAVE(1);
+    DUMP_LOAD(0);
     DUMP_HLS(metadata_size, md_size);
+    DUMP_LOAD(1);
 
     return OAPV_OK;
 }