diff --git a/libavcodec/smacker.c b/libavcodec/smacker.c
index a6f169aca6..162c68ada3 100644
--- a/libavcodec/smacker.c
+++ b/libavcodec/smacker.c
@@ -425,7 +425,7 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, uint8
             break;
         case SMK_BLK_FULL:
             mode = 0;
-            if(avctx->codec_tag != 0) { // In case of Smacker v4 we have three modes
+            if(avctx->codec_tag == MKTAG('S', 'M', 'K', '4')) { // In case of Smacker v4 we have three modes
                 if(get_bits1(&gb)) mode = 1;
                 else if(get_bits1(&gb)) mode = 2;
             }
diff --git a/libavformat/smacker.c b/libavformat/smacker.c
index 7733da3bd7..be01f5bde6 100644
--- a/libavformat/smacker.c
+++ b/libavformat/smacker.c
@@ -156,7 +156,7 @@ static int smacker_read_header(AVFormatContext *s, AVFormatParameters *ap)
     st->codec->pix_fmt = PIX_FMT_PAL8;
     st->codec->codec_type = CODEC_TYPE_VIDEO;
     st->codec->codec_id = CODEC_ID_SMACKVIDEO;
-    st->codec->codec_tag = smk->is_ver4;
+    st->codec->codec_tag = smk->magic;
     /* Smacker uses 100000 as internal timebase */
     if(smk->pts_inc < 0)
         smk->pts_inc = -smk->pts_inc;
@@ -174,7 +174,7 @@ static int smacker_read_header(AVFormatContext *s, AVFormatParameters *ap)
             av_set_pts_info(ast[i], 33, smk->pts_inc, tbase);
             ast[i]->codec->codec_type = CODEC_TYPE_AUDIO;
             ast[i]->codec->codec_id = (smk->rates[i] & SMK_AUD_PACKED) ? CODEC_ID_SMACKAUDIO : CODEC_ID_PCM_U8;
-            ast[i]->codec->codec_tag = 0;
+            ast[i]->codec->codec_tag = MKTAG('S', 'M', 'K', 'A');
             ast[i]->codec->channels = (smk->rates[i] & SMK_AUD_STEREO) ? 2 : 1;
             ast[i]->codec->sample_rate = smk->rates[i] & 0xFFFFFF;
             ast[i]->codec->bits_per_sample = (smk->rates[i] & SMK_AUD_16BITS) ? 16 : 8;