diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index dbf71a7..3062723 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -868,6 +868,23 @@ av_cold int ff_h264_decode_init(AVCodecContext *avctx){
     H264Context *h= avctx->priv_data;
     MpegEncContext * const s = &h->s;
 
+    avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
+
+    ff_h264_context_init(avctx, h);
+
+    if(avctx->codec_id == CODEC_ID_H264){
+        if(avctx->ticks_per_frame == 1){
+            s->avctx->time_base.den *=2;
+        }
+        avctx->ticks_per_frame = 2;
+    }
+
+    return 0;
+}
+
+av_cold int ff_h264_context_init(AVCodecContext *avctx, H264Context *h){
+    MpegEncContext * const s = &h->s;
+
     MPV_decode_defaults(s);
 
     s->avctx = avctx;
@@ -880,9 +897,7 @@ av_cold int ff_h264_decode_init(AVCodecContext *avctx){
 //    s->decode_mb= ff_h263_decode_mb;
     s->quarter_sample = 1;
     if(!avctx->has_b_frames)
-    s->low_delay= 1;
-
-    avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
+        s->low_delay= 1;
 
     ff_h264_decode_init_vlc();
 
@@ -891,18 +906,16 @@ av_cold int ff_h264_decode_init(AVCodecContext *avctx){
     h->prev_poc_msb= 1<<16;
     h->x264_build = -1;
     ff_h264_reset_sei(h);
-    if(avctx->codec_id == CODEC_ID_H264){
-        if(avctx->ticks_per_frame == 1){
-            s->avctx->time_base.den *=2;
-        }
-        avctx->ticks_per_frame = 2;
-    }
 
     if(avctx->extradata_size > 0 && avctx->extradata &&
         ff_h264_decode_extradata(h))
         return -1;
 
     if(h->sps.bitstream_restriction_flag && s->avctx->has_b_frames < h->sps.num_reorder_frames){
+        /*
+         * I'm a bit dubious about touching has_b_frames here, but
+         * has_b_frames usually is modified in tandem with low_delay.
+         */
         s->avctx->has_b_frames = h->sps.num_reorder_frames;
         s->low_delay = 0;
     }
diff --git a/libavcodec/h264.h b/libavcodec/h264.h
index 96720ac..caa13f6 100644
--- a/libavcodec/h264.h
+++ b/libavcodec/h264.h
@@ -681,6 +681,7 @@ void ff_h264_hl_decode_mb(H264Context *h);
 int ff_h264_frame_start(H264Context *h);
 int ff_h264_decode_extradata(H264Context *h);
 av_cold int ff_h264_decode_init(AVCodecContext *avctx);
+av_cold int ff_h264_context_init(AVCodecContext *avctx, H264Context *h);
 av_cold int ff_h264_decode_end(AVCodecContext *avctx);
 av_cold void ff_h264_decode_init_vlc(void);
 
diff --git a/libavcodec/h264_parser.c b/libavcodec/h264_parser.c
index 91fbebc..cdbf96a 100644
--- a/libavcodec/h264_parser.c
+++ b/libavcodec/h264_parser.c
@@ -249,10 +249,7 @@ static int h264_parse(AVCodecParserContext *s,
 
     if (!h->got_first) {
         h->got_first = 1;
-        if (avctx->extradata_size) {
-            h->s.avctx = avctx;
-            ff_h264_decode_extradata(h);
-        }
+        ff_h264_context_init(avctx, h);
     }
 
     if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){