diff --git a/trunk/src/app/srs_app_hls.cpp b/trunk/src/app/srs_app_hls.cpp
index af30d4809f..83326fd6c1 100644
--- a/trunk/src/app/srs_app_hls.cpp
+++ b/trunk/src/app/srs_app_hls.cpp
@@ -1071,7 +1071,7 @@ int SrsHlsCache::write_video(SrsAvcAacCodec* codec, SrsHlsMuxer* muxer, int64_t
         //      b. always reap when not wait keyframe.
         if (!muxer->wait_keyframe() || sample->frame_type == SrsCodecVideoAVCFrameKeyFrame) {
             // when wait keyframe, there must exists idr frame in sample, or NonIDR(open gop) specified.
-            if (!sample->has_non_idr && !sample->has_idr && muxer->wait_keyframe()) {
+            if (!sample->open_gop && !sample->has_idr && muxer->wait_keyframe()) {
                 srs_warn("hls: ts starts without IDR, first nalu=%d, idr=%d", sample->first_nalu_type, sample->has_idr);
             }
             
@@ -1274,6 +1274,8 @@ void SrsHls::on_unpublish()
         srs_error("ignore m3u8 muxer flush/close audio failed. ret=%d", ret);
     }
     
+    sample->reset();
+    
     hls_enabled = false;
 }
 
diff --git a/trunk/src/kernel/srs_kernel_codec.cpp b/trunk/src/kernel/srs_kernel_codec.cpp
index f0e05ced14..a1537a32be 100644
--- a/trunk/src/kernel/srs_kernel_codec.cpp
+++ b/trunk/src/kernel/srs_kernel_codec.cpp
@@ -324,13 +324,20 @@ SrsCodecSampleUnit::~SrsCodecSampleUnit()
 
 SrsCodecSample::SrsCodecSample()
 {
-    clear();
+    reset();
 }
 
 SrsCodecSample::~SrsCodecSample()
 {
 }
 
+void SrsCodecSample::reset()
+{
+    clear();
+    
+    open_gop = false;
+}
+
 void SrsCodecSample::clear()
 {
     is_video = false;
@@ -339,7 +346,7 @@ void SrsCodecSample::clear()
     cts = 0;
     frame_type = SrsCodecVideoAVCFrameReserved;
     avc_packet_type = SrsCodecVideoAVCTypeReserved;
-    has_aud = has_sei = has_non_idr = has_idr = false;
+    has_aud = has_idr = false;
     first_nalu_type = SrsAvcNaluTypeReserved;
     
     acodec = SrsCodecAudioReserved1;
@@ -370,10 +377,6 @@ int SrsCodecSample::add_sample_unit(char* bytes, int size)
         
         if (nal_unit_type == SrsAvcNaluTypeIDR) {
             has_idr = true;
-        } else if (nal_unit_type == SrsAvcNaluTypeNonIDR) {
-            has_non_idr = true;
-        } else if (nal_unit_type == SrsAvcNaluTypeSEI) {
-            has_sei = true;
         } else if (nal_unit_type == SrsAvcNaluTypeAccessUnitDelimiter) {
             has_aud = true;
         }
@@ -698,66 +701,82 @@ int SrsAvcAacCodec::video_avc_demux(char* data, int size, SrsCodecSample* sample
             return ret;
         }
     } else if (avc_packet_type == SrsCodecVideoAVCTypeNALU){
-        // ensure the sequence header demuxed
-        if (!is_avc_codec_ok()) {
-            srs_warn("avc ignore type=%d for no sequence header. ret=%d", avc_packet_type, ret);
+        if ((ret = video_nalu_demux(stream, sample)) != ERROR_SUCCESS) {
             return ret;
         }
+    } else {
+        // ignored.
+    }
+    
+    srs_info("avc decoded, type=%d, codec=%d, avc=%d, cts=%d, size=%d",
+        frame_type, video_codec_id, avc_packet_type, composition_time, size);
+    
+    return ret;
+}
 
-        // guess for the first time.
-        if (payload_format == SrsAvcPayloadFormatGuess) {
-            // One or more NALUs (Full frames are required)
-            // try  "AnnexB" from H.264-AVC-ISO_IEC_14496-10.pdf, page 211.
-            if ((ret = avc_demux_annexb_format(stream, sample)) != ERROR_SUCCESS) {
-                // stop try when system error.
-                if (ret != ERROR_HLS_AVC_TRY_OTHERS) {
-                    srs_error("avc demux for annexb failed. ret=%d", ret);
-                    return ret;
-                }
-                
-                // try "ISO Base Media File Format" from H.264-AVC-ISO_IEC_14496-15.pdf, page 20
-                if ((ret = avc_demux_ibmf_format(stream, sample)) != ERROR_SUCCESS) {
-                    return ret;
-                } else {
-                    payload_format = SrsAvcPayloadFormatIbmf;
-                    srs_info("hls guess avc payload is ibmf format.");
-                }
-            } else {
-                payload_format = SrsAvcPayloadFormatAnnexb;
-                srs_info("hls guess avc payload is annexb format.");
+int SrsAvcAacCodec::video_nalu_demux(SrsStream* stream, SrsCodecSample* sample)
+{
+    int ret = ERROR_SUCCESS;
+    
+    // ensure the sequence header demuxed
+    if (!is_avc_codec_ok()) {
+        srs_warn("avc ignore type=%d for no sequence header. ret=%d", SrsCodecVideoAVCTypeNALU, ret);
+        return ret;
+    }
+    
+    // guess for the first time.
+    if (payload_format == SrsAvcPayloadFormatGuess) {
+        // One or more NALUs (Full frames are required)
+        // try  "AnnexB" from H.264-AVC-ISO_IEC_14496-10.pdf, page 211.
+        if ((ret = avc_demux_annexb_format(stream, sample)) != ERROR_SUCCESS) {
+            // stop try when system error.
+            if (ret != ERROR_HLS_AVC_TRY_OTHERS) {
+                srs_error("avc demux for annexb failed. ret=%d", ret);
+                return ret;
             }
-        } else if (payload_format == SrsAvcPayloadFormatIbmf) {
+            
             // try "ISO Base Media File Format" from H.264-AVC-ISO_IEC_14496-15.pdf, page 20
             if ((ret = avc_demux_ibmf_format(stream, sample)) != ERROR_SUCCESS) {
                 return ret;
+            } else {
+                payload_format = SrsAvcPayloadFormatIbmf;
+                srs_info("hls guess avc payload is ibmf format.");
             }
-            srs_info("hls decode avc payload in ibmf format.");
         } else {
-            // One or more NALUs (Full frames are required)
-            // try  "AnnexB" from H.264-AVC-ISO_IEC_14496-10.pdf, page 211.
-            if ((ret = avc_demux_annexb_format(stream, sample)) != ERROR_SUCCESS) {
-                // ok, we guess out the payload is annexb, but maybe changed to ibmf.
-                if (ret != ERROR_HLS_AVC_TRY_OTHERS) {
-                    srs_error("avc demux for annexb failed. ret=%d", ret);
-                    return ret;
-                }
-                
-                // try "ISO Base Media File Format" from H.264-AVC-ISO_IEC_14496-15.pdf, page 20
-                if ((ret = avc_demux_ibmf_format(stream, sample)) != ERROR_SUCCESS) {
-                    return ret;
-                } else {
-                    payload_format = SrsAvcPayloadFormatIbmf;
-                    srs_warn("hls avc payload change from annexb to ibmf format.");
-                }
-            }
-            srs_info("hls decode avc payload in annexb format.");
+            payload_format = SrsAvcPayloadFormatAnnexb;
+            srs_info("hls guess avc payload is annexb format.");
         }
+    } else if (payload_format == SrsAvcPayloadFormatIbmf) {
+        // try "ISO Base Media File Format" from H.264-AVC-ISO_IEC_14496-15.pdf, page 20
+        if ((ret = avc_demux_ibmf_format(stream, sample)) != ERROR_SUCCESS) {
+            return ret;
+        }
+        srs_info("hls decode avc payload in ibmf format.");
     } else {
-        // ignored.
+        // One or more NALUs (Full frames are required)
+        // try  "AnnexB" from H.264-AVC-ISO_IEC_14496-10.pdf, page 211.
+        if ((ret = avc_demux_annexb_format(stream, sample)) != ERROR_SUCCESS) {
+            // ok, we guess out the payload is annexb, but maybe changed to ibmf.
+            if (ret != ERROR_HLS_AVC_TRY_OTHERS) {
+                srs_error("avc demux for annexb failed. ret=%d", ret);
+                return ret;
+            }
+            
+            // try "ISO Base Media File Format" from H.264-AVC-ISO_IEC_14496-15.pdf, page 20
+            if ((ret = avc_demux_ibmf_format(stream, sample)) != ERROR_SUCCESS) {
+                return ret;
+            } else {
+                payload_format = SrsAvcPayloadFormatIbmf;
+                srs_warn("hls avc payload change from annexb to ibmf format.");
+            }
+        }
+        srs_info("hls decode avc payload in annexb format.");
     }
     
-    srs_info("avc decoded, type=%d, codec=%d, avc=%d, cts=%d, size=%d",
-        frame_type, video_codec_id, avc_packet_type, composition_time, size);
+    // for keyframe, but not IDR, it's open gop.
+    if (sample->frame_type == SrsCodecVideoAVCFrameKeyFrame && !sample->has_idr) {
+        sample->open_gop = true;
+    }
     
     return ret;
 }
diff --git a/trunk/src/kernel/srs_kernel_codec.hpp b/trunk/src/kernel/srs_kernel_codec.hpp
index 362196af55..450bfc77b7 100644
--- a/trunk/src/kernel/srs_kernel_codec.hpp
+++ b/trunk/src/kernel/srs_kernel_codec.hpp
@@ -385,14 +385,14 @@ class SrsCodecSample
     SrsCodecVideoAVCType avc_packet_type;
     // whether sample_units contains IDR frame.
     bool has_idr;
-    // Whether exists NonIDR NALU.
-    bool has_non_idr;
-    // Whether exists SEI NALU.
-    bool has_sei;
     // Whether exists AUD NALU.
     bool has_aud;
     // The first nalu type.
     SrsAvcNaluType first_nalu_type;
+public:
+    // Whether stream is open gop, which means the keyframe is not IDR but NonIDR.
+    // @remark we will identify whether stream is open-gop util reset.
+    bool open_gop;
 public:
     // audio specified
     SrsCodecAudio acodec;
@@ -405,6 +405,8 @@ class SrsCodecSample
     SrsCodecSample();
     virtual ~SrsCodecSample();
 public:
+    // Reset the sample, clear the sample-base and stream-base data.
+    void reset();
     /**
     * clear all samples.
     * the sample units never copy the bytes, it directly use the ptr,
@@ -637,6 +639,8 @@ class SrsAvcAacCodec
     * demux the h.264 NALUs to sampe units.
     */
     virtual int video_avc_demux(char* data, int size, SrsCodecSample* sample);
+private:
+    virtual int video_nalu_demux(SrsStream* stream, SrsCodecSample* sample);
 public:
     /**
     * directly demux the sequence header, without RTMP packet header.
diff --git a/trunk/src/kernel/srs_kernel_ts.cpp b/trunk/src/kernel/srs_kernel_ts.cpp
index d0ac1e4953..969949a032 100644
--- a/trunk/src/kernel/srs_kernel_ts.cpp
+++ b/trunk/src/kernel/srs_kernel_ts.cpp
@@ -3010,7 +3010,7 @@ int SrsTsCache::do_cache_avc(SrsAvcAacCodec* codec, SrsCodecSample* sample)
     static u_int8_t aud_nalu_7[] = { 0x09, 0xf0};
     
     // For NonIDR(open gop), we directly appends all frames.
-    if (sample->has_non_idr || (sample->has_aud && sample->has_sei)) {
+    if (sample->open_gop) {
         for (int i = 0; i < sample->nb_sample_units; i++) {
             SrsCodecSampleUnit* sample_unit = &sample->sample_units[i];
             int32_t size = sample_unit->size;
@@ -3132,6 +3132,8 @@ int SrsTsEncoder::initialize(SrsFileWriter* fw)
         return ret;
     }
     
+    sample->reset();
+    
     return ret;
 }