diff --git a/trunk/src/app/srs_app_hls.cpp b/trunk/src/app/srs_app_hls.cpp
index c6b1f5d72..713dc9341 100644
--- a/trunk/src/app/srs_app_hls.cpp
+++ b/trunk/src/app/srs_app_hls.cpp
@@ -758,7 +758,7 @@ int SrsHlsCache::write_video(SrsAvcAacCodec* codec, SrsHlsMuxer* muxer, int64_t
     // new segment when:
     // 1. base on gop.
     // 2. some gops duration overflow.
-    if (cache->vf->key && muxer->is_segment_overflow()) {
+    if (sample->frame_type == SrsCodecVideoAVCFrameKeyFrame && muxer->is_segment_overflow()) {
         if ((ret = reap_segment("video", muxer, cache->vf->dts)) != ERROR_SUCCESS) {
             return ret;
         }
@@ -788,6 +788,7 @@ int SrsHlsCache::reap_segment(string log_desc, SrsHlsMuxer* muxer, int64_t segme
     }
 
     // TODO: flush audio before or after segment?
+    // TODO: fresh segment begin with audio or video?
     
     // segment open, flush video first.
     if ((ret = muxer->flush_video(cache->af, cache->ab, cache->vf, cache->vb)) != ERROR_SUCCESS) {
diff --git a/trunk/src/kernel/srs_kernel_codec.hpp b/trunk/src/kernel/srs_kernel_codec.hpp
index e41793dcc..8608260a7 100644
--- a/trunk/src/kernel/srs_kernel_codec.hpp
+++ b/trunk/src/kernel/srs_kernel_codec.hpp
@@ -233,10 +233,10 @@ extern int aac_sample_rates[];
 #define __SRS_AAC_SAMPLE_RATE_UNSET 15
 
 // in ms, for HLS aac flush the audio
-#define SRS_CONF_DEFAULT_AAC_DELAY 100
+#define SRS_CONF_DEFAULT_AAC_DELAY 60
 
 // max PES packets size to flush the video.
-#define SRS_AUTO_HLS_AUDIO_CACHE_SIZE 1024 * 1024
+#define SRS_AUTO_HLS_AUDIO_CACHE_SIZE 128 * 1024
 
 /**
 * the FLV/RTMP supported audio sample size.
diff --git a/trunk/src/kernel/srs_kernel_ts.cpp b/trunk/src/kernel/srs_kernel_ts.cpp
index 3ba7f16fa..af1a75224 100644
--- a/trunk/src/kernel/srs_kernel_ts.cpp
+++ b/trunk/src/kernel/srs_kernel_ts.cpp
@@ -224,7 +224,7 @@ public:
             
             if (first) {
                 first = false;
-                if (frame->key) {
+                if (frame->write_pcr) {
                     p[-1] |= 0x20; // Both Adaption and Payload
                     *p++ = 7;    // size
                     *p++ = 0x50; // random access + PCR
@@ -399,7 +399,7 @@ SrsMpegtsFrame::SrsMpegtsFrame()
 {
     pts = dts = 0;
     pid = sid = cc = 0;
-    key = false;
+    write_pcr = false;
 }
 
 string srs_ts_stream2string(SrsTsStream stream)
@@ -1971,7 +1971,7 @@ int SrsTsCache::cache_video(SrsAvcAacCodec* codec, int64_t dts, SrsCodecSample*
     vf->pts = vf->dts + sample->cts * 90;
     vf->pid = TS_VIDEO_PID;
     vf->sid = TS_VIDEO_AVC;
-    vf->key = sample->frame_type == SrsCodecVideoAVCFrameKeyFrame;
+    vf->write_pcr = sample->frame_type == SrsCodecVideoAVCFrameKeyFrame;
     
     return ret;
 }
diff --git a/trunk/src/kernel/srs_kernel_ts.hpp b/trunk/src/kernel/srs_kernel_ts.hpp
index 4c5d325cd..62a45808e 100644
--- a/trunk/src/kernel/srs_kernel_ts.hpp
+++ b/trunk/src/kernel/srs_kernel_ts.hpp
@@ -60,7 +60,7 @@ public:
     int             pid;
     int             sid;
     int             cc;
-    bool            key;
+    bool            write_pcr;
     
     SrsMpegtsFrame();
 };