diff --git a/README.md b/README.md
index c3d7de337..1e05e8a35 100755
--- a/README.md
+++ b/README.md
@@ -501,8 +501,9 @@ Supported operating systems and hardware:
 * 2013-10-17, Created.<br/>
 
 ## History
-* v2.0, 2014-12-22, hotfix #264, ignore NALU when sequence header to make HLS happy. 2.0.76
-* v2.0, 2014-12-20, hotfix #264, support disconnect publish connect when hls error. 2.0.75
+* v2.0, 2014-12-29, hotfix [#268](https://github.com/winlinvip/simple-rtmp-server/issues/268), the hls pcr is negative when startup. 2.0.78
+* v2.0, 2014-12-22, hotfix [#264](https://github.com/winlinvip/simple-rtmp-server/issues/264), ignore NALU when sequence header to make HLS happy. 2.0.76
+* v2.0, 2014-12-20, hotfix [#264](https://github.com/winlinvip/simple-rtmp-server/issues/264), support disconnect publish connect when hls error. 2.0.75
 * v2.0, 2014-12-12, fix [#257](https://github.com/winlinvip/simple-rtmp-server/issues/257), support 0.1s+ latency. 2.0.70
 * v2.0, 2014-12-08, update wiki for mr([EN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_EN_LowLatency#merged-read), [CN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_CN_LowLatency#merged-read)) and mw([EN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_EN_LowLatency#merged-write), [CN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_CN_LowLatency#merged-write)).
 * v2.0, 2014-12-07, fix [#251](https://github.com/winlinvip/simple-rtmp-server/issues/251), 10k+ clients, use queue cond wait and fast vector. 2.0.67
diff --git a/trunk/src/app/srs_app_hls.cpp b/trunk/src/app/srs_app_hls.cpp
index 5acb3cfc1..2b953c8b8 100644
--- a/trunk/src/app/srs_app_hls.cpp
+++ b/trunk/src/app/srs_app_hls.cpp
@@ -368,11 +368,16 @@ private:
     }
     static char* write_pcr(char* p, int64_t pcr)
     {
-        *p++ = (char) (pcr >> 25);
-        *p++ = (char) (pcr >> 17);
-        *p++ = (char) (pcr >> 9);
-        *p++ = (char) (pcr >> 1);
-        *p++ = (char) (pcr << 7 | 0x7e);
+        // the pcr=dts-delay
+        // and the pcr maybe negative
+        // @see https://github.com/winlinvip/simple-rtmp-server/issues/268
+        int64_t v = srs_max(0, pcr);
+        
+        *p++ = (char) (v >> 25);
+        *p++ = (char) (v >> 17);
+        *p++ = (char) (v >> 9);
+        *p++ = (char) (v >> 1);
+        *p++ = (char) (v << 7 | 0x7e);
         *p++ = 0;
     
         return p;
diff --git a/trunk/src/core/srs_core.hpp b/trunk/src/core/srs_core.hpp
index 259fc22c4..d256bd756 100644
--- a/trunk/src/core/srs_core.hpp
+++ b/trunk/src/core/srs_core.hpp
@@ -31,7 +31,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 // current release version
 #define VERSION_MAJOR       2
 #define VERSION_MINOR       0
-#define VERSION_REVISION    77
+#define VERSION_REVISION    78
 // server info.
 #define RTMP_SIG_SRS_KEY "SRS"
 #define RTMP_SIG_SRS_ROLE "origin/edge server"