diff --git a/trunk/research/librtmp/srs_bandwidth_check.c b/trunk/research/librtmp/srs_bandwidth_check.c
index 3ce5d66eb..84666a4ab 100644
--- a/trunk/research/librtmp/srs_bandwidth_check.c
+++ b/trunk/research/librtmp/srs_bandwidth_check.c
@@ -35,9 +35,10 @@ int main(int argc, char** argv)
     srs_rtmp_t rtmp;
     
     // packet data
-    int type, size;
-    u_int32_t timestamp = 0;
+    int size;
+    char type;
     char* data;
+    u_int32_t timestamp;
     
     // srs debug info.
     char srs_server_ip[128];
diff --git a/trunk/research/librtmp/srs_detect_rtmp.c b/trunk/research/librtmp/srs_detect_rtmp.c
index a1b12d121..083392f26 100644
--- a/trunk/research/librtmp/srs_detect_rtmp.c
+++ b/trunk/research/librtmp/srs_detect_rtmp.c
@@ -49,10 +49,11 @@ int main(int argc, char** argv)
     int64_t bytes_nrecv = 0;
     
     // packet data
-    int type, size;
-    u_int32_t basetime = 0;
-    u_int32_t timestamp = 0;
+    int size;
+    char type;
     char* data;
+    u_int32_t timestamp;
+    u_int32_t basetime = 0;
     
     // user options
     const char* rtmp_url = NULL;
diff --git a/trunk/research/librtmp/srs_flv_parser.c b/trunk/research/librtmp/srs_flv_parser.c
index fa4acd86a..22108d522 100644
--- a/trunk/research/librtmp/srs_flv_parser.c
+++ b/trunk/research/librtmp/srs_flv_parser.c
@@ -125,7 +125,7 @@ int parse_bytes(char* data, int size, char* hbuf, int hsize, char* tbuf, int tsi
 }
 
 #define FLV_HEADER_SIZE 11
-int parse_script_data(u_int32_t timestamp, char* data, int size, int64_t offset)
+int parse_script_data(u_int32_t timestamp, u_int32_t pts, char* data, int size, int64_t offset)
 {
     int ret = 0;
     
@@ -152,10 +152,10 @@ int parse_script_data(u_int32_t timestamp, char* data, int size, int64_t offset)
     }
     amf0_data = srs_amf0_parse(data + nparsed, size - nparsed, &nparsed);
     
-    srs_lib_trace("packet type=%s, time=%d, size=%d, data-size=%d, \n"
+    srs_lib_trace("packet type=%s, dts=%d, pts=%d, size=%d, data-size=%d, \n"
         "offset=%d\n[+00, +15] %s\n[-15, EOF] %s\n%s%s", 
-        srs_type2string(SRS_RTMP_TYPE_SCRIPT), timestamp, size + FLV_HEADER_SIZE, size, 
-        (int)offset, hbuf, tbuf, 
+        srs_type2string(SRS_RTMP_TYPE_SCRIPT), timestamp, pts, 
+        size + FLV_HEADER_SIZE, size, (int)offset, hbuf, tbuf, 
         srs_amf0_human_print(amf0_name, &amf0_name_str, &amf0_size), 
         srs_amf0_human_print(amf0_data, &amf0_data_str, &amf0_size));
     
@@ -168,7 +168,7 @@ int parse_script_data(u_int32_t timestamp, char* data, int size, int64_t offset)
     return ret;
 }
 
-int parse_audio_data(u_int32_t timestamp, char* data, int size, int64_t offset)
+int parse_audio_data(u_int32_t timestamp, u_int32_t pts, char* data, int size, int64_t offset)
 {
     int ret = 0;
     
@@ -178,15 +178,15 @@ int parse_audio_data(u_int32_t timestamp, char* data, int size, int64_t offset)
     // bytes
     parse_bytes(data, size, hbuf, sizeof(hbuf), tbuf, sizeof(tbuf), 16);
     
-    srs_lib_trace("packet type=%s, time=%d, size=%d, data-size=%d, \n"
+    srs_lib_trace("packet type=%s, dts=%d, pts=%d, size=%d, data-size=%d, \n"
         "offset=%d\n[+00, +15] %s\n[-15, EOF] %s\n", 
-        srs_type2string(SRS_RTMP_TYPE_AUDIO), timestamp, size + FLV_HEADER_SIZE, size, 
-        (int)offset, hbuf, tbuf);
+        srs_type2string(SRS_RTMP_TYPE_AUDIO), timestamp, pts, 
+        size + FLV_HEADER_SIZE, size, (int)offset, hbuf, tbuf);
     
     return ret;
 }
 
-int parse_video_data(u_int32_t timestamp, char* data, int size, int64_t offset)
+int parse_video_data(u_int32_t timestamp, u_int32_t pts, char* data, int size, int64_t offset)
 {
     int ret = 0;
     
@@ -196,10 +196,10 @@ int parse_video_data(u_int32_t timestamp, char* data, int size, int64_t offset)
     // bytes
     parse_bytes(data, size, hbuf, sizeof(hbuf), tbuf, sizeof(tbuf), 16);
     
-    srs_lib_trace("packet type=%s, time=%d, size=%d, data-size=%d, \n"
+    srs_lib_trace("packet type=%s, dts=%d, pts=%d, size=%d, data-size=%d, \n"
         "offset=%d\n[+00, +15] %s\n[-15, EOF] %s\n", 
-        srs_type2string(SRS_RTMP_TYPE_VIDEO), timestamp, size + FLV_HEADER_SIZE, size, 
-        (int)offset, hbuf, tbuf);
+        srs_type2string(SRS_RTMP_TYPE_VIDEO), timestamp, pts, 
+        size + FLV_HEADER_SIZE, size, (int)offset, hbuf, tbuf);
         
     return ret;
 }
@@ -240,27 +240,27 @@ int parse_flv(srs_flv_t flv)
             break;
         }
         
+        u_int32_t pts = 0;
         data = (char*)malloc(size);
-        if ((ret = srs_flv_read_tag_data(flv, data, size)) != 0) {
-            return ret;
-        }
         
-        // data tag
-        if (type == SRS_RTMP_TYPE_AUDIO) {
-            if ((ret = parse_audio_data(timestamp, data, size, offset)) != 0) {
-                return ret;
-            }
-        } else if (type == SRS_RTMP_TYPE_VIDEO) {
-            if ((ret = parse_video_data(timestamp, data, size, offset)) != 0) {
-                return ret;
-            }
-        } else {
-            if ((ret = parse_script_data(timestamp, data, size, offset)) != 0) {
-                return ret;
+        if ((ret = srs_flv_read_tag_data(flv, data, size)) == 0
+            && (ret = srs_parse_timestamp(timestamp, type, data, size, &pts)) == 0
+        ) {
+            if (type == SRS_RTMP_TYPE_AUDIO) {
+                ret = parse_audio_data(timestamp, pts, data, size, offset);
+            } else if (type == SRS_RTMP_TYPE_VIDEO) {
+                ret = parse_video_data(timestamp, pts, data, size, offset);
+            } else {
+                ret = parse_script_data(timestamp, pts, data, size, offset);
             }
         }
         
         free(data);
+        
+        if (ret != 0) {
+            srs_lib_trace("parse failed, ret=%d", ret);
+            return ret;
+        }
     }
     
     return ret;
diff --git a/trunk/research/librtmp/srs_ingest_rtmp.c b/trunk/research/librtmp/srs_ingest_rtmp.c
index 48a370238..3bec458c6 100644
--- a/trunk/research/librtmp/srs_ingest_rtmp.c
+++ b/trunk/research/librtmp/srs_ingest_rtmp.c
@@ -94,9 +94,10 @@ int proxy(srs_rtmp_t irtmp, srs_rtmp_t ortmp)
     int ret = 0;
     
     // packet data
-    int type, size;
-    u_int32_t timestamp = 0;
-    char* data = NULL;
+    int size;
+    char type;
+    char* data;
+    u_int32_t timestamp;
 
     if ((ret = connect_ic(irtmp)) != 0) {
         return ret;
diff --git a/trunk/research/librtmp/srs_play.c b/trunk/research/librtmp/srs_play.c
index 1106f3a22..0b0410474 100644
--- a/trunk/research/librtmp/srs_play.c
+++ b/trunk/research/librtmp/srs_play.c
@@ -66,15 +66,19 @@ int main(int argc, char** argv)
     srs_lib_trace("play stream success");
     
     for (;;) {
-        int type, size;
-        u_int32_t timestamp = 0;
+        int size;
+        char type;
         char* data;
+        u_int32_t timestamp, pts;
         
         if (srs_read_packet(rtmp, &type, &timestamp, &data, &size) != 0) {
             goto rtmp_destroy;
         }
-        srs_lib_trace("got packet: type=%s, time=%d, size=%d", 
-            srs_type2string(type), timestamp, size);
+        if (srs_parse_timestamp(timestamp, type, data, size, &pts) != 0) {
+            goto rtmp_destroy;
+        }
+        srs_lib_trace("got packet: type=%s, dts=%d, pts=%d, size=%d", 
+            srs_type2string(type), timestamp, pts, size);
         
         free(data);
     }
diff --git a/trunk/research/librtmp/srs_publish.c b/trunk/research/librtmp/srs_publish.c
index 0865a4b98..beea77692 100644
--- a/trunk/research/librtmp/srs_publish.c
+++ b/trunk/research/librtmp/srs_publish.c
@@ -75,7 +75,7 @@ int main(int argc, char** argv)
     
     u_int32_t timestamp = 0;
     for (;;) {
-        int type = SRS_RTMP_TYPE_VIDEO;
+        char type = SRS_RTMP_TYPE_VIDEO;
         int size = 4096;
         char* data = (char*)malloc(4096);
         
diff --git a/trunk/src/core/srs_core.hpp b/trunk/src/core/srs_core.hpp
index d7450a9e6..d344ceac1 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    18
+#define VERSION_REVISION    19
 // server info.
 #define RTMP_SIG_SRS_KEY "SRS"
 #define RTMP_SIG_SRS_ROLE "origin/edge server"
diff --git a/trunk/src/kernel/srs_kernel_error.hpp b/trunk/src/kernel/srs_kernel_error.hpp
index 21ca885de..d9997c16c 100644
--- a/trunk/src/kernel/srs_kernel_error.hpp
+++ b/trunk/src/kernel/srs_kernel_error.hpp
@@ -185,6 +185,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #define ERROR_EDGE_VHOST_REMOVED            3039
 #define ERROR_HLS_AVC_TRY_OTHERS            3040
 #define ERROR_H264_API_NO_PREFIXED          3041
+#define ERROR_FLV_INVALID_VIDEO_TAG         3042
 
 /**
 * whether the error code is an system control error.
diff --git a/trunk/src/libs/srs_librtmp.cpp b/trunk/src/libs/srs_librtmp.cpp
index 38e75542c..afa018b55 100644
--- a/trunk/src/libs/srs_librtmp.cpp
+++ b/trunk/src/libs/srs_librtmp.cpp
@@ -337,7 +337,7 @@ int srs_publish_stream(srs_rtmp_t rtmp)
     return ret;
 }
 
-const char* srs_type2string(int type)
+const char* srs_type2string(char type)
 {
     static const char* audio = "Audio";
     static const char* video = "Video";
@@ -390,7 +390,7 @@ int srs_bandwidth_check(srs_rtmp_t rtmp,
     return ret;
 }
 
-int srs_read_packet(srs_rtmp_t rtmp, int* type, u_int32_t* timestamp, char** data, int* size)
+int srs_read_packet(srs_rtmp_t rtmp, char* type, u_int32_t* timestamp, char** data, int* size)
 {
     *type = 0;
     *timestamp = 0;
@@ -445,7 +445,7 @@ int srs_read_packet(srs_rtmp_t rtmp, int* type, u_int32_t* timestamp, char** dat
     return ret;
 }
 
-int srs_write_packet(srs_rtmp_t rtmp, int type, u_int32_t timestamp, char* data, int size)
+int srs_write_packet(srs_rtmp_t rtmp, char type, u_int32_t timestamp, char* data, int size)
 {
     int ret = ERROR_SUCCESS;
     
@@ -531,6 +531,47 @@ int64_t srs_get_nrecv_bytes(srs_rtmp_t rtmp)
     return context->rtmp->get_recv_bytes();
 }
 
+int srs_parse_timestamp(
+    u_int32_t time, char type, char* data, int size,
+    u_int32_t* ppts
+) {
+    int ret = ERROR_SUCCESS;
+    
+    if (type != SRS_RTMP_TYPE_VIDEO) {
+        *ppts = time;
+        return ret;
+    }
+
+    if (!SrsFlvCodec::video_is_h264(data, size)) {
+        return ERROR_FLV_INVALID_VIDEO_TAG;
+    }
+
+    if (SrsFlvCodec::video_is_sequence_header(data, size)) {
+        *ppts = time;
+        return ret;
+    }
+    
+    // 1bytes, frame type and codec id.
+    // 1bytes, avc packet type.
+    // 3bytes, cts, composition time,
+    //      pts = dts + cts, or 
+    //      cts = pts - dts.
+    if (size < 5) {
+        return ERROR_FLV_INVALID_VIDEO_TAG;
+    }
+    
+    u_int32_t cts = 0;
+    char* p = data + 2;
+    char* pp = (char*)&cts;
+    pp[2] = *p++;
+    pp[1] = *p++;
+    pp[0] = *p++;
+
+    *ppts = time + cts;
+    
+    return ret;
+}
+
 const char* srs_format_time()
 {
     struct timeval tv;
diff --git a/trunk/src/libs/srs_librtmp.hpp b/trunk/src/libs/srs_librtmp.hpp
index 9eccd7511..65c1eb756 100644
--- a/trunk/src/libs/srs_librtmp.hpp
+++ b/trunk/src/libs/srs_librtmp.hpp
@@ -192,7 +192,7 @@ extern int srs_bandwidth_check(srs_rtmp_t rtmp,
 * @remark user never free the return char*, 
 *   it's static shared const string.
 */
-extern const char* srs_type2string(int type);
+extern const char* srs_type2string(char type);
 /**
 * read a audio/video/script-data packet from rtmp stream.
 * @param type, output the packet type, macros:
@@ -215,10 +215,10 @@ extern const char* srs_type2string(int type);
 * @return 0, success; otherswise, failed.
 */
 extern int srs_read_packet(srs_rtmp_t rtmp, 
-    int* type, u_int32_t* timestamp, char** data, int* size
+    char* type, u_int32_t* timestamp, char** data, int* size
 );
 extern int srs_write_packet(srs_rtmp_t rtmp, 
-    int type, u_int32_t timestamp, char* data, int size
+    char type, u_int32_t timestamp, char* data, int size
 );
 
 // get protocol stack version
@@ -234,6 +234,25 @@ extern int srs_version_revision();
 extern int64_t srs_get_time_ms();
 extern int64_t srs_get_nsend_bytes(srs_rtmp_t rtmp);
 extern int64_t srs_get_nrecv_bytes(srs_rtmp_t rtmp);
+/**
+* parse the dts and pts by time in header and data in tag,
+* or to parse the RTMP packet by srs_read_packet().
+*
+* @param time, the timestamp of tag, read by srs_flv_read_tag_header().
+* @param type, the type of tag, read by srs_flv_read_tag_header().
+* @param data, the data of tag, read by srs_flv_read_tag_data().
+* @param size, the size of tag, read by srs_flv_read_tag_header().
+* @param ppts, output the pts in ms,
+*
+* @return 0, success; otherswise, failed.
+* @remark, the dts always equals to @param time.
+* @remark, the pts=dts for audio or data.
+* @remark, video only support h.264.
+*/
+extern int srs_parse_timestamp(
+    u_int32_t time, char type, char* data, int size,
+    u_int32_t* ppts
+);
 
 // log to console, for use srs-librtmp application.
 extern const char* srs_format_time();
@@ -255,19 +274,68 @@ typedef int flv_bool;
 extern srs_flv_t srs_flv_open_read(const char* file);
 extern srs_flv_t srs_flv_open_write(const char* file);
 extern void srs_flv_close(srs_flv_t flv);
-/* read the flv header. 9bytes header. drop the 4bytes zero previous tag size */
+/**
+* read the flv header. 9bytes header. 
+* @param header, @see E.2 The FLV header, flv_v10_1.pdf in SRS doc.
+*   3bytes, signature, "FLV",
+*   1bytes, version, 0x01,
+*   1bytes, flags, UB[5] 0, UB[1] audio present, UB[1] 0, UB[1] video present.
+*   4bytes, dataoffset, 0x09, The length of this header in bytes
+*
+* @return 0, success; otherswise, failed.
+* @remark, drop the 4bytes zero previous tag size.
+*/
 extern int srs_flv_read_header(srs_flv_t flv, char header[9]);
-/* read the flv tag header, 1bytes tag, 3bytes data_size, 4bytes time, 3bytes stream id. */
+/**
+* read the flv tag header, 1bytes tag, 3bytes data_size, 
+* 4bytes time, 3bytes stream id. 
+* @param ptype, output the type of tag, macros:
+*            SRS_RTMP_TYPE_AUDIO, FlvTagAudio
+*            SRS_RTMP_TYPE_VIDEO, FlvTagVideo
+*            SRS_RTMP_TYPE_SCRIPT, FlvTagScript
+* @param pdata_size, output the size of tag data.
+* @param ptime, output the time of tag, the dts in ms.
+*
+* @return 0, success; otherswise, failed.
+* @remark, user must ensure the next is a tag, srs never check it.
+*/
 extern int srs_flv_read_tag_header(srs_flv_t flv, 
     char* ptype, int32_t* pdata_size, u_int32_t* ptime
 );
-/* read the tag data. drop the 4bytes previous tag size */
+/**
+* read the tag data. drop the 4bytes previous tag size 
+* @param data, the data to read, user alloc and free it.
+* @param size, the size of data to read, get by srs_flv_read_tag_header().
+* @remark, srs will ignore and drop the 4bytes previous tag size.
+*/
 extern int srs_flv_read_tag_data(srs_flv_t flv, char* data, int32_t size);
-/* write flv header to file, auto write the 4bytes zero previous tag size. */
+/**
+* write the flv header. 9bytes header. 
+* @param header, @see E.2 The FLV header, flv_v10_1.pdf in SRS doc.
+*   3bytes, signature, "FLV",
+*   1bytes, version, 0x01,
+*   1bytes, flags, UB[5] 0, UB[1] audio present, UB[1] 0, UB[1] video present.
+*   4bytes, dataoffset, 0x09, The length of this header in bytes
+*
+* @return 0, success; otherswise, failed.
+* @remark, auto write the 4bytes zero previous tag size.
+*/
 extern int srs_flv_write_header(srs_flv_t flv, char header[9]);
+/**
+* write the flv tag to file.
+*
+* @return 0, success; otherswise, failed.
+* @remark, auto write the 4bytes zero previous tag size.
+*/
 /* write flv tag to file, auto write the 4bytes previous tag size */
-extern int srs_flv_write_tag(srs_flv_t flv, char type, int32_t time, char* data, int size);
-/* get the tag size, for flv injecter to adjust offset, size=tag_header+data+previous_tag */
+extern int srs_flv_write_tag(srs_flv_t flv, 
+    char type, int32_t time, char* data, int size
+);
+/**
+* get the tag size, for flv injecter to adjust offset, 
+*       size = tag_header(11B) + data_size + previous_tag(4B)
+* @return the size of tag.
+*/
 extern int srs_flv_size_tag(int data_size);
 /* file stream */
 /* file stream tellg to get offset */
@@ -278,9 +346,17 @@ extern void srs_flv_lseek(srs_flv_t flv, int64_t offset);
 /* whether the error code indicates EOF */
 extern flv_bool srs_flv_is_eof(int error_code);
 /* media codec */
-/* whether the video body is sequence header */
+/**
+* whether the video body is sequence header 
+* @param data, the data of tag, read by srs_flv_read_tag_data().
+* @param size, the size of tag, read by srs_flv_read_tag_data().
+*/
 extern flv_bool srs_flv_is_sequence_header(char* data, int32_t size);
-/* whether the video body is keyframe */
+/**
+* whether the video body is keyframe 
+* @param data, the data of tag, read by srs_flv_read_tag_data().
+* @param size, the size of tag, read by srs_flv_read_tag_data().
+*/
 extern flv_bool srs_flv_is_keyframe(char* data, int32_t size);
 
 /*************************************************************