diff --git a/trunk/src/core/srs_core_performance.hpp b/trunk/src/core/srs_core_performance.hpp
index c9441938b..285513bb2 100644
--- a/trunk/src/core/srs_core_performance.hpp
+++ b/trunk/src/core/srs_core_performance.hpp
@@ -59,7 +59,7 @@
 #define SRS_PERF_MR_SLEEP (350 * SRS_UTIME_MILLISECONDS)
 
 /**
- * the MW(merged-write) send cache time in ms.
+ * the MW(merged-write) send cache time in srs_utime_t.
  * the default value, user can override it in config.
  * to improve send performance, cache msgs and send in a time.
  * for example, cache 500ms videos and audios, then convert all these
diff --git a/trunk/src/kernel/srs_kernel_ts.cpp b/trunk/src/kernel/srs_kernel_ts.cpp
index 001b03594..5541923bc 100644
--- a/trunk/src/kernel/srs_kernel_ts.cpp
+++ b/trunk/src/kernel/srs_kernel_ts.cpp
@@ -46,14 +46,6 @@ using namespace std;
 
 #define HLS_AES_ENCRYPT_BLOCK_LENGTH SRS_TS_PACKET_SIZE * 4
 
-// in ms, for HLS aac sync time.
-#define SRS_CONF_DEFAULT_AAC_SYNC 100
-
-// @see: ngx_rtmp_hls_audio
-/* We assume here AAC frame size is 1024
- * Need to handle AAC frames with frame size of 960 */
-#define _SRS_AAC_SAMPLE_SIZE 1024
-
 // the mpegts header specifed the video/audio pid.
 #define TS_PMT_NUMBER 1
 #define TS_PMT_PID 0x1001