diff --git a/include/core/common/time_stamp.h b/include/core/common/time_stamp.h
index 7e17ac4f9e1b44337923c8f19230b11fe2f76ea3..2643f13c8f9629dce921726d6dfacf3171c3417f 100644
--- a/include/core/common/time_stamp.h
+++ b/include/core/common/time_stamp.h
@@ -290,8 +290,6 @@ inline double TimeStamp::operator -(const TimeStamp& ts) const
     return double((long int)(time_stamp_nano_ - ts.time_stamp_nano_))*1e-9; // long int cast fix overflow in case of negative substraction result
 }
 
-//static const TimeStamp TimeStampInvalid() {return TimeStamp(-1.0);}
-
 } // namespace wolf
 
 #endif
diff --git a/src/common/time_stamp.cpp b/src/common/time_stamp.cpp
index 595023484187d36e0bb5c8a6e361beda1ff2f089..0421efa9b06aaf3f2f75796910485aa687217bba 100644
--- a/src/common/time_stamp.cpp
+++ b/src/common/time_stamp.cpp
@@ -37,7 +37,7 @@ TimeStamp::TimeStamp(const TimeStamp& _ts) :
 
 TimeStamp::TimeStamp(const double& _ts) :
         time_stamp_nano_(_ts > 0 ? (unsigned long int)(_ts*1e9) : 0),
-        is_valid_(_ts > 0)
+        is_valid_(_ts >= 0)
 {
     //
 }
diff --git a/src/processor/processor_motion.cpp b/src/processor/processor_motion.cpp
index 181ea7f662b6c6622112f88d733faafd9417bb61..c403a87828f9266089f63c8e8cb274cb03616729 100644
--- a/src/processor/processor_motion.cpp
+++ b/src/processor/processor_motion.cpp
@@ -58,6 +58,24 @@ void ProcessorMotion::splitBuffer(const wolf::CaptureMotionPtr& _capture_source,
                                   const FrameBasePtr& _keyframe_target,
                                   const wolf::CaptureMotionPtr& _capture_target)
 {
+    /** we are doing this:
+     *
+     *  Before split:
+     *
+     *             ts_split
+     *    KF          |          F or KF
+     *    * -----------------------*
+     *  origin                   source
+     *
+     *
+     *  After split:
+     *
+     *    KF          KF         F or KF
+     *    * ----------* -----------*
+     *  origin     target        source
+     *
+     */
+
     // split the buffer
     // and give the part of the buffer before the new keyframe to the capture for the KF callback
     _capture_source->getBuffer().split(_ts_split, _capture_target->getBuffer());