diff --git a/app/src/clock.c b/app/src/clock.c
index 7a1e0940..1b353347 100644
--- a/app/src/clock.c
+++ b/app/src/clock.c
@@ -1,5 +1,9 @@
 #include "clock.h"
 
+#include "util/log.h"
+
+#define SC_CLOCK_NDEBUG // comment to debug
+
 void
 sc_clock_init(struct sc_clock *clock) {
     clock->count = 0;
@@ -80,6 +84,11 @@ sc_clock_update(struct sc_clock *clock, sc_tick system, sc_tick stream) {
     if (clock->count > 1) {
         // Update estimation
         sc_clock_estimate(clock, &clock->slope, &clock->offset);
+
+#ifndef SC_CLOCK_NDEBUG
+        LOGD("Clock estimation: %g * pts + %" PRItick,
+             clock->slope, clock->offset);
+#endif
     }
 }
 
diff --git a/app/src/util/tick.h b/app/src/util/tick.h
index a7494458..472a18a7 100644
--- a/app/src/util/tick.h
+++ b/app/src/util/tick.h
@@ -4,6 +4,7 @@
 #include <stdint.h>
 
 typedef int64_t sc_tick;
+#define PRItick PRIi64
 #define SC_TICK_FREQ 1000000 // microsecond
 
 // To be adapted if SC_TICK_FREQ changes
diff --git a/app/src/video_buffer.c b/app/src/video_buffer.c
index e75c8873..f71a4e78 100644
--- a/app/src/video_buffer.c
+++ b/app/src/video_buffer.c
@@ -8,6 +8,8 @@
 
 #include "util/log.h"
 
+#define SC_BUFFERING_NDEBUG // comment to debug
+
 static struct sc_video_buffer_frame *
 sc_video_buffer_frame_new(const AVFrame *frame) {
     struct sc_video_buffer_frame *vb_frame = malloc(sizeof(*vb_frame));
@@ -94,6 +96,11 @@ run_buffering(void *data) {
 
         sc_mutex_unlock(&vb->b.mutex);
 
+#ifndef SC_BUFFERING_NDEBUG
+        LOGD("Buffering: %" PRItick ";%" PRItick ";%" PRItick,
+             pts, vb_frame->push_date, sc_tick_now());
+#endif
+
         sc_video_buffer_offer(vb, vb_frame->frame);
 
         sc_video_buffer_frame_delete(vb_frame);
@@ -231,6 +238,9 @@ sc_video_buffer_push(struct sc_video_buffer *vb, const AVFrame *frame) {
         return false;
     }
 
+#ifndef SC_BUFFERING_NDEBUG
+    vb_frame->push_date = sc_tick_now();
+#endif
     sc_queue_push(&vb->b.queue, next, vb_frame);
     sc_cond_signal(&vb->b.queue_cond);
 
diff --git a/app/src/video_buffer.h b/app/src/video_buffer.h
index bfdafab5..48777703 100644
--- a/app/src/video_buffer.h
+++ b/app/src/video_buffer.h
@@ -17,6 +17,9 @@ typedef struct AVFrame AVFrame;
 struct sc_video_buffer_frame {
     AVFrame *frame;
     struct sc_video_buffer_frame *next;
+#ifndef NDEBUG
+    sc_tick push_date;
+#endif
 };
 
 struct sc_video_buffer_frame_queue SC_QUEUE(struct sc_video_buffer_frame);