From e17e8077d26db110cee880b4d785a3f12efe17bf Mon Sep 17 00:00:00 2001
From: Romain Vimont <rom@rom1v.com>
Date: Sun, 4 Jul 2021 17:19:47 +0200
Subject: [PATCH] wip

---
 app/src/screen.c       |  2 +-
 app/src/v4l2_sink.c    |  2 +-
 app/src/video_buffer.c | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/app/src/screen.c b/app/src/screen.c
index 126caf9b..02f2f9cb 100644
--- a/app/src/screen.c
+++ b/app/src/screen.c
@@ -308,7 +308,7 @@ screen_init(struct screen *screen, const struct screen_params *params) {
         .on_new_frame = sc_video_buffer_on_new_frame,
     };
 
-    bool ok = sc_video_buffer_init(&screen->vb, 0, &cbs, screen);
+    bool ok = sc_video_buffer_init(&screen->vb, 1000, &cbs, screen);
     if (!ok) {
         LOGE("Could not initialize video buffer");
         return false;
diff --git a/app/src/v4l2_sink.c b/app/src/v4l2_sink.c
index 8f8b98ee..63f14dd9 100644
--- a/app/src/v4l2_sink.c
+++ b/app/src/v4l2_sink.c
@@ -159,7 +159,7 @@ sc_v4l2_sink_open(struct sc_v4l2_sink *vs) {
         .on_new_frame = sc_video_buffer_on_new_frame,
     };
 
-    bool ok = sc_video_buffer_init(&vs->vb, 0, &cbs, vs);
+    bool ok = sc_video_buffer_init(&vs->vb, 1, &cbs, vs);
     if (!ok) {
         LOGE("Could not initialize video buffer");
         return false;
diff --git a/app/src/video_buffer.c b/app/src/video_buffer.c
index 2b527db8..967b29ce 100644
--- a/app/src/video_buffer.c
+++ b/app/src/video_buffer.c
@@ -6,6 +6,40 @@
 
 #include "util/log.h"
 
+struct sc_clock {
+    double coeff;
+    sc_tick offset;
+    unsigned range;
+
+    struct {
+        sc_tick system;
+        sc_tick stream;
+    } last;
+};
+
+static void
+sc_clock_init(struct sc_clock *clock) {
+    clock->coeff = 1;
+    clock->offset = 0;
+    clock->range = 0;
+
+    clock->last.system = 0;
+    clock->last.stream = 0;
+}
+
+static void
+sc_clock_update(struct sc_clock *clock, sc_tick now, sc_tick stream_ts) {
+    sc_tick system_delta = now - clock->last.system;
+    sc_tick stream_delta = stream_ts - clock->last.stream;
+    double instant_coeff = (double) system_delta / stream_delta;
+
+}
+
+static sc_tick
+sc_clock_get_system_ts(struct sc_clock *clock, sc_tick stream_ts) {
+    return (sc_tick) (stream_ts * clock->coeff) + clock->offset;
+}
+
 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));