From 0d7406bc438943887114fcc598f5824bec2b351d Mon Sep 17 00:00:00 2001
From: ptg <ptg@monster-machine>
Date: Wed, 9 Oct 2024 18:07:07 -0400
Subject: [PATCH] fix precise fps

---
 ptgctl/tools/mock.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/ptgctl/tools/mock.py b/ptgctl/tools/mock.py
index 3a81b5d..1936fba 100644
--- a/ptgctl/tools/mock.py
+++ b/ptgctl/tools/mock.py
@@ -85,6 +85,8 @@ async def _video_feed(src, fps=None, shape=None):
         if not cap.isOpened():
             raise ValueError(f"{cap}")
         i = 0
+        t0 = time.time()
+        lag = 0
         while True:
             ret, im = cap.read()
             if not ret:
@@ -100,7 +102,11 @@ async def _video_feed(src, fps=None, shape=None):
             yield im
             pbar.update()
             if fps:
-                await asyncio.sleep(1/fps)
+                t = time.time()
+                dt = 1/fps - (t-t0) - lag
+                await asyncio.sleep(max(0, dt))
+                lag = max(-dt, 0)
+                t0 = t + max(0, dt)
 
 
 @util.async2sync