From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Fri, 23 Mar 2018 15:15:30 +0000 (+0100)
Subject: Stop changing video rates unneededly; it causes frequent wakeups.
X-Git-Url: https://git.sesse.net/?p=ultimatescore;a=commitdiff_plain;h=3c3a5c028bed3922840a2b5ad7ab861fca092582

Stop changing video rates unneededly; it causes frequent wakeups.
---

diff --git a/nageru/ultimate.lua b/nageru/ultimate.lua
index 844a89c..586b36d 100644
--- a/nageru/ultimate.lua
+++ b/nageru/ultimate.lua
@@ -693,6 +693,8 @@ function get_sbs_chain(signals, t, width, height, input_resolution)
 	return sbs_chains[input0_type][overlay_enabled][input1_type][true]
 end
 
+local last_rate = 0.0
+
 -- API ENTRY POINT
 -- Called every frame. Get the chain for displaying at input <num>,
 -- where 0 is live, 1 is preview, 2 is the first channel to display
@@ -746,12 +748,18 @@ function get_chain(num, t, width, height, signals)
 	last_resolution = input_resolution
 
 	-- Save some CPU time if we're not having SBS on live.
+	local new_rate
 	if live_signal_num == SBS_SIGNAL_NUM or
 	   preview_signal_num == SBS_SIGNAL_NUM or
 	   transition_type == ZOOM_TRANSITION then
-		bg_video:change_rate(1.0)
+		new_rate = 1.0
 	else
-		bg_video:change_rate(0.0001)
+		new_rate = 0.0001
+	end
+	if new_rate ~= last_rate then
+		-- Avoid waking up the video thread (which may be sleeping) if the rate is the same.
+		bg_video:change_rate(new_rate)
+		last_rate = new_rate
 	end
 
 	if num == 0 then  -- Live.