Stop changing video rates unneededly; it causes frequent wakeups.

diff --git a/nageru/ultimate.lua b/nageru/ultimate.lua
index 844a89c5ebd4e0d1c388b747d4c026b3822d9b32..586b36d7223cb0b29fc6de1d24dd85aa4d45fa55 100644 (file)
--- 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.