From 64815d6bae6b6bbdf8b47a971d19c5aed8126bef Mon Sep 17 00:00:00 2001
From: Jonathan Thomas <jonathan@openshot.org>
Date: Thu, 24 Feb 2022 15:56:39 -0600
Subject: [PATCH] Removing adaptive caching support, and make things generally
 less aggressive. Do not cache when paused (to allow for transform tool and
 timeline scrubbing to only render the current frame needed, for speed). This
 results in very smooth transform tool editing, very smooth timeline
 scrubbing, and I'm still seeing very smooth video playback when not paused.
 Needs more testing though.

---
 src/Qt/VideoCacheThread.cpp | 34 +++-------------------------------
 1 file changed, 3 insertions(+), 31 deletions(-)

diff --git a/src/Qt/VideoCacheThread.cpp b/src/Qt/VideoCacheThread.cpp
index 9456f471..fcaa424a 100644
--- a/src/Qt/VideoCacheThread.cpp
+++ b/src/Qt/VideoCacheThread.cpp
@@ -27,7 +27,7 @@ namespace openshot
 	VideoCacheThread::VideoCacheThread()
 	: Thread("video-cache"), speed(0), last_speed(1), is_playing(false),
 	reader(NULL), current_display_frame(1), cached_frame_count(0),
-	min_frames_ahead(24), max_frames_ahead(OPEN_MP_NUM_PROCESSORS * 6)
+	min_frames_ahead(4), max_frames_ahead(8)
     {
     }
 
@@ -80,40 +80,12 @@ namespace openshot
             const auto frame_duration = double_micro_sec(1000000.0 / reader->info.fps.ToDouble());
             int current_speed = speed;
 
-            // Calculate bytes per frame. If we have a reference openshot::Frame, use that instead (the preview
-            // window can be smaller, can thus reduce the bytes per frame)
-            int64_t bytes_per_frame = (reader->info.height * reader->info.width * 4) +
-                    (reader->info.sample_rate * reader->info.channels * 4);
-            if (last_cached_frame && last_cached_frame->has_image_data && last_cached_frame->has_audio_data) {
-                bytes_per_frame = last_cached_frame->GetBytes();
-            }
-
-            // Calculate # of frames on Timeline cache (when paused)
-            if (reader->GetCache() && reader->GetCache()->GetMaxBytes() > 0) {
-                if (speed == 0) {
-                    // When paused, use 1/2 the cache size (so our cache will be 50% before the play-head, and 50% after it)
-                    max_frames_ahead = (reader->GetCache()->GetMaxBytes() / bytes_per_frame) / 2;
-                    if (max_frames_ahead > 300) {
-                        // Ignore values that are too large, and default to a safer value
-                        max_frames_ahead = 300;
-                    }
-                } else {
-                    // When playing back video (speed == 1), keep cache # small
-                    max_frames_ahead = min_frames_ahead;
-                }
-            }
-
             // Calculate increment (based on speed)
             // Support caching in both directions
             int16_t increment = speed;
             if (speed == 0) {
-                // When paused, we still want to increment our cache position
-                // to fully cache frames while paused
-                if (last_speed > 0) {
-                    increment = 1;
-                } else {
-                    increment = -1;
-                }
+                std::this_thread::sleep_for(frame_duration / 4);
+                continue;
             }
 
 			// Always cache frames from the current display position to our maximum (based on the cache size).