vo: minor simplification for queue size handling

Instead of calling it "future frames" and adding or subtracting 1 from
it, always call it "requested frames". This simplifies it a bit.

MPContext.next_frames had 2 added to it; this was mainly to ensure a
minimum size of 2. Drop it and assume VO_MAX_REQ_FRAMES is at least 2;
together with the other changes, this can be the exact size of the
array.

4 files changed, 14 insertions, 15 deletions

diff --git a/video/out/gl_video.c b/video/out/gl_video.c
index 8f46daa8d6..00c5038362 100644
--- a/video/out/gl_video.c
+++ b/video/out/gl_video.c
@@ -2832,7 +2832,7 @@ void gl_video_set_options(struct gl_video *p, struct gl_video_opts *opts)
 
 void gl_video_configure_queue(struct gl_video *p, struct vo *vo)
 {
-    int queue_size = 0;
+    int queue_size = 1;
 
     // Figure out an adequate size for the interpolation queue. The larger
     // the radius, the earlier we need to queue frames.
@@ -2842,10 +2842,10 @@ void gl_video_configure_queue(struct gl_video *p, struct vo *vo)
         if (kernel) {
             double radius = kernel->f.radius;
             radius = radius > 0 ? radius : p->opts.scaler[3].radius;
-            queue_size = 1 + ceil(radius);
+            queue_size += 1 + ceil(radius);
         } else {
             // Oversample case
-            queue_size = 2;
+            queue_size += 2;
         }
     }
 
diff --git a/video/out/vo.c b/video/out/vo.c
index 1db8fa3490..e538860452 100644
--- a/video/out/vo.c
+++ b/video/out/vo.c
@@ -959,25 +959,24 @@ const char *vo_get_window_title(struct vo *vo)
 // flip_page[_timed] will be called offset_us microseconds too early.
 // (For vo_vdpau, which does its own timing.)
 // Setting vsync_timed to true redraws as fast as possible.
-// num_future_frames set the requested number of future frames in
-// struct frame_timing.
-// (For vo_opengl smoothmotion.)
+// num_req_frames set the requested number of requested vo_frame.frames.
+// (For vo_opengl interpolation.)
 void vo_set_queue_params(struct vo *vo, int64_t offset_us, bool vsync_timed,
-                         int num_future_frames)
+                         int num_req_frames)
 {
     struct vo_internal *in = vo->in;
     pthread_mutex_lock(&in->lock);
     in->flip_queue_offset = offset_us;
     in->vsync_timed = vsync_timed;
-    in->req_frames = 1 + MPMIN(num_future_frames, VO_MAX_FUTURE_FRAMES);
+    in->req_frames = MPCLAMP(num_req_frames, 1, VO_MAX_REQ_FRAMES);
     pthread_mutex_unlock(&in->lock);
 }
 
-int vo_get_num_future_frames(struct vo *vo)
+int vo_get_num_req_frames(struct vo *vo)
 {
     struct vo_internal *in = vo->in;
     pthread_mutex_lock(&in->lock);
-    int res = in->req_frames - 1;
+    int res = in->req_frames;
     pthread_mutex_unlock(&in->lock);
     return res;
 }
diff --git a/video/out/vo.h b/video/out/vo.h
index f264694c08..06a923bf41 100644
--- a/video/out/vo.h
+++ b/video/out/vo.h
@@ -140,7 +140,7 @@ struct voctrl_get_equalizer_args {
 // VO does framedrop itself (vo_vdpau). Untimed/encoding VOs never drop.
 #define VO_CAP_FRAMEDROP 2
 
-#define VO_MAX_FUTURE_FRAMES 10
+#define VO_MAX_REQ_FRAMES 10
 
 struct vo;
 struct osd_state;
@@ -185,7 +185,7 @@ struct vo_frame {
     // Note that some future frames may never be sent as current frame to the
     // VO if frames are dropped.
     int num_frames;
-    struct mp_image *frames[VO_MAX_FUTURE_FRAMES + 1];
+    struct mp_image *frames[VO_MAX_REQ_FRAMES];
 };
 
 struct vo_driver {
@@ -338,8 +338,8 @@ void vo_event(struct vo *vo, int event);
 int vo_query_and_reset_events(struct vo *vo, int events);
 struct mp_image *vo_get_current_frame(struct vo *vo);
 void vo_set_queue_params(struct vo *vo, int64_t offset_us, bool vsync_timed,
-                         int num_future_frames);
-int vo_get_num_future_frames(struct vo *vo);
+                         int num_req_frames);
+int vo_get_num_req_frames(struct vo *vo);
 int64_t vo_get_vsync_interval(struct vo *vo);
 double vo_get_display_fps(struct vo *vo);
 
diff --git a/video/out/vo_vdpau.c b/video/out/vo_vdpau.c
index a75557db0c..7e7771f209 100644
--- a/video/out/vo_vdpau.c
+++ b/video/out/vo_vdpau.c
@@ -301,7 +301,7 @@ static void resize(struct vo *vo)
     vc->flip_offset_us = vo->opts->fullscreen ?
                          1000LL * vc->flip_offset_fs :
                          1000LL * vc->flip_offset_window;
-    vo_set_queue_params(vo, vc->flip_offset_us, false, 0);
+    vo_set_queue_params(vo, vc->flip_offset_us, false, 1);
 
     if (vc->output_surface_w < vo->dwidth || vc->output_surface_h < vo->dheight) {
         vc->output_surface_w = s_size(max_w, vc->output_surface_w, vo->dwidth);