vo: do final frame draw only near page flip

Separate passing a new frame to VOs using the new API into two steps.
The first, vo_draw_image(), happens after a new frame is available
from the filter chain. In constrast to old behavior, now the frame is
not actually rendered yet at this point (though possible slice draw
calls can already reach the VO before). The second step,
vo_new_frame_imminent(), happens when we're close enough to the
display time of the new frame that we'll commit to flipping it as the
next action and will not change the OSD over the previous frame any
more.

This new behavior fixes a previous problem with vo_vdpau and vo_gl in
the situation where the player is paused after decoding a new frame
but before flipping it; previously changing OSD in that state would
switch to the new frame as a side effect. It would also allow an easy
way to fix extra output files produced with something like "--vo=png
--frames=1" with precise seeking, but this is not done yet.

The code now relies on a new mp_image from the filter chain staying
valid even after the vf_vo put_image() call providing it returns. In
other words decoders/filters must not deallocate or otherwise
invalidate their output frame between passing it forward and returning
from the decode/filter call.

1 files changed, 26 insertions, 12 deletions

diff --git a/libvo/vo_vdpau.c b/libvo/vo_vdpau.c
index be4540002b..f087f6cf38 100644
--- a/libvo/vo_vdpau.c
+++ b/libvo/vo_vdpau.c
@@ -80,7 +80,7 @@
 /* number of video and output surfaces */
 #define MAX_OUTPUT_SURFACES                15
 #define MAX_VIDEO_SURFACES                 50
-#define NUM_BUFFERED_VIDEO                 4
+#define NUM_BUFFERED_VIDEO                 5
 
 /* number of palette entries */
 #define PALETTE_SIZE 256
@@ -295,7 +295,7 @@ static int video_to_output_surface(struct vo *vo)
                                           &vc->out_rect_vid);
 }
 
-static void get_buffered_frame(struct vo *vo, bool eof)
+static int next_deint_queue_pos(struct vo *vo, bool eof)
 {
     struct vdpctx *vc = vo->priv;
 
@@ -305,15 +305,23 @@ static void get_buffered_frame(struct vo *vo, bool eof)
     else
         dqp = vc->deint >= 2 ? dqp - 1 : dqp - 2 | 1;
     if (dqp < (eof ? 0 : 3))
-        return;
+        return -1;
+    return dqp;
+}
+
+static void set_next_frame_info(struct vo *vo, bool eof)
+{
+    struct vdpctx *vc = vo->priv;
 
-    dqp = FFMIN(dqp, 4);
-    vc->deint_queue_pos = dqp;
+    vo->frame_loaded = false;
+    int dqp = next_deint_queue_pos(vo, eof);
+    if (dqp < 0)
+        return;
     vo->frame_loaded = true;
 
     // Set pts values
     struct buffered_video_surface *bv = vc->buffered_video;
-    int idx = vc->deint_queue_pos >> 1;
+    int idx = dqp >> 1;
     if (idx == 0) {  // no future frame/pts available
         vo->next_pts = bv[0].pts;
         vo->next_pts2 = MP_NOPTS_VALUE;
@@ -327,7 +335,7 @@ static void get_buffered_frame(struct vo *vo, bool eof)
             intermediate_pts = (bv[idx].pts + bv[idx - 1].pts) / 2;
         else
             intermediate_pts =  bv[idx].pts;
-        if (vc->deint_queue_pos & 1) { // first field
+        if (dqp & 1) { // first field
             vo->next_pts = bv[idx].pts;
             vo->next_pts2 = intermediate_pts;
         } else {
@@ -335,8 +343,6 @@ static void get_buffered_frame(struct vo *vo, bool eof)
             vo->next_pts2 = bv[idx - 1].pts;
         }
     }
-
-    video_to_output_surface(vo);
 }
 
 static void add_new_video_surface(struct vo *vo, VdpVideoSurface surface,
@@ -358,8 +364,9 @@ static void add_new_video_surface(struct vo *vo, VdpVideoSurface surface,
         .pts = pts,
     };
 
-    vc->deint_queue_pos += 2;
-    get_buffered_frame(vo, false);
+    vc->deint_queue_pos = FFMIN(vc->deint_queue_pos + 2,
+                                NUM_BUFFERED_VIDEO * 2 - 3);
+    set_next_frame_info(vo, false);
 }
 
 static void forget_frames(struct vo *vo)
@@ -1858,6 +1865,13 @@ static int control(struct vo *vo, uint32_t request, void *data)
         r->mt = r->mb = vc->border_y;
         return VO_TRUE;
     }
+    case VOCTRL_NEWFRAME:
+        vc->deint_queue_pos = next_deint_queue_pos(vo, true);
+        video_to_output_surface(vo);
+        return true;
+    case VOCTRL_SKIPFRAME:
+        vc->deint_queue_pos = next_deint_queue_pos(vo, true);
+        return true;
     case VOCTRL_REDRAW_OSD:
         video_to_output_surface(vo);
         draw_eosd(vo);
@@ -1892,7 +1906,7 @@ const struct vo_driver video_out_vdpau = {
     .config = config,
     .control = control,
     .draw_image = draw_image,
-    .get_buffered_frame = get_buffered_frame,
+    .get_buffered_frame = set_next_frame_info,
     .draw_slice = draw_slice,
     .draw_osd = draw_osd,
     .flip_page_timed = flip_page_timed,