From 580cf433bd3713f1c00a612be2d57d5b959e8496 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Thu, 18 Sep 2014 19:25:46 +0200
Subject: video/filter: allow better dataflow

Consider a filter which turns 1 frame into 2 frames (such as an
deinterlacer). Until now, we forced filters to produce all output frames
at once. This was done for simplicity.

Change the filter API such that a filter can produce frames
incrementally.
---
 video/filter/vf.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

(limited to 'video/filter/vf.c')

diff --git a/video/filter/vf.c b/video/filter/vf.c
index e76d30ea23..f00e9689c6 100644
--- a/video/filter/vf.c
+++ b/video/filter/vf.c
@@ -379,10 +379,19 @@ void vf_add_output_frame(struct vf_instance *vf, struct mp_image *img)
     }
 }
 
+static bool vf_has_output_frame(struct vf_instance *vf)
+{
+    if (!vf->num_out_queued && vf->filter_out) {
+        if (vf->filter_out(vf) < 0)
+            MP_ERR(vf, "Error filtering frame.\n");
+    }
+    return vf->num_out_queued > 0;
+}
+
 static struct mp_image *vf_dequeue_output_frame(struct vf_instance *vf)
 {
     struct mp_image *res = NULL;
-    if (vf->num_out_queued) {
+    if (vf_has_output_frame(vf)) {
         res = vf->out_queued[0];
         MP_TARRAY_REMOVE_AT(vf->out_queued, vf->num_out_queued, 0);
     }
@@ -445,7 +454,7 @@ int vf_output_frame(struct vf_chain *c, bool eof)
                 if (r < 0)
                     return r;
             }
-            if (cur->num_out_queued)
+            if (vf_has_output_frame(cur))
                 last = cur;
         }
         if (!last)
-- 
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