Add flush function

include/dav1d/dav1d.h

@@ -84,4 +84,9 @@ DAV1D_API int dav1d_decode(Dav1dContext *c, Dav1dData *in, Dav1dPicture *out);
  */
 DAV1D_API void dav1d_close(Dav1dContext **c_out);
 
+/**
+ * Flush all delayed frames in decoder, to be used when seeking.
+ */
+DAV1D_API void dav1d_flush(Dav1dContext *c);
+
 #endif /* __DAV1D_H__ */

src/decode.c

@@ -2688,7 +2688,7 @@ int submit_frame(Dav1dContext *const c) {
                               &f->frame_thread.td.lock);
         out_delayed = &c->frame_thread.out_delayed[next];
         if (out_delayed->p.data[0]) {
-            if (out_delayed->visible)
+            if (out_delayed->visible && !out_delayed->flushed)
                 dav1d_picture_ref(&c->out, &out_delayed->p);
             dav1d_thread_picture_unref(out_delayed);
         }

src/lib.c

@@ -178,7 +178,7 @@ int dav1d_decode(Dav1dContext *const c,
             if (++c->frame_thread.next == c->n_fc)
                 c->frame_thread.next = 0;
             if (out_delayed->p.data[0]) {
-                if (out_delayed->visible) {
+                if (out_delayed->visible && !out_delayed->flushed) {
                     dav1d_picture_ref(out, &out_delayed->p);
                 }
                 dav1d_thread_picture_unref(out_delayed);
@@ -215,6 +215,13 @@ int dav1d_decode(Dav1dContext *const c,
     return -EAGAIN;
 }
 
+void dav1d_flush(Dav1dContext *const c) {
+    if (c->n_fc == 1) return;
+
+    for (int n = 0; n < c->n_fc; n++)
+        c->frame_thread.out_delayed[n].flushed = 1;
+}
+
 void dav1d_close(Dav1dContext **const c_out) {
     validate_input(c_out != NULL);
 

src/obu.c

@@ -1088,13 +1088,14 @@ int parse_obus(Dav1dContext *const c, Dav1dData *const in) {
             Dav1dThreadPicture *const out_delayed =
                 &c->frame_thread.out_delayed[next];
             if (out_delayed->p.data[0]) {
-                if (out_delayed->visible)
+                if (out_delayed->visible && !out_delayed->flushed)
                     dav1d_picture_ref(&c->out, &out_delayed->p);
                 dav1d_thread_picture_unref(out_delayed);
             }
             dav1d_thread_picture_ref(out_delayed,
                                      &c->refs[c->frame_hdr.existing_frame_idx].p);
             out_delayed->visible = 1;
+            out_delayed->flushed = 0;
             pthread_mutex_unlock(&f->frame_thread.td.lock);
         }
         c->have_frame_hdr = 0;

src/picture.c

@@ -102,6 +102,7 @@ int dav1d_thread_picture_alloc(Dav1dThreadPicture *const p,
                                  (void **) &p->progress);
 
     p->visible = visible;
+    p->flushed = 0;
     if (t) {
         atomic_init(&p->progress[0], 0);
         atomic_init(&p->progress[1], 0);
@@ -128,6 +129,7 @@ void dav1d_thread_picture_ref(Dav1dThreadPicture *dst,
     dst->t = src->t;
     dst->visible = src->visible;
     dst->progress = src->progress;
+    dst->flushed = src->flushed;
 }
 
 void dav1d_picture_unref(Dav1dPicture *const p) {

src/picture.h

@@ -44,7 +44,7 @@ enum PlaneType {
 
 typedef struct Dav1dThreadPicture {
     Dav1dPicture p;
-    int visible;
+    int visible, flushed;
     struct thread_data *t;
     // [0] block data (including segmentation map and motion vectors)
     // [1] pixel data