ffmpeg: move flushing the queued frames to configure_filtergraph()

This is a more appropriate place for it, and will also be useful in the
following commit.

This merges Libav commit d2e56cf7. It was previously skipped.
Signed-off-by: wm4 <nfxjfg@googlemail.com>

ffmpeg.c

@@ -2186,17 +2186,6 @@ static int ifilter_send_frame(InputFilter *ifilter, AVFrame *frame)
             av_log(NULL, AV_LOG_ERROR, "Error reinitializing filters!\n");
             return ret;
         }
-
-        for (i = 0; i < fg->nb_inputs; i++) {
-            while (av_fifo_size(fg->inputs[i]->frame_queue)) {
-                AVFrame *tmp;
-                av_fifo_generic_read(fg->inputs[i]->frame_queue, &tmp, sizeof(tmp), NULL);
-                ret = av_buffersrc_add_frame(fg->inputs[i]->filter, tmp);
-                av_frame_free(&tmp);
-                if (ret < 0)
-                    return ret;
-            }
-        }
     }
 
     ret = av_buffersrc_add_frame_flags(ifilter->filter, frame, AV_BUFFERSRC_FLAG_PUSH);

ffmpeg_filter.c

@@ -1117,6 +1117,17 @@ int configure_filtergraph(FilterGraph *fg)
                                          ost->enc_ctx->frame_size);
     }
 
+    for (i = 0; i < fg->nb_inputs; i++) {
+        while (av_fifo_size(fg->inputs[i]->frame_queue)) {
+            AVFrame *tmp;
+            av_fifo_generic_read(fg->inputs[i]->frame_queue, &tmp, sizeof(tmp), NULL);
+            ret = av_buffersrc_add_frame(fg->inputs[i]->filter, tmp);
+            av_frame_free(&tmp);
+            if (ret < 0)
+                return ret;
+        }
+    }
+
     return 0;
 }