lavu: add AV_FRAME_DATA_DOWNMIX_INFO side data type.

libavutil/downmix_info.c

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2014 Tim Walker <tdskywalker@gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "downmix_info.h"
+#include "frame.h"
+
+AVDownmixInfo *av_downmix_info_update_side_data(AVFrame *frame)
+{
+    AVFrameSideData *side_data;
+
+    side_data = av_frame_get_side_data(frame, AV_FRAME_DATA_DOWNMIX_INFO);
+
+    if (!side_data)
+        side_data = av_frame_new_side_data(frame, AV_FRAME_DATA_DOWNMIX_INFO,
+                                           sizeof(AVDownmixInfo));
+
+    if (!side_data)
+        return NULL;
+
+    return (AVDownmixInfo*)side_data->data;
+}