1 files changed, 66 insertions, 0 deletions
diff --git a/media/ffvpx/libavcodec/vp89_rac.h b/media/ffvpx/libavcodec/vp89_rac.h
new file mode 100644
index 0000000000..bc0924c387
--- /dev/null
+++ b/media/ffvpx/libavcodec/vp89_rac.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2006  Aurelien Jacobs <aurel@gnuage.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * Range decoder functions common to VP8 and VP9
+ */
+
+#ifndef AVCODEC_VP89_RAC_H
+#define AVCODEC_VP89_RAC_H
+
+#include <stdint.h>
+
+#include "libavutil/attributes.h"
+
+#include "vpx_rac.h"
+
+// rounding is different than vpx_rac_get, is vpx_rac_get wrong?
+static av_always_inline int vp89_rac_get(VPXRangeCoder *c)
+{
+    return vpx_rac_get_prob(c, 128);
+}
+
+static av_unused int vp89_rac_get_uint(VPXRangeCoder *c, int bits)
+{
+    int value = 0;
+
+    while (bits--) {
+        value = (value << 1) | vp89_rac_get(c);
+    }
+
+    return value;
+}
+
+// how probabilities are associated with decisions is different I think
+// well, the new scheme fits in the old but this way has one fewer branches per decision
+static av_always_inline int vp89_rac_get_tree(VPXRangeCoder *c, const int8_t (*tree)[2],
+                                              const uint8_t *probs)
+{
+    int i = 0;
+
+    do {
+        i = tree[i][vpx_rac_get_prob(c, probs[i])];
+    } while (i > 0);
+
+    return -i;
+}
+
+#endif /* AVCODEC_VP89_RAC_H */