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-rw-r--r--media/libvpx/vp9/encoder/vp9_writer.h98
1 files changed, 98 insertions, 0 deletions
diff --git a/media/libvpx/vp9/encoder/vp9_writer.h b/media/libvpx/vp9/encoder/vp9_writer.h
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+++ b/media/libvpx/vp9/encoder/vp9_writer.h
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2010 The WebM project authors. All Rights Reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef VP9_ENCODER_VP9_WRITER_H_
+#define VP9_ENCODER_VP9_WRITER_H_
+
+#include "vpx_ports/mem.h"
+
+#include "vp9/common/vp9_prob.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct vp9_writer {
+ unsigned int lowvalue;
+ unsigned int range;
+ int count;
+ unsigned int pos;
+ uint8_t *buffer;
+} vp9_writer;
+
+void vp9_start_encode(vp9_writer *bc, uint8_t *buffer);
+void vp9_stop_encode(vp9_writer *bc);
+
+static INLINE void vp9_write(vp9_writer *br, int bit, int probability) {
+ unsigned int split;
+ int count = br->count;
+ unsigned int range = br->range;
+ unsigned int lowvalue = br->lowvalue;
+ register unsigned int shift;
+
+ split = 1 + (((range - 1) * probability) >> 8);
+
+ range = split;
+
+ if (bit) {
+ lowvalue += split;
+ range = br->range - split;
+ }
+
+ shift = vp9_norm[range];
+
+ range <<= shift;
+ count += shift;
+
+ if (count >= 0) {
+ int offset = shift - count;
+
+ if ((lowvalue << (offset - 1)) & 0x80000000) {
+ int x = br->pos - 1;
+
+ while (x >= 0 && br->buffer[x] == 0xff) {
+ br->buffer[x] = 0;
+ x--;
+ }
+
+ br->buffer[x] += 1;
+ }
+
+ br->buffer[br->pos++] = (lowvalue >> (24 - offset));
+ lowvalue <<= offset;
+ shift = count;
+ lowvalue &= 0xffffff;
+ count -= 8;
+ }
+
+ lowvalue <<= shift;
+ br->count = count;
+ br->lowvalue = lowvalue;
+ br->range = range;
+}
+
+static INLINE void vp9_write_bit(vp9_writer *w, int bit) {
+ vp9_write(w, bit, 128); // vp9_prob_half
+}
+
+static INLINE void vp9_write_literal(vp9_writer *w, int data, int bits) {
+ int bit;
+
+ for (bit = bits - 1; bit >= 0; bit--)
+ vp9_write_bit(w, 1 & (data >> bit));
+}
+
+#define vp9_write_prob(w, v) vp9_write_literal((w), (v), 8)
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif // VP9_ENCODER_VP9_WRITER_H_