1/*
2 *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#ifndef WEBRTC_MODULES_VIDEO_CODING_UTILITY_VP8_HEADER_PARSER_H_
12#define WEBRTC_MODULES_VIDEO_CODING_UTILITY_VP8_HEADER_PARSER_H_
13
14#include <stdint.h>
15#include <stdio.h>
16
17namespace webrtc {
18
19namespace vp8 {
20
21enum {
22  MB_FEATURE_TREE_PROBS = 3,
23  NUM_MB_SEGMENTS = 4,
24  NUM_REF_LF_DELTAS = 4,
25  NUM_MODE_LF_DELTAS = 4,
26};
27
28typedef struct VP8BitReader VP8BitReader;
29struct VP8BitReader {
30  // Boolean decoder.
31  uint32_t value_;  // Current value.
32  uint32_t range_;  // Current range minus 1. In [127, 254] interval.
33  int bits_;        // Number of valid bits left.
34  // Read buffer.
35  const uint8_t* buf_;      // Next byte to be read.
36  const uint8_t* buf_end_;  // End of read buffer.
37  int eof_;                 // True if input is exhausted.
38};
39
40const uint8_t kVP8Log2Range[128] = {
41    7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3,
42    3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
43    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1,
44    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
45    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
46    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0};
47
48// range = ((range - 1) << kVP8Log2Range[range]) + 1
49const uint8_t kVP8NewRange[128] = {
50    127, 127, 191, 127, 159, 191, 223, 127, 143, 159, 175, 191, 207, 223, 239,
51    127, 135, 143, 151, 159, 167, 175, 183, 191, 199, 207, 215, 223, 231, 239,
52    247, 127, 131, 135, 139, 143, 147, 151, 155, 159, 163, 167, 171, 175, 179,
53    183, 187, 191, 195, 199, 203, 207, 211, 215, 219, 223, 227, 231, 235, 239,
54    243, 247, 251, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149,
55    151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179,
56    181, 183, 185, 187, 189, 191, 193, 195, 197, 199, 201, 203, 205, 207, 209,
57    211, 213, 215, 217, 219, 221, 223, 225, 227, 229, 231, 233, 235, 237, 239,
58    241, 243, 245, 247, 249, 251, 253, 127};
59
60// Gets the QP, QP range: [0, 127].
61// Returns true on success, false otherwise.
62bool GetQp(const uint8_t* buf, size_t length, int* qp);
63
64}  // namespace vp8
65
66}  // namespace webrtc
67
68#endif  // WEBRTC_MODULES_VIDEO_CODING_UTILITY_VP8_HEADER_PARSER_H_
69