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 17 namespace webrtc { 18 19 namespace vp8 { 20 21 enum { 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 28 typedef struct VP8BitReader VP8BitReader; 29 struct 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 40 const 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 49 const 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. 62 bool 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