| 1 | /***************************************************************************** |
| 2 | * Copyright (C) 2013 x265 project |
| 3 | * |
| 4 | * Author: Steve Borho <steve@borho.org> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111, USA. |
| 19 | * |
| 20 | * This program is also available under a commercial proprietary license. |
| 21 | * For more information, contact us at license @ x265.com. |
| 22 | *****************************************************************************/ |
| 23 | |
| 24 | #ifndef X265_BITSTREAM_H |
| 25 | #define X265_BITSTREAM_H 1 |
| 26 | |
| 27 | namespace x265 { |
| 28 | // private namespace |
| 29 | |
| 30 | class BitInterface |
| 31 | { |
| 32 | public: |
| 33 | |
| 34 | virtual void write(uint32_t val, uint32_t numBits) = 0; |
| 35 | virtual void writeByte(uint32_t val) = 0; |
| 36 | virtual void resetBits() = 0; |
| 37 | virtual uint32_t getNumberOfWrittenBits() const = 0; |
| 38 | virtual void writeAlignOne() = 0; |
| 39 | virtual void writeAlignZero() = 0; |
| 40 | virtual ~BitInterface() {} |
| 41 | }; |
| 42 | |
| 43 | class BitCounter : public BitInterface |
| 44 | { |
| 45 | protected: |
| 46 | |
| 47 | uint32_t m_bitCounter; |
| 48 | |
| 49 | public: |
| 50 | |
| 51 | BitCounter() : m_bitCounter(0) {} |
| 52 | |
| 53 | void write(uint32_t, uint32_t num) { m_bitCounter += num; } |
| 54 | void writeByte(uint32_t) { m_bitCounter += 8; } |
| 55 | void resetBits() { m_bitCounter = 0; } |
| 56 | uint32_t getNumberOfWrittenBits() const { return m_bitCounter; } |
| 57 | void writeAlignOne() { } |
| 58 | void writeAlignZero() { } |
| 59 | }; |
| 60 | |
| 61 | |
| 62 | class Bitstream : public BitInterface |
| 63 | { |
| 64 | public: |
| 65 | |
| 66 | Bitstream(); |
| 67 | ~Bitstream() { X265_FREE(m_fifo); } |
| 68 | |
| 69 | void resetBits() { m_partialByteBits = m_byteOccupancy = 0; m_partialByte = 0; } |
| 70 | uint32_t getNumberOfWrittenBytes() const { return m_byteOccupancy; } |
| 71 | uint32_t getNumberOfWrittenBits() const { return m_byteOccupancy * 8 + m_partialByteBits; } |
| 72 | const uint8_t* getFIFO() const { return m_fifo; } |
| 73 | |
| 74 | void write(uint32_t val, uint32_t numBits); |
| 75 | void writeByte(uint32_t val); |
| 76 | |
| 77 | void writeAlignOne(); // insert one bits until the bitstream is byte-aligned |
| 78 | void writeAlignZero(); // insert zero bits until the bitstream is byte-aligned |
| 79 | void writeByteAlignment(); // insert 1 bit, then pad to byte-align with zero |
| 80 | |
| 81 | private: |
| 82 | |
| 83 | uint8_t *m_fifo; |
| 84 | uint32_t m_byteAlloc; |
| 85 | uint32_t m_byteOccupancy; |
| 86 | uint32_t m_partialByteBits; |
| 87 | uint8_t m_partialByte; |
| 88 | |
| 89 | void push_back(uint8_t val); |
| 90 | }; |
| 91 | |
| 92 | static const uint8_t bitSize[256] = |
| 93 | { |
| 94 | 1, 1, 3, 3, 5, 5, 5, 5, 7, 7, 7, 7, 7, 7, 7, 7, |
| 95 | 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, |
| 96 | 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, |
| 97 | 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, |
| 98 | 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, |
| 99 | 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, |
| 100 | 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, |
| 101 | 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, |
| 102 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, |
| 103 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, |
| 104 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, |
| 105 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, |
| 106 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, |
| 107 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, |
| 108 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, |
| 109 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, |
| 110 | }; |
| 111 | |
| 112 | static inline int bs_size_ue(unsigned int val) |
| 113 | { |
| 114 | return bitSize[val + 1]; |
| 115 | } |
| 116 | |
| 117 | static inline int bs_size_ue_big(unsigned int val) |
| 118 | { |
| 119 | if (val < 255) |
| 120 | return bitSize[val + 1]; |
| 121 | else |
| 122 | return bitSize[(val + 1) >> 8] + 16; |
| 123 | } |
| 124 | |
| 125 | static inline int bs_size_se(int val) |
| 126 | { |
| 127 | int tmp = 1 - val * 2; |
| 128 | |
| 129 | if (tmp < 0) tmp = val * 2; |
| 130 | if (tmp < 256) |
| 131 | return bitSize[tmp]; |
| 132 | else |
| 133 | return bitSize[tmp >> 8] + 16; |
| 134 | } |
| 135 | |
| 136 | class SyntaxElementWriter |
| 137 | { |
| 138 | public: |
| 139 | |
| 140 | BitInterface* m_bitIf; |
| 141 | |
| 142 | SyntaxElementWriter() : m_bitIf(NULL) {} |
| 143 | |
| 144 | /* silently discard the name of the syntax element */ |
| 145 | inline void WRITE_CODE(uint32_t code, uint32_t length, const char *) { writeCode(code, length); } |
| 146 | inline void WRITE_UVLC(uint32_t code, const char *) { writeUvlc(code); } |
| 147 | inline void WRITE_SVLC(int32_t code, const char *) { writeSvlc(code); } |
| 148 | inline void WRITE_FLAG(bool flag, const char *) { writeFlag(flag); } |
| 149 | |
| 150 | void writeCode(uint32_t code, uint32_t length) { m_bitIf->write(code, length); } |
| 151 | void writeUvlc(uint32_t code); |
| 152 | void writeSvlc(int32_t code) { uint32_t ucode = (code <= 0) ? -code << 1 : (code << 1) - 1; writeUvlc(ucode); } |
| 153 | void writeFlag(bool code) { m_bitIf->write(code, 1); } |
| 154 | }; |
| 155 | |
| 156 | } |
| 157 | |
| 158 | #endif // ifndef X265_BITSTREAM_H |