| 1 | /* |
| 2 | * MLP codec common header file |
| 3 | * Copyright (c) 2007-2008 Ian Caulfield |
| 4 | * |
| 5 | * This file is part of FFmpeg. |
| 6 | * |
| 7 | * FFmpeg is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU Lesser General Public |
| 9 | * License as published by the Free Software Foundation; either |
| 10 | * version 2.1 of the License, or (at your option) any later version. |
| 11 | * |
| 12 | * FFmpeg is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * Lesser General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU Lesser General Public |
| 18 | * License along with FFmpeg; if not, write to the Free Software |
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 20 | */ |
| 21 | |
| 22 | #ifndef AVCODEC_MLP_H |
| 23 | #define AVCODEC_MLP_H |
| 24 | |
| 25 | #include <stdint.h> |
| 26 | |
| 27 | #include "avcodec.h" |
| 28 | |
| 29 | /** Last possible matrix channel for each codec */ |
| 30 | #define MAX_MATRIX_CHANNEL_MLP 5 |
| 31 | #define MAX_MATRIX_CHANNEL_TRUEHD 7 |
| 32 | /** Maximum number of channels in a valid stream. |
| 33 | * MLP : 5.1 + 2 noise channels -> 8 channels |
| 34 | * TrueHD: 7.1 -> 8 channels |
| 35 | */ |
| 36 | #define MAX_CHANNELS 8 |
| 37 | |
| 38 | /** Maximum number of matrices used in decoding; most streams have one matrix |
| 39 | * per output channel, but some rematrix a channel (usually 0) more than once. |
| 40 | */ |
| 41 | #define MAX_MATRICES_MLP 6 |
| 42 | #define MAX_MATRICES_TRUEHD 8 |
| 43 | #define MAX_MATRICES 8 |
| 44 | |
| 45 | /** Maximum number of substreams that can be decoded. |
| 46 | * MLP's limit is 2. TrueHD supports at least up to 3. |
| 47 | */ |
| 48 | #define MAX_SUBSTREAMS 4 |
| 49 | |
| 50 | /** which multiple of 48000 the maximum sample rate is */ |
| 51 | #define MAX_RATEFACTOR 4 |
| 52 | /** maximum sample frequency seen in files */ |
| 53 | #define MAX_SAMPLERATE (MAX_RATEFACTOR * 48000) |
| 54 | |
| 55 | /** maximum number of audio samples within one access unit */ |
| 56 | #define MAX_BLOCKSIZE (40 * MAX_RATEFACTOR) |
| 57 | /** next power of two greater than MAX_BLOCKSIZE */ |
| 58 | #define MAX_BLOCKSIZE_POW2 (64 * MAX_RATEFACTOR) |
| 59 | |
| 60 | /** number of allowed filters */ |
| 61 | #define NUM_FILTERS 2 |
| 62 | |
| 63 | /** The maximum number of taps in IIR and FIR filters. */ |
| 64 | #define MAX_FIR_ORDER 8 |
| 65 | #define MAX_IIR_ORDER 4 |
| 66 | |
| 67 | /** Code that signals end of a stream. */ |
| 68 | #define END_OF_STREAM 0xd234d234 |
| 69 | |
| 70 | #define FIR 0 |
| 71 | #define IIR 1 |
| 72 | |
| 73 | /** filter data */ |
| 74 | typedef struct FilterParams { |
| 75 | uint8_t order; ///< number of taps in filter |
| 76 | uint8_t shift; ///< Right shift to apply to output of filter. |
| 77 | |
| 78 | int32_t state[MAX_FIR_ORDER]; |
| 79 | } FilterParams; |
| 80 | |
| 81 | /** sample data coding information */ |
| 82 | typedef struct ChannelParams { |
| 83 | FilterParams filter_params[NUM_FILTERS]; |
| 84 | int32_t coeff[NUM_FILTERS][MAX_FIR_ORDER]; |
| 85 | |
| 86 | int16_t huff_offset; ///< Offset to apply to residual values. |
| 87 | int32_t sign_huff_offset; ///< sign/rounding-corrected version of huff_offset |
| 88 | uint8_t codebook; ///< Which VLC codebook to use to read residuals. |
| 89 | uint8_t huff_lsbs; ///< Size of residual suffix not encoded using VLC. |
| 90 | } ChannelParams; |
| 91 | |
| 92 | /** Tables defining the Huffman codes. |
| 93 | * There are three entropy coding methods used in MLP (four if you count |
| 94 | * "none" as a method). These use the same sequences for codes starting with |
| 95 | * 00 or 01, but have different codes starting with 1. |
| 96 | */ |
| 97 | extern const uint8_t ff_mlp_huffman_tables[3][18][2]; |
| 98 | |
| 99 | /** MLP uses checksums that seem to be based on the standard CRC algorithm, but |
| 100 | * are not (in implementation terms, the table lookup and XOR are reversed). |
| 101 | * We can implement this behavior using a standard av_crc on all but the |
| 102 | * last element, then XOR that with the last element. |
| 103 | */ |
| 104 | uint8_t ff_mlp_checksum8 (const uint8_t *buf, unsigned int buf_size); |
| 105 | uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size); |
| 106 | |
| 107 | /** Calculate an 8-bit checksum over a restart header -- a non-multiple-of-8 |
| 108 | * number of bits, starting two bits into the first byte of buf. |
| 109 | */ |
| 110 | uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size); |
| 111 | |
| 112 | /** XOR together all the bytes of a buffer. |
| 113 | * Does this belong in dspcontext? |
| 114 | */ |
| 115 | uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size); |
| 116 | |
| 117 | void ff_mlp_init_crc(void); |
| 118 | |
| 119 | /** XOR four bytes into one. */ |
| 120 | static inline uint8_t xor_32_to_8(uint32_t value) |
| 121 | { |
| 122 | value ^= value >> 16; |
| 123 | value ^= value >> 8; |
| 124 | return value; |
| 125 | } |
| 126 | |
| 127 | typedef enum THDChannelModifier { |
| 128 | THD_CH_MODIFIER_NOTINDICATED = 0x0, |
| 129 | THD_CH_MODIFIER_STEREO = 0x0, // Stereo (not Dolby Surround) |
| 130 | THD_CH_MODIFIER_LTRT = 0x1, // Dolby Surround |
| 131 | THD_CH_MODIFIER_LBINRBIN = 0x2, // Dolby Headphone |
| 132 | THD_CH_MODIFIER_MONO = 0x3, // Mono or Dual Mono |
| 133 | THD_CH_MODIFIER_NOTSURROUNDEX = 0x1, // Not Dolby Digital EX |
| 134 | THD_CH_MODIFIER_SURROUNDEX = 0x2, // Dolby Digital EX |
| 135 | } THDChannelModifier; |
| 136 | |
| 137 | #endif /* AVCODEC_MLP_H */ |