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 3 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 */ 74typedef struct { 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 */ 82typedef struct { 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 */ 97extern 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 */ 104uint8_t ff_mlp_checksum8 (const uint8_t *buf, unsigned int buf_size); 105uint16_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 */ 110uint8_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 */ 115uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size); 116 117void ff_mlp_init_crc(void); 118 119/** XOR four bytes into one. */ 120static 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#endif /* AVCODEC_MLP_H */ 128