gfiber / vendor / opensource / ffmpeg / 0fda37cff9470c602fd59366ac4250a9a4eae6b1 / . / libavcodec / mlp.h

/* | |

* MLP codec common header file | |

* Copyright (c) 2007-2008 Ian Caulfield | |

* | |

* This file is part of FFmpeg. | |

* | |

* FFmpeg is free software; you can redistribute it and/or | |

* modify it under the terms of the GNU Lesser General Public | |

* License as published by the Free Software Foundation; either | |

* version 2.1 of the License, or (at your option) any later version. | |

* | |

* FFmpeg is distributed in the hope that it will be useful, | |

* but WITHOUT ANY WARRANTY; without even the implied warranty of | |

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |

* Lesser General Public License for more details. | |

* | |

* You should have received a copy of the GNU Lesser General Public | |

* License along with FFmpeg; if not, write to the Free Software | |

* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |

*/ | |

#ifndef AVCODEC_MLP_H | |

#define AVCODEC_MLP_H | |

#include <stdint.h> | |

#include "avcodec.h" | |

/** Maximum number of channels that can be decoded. */ | |

#define MAX_CHANNELS 16 | |

/** Maximum number of matrices used in decoding; most streams have one matrix | |

* per output channel, but some rematrix a channel (usually 0) more than once. | |

*/ | |

#define MAX_MATRICES 15 | |

/** Maximum number of substreams that can be decoded. This could also be set | |

* higher, but I haven't seen any examples with more than two. | |

*/ | |

#define MAX_SUBSTREAMS 2 | |

/** maximum sample frequency seen in files */ | |

#define MAX_SAMPLERATE 192000 | |

/** maximum number of audio samples within one access unit */ | |

#define MAX_BLOCKSIZE (40 * (MAX_SAMPLERATE / 48000)) | |

/** next power of two greater than MAX_BLOCKSIZE */ | |

#define MAX_BLOCKSIZE_POW2 (64 * (MAX_SAMPLERATE / 48000)) | |

/** number of allowed filters */ | |

#define NUM_FILTERS 2 | |

/** The maximum number of taps in either the IIR or FIR filter; | |

* I believe MLP actually specifies the maximum order for IIR filters as four, | |

* and that the sum of the orders of both filters must be <= 8. | |

*/ | |

#define MAX_FILTER_ORDER 8 | |

/** Code that signals end of a stream. */ | |

#define END_OF_STREAM 0xd234d234 | |

#define FIR 0 | |

#define IIR 1 | |

/** filter data */ | |

typedef struct { | |

uint8_t order; ///< number of taps in filter | |

uint8_t shift; ///< Right shift to apply to output of filter. | |

int32_t coeff[MAX_FILTER_ORDER]; | |

int32_t state[MAX_FILTER_ORDER]; | |

} FilterParams; | |

/** sample data coding information */ | |

typedef struct { | |

FilterParams filter_params[NUM_FILTERS]; | |

int16_t huff_offset; ///< Offset to apply to residual values. | |

int32_t sign_huff_offset; ///< sign/rounding-corrected version of huff_offset | |

uint8_t codebook; ///< Which VLC codebook to use to read residuals. | |

uint8_t huff_lsbs; ///< Size of residual suffix not encoded using VLC. | |

} ChannelParams; | |

/** Tables defining the Huffman codes. | |

* There are three entropy coding methods used in MLP (four if you count | |

* "none" as a method). These use the same sequences for codes starting with | |

* 00 or 01, but have different codes starting with 1. | |

*/ | |

extern const uint8_t ff_mlp_huffman_tables[3][18][2]; | |

/** MLP uses checksums that seem to be based on the standard CRC algorithm, but | |

* are not (in implementation terms, the table lookup and XOR are reversed). | |

* We can implement this behavior using a standard av_crc on all but the | |

* last element, then XOR that with the last element. | |

*/ | |

uint8_t ff_mlp_checksum8 (const uint8_t *buf, unsigned int buf_size); | |

uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size); | |

/** Calculate an 8-bit checksum over a restart header -- a non-multiple-of-8 | |

* number of bits, starting two bits into the first byte of buf. | |

*/ | |

uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size); | |

/** XOR together all the bytes of a buffer. | |

* Does this belong in dspcontext? | |

*/ | |

uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size); | |

void ff_mlp_init_crc(void); | |

/** XOR four bytes into one. */ | |

static inline uint8_t xor_32_to_8(uint32_t value) | |

{ | |

value ^= value >> 16; | |

value ^= value >> 8; | |

return value; | |

} | |

#endif /* AVCODEC_MLP_H */ |