yading@10: /*
yading@10:  * MLP codec common header file
yading@10:  * Copyright (c) 2007-2008 Ian Caulfield
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #ifndef AVCODEC_MLP_H
yading@10: #define AVCODEC_MLP_H
yading@10: 
yading@10: #include <stdint.h>
yading@10: 
yading@10: #include "avcodec.h"
yading@10: 
yading@10: /** Last possible matrix channel for each codec */
yading@10: #define MAX_MATRIX_CHANNEL_MLP      5
yading@10: #define MAX_MATRIX_CHANNEL_TRUEHD   7
yading@10: /** Maximum number of channels in a valid stream.
yading@10:  *  MLP   : 5.1 + 2 noise channels -> 8 channels
yading@10:  *  TrueHD: 7.1                    -> 8 channels
yading@10:  */
yading@10: #define MAX_CHANNELS                8
yading@10: 
yading@10: /** Maximum number of matrices used in decoding; most streams have one matrix
yading@10:  *  per output channel, but some rematrix a channel (usually 0) more than once.
yading@10:  */
yading@10: #define MAX_MATRICES_MLP            6
yading@10: #define MAX_MATRICES_TRUEHD         8
yading@10: #define MAX_MATRICES                8
yading@10: 
yading@10: /** Maximum number of substreams that can be decoded.
yading@10:  *  MLP's limit is 2. TrueHD supports at least up to 3.
yading@10:  */
yading@10: #define MAX_SUBSTREAMS      3
yading@10: 
yading@10: /** which multiple of 48000 the maximum sample rate is */
yading@10: #define MAX_RATEFACTOR      4
yading@10: /** maximum sample frequency seen in files */
yading@10: #define MAX_SAMPLERATE      (MAX_RATEFACTOR * 48000)
yading@10: 
yading@10: /** maximum number of audio samples within one access unit */
yading@10: #define MAX_BLOCKSIZE       (40 * MAX_RATEFACTOR)
yading@10: /** next power of two greater than MAX_BLOCKSIZE */
yading@10: #define MAX_BLOCKSIZE_POW2  (64 * MAX_RATEFACTOR)
yading@10: 
yading@10: /** number of allowed filters */
yading@10: #define NUM_FILTERS         2
yading@10: 
yading@10: /** The maximum number of taps in IIR and FIR filters. */
yading@10: #define MAX_FIR_ORDER       8
yading@10: #define MAX_IIR_ORDER       4
yading@10: 
yading@10: /** Code that signals end of a stream. */
yading@10: #define END_OF_STREAM       0xd234d234
yading@10: 
yading@10: #define FIR 0
yading@10: #define IIR 1
yading@10: 
yading@10: /** filter data */
yading@10: typedef struct FilterParams {
yading@10:     uint8_t     order; ///< number of taps in filter
yading@10:     uint8_t     shift; ///< Right shift to apply to output of filter.
yading@10: 
yading@10:     int32_t     state[MAX_FIR_ORDER];
yading@10: } FilterParams;
yading@10: 
yading@10: /** sample data coding information */
yading@10: typedef struct ChannelParams {
yading@10:     FilterParams filter_params[NUM_FILTERS];
yading@10:     int32_t     coeff[NUM_FILTERS][MAX_FIR_ORDER];
yading@10: 
yading@10:     int16_t     huff_offset;      ///< Offset to apply to residual values.
yading@10:     int32_t     sign_huff_offset; ///< sign/rounding-corrected version of huff_offset
yading@10:     uint8_t     codebook;         ///< Which VLC codebook to use to read residuals.
yading@10:     uint8_t     huff_lsbs;        ///< Size of residual suffix not encoded using VLC.
yading@10: } ChannelParams;
yading@10: 
yading@10: /** Tables defining the Huffman codes.
yading@10:  *  There are three entropy coding methods used in MLP (four if you count
yading@10:  *  "none" as a method). These use the same sequences for codes starting with
yading@10:  *  00 or 01, but have different codes starting with 1.
yading@10:  */
yading@10: extern const uint8_t ff_mlp_huffman_tables[3][18][2];
yading@10: 
yading@10: /** MLP uses checksums that seem to be based on the standard CRC algorithm, but
yading@10:  *  are not (in implementation terms, the table lookup and XOR are reversed).
yading@10:  *  We can implement this behavior using a standard av_crc on all but the
yading@10:  *  last element, then XOR that with the last element.
yading@10:  */
yading@10: uint8_t  ff_mlp_checksum8 (const uint8_t *buf, unsigned int buf_size);
yading@10: uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size);
yading@10: 
yading@10: /** Calculate an 8-bit checksum over a restart header -- a non-multiple-of-8
yading@10:  *  number of bits, starting two bits into the first byte of buf.
yading@10:  */
yading@10: uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size);
yading@10: 
yading@10: /** XOR together all the bytes of a buffer.
yading@10:  *  Does this belong in dspcontext?
yading@10:  */
yading@10: uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size);
yading@10: 
yading@10: void ff_mlp_init_crc(void);
yading@10: 
yading@10: /** XOR four bytes into one. */
yading@10: static inline uint8_t xor_32_to_8(uint32_t value)
yading@10: {
yading@10:     value ^= value >> 16;
yading@10:     value ^= value >>  8;
yading@10:     return value;
yading@10: }
yading@10: 
yading@10: #endif /* AVCODEC_MLP_H */