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1
/*
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 * MPEG-4 ALS decoder
3
 * Copyright (c) 2009 Thilo Borgmann <thilo.borgmann _at_ googlemail.com>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file libavcodec/alsdec.c
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 * MPEG-4 ALS decoder
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 * @author Thilo Borgmann <thilo.borgmann _at_ googlemail.com>
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 */
27

    
28

    
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//#define DEBUG
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31

    
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#include "avcodec.h"
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#include "get_bits.h"
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#include "unary.h"
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#include "mpeg4audio.h"
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#include "bytestream.h"
37

    
38
#include <stdint.h>
39

    
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/** Rice parameters and corresponding index offsets for decoding the
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 *  indices of scaled PARCOR values. The table choosen is set globally
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 *  by the encoder and stored in ALSSpecificConfig.
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 */
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static const int8_t parcor_rice_table[3][20][2] = {
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    { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4},
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      { 12, 3}, { -7, 3}, {  9, 3}, { -5, 3}, {  6, 3},
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      { -4, 3}, {  3, 3}, { -3, 2}, {  3, 2}, { -2, 2},
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      {  3, 2}, { -1, 2}, {  2, 2}, { -1, 2}, {  2, 2} },
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    { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4},
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      { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4},
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      {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4},
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      {  7, 3}, { -4, 4}, {  3, 3}, { -1, 3}, {  1, 3} },
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    { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4},
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      { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3},
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      {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3},
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      {  3, 3}, {  0, 3}, { -1, 3}, {  2, 3}, { -1, 2} }
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};
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59

    
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/** Scaled PARCOR values used for the first two PARCOR coefficients.
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 *  To be indexed by the Rice coded indices.
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 *  Generated by: parcor_scaled_values[i] = 32 + ((i * (i+1)) << 7) - (1 << 20)
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 *  Actual values are divided by 32 in order to be stored in 16 bits.
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 */
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static const int16_t parcor_scaled_values[] = {
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    -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32,
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    -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32,
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    -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32,
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    -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32,
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    -1013728 / 32, -1009376 / 32, -1004768 / 32,  -999904 / 32,
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     -994784 / 32,  -989408 / 32,  -983776 / 32,  -977888 / 32,
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     -971744 / 32,  -965344 / 32,  -958688 / 32,  -951776 / 32,
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     -944608 / 32,  -937184 / 32,  -929504 / 32,  -921568 / 32,
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     -913376 / 32,  -904928 / 32,  -896224 / 32,  -887264 / 32,
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     -878048 / 32,  -868576 / 32,  -858848 / 32,  -848864 / 32,
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     -838624 / 32,  -828128 / 32,  -817376 / 32,  -806368 / 32,
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     -795104 / 32,  -783584 / 32,  -771808 / 32,  -759776 / 32,
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     -747488 / 32,  -734944 / 32,  -722144 / 32,  -709088 / 32,
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     -695776 / 32,  -682208 / 32,  -668384 / 32,  -654304 / 32,
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     -639968 / 32,  -625376 / 32,  -610528 / 32,  -595424 / 32,
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     -580064 / 32,  -564448 / 32,  -548576 / 32,  -532448 / 32,
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     -516064 / 32,  -499424 / 32,  -482528 / 32,  -465376 / 32,
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     -447968 / 32,  -430304 / 32,  -412384 / 32,  -394208 / 32,
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     -375776 / 32,  -357088 / 32,  -338144 / 32,  -318944 / 32,
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     -299488 / 32,  -279776 / 32,  -259808 / 32,  -239584 / 32,
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     -219104 / 32,  -198368 / 32,  -177376 / 32,  -156128 / 32,
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     -134624 / 32,  -112864 / 32,   -90848 / 32,   -68576 / 32,
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      -46048 / 32,   -23264 / 32,     -224 / 32,    23072 / 32,
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       46624 / 32,    70432 / 32,    94496 / 32,   118816 / 32,
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      143392 / 32,   168224 / 32,   193312 / 32,   218656 / 32,
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      244256 / 32,   270112 / 32,   296224 / 32,   322592 / 32,
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      349216 / 32,   376096 / 32,   403232 / 32,   430624 / 32,
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      458272 / 32,   486176 / 32,   514336 / 32,   542752 / 32,
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      571424 / 32,   600352 / 32,   629536 / 32,   658976 / 32,
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      688672 / 32,   718624 / 32,   748832 / 32,   779296 / 32,
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      810016 / 32,   840992 / 32,   872224 / 32,   903712 / 32,
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      935456 / 32,   967456 / 32,   999712 / 32,  1032224 / 32
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};
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/** Gain values of p(0) for long-term prediction.
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 *  To be indexed by the Rice coded indices.
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 */
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static const uint8_t ltp_gain_values [4][4] = {
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    { 0,  8, 16,  24},
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    {32, 40, 48,  56},
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    {64, 70, 76,  82},
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    {88, 92, 96, 100}
109
};
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111

    
112
enum RA_Flag {
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    RA_FLAG_NONE,
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    RA_FLAG_FRAMES,
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    RA_FLAG_HEADER
116
};
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118

    
119
typedef struct {
120
    uint32_t samples;         ///< number of samples, 0xFFFFFFFF if unknown
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    int resolution;           ///< 000 = 8-bit; 001 = 16-bit; 010 = 24-bit; 011 = 32-bit
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    int floating;             ///< 1 = IEEE 32-bit floating-point, 0 = integer
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    int frame_length;         ///< frame length for each frame (last frame may differ)
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    int ra_distance;          ///< distance between RA frames (in frames, 0...255)
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    enum RA_Flag ra_flag;     ///< indicates where the size of ra units is stored
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    int adapt_order;          ///< adaptive order: 1 = on, 0 = off
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    int coef_table;           ///< table index of Rice code parameters
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    int long_term_prediction; ///< long term prediction (LTP): 1 = on, 0 = off
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    int max_order;            ///< maximum prediction order (0..1023)
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    int block_switching;      ///< number of block switching levels
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    int bgmc;                 ///< "Block Gilbert-Moore Code": 1 = on, 0 = off (Rice coding only)
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    int sb_part;              ///< sub-block partition
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    int joint_stereo;         ///< joint stereo: 1 = on, 0 = off
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    int mc_coding;            ///< extended inter-channel coding (multi channel coding): 1 = on, 0 = off
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    int chan_config;          ///< indicates that a chan_config_info field is present
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    int chan_sort;            ///< channel rearrangement: 1 = on, 0 = off
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    int rlslms;               ///< use "Recursive Least Square-Least Mean Square" predictor: 1 = on, 0 = off
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    int chan_config_info;     ///< mapping of channels to loudspeaker locations. Unused until setting channel configuration is implemented.
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    int *chan_pos;            ///< original channel positions
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    uint32_t header_size;     ///< header size of original audio file in bytes, provided for debugging
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    uint32_t trailer_size;    ///< trailer size of original audio file in bytes, provided for debugging
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} ALSSpecificConfig;
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typedef struct {
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    AVCodecContext *avctx;
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    ALSSpecificConfig sconf;
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    GetBitContext gb;
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    unsigned int cur_frame_length;  ///< length of the current frame to decode
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    unsigned int frame_id;          ///< the frame ID / number of the current frame
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    unsigned int js_switch;         ///< if true, joint-stereo decoding is enforced
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    unsigned int num_blocks;        ///< number of blocks used in the current frame
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    int ltp_lag_length;             ///< number of bits used for ltp lag value
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    int *use_ltp;                   ///< contains use_ltp flags for all channels
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    int *ltp_lag;                   ///< contains ltp lag values for all channels
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    int **ltp_gain;                 ///< gain values for ltp 5-tap filter for a channel
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    int *ltp_gain_buffer;           ///< contains all gain values for ltp 5-tap filter
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    int32_t *quant_cof;             ///< quantized parcor coefficients
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    int32_t *lpc_cof;               ///< coefficients of the direct form prediction filter
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    int32_t *prev_raw_samples;      ///< contains unshifted raw samples from the previous block
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    int32_t **raw_samples;          ///< decoded raw samples for each channel
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    int32_t *raw_buffer;            ///< contains all decoded raw samples including carryover samples
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} ALSDecContext;
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165

    
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typedef struct {
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    unsigned int block_length;      ///< number of samples within the block
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    unsigned int ra_block;          ///< if true, this is a random access block
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    int          const_block;       ///< if true, this is a constant value block
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    int32_t      const_val;         ///< the sample value of a constant block
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    int          js_blocks;         ///< true if this block contains a difference signal
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    unsigned int shift_lsbs;        ///< shift of values for this block
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    unsigned int opt_order;         ///< prediction order of this block
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    int          store_prev_samples;///< if true, carryover samples have to be stored
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    int          *use_ltp;          ///< if true, long-term prediction is used
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    int          *ltp_lag;          ///< lag value for long-term prediction
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    int          *ltp_gain;         ///< gain values for ltp 5-tap filter
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    int32_t      *quant_cof;        ///< quantized parcor coefficients
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    int32_t      *lpc_cof;          ///< coefficients of the direct form prediction
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    int32_t      *raw_samples;      ///< decoded raw samples / residuals for this block
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    int32_t      *prev_raw_samples; ///< contains unshifted raw samples from the previous block
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    int32_t      *raw_other;        ///< decoded raw samples of the other channel of a channel pair
183
} ALSBlockData;
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185

    
186
static av_cold void dprint_specific_config(ALSDecContext *ctx)
187
{
188
#ifdef DEBUG
189
    AVCodecContext *avctx    = ctx->avctx;
190
    ALSSpecificConfig *sconf = &ctx->sconf;
191

    
192
    dprintf(avctx, "resolution = %i\n",           sconf->resolution);
193
    dprintf(avctx, "floating = %i\n",             sconf->floating);
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    dprintf(avctx, "frame_length = %i\n",         sconf->frame_length);
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    dprintf(avctx, "ra_distance = %i\n",          sconf->ra_distance);
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    dprintf(avctx, "ra_flag = %i\n",              sconf->ra_flag);
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    dprintf(avctx, "adapt_order = %i\n",          sconf->adapt_order);
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    dprintf(avctx, "coef_table = %i\n",           sconf->coef_table);
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    dprintf(avctx, "long_term_prediction = %i\n", sconf->long_term_prediction);
200
    dprintf(avctx, "max_order = %i\n",            sconf->max_order);
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    dprintf(avctx, "block_switching = %i\n",      sconf->block_switching);
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    dprintf(avctx, "bgmc = %i\n",                 sconf->bgmc);
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    dprintf(avctx, "sb_part = %i\n",              sconf->sb_part);
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    dprintf(avctx, "joint_stereo = %i\n",         sconf->joint_stereo);
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    dprintf(avctx, "mc_coding = %i\n",            sconf->mc_coding);
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    dprintf(avctx, "chan_config = %i\n",          sconf->chan_config);
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    dprintf(avctx, "chan_sort = %i\n",            sconf->chan_sort);
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    dprintf(avctx, "RLSLMS = %i\n",               sconf->rlslms);
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    dprintf(avctx, "chan_config_info = %i\n",     sconf->chan_config_info);
210
    dprintf(avctx, "header_size = %i\n",          sconf->header_size);
211
    dprintf(avctx, "trailer_size = %i\n",         sconf->trailer_size);
212
#endif
213
}
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/** Reads an ALSSpecificConfig from a buffer into the output struct.
217
 */
218
static av_cold int read_specific_config(ALSDecContext *ctx)
219
{
220
    GetBitContext gb;
221
    uint64_t ht_size;
222
    int i, config_offset, crc_enabled;
223
    MPEG4AudioConfig m4ac;
224
    ALSSpecificConfig *sconf = &ctx->sconf;
225
    AVCodecContext *avctx    = ctx->avctx;
226
    uint32_t als_id;
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228
    init_get_bits(&gb, avctx->extradata, avctx->extradata_size * 8);
229

    
230
    config_offset = ff_mpeg4audio_get_config(&m4ac, avctx->extradata,
231
                                             avctx->extradata_size);
232

    
233
    if (config_offset < 0)
234
        return -1;
235

    
236
    skip_bits_long(&gb, config_offset);
237

    
238
    if (get_bits_left(&gb) < (30 << 3))
239
        return -1;
240

    
241
    // read the fixed items
242
    als_id                      = get_bits_long(&gb, 32);
243
    avctx->sample_rate          = m4ac.sample_rate;
244
    skip_bits_long(&gb, 32); // sample rate already known
245
    sconf->samples              = get_bits_long(&gb, 32);
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    avctx->channels             = m4ac.channels;
247
    skip_bits(&gb, 16);      // number of channels already knwon
248
    skip_bits(&gb, 3);       // skip file_type
249
    sconf->resolution           = get_bits(&gb, 3);
250
    sconf->floating             = get_bits1(&gb);
251
    skip_bits1(&gb);         // skip msb_first
252
    sconf->frame_length         = get_bits(&gb, 16) + 1;
253
    sconf->ra_distance          = get_bits(&gb, 8);
254
    sconf->ra_flag              = get_bits(&gb, 2);
255
    sconf->adapt_order          = get_bits1(&gb);
256
    sconf->coef_table           = get_bits(&gb, 2);
257
    sconf->long_term_prediction = get_bits1(&gb);
258
    sconf->max_order            = get_bits(&gb, 10);
259
    sconf->block_switching      = get_bits(&gb, 2);
260
    sconf->bgmc                 = get_bits1(&gb);
261
    sconf->sb_part              = get_bits1(&gb);
262
    sconf->joint_stereo         = get_bits1(&gb);
263
    sconf->mc_coding            = get_bits1(&gb);
264
    sconf->chan_config          = get_bits1(&gb);
265
    sconf->chan_sort            = get_bits1(&gb);
266
    crc_enabled                 = get_bits1(&gb);
267
    sconf->rlslms               = get_bits1(&gb);
268
    skip_bits(&gb, 5);       // skip 5 reserved bits
269
    skip_bits1(&gb);         // skip aux_data_enabled
270

    
271

    
272
    // check for ALSSpecificConfig struct
273
    if (als_id != MKBETAG('A','L','S','\0'))
274
        return -1;
275

    
276
    ctx->cur_frame_length = sconf->frame_length;
277

    
278
    // allocate quantized parcor coefficient buffer
279
    if (!(ctx->quant_cof = av_malloc(sizeof(*ctx->quant_cof) * sconf->max_order)) ||
280
        !(ctx->lpc_cof   = av_malloc(sizeof(*ctx->lpc_cof)   * sconf->max_order))) {
281
        av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
282
        return AVERROR(ENOMEM);
283
    }
284

    
285
    // read channel config
286
    if (sconf->chan_config)
287
        sconf->chan_config_info = get_bits(&gb, 16);
288
    // TODO: use this to set avctx->channel_layout
289

    
290

    
291
    // read channel sorting
292
    if (sconf->chan_sort && avctx->channels > 1) {
293
        int chan_pos_bits = av_ceil_log2(avctx->channels);
294
        int bits_needed  = avctx->channels * chan_pos_bits + 7;
295
        if (get_bits_left(&gb) < bits_needed)
296
            return -1;
297

    
298
        if (!(sconf->chan_pos = av_malloc(avctx->channels * sizeof(*sconf->chan_pos))))
299
            return AVERROR(ENOMEM);
300

    
301
        for (i = 0; i < avctx->channels; i++)
302
            sconf->chan_pos[i] = get_bits(&gb, chan_pos_bits);
303

    
304
        align_get_bits(&gb);
305
        // TODO: use this to actually do channel sorting
306
    } else {
307
        sconf->chan_sort = 0;
308
    }
309

    
310

    
311
    // read fixed header and trailer sizes,
312
    // if size = 0xFFFFFFFF then there is no data field!
313
    if (get_bits_left(&gb) < 64)
314
        return -1;
315

    
316
    sconf->header_size  = get_bits_long(&gb, 32);
317
    sconf->trailer_size = get_bits_long(&gb, 32);
318
    if (sconf->header_size  == 0xFFFFFFFF)
319
        sconf->header_size  = 0;
320
    if (sconf->trailer_size == 0xFFFFFFFF)
321
        sconf->trailer_size = 0;
322

    
323
    ht_size = ((int64_t)(sconf->header_size) + (int64_t)(sconf->trailer_size)) << 3;
324

    
325

    
326
    // skip the header and trailer data
327
    if (get_bits_left(&gb) < ht_size)
328
        return -1;
329

    
330
    if (ht_size > INT32_MAX)
331
        return -1;
332

    
333
    skip_bits_long(&gb, ht_size);
334

    
335

    
336
    // skip the crc data
337
    if (crc_enabled) {
338
        if (get_bits_left(&gb) < 32)
339
            return -1;
340

    
341
        skip_bits_long(&gb, 32);
342
    }
343

    
344

    
345
    // no need to read the rest of ALSSpecificConfig (ra_unit_size & aux data)
346

    
347
    dprint_specific_config(ctx);
348

    
349
    return 0;
350
}
351

    
352

    
353
/** Checks the ALSSpecificConfig for unsupported features.
354
 */
355
static int check_specific_config(ALSDecContext *ctx)
356
{
357
    ALSSpecificConfig *sconf = &ctx->sconf;
358
    int error = 0;
359

    
360
    // report unsupported feature and set error value
361
    #define MISSING_ERR(cond, str, errval)              \
362
    {                                                   \
363
        if (cond) {                                     \
364
            av_log_missing_feature(ctx->avctx, str, 0); \
365
            error = errval;                             \
366
        }                                               \
367
    }
368

    
369
    MISSING_ERR(sconf->floating,             "Floating point decoding",     -1);
370
    MISSING_ERR(sconf->bgmc,                 "BGMC entropy decoding",       -1);
371
    MISSING_ERR(sconf->mc_coding,            "Multi-channel correlation",   -1);
372
    MISSING_ERR(sconf->rlslms,               "Adaptive RLS-LMS prediction", -1);
373
    MISSING_ERR(sconf->chan_sort,            "Channel sorting",              0);
374

    
375
    return error;
376
}
377

    
378

    
379
/** Parses the bs_info field to extract the block partitioning used in
380
 *  block switching mode, refer to ISO/IEC 14496-3, section 11.6.2.
381
 */
382
static void parse_bs_info(const uint32_t bs_info, unsigned int n,
383
                          unsigned int div, unsigned int **div_blocks,
384
                          unsigned int *num_blocks)
385
{
386
    if (n < 31 && ((bs_info << n) & 0x40000000)) {
387
        // if the level is valid and the investigated bit n is set
388
        // then recursively check both children at bits (2n+1) and (2n+2)
389
        n   *= 2;
390
        div += 1;
391
        parse_bs_info(bs_info, n + 1, div, div_blocks, num_blocks);
392
        parse_bs_info(bs_info, n + 2, div, div_blocks, num_blocks);
393
    } else {
394
        // else the bit is not set or the last level has been reached
395
        // (bit implicitly not set)
396
        **div_blocks = div;
397
        (*div_blocks)++;
398
        (*num_blocks)++;
399
    }
400
}
401

    
402

    
403
/** Reads and decodes a Rice codeword.
404
 */
405
static int32_t decode_rice(GetBitContext *gb, unsigned int k)
406
{
407
    int max = get_bits_left(gb) - k;
408
    int q   = get_unary(gb, 0, max);
409
    int r   = k ? get_bits1(gb) : !(q & 1);
410

    
411
    if (k > 1) {
412
        q <<= (k - 1);
413
        q  += get_bits_long(gb, k - 1);
414
    } else if (!k) {
415
        q >>= 1;
416
    }
417
    return r ? q : ~q;
418
}
419

    
420

    
421
/** Converts PARCOR coefficient k to direct filter coefficient.
422
 */
423
static void parcor_to_lpc(unsigned int k, const int32_t *par, int32_t *cof)
424
{
425
    int i, j;
426

    
427
    for (i = 0, j = k - 1; i < j; i++, j--) {
428
        int tmp1 = ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
429
        cof[j]  += ((MUL64(par[k], cof[i]) + (1 << 19)) >> 20);
430
        cof[i]  += tmp1;
431
    }
432
    if (i == j)
433
        cof[i] += ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
434

    
435
    cof[k] = par[k];
436
}
437

    
438

    
439
/** Reads block switching field if necessary and sets actual block sizes.
440
 *  Also assures that the block sizes of the last frame correspond to the
441
 *  actual number of samples.
442
 */
443
static void get_block_sizes(ALSDecContext *ctx, unsigned int *div_blocks,
444
                            uint32_t *bs_info)
445
{
446
    ALSSpecificConfig *sconf     = &ctx->sconf;
447
    GetBitContext *gb            = &ctx->gb;
448
    unsigned int *ptr_div_blocks = div_blocks;
449
    unsigned int b;
450

    
451
    if (sconf->block_switching) {
452
        unsigned int bs_info_len = 1 << (sconf->block_switching + 2);
453
        *bs_info = get_bits_long(gb, bs_info_len);
454
        *bs_info <<= (32 - bs_info_len);
455
    }
456

    
457
    ctx->num_blocks = 0;
458
    parse_bs_info(*bs_info, 0, 0, &ptr_div_blocks, &ctx->num_blocks);
459

    
460
    // The last frame may have an overdetermined block structure given in
461
    // the bitstream. In that case the defined block structure would need
462
    // more samples than available to be consistent.
463
    // The block structure is actually used but the block sizes are adapted
464
    // to fit the actual number of available samples.
465
    // Example: 5 samples, 2nd level block sizes: 2 2 2 2.
466
    // This results in the actual block sizes:    2 2 1 0.
467
    // This is not specified in 14496-3 but actually done by the reference
468
    // codec RM22 revision 2.
469
    // This appears to happen in case of an odd number of samples in the last
470
    // frame which is actually not allowed by the block length switching part
471
    // of 14496-3.
472
    // The ALS conformance files feature an odd number of samples in the last
473
    // frame.
474

    
475
    for (b = 0; b < ctx->num_blocks; b++)
476
        div_blocks[b] = ctx->sconf.frame_length >> div_blocks[b];
477

    
478
    if (ctx->cur_frame_length != ctx->sconf.frame_length) {
479
        unsigned int remaining = ctx->cur_frame_length;
480

    
481
        for (b = 0; b < ctx->num_blocks; b++) {
482
            if (remaining < div_blocks[b]) {
483
                div_blocks[b] = remaining;
484
                ctx->num_blocks = b + 1;
485
                break;
486
            }
487

    
488
            remaining -= div_blocks[b];
489
        }
490
    }
491
}
492

    
493

    
494
/** Reads the block data for a constant block
495
 */
496
static void read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
497
{
498
    ALSSpecificConfig *sconf = &ctx->sconf;
499
    AVCodecContext *avctx    = ctx->avctx;
500
    GetBitContext *gb        = &ctx->gb;
501

    
502
    bd->const_val    = 0;
503
    bd->const_block  = get_bits1(gb);    // 1 = constant value, 0 = zero block (silence)
504
    bd->js_blocks    = get_bits1(gb);
505

    
506
    // skip 5 reserved bits
507
    skip_bits(gb, 5);
508

    
509
    if (bd->const_block) {
510
        unsigned int const_val_bits = sconf->floating ? 24 : avctx->bits_per_raw_sample;
511
        bd->const_val = get_sbits_long(gb, const_val_bits);
512
    }
513

    
514
    // ensure constant block decoding by reusing this field
515
    bd->const_block = 1;
516
}
517

    
518

    
519
/** Decodes the block data for a constant block
520
 */
521
static void decode_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
522
{
523
    int      smp = bd->block_length;
524
    int32_t  val = bd->const_val;
525
    int32_t *dst = bd->raw_samples;
526

    
527
    // write raw samples into buffer
528
    for (; smp; smp--)
529
        *dst++ = val;
530
}
531

    
532

    
533
/** Reads the block data for a non-constant block
534
 */
535
static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
536
{
537
    ALSSpecificConfig *sconf = &ctx->sconf;
538
    AVCodecContext *avctx    = ctx->avctx;
539
    GetBitContext *gb        = &ctx->gb;
540
    unsigned int k;
541
    unsigned int s[8];
542
    unsigned int sub_blocks, log2_sub_blocks, sb_length;
543
    unsigned int start      = 0;
544
    unsigned int opt_order;
545
    int          sb;
546
    int32_t      *quant_cof = bd->quant_cof;
547

    
548

    
549
    // ensure variable block decoding by reusing this field
550
    bd->const_block = 0;
551

    
552
    bd->opt_order   = 1;
553
    bd->js_blocks   = get_bits1(gb);
554

    
555
    opt_order       = bd->opt_order;
556

    
557
    // determine the number of subblocks for entropy decoding
558
    if (!sconf->bgmc && !sconf->sb_part) {
559
        log2_sub_blocks = 0;
560
    } else {
561
        if (sconf->bgmc && sconf->sb_part)
562
            log2_sub_blocks = get_bits(gb, 2);
563
        else
564
            log2_sub_blocks = 2 * get_bits1(gb);
565
    }
566

    
567
    sub_blocks = 1 << log2_sub_blocks;
568

    
569
    // do not continue in case of a damaged stream since
570
    // block_length must be evenly divisible by sub_blocks
571
    if (bd->block_length & (sub_blocks - 1)) {
572
        av_log(avctx, AV_LOG_WARNING,
573
               "Block length is not evenly divisible by the number of subblocks.\n");
574
        return -1;
575
    }
576

    
577
    sb_length = bd->block_length >> log2_sub_blocks;
578

    
579

    
580
    if (sconf->bgmc) {
581
        // TODO: BGMC mode
582
    } else {
583
        s[0] = get_bits(gb, 4 + (sconf->resolution > 1));
584
        for (k = 1; k < sub_blocks; k++)
585
            s[k] = s[k - 1] + decode_rice(gb, 0);
586
    }
587

    
588
    if (get_bits1(gb))
589
        bd->shift_lsbs = get_bits(gb, 4) + 1;
590

    
591
    bd->store_prev_samples = (bd->js_blocks && bd->raw_other) || bd->shift_lsbs;
592

    
593

    
594
    if (!sconf->rlslms) {
595
        if (sconf->adapt_order) {
596
            int opt_order_length = av_ceil_log2(av_clip((bd->block_length >> 3) - 1,
597
                                                2, sconf->max_order + 1));
598
            bd->opt_order        = get_bits(gb, opt_order_length);
599
        } else {
600
            bd->opt_order = sconf->max_order;
601
        }
602

    
603
        opt_order = bd->opt_order;
604

    
605
        if (opt_order) {
606
            int add_base;
607

    
608
            if (sconf->coef_table == 3) {
609
                add_base = 0x7F;
610

    
611
                // read coefficient 0
612
                quant_cof[0] = 32 * parcor_scaled_values[get_bits(gb, 7)];
613

    
614
                // read coefficient 1
615
                if (opt_order > 1)
616
                    quant_cof[1] = -32 * parcor_scaled_values[get_bits(gb, 7)];
617

    
618
                // read coefficients 2 to opt_order
619
                for (k = 2; k < opt_order; k++)
620
                    quant_cof[k] = get_bits(gb, 7);
621
            } else {
622
                int k_max;
623
                add_base = 1;
624

    
625
                // read coefficient 0 to 19
626
                k_max = FFMIN(opt_order, 20);
627
                for (k = 0; k < k_max; k++) {
628
                    int rice_param = parcor_rice_table[sconf->coef_table][k][1];
629
                    int offset     = parcor_rice_table[sconf->coef_table][k][0];
630
                    quant_cof[k] = decode_rice(gb, rice_param) + offset;
631
                }
632

    
633
                // read coefficients 20 to 126
634
                k_max = FFMIN(opt_order, 127);
635
                for (; k < k_max; k++)
636
                    quant_cof[k] = decode_rice(gb, 2) + (k & 1);
637

    
638
                // read coefficients 127 to opt_order
639
                for (; k < opt_order; k++)
640
                    quant_cof[k] = decode_rice(gb, 1);
641

    
642
                quant_cof[0] = 32 * parcor_scaled_values[quant_cof[0] + 64];
643

    
644
                if (opt_order > 1)
645
                    quant_cof[1] = -32 * parcor_scaled_values[quant_cof[1] + 64];
646
            }
647

    
648
            for (k = 2; k < opt_order; k++)
649
                quant_cof[k] = (quant_cof[k] << 14) + (add_base << 13);
650
        }
651
    }
652

    
653
    // read LTP gain and lag values
654
    if (sconf->long_term_prediction) {
655
        *bd->use_ltp = get_bits1(gb);
656

    
657
        if (*bd->use_ltp) {
658
            bd->ltp_gain[0]   = decode_rice(gb, 1) << 3;
659
            bd->ltp_gain[1]   = decode_rice(gb, 2) << 3;
660

    
661
            bd->ltp_gain[2]   = ltp_gain_values[get_unary(gb, 0, 4)][get_bits(gb, 2)];
662

    
663
            bd->ltp_gain[3]   = decode_rice(gb, 2) << 3;
664
            bd->ltp_gain[4]   = decode_rice(gb, 1) << 3;
665

    
666
            *bd->ltp_lag      = get_bits(gb, ctx->ltp_lag_length);
667
            *bd->ltp_lag     += FFMAX(4, opt_order + 1);
668
        }
669
    }
670

    
671
    // read first value and residuals in case of a random access block
672
    if (bd->ra_block) {
673
        if (opt_order)
674
            bd->raw_samples[0] = decode_rice(gb, avctx->bits_per_raw_sample - 4);
675
        if (opt_order > 1)
676
            bd->raw_samples[1] = decode_rice(gb, s[0] + 3);
677
        if (opt_order > 2)
678
            bd->raw_samples[2] = decode_rice(gb, s[0] + 1);
679

    
680
        start = FFMIN(opt_order, 3);
681
    }
682

    
683
    // read all residuals
684
    if (sconf->bgmc) {
685
        // TODO: BGMC mode
686
    } else {
687
        int32_t *current_res = bd->raw_samples + start;
688

    
689
        for (sb = 0; sb < sub_blocks; sb++, start = 0)
690
            for (; start < sb_length; start++)
691
                *current_res++ = decode_rice(gb, s[sb]);
692
     }
693

    
694
    if (!sconf->mc_coding || ctx->js_switch)
695
        align_get_bits(gb);
696

    
697
    return 0;
698
}
699

    
700

    
701
/** Decodes the block data for a non-constant block
702
 */
703
static int decode_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
704
{
705
    ALSSpecificConfig *sconf = &ctx->sconf;
706
    unsigned int block_length = bd->block_length;
707
    unsigned int smp = 0;
708
    unsigned int k;
709
    unsigned int opt_order    = bd->opt_order;
710
    int sb;
711
    int64_t y;
712
    int32_t *quant_cof        = bd->quant_cof;
713
    int32_t *lpc_cof          = bd->lpc_cof;
714
    int32_t *raw_samples      = bd->raw_samples;
715
    int32_t *raw_samples_end  = bd->raw_samples + bd->block_length;
716
    int32_t lpc_cof_reversed[opt_order];
717

    
718
    // reverse long-term prediction
719
    if (*bd->use_ltp) {
720
        int ltp_smp;
721

    
722
        for (ltp_smp = FFMAX(*bd->ltp_lag - 2, 0); ltp_smp < block_length; ltp_smp++) {
723
            int center = ltp_smp - *bd->ltp_lag;
724
            int begin  = FFMAX(0, center - 2);
725
            int end    = center + 3;
726
            int tab    = 5 - (end - begin);
727
            int base;
728

    
729
            y = 1 << 6;
730

    
731
            for (base = begin; base < end; base++, tab++)
732
                y += MUL64(bd->ltp_gain[tab], raw_samples[base]);
733

    
734
            raw_samples[ltp_smp] += y >> 7;
735
        }
736
    }
737

    
738
    // reconstruct all samples from residuals
739
    if (bd->ra_block) {
740
        for (smp = 0; smp < opt_order; smp++) {
741
            y = 1 << 19;
742

    
743
            for (sb = 0; sb < smp; sb++)
744
                y += MUL64(lpc_cof[sb], raw_samples[-(sb + 1)]);
745

    
746
            *raw_samples++ -= y >> 20;
747
            parcor_to_lpc(smp, quant_cof, lpc_cof);
748
        }
749
    } else {
750
        for (k = 0; k < opt_order; k++)
751
            parcor_to_lpc(k, quant_cof, lpc_cof);
752

    
753
        // store previous samples in case that they have to be altered
754
        if (bd->store_prev_samples)
755
            memcpy(bd->prev_raw_samples, raw_samples - sconf->max_order,
756
                   sizeof(*bd->prev_raw_samples) * sconf->max_order);
757

    
758
        // reconstruct difference signal for prediction (joint-stereo)
759
        if (bd->js_blocks && bd->raw_other) {
760
            int32_t *left, *right;
761

    
762
            if (bd->raw_other > raw_samples) {  // D = R - L
763
                left  = raw_samples;
764
                right = bd->raw_other;
765
            } else {                                // D = R - L
766
                left  = bd->raw_other;
767
                right = raw_samples;
768
            }
769

    
770
            for (sb = -1; sb >= -sconf->max_order; sb--)
771
                raw_samples[sb] = right[sb] - left[sb];
772
        }
773

    
774
        // reconstruct shifted signal
775
        if (bd->shift_lsbs)
776
            for (sb = -1; sb >= -sconf->max_order; sb--)
777
                raw_samples[sb] >>= bd->shift_lsbs;
778
    }
779

    
780
    // reverse linear prediction coefficients for efficiency
781
    lpc_cof = lpc_cof + opt_order;
782

    
783
    for (sb = 0; sb < opt_order; sb++)
784
        lpc_cof_reversed[sb] = lpc_cof[-(sb + 1)];
785

    
786
    // reconstruct raw samples
787
    raw_samples = bd->raw_samples + smp;
788
    lpc_cof     = lpc_cof_reversed + opt_order;
789

    
790
    for (; raw_samples < raw_samples_end; raw_samples++) {
791
        y = 1 << 19;
792

    
793
        for (sb = -opt_order; sb < 0; sb++)
794
            y += MUL64(lpc_cof[sb], raw_samples[sb]);
795

    
796
        *raw_samples -= y >> 20;
797
    }
798

    
799
    raw_samples = bd->raw_samples;
800

    
801
    // restore previous samples in case that they have been altered
802
    if (bd->store_prev_samples)
803
        memcpy(raw_samples - sconf->max_order, bd->prev_raw_samples,
804
               sizeof(*raw_samples) * sconf->max_order);
805

    
806
    return 0;
807
}
808

    
809

    
810
/** Reads the block data.
811
 */
812
static int read_block(ALSDecContext *ctx, ALSBlockData *bd)
813
{
814
    GetBitContext *gb        = &ctx->gb;
815

    
816
    // read block type flag and read the samples accordingly
817
    if (get_bits1(gb)) {
818
        if (read_var_block_data(ctx, bd))
819
            return -1;
820
    } else {
821
        read_const_block_data(ctx, bd);
822
    }
823

    
824
    return 0;
825
}
826

    
827

    
828
/** Decodes the block data.
829
 */
830
static int decode_block(ALSDecContext *ctx, ALSBlockData *bd)
831
{
832
    unsigned int smp;
833

    
834
    // read block type flag and read the samples accordingly
835
    if (bd->const_block)
836
        decode_const_block_data(ctx, bd);
837
    else if (decode_var_block_data(ctx, bd))
838
        return -1;
839

    
840
    // TODO: read RLSLMS extension data
841

    
842
    if (bd->shift_lsbs)
843
        for (smp = 0; smp < bd->block_length; smp++)
844
            bd->raw_samples[smp] <<= bd->shift_lsbs;
845

    
846
    return 0;
847
}
848

    
849

    
850
/** Reads and decodes block data successively.
851
 */
852
static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)
853
{
854
    int ret;
855

    
856
    ret = read_block(ctx, bd);
857

    
858
    if (ret)
859
        return ret;
860

    
861
    ret = decode_block(ctx, bd);
862

    
863
    return ret;
864
}
865

    
866

    
867
/** Computes the number of samples left to decode for the current frame and
868
 *  sets these samples to zero.
869
 */
870
static void zero_remaining(unsigned int b, unsigned int b_max,
871
                           const unsigned int *div_blocks, int32_t *buf)
872
{
873
    unsigned int count = 0;
874

    
875
    while (b < b_max)
876
        count += div_blocks[b];
877

    
878
    if (count)
879
        memset(buf, 0, sizeof(*buf) * count);
880
}
881

    
882

    
883
/** Decodes blocks independently.
884
 */
885
static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,
886
                             unsigned int c, const unsigned int *div_blocks,
887
                             unsigned int *js_blocks)
888
{
889
    unsigned int b;
890
    ALSBlockData bd;
891

    
892
    memset(&bd, 0, sizeof(ALSBlockData));
893

    
894
    bd.ra_block         = ra_frame;
895
    bd.use_ltp          = ctx->use_ltp;
896
    bd.ltp_lag          = ctx->ltp_lag;
897
    bd.ltp_gain         = ctx->ltp_gain[0];
898
    bd.quant_cof        = ctx->quant_cof;
899
    bd.lpc_cof          = ctx->lpc_cof;
900
    bd.prev_raw_samples = ctx->prev_raw_samples;
901
    bd.raw_samples      = ctx->raw_samples[c];
902

    
903

    
904
    for (b = 0; b < ctx->num_blocks; b++) {
905
        bd.shift_lsbs       = 0;
906
        bd.block_length     = div_blocks[b];
907

    
908
        if (read_decode_block(ctx, &bd)) {
909
            // damaged block, write zero for the rest of the frame
910
            zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);
911
            return -1;
912
        }
913
        bd.raw_samples += div_blocks[b];
914
        bd.ra_block     = 0;
915
    }
916

    
917
    return 0;
918
}
919

    
920

    
921
/** Decodes blocks dependently.
922
 */
923
static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,
924
                         unsigned int c, const unsigned int *div_blocks,
925
                         unsigned int *js_blocks)
926
{
927
    ALSSpecificConfig *sconf = &ctx->sconf;
928
    unsigned int offset = 0;
929
    unsigned int b;
930
    ALSBlockData bd[2];
931

    
932
    memset(bd, 0, 2 * sizeof(ALSBlockData));
933

    
934
    bd[0].ra_block         = ra_frame;
935
    bd[0].use_ltp          = ctx->use_ltp;
936
    bd[0].ltp_lag          = ctx->ltp_lag;
937
    bd[0].ltp_gain         = ctx->ltp_gain[0];
938
    bd[0].quant_cof        = ctx->quant_cof;
939
    bd[0].lpc_cof          = ctx->lpc_cof;
940
    bd[0].prev_raw_samples = ctx->prev_raw_samples;
941
    bd[0].js_blocks        = *js_blocks;
942

    
943
    bd[1].ra_block         = ra_frame;
944
    bd[1].use_ltp          = ctx->use_ltp;
945
    bd[1].ltp_lag          = ctx->ltp_lag;
946
    bd[1].ltp_gain         = ctx->ltp_gain[0];
947
    bd[1].quant_cof        = ctx->quant_cof;
948
    bd[1].lpc_cof          = ctx->lpc_cof;
949
    bd[1].prev_raw_samples = ctx->prev_raw_samples;
950
    bd[1].js_blocks        = *(js_blocks + 1);
951

    
952
    // decode all blocks
953
    for (b = 0; b < ctx->num_blocks; b++) {
954
        unsigned int s;
955

    
956
        bd[0].shift_lsbs   = 0;
957
        bd[1].shift_lsbs   = 0;
958

    
959
        bd[0].block_length = div_blocks[b];
960
        bd[1].block_length = div_blocks[b];
961

    
962
        bd[0].raw_samples  = ctx->raw_samples[c    ] + offset;
963
        bd[1].raw_samples  = ctx->raw_samples[c + 1] + offset;
964

    
965
        bd[0].raw_other    = bd[1].raw_samples;
966
        bd[1].raw_other    = bd[0].raw_samples;
967

    
968
        if(read_decode_block(ctx, &bd[0]) || read_decode_block(ctx, &bd[1])) {
969
            // damaged block, write zero for the rest of the frame
970
            zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);
971
            zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);
972
            return -1;
973
        }
974

    
975
        // reconstruct joint-stereo blocks
976
        if (bd[0].js_blocks) {
977
            if (bd[1].js_blocks)
978
                av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair!\n");
979

    
980
            for (s = 0; s < div_blocks[b]; s++)
981
                bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];
982
        } else if (bd[1].js_blocks) {
983
            for (s = 0; s < div_blocks[b]; s++)
984
                bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];
985
        }
986

    
987
        offset  += div_blocks[b];
988
        bd[0].ra_block = 0;
989
        bd[1].ra_block = 0;
990
    }
991

    
992
    // store carryover raw samples,
993
    // the others channel raw samples are stored by the calling function.
994
    memmove(ctx->raw_samples[c] - sconf->max_order,
995
            ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
996
            sizeof(*ctx->raw_samples[c]) * sconf->max_order);
997

    
998
    return 0;
999
}
1000

    
1001

    
1002
/** Reads the frame data.
1003
 */
1004
static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)
1005
{
1006
    ALSSpecificConfig *sconf = &ctx->sconf;
1007
    AVCodecContext *avctx    = ctx->avctx;
1008
    GetBitContext *gb = &ctx->gb;
1009
    unsigned int div_blocks[32];                ///< block sizes.
1010
    unsigned int c;
1011
    unsigned int js_blocks[2];
1012

    
1013
    uint32_t bs_info = 0;
1014

    
1015
    // skip the size of the ra unit if present in the frame
1016
    if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)
1017
        skip_bits_long(gb, 32);
1018

    
1019
    if (sconf->mc_coding && sconf->joint_stereo) {
1020
        ctx->js_switch = get_bits1(gb);
1021
        align_get_bits(gb);
1022
    }
1023

    
1024
    if (!sconf->mc_coding || ctx->js_switch) {
1025
        int independent_bs = !sconf->joint_stereo;
1026

    
1027
        for (c = 0; c < avctx->channels; c++) {
1028
            js_blocks[0] = 0;
1029
            js_blocks[1] = 0;
1030

    
1031
            get_block_sizes(ctx, div_blocks, &bs_info);
1032

    
1033
            // if joint_stereo and block_switching is set, independent decoding
1034
            // is signaled via the first bit of bs_info
1035
            if (sconf->joint_stereo && sconf->block_switching)
1036
                if (bs_info >> 31)
1037
                    independent_bs = 2;
1038

    
1039
            // if this is the last channel, it has to be decoded independently
1040
            if (c == avctx->channels - 1)
1041
                independent_bs = 1;
1042

    
1043
            if (independent_bs) {
1044
                if (decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks))
1045
                    return -1;
1046

    
1047
                independent_bs--;
1048
            } else {
1049
                if (decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks))
1050
                    return -1;
1051

    
1052
                c++;
1053
            }
1054

    
1055
            // store carryover raw samples
1056
            memmove(ctx->raw_samples[c] - sconf->max_order,
1057
                    ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1058
                    sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1059
        }
1060
    } else { // multi-channel coding
1061
        get_block_sizes(ctx, div_blocks, &bs_info);
1062

    
1063
        // TODO: multi channel coding might use a temporary buffer instead as
1064
        //       the actual channel is not known when read_block-data is called
1065
        if (decode_blocks_ind(ctx, ra_frame, 0, div_blocks, js_blocks))
1066
            return -1;
1067
        // TODO: read_channel_data
1068
    }
1069

    
1070
    // TODO: read_diff_float_data
1071

    
1072
    return 0;
1073
}
1074

    
1075

    
1076
/** Decodes an ALS frame.
1077
 */
1078
static int decode_frame(AVCodecContext *avctx,
1079
                        void *data, int *data_size,
1080
                        AVPacket *avpkt)
1081
{
1082
    ALSDecContext *ctx       = avctx->priv_data;
1083
    ALSSpecificConfig *sconf = &ctx->sconf;
1084
    const uint8_t *buffer    = avpkt->data;
1085
    int buffer_size          = avpkt->size;
1086
    int invalid_frame, size;
1087
    unsigned int c, sample, ra_frame, bytes_read, shift;
1088

    
1089
    init_get_bits(&ctx->gb, buffer, buffer_size * 8);
1090

    
1091
    // In the case that the distance between random access frames is set to zero
1092
    // (sconf->ra_distance == 0) no frame is treated as a random access frame.
1093
    // For the first frame, if prediction is used, all samples used from the
1094
    // previous frame are assumed to be zero.
1095
    ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);
1096

    
1097
    // the last frame to decode might have a different length
1098
    if (sconf->samples != 0xFFFFFFFF)
1099
        ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,
1100
                                      sconf->frame_length);
1101
    else
1102
        ctx->cur_frame_length = sconf->frame_length;
1103

    
1104
    // decode the frame data
1105
    if ((invalid_frame = read_frame_data(ctx, ra_frame) < 0))
1106
        av_log(ctx->avctx, AV_LOG_WARNING,
1107
               "Reading frame data failed. Skipping RA unit.\n");
1108

    
1109
    ctx->frame_id++;
1110

    
1111
    // check for size of decoded data
1112
    size = ctx->cur_frame_length * avctx->channels *
1113
           (av_get_bits_per_sample_format(avctx->sample_fmt) >> 3);
1114

    
1115
    if (size > *data_size) {
1116
        av_log(avctx, AV_LOG_ERROR, "Decoded data exceeds buffer size.\n");
1117
        return -1;
1118
    }
1119

    
1120
    *data_size = size;
1121

    
1122
    // transform decoded frame into output format
1123
    #define INTERLEAVE_OUTPUT(bps)                                 \
1124
    {                                                              \
1125
        int##bps##_t *dest = (int##bps##_t*) data;                 \
1126
        shift = bps - ctx->avctx->bits_per_raw_sample;             \
1127
        for (sample = 0; sample < ctx->cur_frame_length; sample++) \
1128
            for (c = 0; c < avctx->channels; c++)                  \
1129
                *dest++ = ctx->raw_samples[c][sample] << shift;    \
1130
    }
1131

    
1132
    if (ctx->avctx->bits_per_raw_sample <= 16) {
1133
        INTERLEAVE_OUTPUT(16)
1134
    } else {
1135
        INTERLEAVE_OUTPUT(32)
1136
    }
1137

    
1138
    bytes_read = invalid_frame ? buffer_size :
1139
                                 (get_bits_count(&ctx->gb) + 7) >> 3;
1140

    
1141
    return bytes_read;
1142
}
1143

    
1144

    
1145
/** Uninitializes the ALS decoder.
1146
 */
1147
static av_cold int decode_end(AVCodecContext *avctx)
1148
{
1149
    ALSDecContext *ctx = avctx->priv_data;
1150

    
1151
    av_freep(&ctx->sconf.chan_pos);
1152

    
1153
    av_freep(&ctx->use_ltp);
1154
    av_freep(&ctx->ltp_lag);
1155
    av_freep(&ctx->ltp_gain);
1156
    av_freep(&ctx->ltp_gain_buffer);
1157
    av_freep(&ctx->quant_cof);
1158
    av_freep(&ctx->lpc_cof);
1159
    av_freep(&ctx->prev_raw_samples);
1160
    av_freep(&ctx->raw_samples);
1161
    av_freep(&ctx->raw_buffer);
1162

    
1163
    return 0;
1164
}
1165

    
1166

    
1167
/** Initializes the ALS decoder.
1168
 */
1169
static av_cold int decode_init(AVCodecContext *avctx)
1170
{
1171
    unsigned int c;
1172
    unsigned int channel_size;
1173
    int num_buffers;
1174
    ALSDecContext *ctx = avctx->priv_data;
1175
    ALSSpecificConfig *sconf = &ctx->sconf;
1176
    ctx->avctx = avctx;
1177

    
1178
    if (!avctx->extradata) {
1179
        av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");
1180
        return -1;
1181
    }
1182

    
1183
    if (read_specific_config(ctx)) {
1184
        av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");
1185
        decode_end(avctx);
1186
        return -1;
1187
    }
1188

    
1189
    if (check_specific_config(ctx)) {
1190
        decode_end(avctx);
1191
        return -1;
1192
    }
1193

    
1194
    if (sconf->floating) {
1195
        avctx->sample_fmt          = SAMPLE_FMT_FLT;
1196
        avctx->bits_per_raw_sample = 32;
1197
    } else {
1198
        avctx->sample_fmt          = sconf->resolution > 1
1199
                                     ? SAMPLE_FMT_S32 : SAMPLE_FMT_S16;
1200
        avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;
1201
    }
1202

    
1203
    // set lag value for long-term prediction
1204
    ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +
1205
                              (avctx->sample_rate >= 192000);
1206

    
1207
    // allocate quantized parcor coefficient buffer
1208
    num_buffers = sconf->mc_coding ? avctx->channels : 1;
1209

    
1210
    // allocate and assign lag and gain data buffer for ltp mode
1211
    ctx->use_ltp         = av_mallocz(sizeof(*ctx->use_ltp)  * num_buffers);
1212
    ctx->ltp_lag         = av_malloc (sizeof(*ctx->ltp_lag)  * num_buffers);
1213
    ctx->ltp_gain        = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);
1214
    ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *
1215
                                      num_buffers * 5);
1216

    
1217
    if (!ctx->use_ltp  || !ctx->ltp_lag ||
1218
        !ctx->ltp_gain || !ctx->ltp_gain_buffer) {
1219
        av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1220
        decode_end(avctx);
1221
        return AVERROR(ENOMEM);
1222
    }
1223

    
1224
    for (c = 0; c < num_buffers; c++)
1225
        ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;
1226

    
1227
    avctx->frame_size = sconf->frame_length;
1228
    channel_size      = sconf->frame_length + sconf->max_order;
1229

    
1230
    ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);
1231
    ctx->raw_buffer       = av_mallocz(sizeof(*ctx->     raw_buffer)  * avctx->channels * channel_size);
1232
    ctx->raw_samples      = av_malloc (sizeof(*ctx->     raw_samples) * avctx->channels);
1233

    
1234
    // allocate previous raw sample buffer
1235
    if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {
1236
        av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1237
        decode_end(avctx);
1238
        return AVERROR(ENOMEM);
1239
    }
1240

    
1241
    // assign raw samples buffers
1242
    ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;
1243
    for (c = 1; c < avctx->channels; c++)
1244
        ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;
1245

    
1246
    return 0;
1247
}
1248

    
1249

    
1250
/** Flushes (resets) the frame ID after seeking.
1251
 */
1252
static av_cold void flush(AVCodecContext *avctx)
1253
{
1254
    ALSDecContext *ctx = avctx->priv_data;
1255

    
1256
    ctx->frame_id = 0;
1257
}
1258

    
1259

    
1260
AVCodec als_decoder = {
1261
    "als",
1262
    CODEC_TYPE_AUDIO,
1263
    CODEC_ID_MP4ALS,
1264
    sizeof(ALSDecContext),
1265
    decode_init,
1266
    NULL,
1267
    decode_end,
1268
    decode_frame,
1269
    .flush = flush,
1270
    .capabilities = CODEC_CAP_SUBFRAMES,
1271
    .long_name = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),
1272
};
1273