rockbox/apps/codecs/libwma/wmadec.h

#ifndef _WMADEC_H
#define _WMADEC_H

#include "asf.h"
#include "common.h"  /* For GetBitContext */
//#include "dsputil.h"  /* For MDCTContext */


//#define TRACE
/* size of blocks */
#define BLOCK_MIN_BITS 7
#define BLOCK_MAX_BITS 11
#define BLOCK_MAX_SIZE (1 << BLOCK_MAX_BITS)

#define BLOCK_NB_SIZES (BLOCK_MAX_BITS - BLOCK_MIN_BITS + 1)

/* XXX: find exact max size */
#define HIGH_BAND_MAX_SIZE 16

#define NB_LSP_COEFS 10

/* XXX: is it a suitable value ? */
#define MAX_CODED_SUPERFRAME_SIZE 16384

#define M_PI    3.14159265358979323846

#define M_PI_F  0x3243f // in fixed 32 format
#define TWO_M_PI_F  0x6487f   //in fixed 32

#define MAX_CHANNELS 2

#define NOISE_TAB_SIZE 8192

#define LSP_POW_BITS 7

#define fixed32         int32_t
#define fixed64         int64_t

typedef fixed32 FFTSample;

typedef struct FFTComplex
{
    fixed32 re, im;
}
FFTComplex;

typedef struct FFTContext
{
    int nbits;
    int inverse;
    uint16_t *revtab;
    FFTComplex *exptab;
    FFTComplex *exptab1; /* only used by SSE code */
    int (*fft_calc)(struct FFTContext *s, FFTComplex *z);
}
FFTContext;

typedef struct MDCTContext
{
    int n;  /* size of MDCT (i.e. number of input data * 2) */
    int nbits; /* n = 2^nbits */
    /* pre/post rotation tables */
    fixed32 *tcos;
    fixed32 *tsin;
    FFTContext fft;
}
MDCTContext;

typedef struct WMADecodeContext
{
    GetBitContext gb;

    int nb_block_sizes;  /* number of block sizes */

    int sample_rate;
    int nb_channels;
    int bit_rate;
    int version; /* 1 = 0x160 (WMAV1), 2 = 0x161 (WMAV2) */
    int block_align;
    int use_bit_reservoir;
    int use_variable_block_len;
    int use_exp_vlc;  /* exponent coding: 0 = lsp, 1 = vlc + delta */
    int use_noise_coding; /* true if perceptual noise is added */
    int byte_offset_bits;
    VLC exp_vlc;
    int exponent_sizes[BLOCK_NB_SIZES];
    uint16_t exponent_bands[BLOCK_NB_SIZES][25];
    int high_band_start[BLOCK_NB_SIZES]; /* index of first coef in high band */
    int coefs_start;               /* first coded coef */
    int coefs_end[BLOCK_NB_SIZES]; /* max number of coded coefficients */
    int exponent_high_sizes[BLOCK_NB_SIZES];
    int exponent_high_bands[BLOCK_NB_SIZES][HIGH_BAND_MAX_SIZE];
    VLC hgain_vlc;

    /* coded values in high bands */
    int high_band_coded[MAX_CHANNELS][HIGH_BAND_MAX_SIZE];
    int high_band_values[MAX_CHANNELS][HIGH_BAND_MAX_SIZE];

    /* there are two possible tables for spectral coefficients */
    VLC coef_vlc[2];
    uint16_t *run_table[2];
    uint16_t *level_table[2];
    /* frame info */
    int frame_len;       /* frame length in samples */
    int frame_len_bits;  /* frame_len = 1 << frame_len_bits */

    /* block info */
    int reset_block_lengths;
    int block_len_bits; /* log2 of current block length */
    int next_block_len_bits; /* log2 of next block length */
    int prev_block_len_bits; /* log2 of prev block length */
    int block_len; /* block length in samples */
    int block_num; /* block number in current frame */
    int block_pos; /* current position in frame */
    uint8_t ms_stereo; /* true if mid/side stereo mode */
    uint8_t channel_coded[MAX_CHANNELS]; /* true if channel is coded */
    int exponents_bsize[MAX_CHANNELS];      // log2 ratio frame/exp. length
    fixed32 exponents[MAX_CHANNELS][BLOCK_MAX_SIZE];
    fixed32 max_exponent[MAX_CHANNELS];
    int16_t coefs1[MAX_CHANNELS][BLOCK_MAX_SIZE];
    fixed32 (*coefs)[MAX_CHANNELS][BLOCK_MAX_SIZE];
    MDCTContext mdct_ctx[BLOCK_NB_SIZES];
    fixed32 *windows[BLOCK_NB_SIZES];
    FFTComplex *mdct_tmp; /* temporary storage for imdct */
    /* output buffer for one frame and the last for IMDCT windowing */
    fixed32 frame_out[MAX_CHANNELS][BLOCK_MAX_SIZE * 2];
    /* last frame info */
    uint8_t last_superframe[MAX_CODED_SUPERFRAME_SIZE + 4]; /* padding added */
    int last_bitoffset;
    int last_superframe_len;
    fixed32 noise_table[NOISE_TAB_SIZE];
    int noise_index;
    fixed32 noise_mult; /* XXX: suppress that and integrate it in the noise array */
    /* lsp_to_curve tables */
    fixed32 lsp_cos_table[BLOCK_MAX_SIZE];
    fixed64 lsp_pow_e_table[256];
    fixed64 lsp_pow_m_table1[(1 << LSP_POW_BITS)];
    fixed64 lsp_pow_m_table2[(1 << LSP_POW_BITS)];

    /* State of current superframe decoding */
    int bit_offset;
    int nb_frames;
    int current_frame;

#ifdef TRACE

    int frame_count;
#endif
}
WMADecodeContext;

int wma_decode_init(WMADecodeContext* s, asf_waveformatex_t *wfx);
int wma_decode_superframe_init(WMADecodeContext* s,
                               uint8_t *buf, int buf_size);
int wma_decode_superframe_frame(WMADecodeContext* s,
                                int16_t *samples,
                                uint8_t *buf, int buf_size);
#endif