wma: Decode as much as possible.

[paraslash.git] / wmadec_filter.c

/*
 * WMA compatible decoder
 *
 * Extracted 2009 from the mplayer source code 2009-02-10.
 *
 * Copyright (c) 2002 The FFmpeg Project
 *
 * Licensed under the GNU Lesser General Public License.
 * For licencing details see COPYING.LIB.
 */

/** \file wmadec_filter.c paraslash's WMA decoder. */

/*
 * This decoder handles Microsoft Windows Media Audio data version 2.
 */

#define _XOPEN_SOURCE 600

#include <sys/time.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <regex.h>
#include <sys/select.h>

#include "para.h"
#include "error.h"
#include "list.h"
#include "ggo.h"
#include "string.h"
#include "sched.h"
#include "filter.h"
#include "bitstream.h"
#include "imdct.h"
#include "wma.h"
#include "wmadata.h"


/* 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

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

#define MAX_CHANNELS 2

#define NOISE_TAB_SIZE 8192

#define LSP_POW_BITS 7

struct private_wmadec_data {
        struct asf_header_info ahi;
        struct getbit_context gb;
        /** Whether to use the bit reservoir. */
        int use_bit_reservoir;
        /** Whether to use variable block length. */
        int use_variable_block_len;
        /** Whether to use exponent coding. */
        int use_exp_vlc;
        /** Whether perceptual noise is added. */
        int use_noise_coding;
        int byte_offset_bits;
        struct vlc exp_vlc;
        int exponent_sizes[BLOCK_NB_SIZES];
        uint16_t exponent_bands[BLOCK_NB_SIZES][25];
        /** The index of the first coef in high band. */
        int high_band_start[BLOCK_NB_SIZES];
        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];
        struct 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 */
        struct vlc coef_vlc[2];
        uint16_t *run_table[2];
        uint16_t *level_table[2];
        const struct coef_vlc_table *coef_vlcs[2];
        /* frame info */
        int frame_len;          ///< frame length in samples
        int frame_len_bits;     ///< frame_len = 1 << frame_len_bits
        int nb_block_sizes;     ///< number of block sizes
        /* 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_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
        float exponents[MAX_CHANNELS][BLOCK_MAX_SIZE];
        float max_exponent[MAX_CHANNELS];
        int16_t coefs1[MAX_CHANNELS][BLOCK_MAX_SIZE];
        float coefs[MAX_CHANNELS][BLOCK_MAX_SIZE];
        float output[BLOCK_MAX_SIZE * 2];
        struct mdct_context *mdct_ctx[BLOCK_NB_SIZES];
        float *windows[BLOCK_NB_SIZES];
        /* output buffer for one frame and the last for IMDCT windowing */
        float 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;
        float noise_table[NOISE_TAB_SIZE];
        int noise_index;
        float noise_mult;       /* XXX: suppress that and integrate it in the noise array */
        /* lsp_to_curve tables */
        float lsp_cos_table[BLOCK_MAX_SIZE];
        float lsp_pow_e_table[256];
        float lsp_pow_m_table1[(1 << LSP_POW_BITS)];
        float lsp_pow_m_table2[(1 << LSP_POW_BITS)];
};

#define EXPVLCBITS 8
#define EXPMAX ((19 + EXPVLCBITS - 1) / EXPVLCBITS)

#define HGAINVLCBITS 9
#define HGAINMAX ((13 + HGAINVLCBITS - 1) / HGAINVLCBITS)

#define VLCBITS 9
#define VLCMAX ((22 + VLCBITS - 1) / VLCBITS)

#define SINE_WINDOW(x) float sine_ ## x[x] __aligned(16)

SINE_WINDOW(128);
SINE_WINDOW(256);
SINE_WINDOW(512);
SINE_WINDOW(1024);
SINE_WINDOW(2048);
SINE_WINDOW(4096);

static float *sine_windows[6] = {
        sine_128, sine_256, sine_512, sine_1024, sine_2048, sine_4096
};

/* Generate a sine window. */
static void sine_window_init(float *window, int n)
{
        int i;

        for (i = 0; i < n; i++)
                window[i] = sinf((i + 0.5) * (M_PI / (2.0 * n)));
}

static void wmadec_cleanup(struct private_wmadec_data *pwd)
{
        int i;

        for (i = 0; i < pwd->nb_block_sizes; i++)
                imdct_end(pwd->mdct_ctx[i]);
        if (pwd->use_exp_vlc)
                free_vlc(&pwd->exp_vlc);
        if (pwd->use_noise_coding)
                free_vlc(&pwd->hgain_vlc);
        for (i = 0; i < 2; i++) {
                free_vlc(&pwd->coef_vlc[i]);
                free(pwd->run_table[i]);
                free(pwd->level_table[i]);
        }
}

static void init_coef_vlc(struct vlc *vlc, uint16_t **prun_table,
                uint16_t **plevel_table, const struct coef_vlc_table *vlc_table)
{
        int n = vlc_table->n;
        const uint8_t *table_bits = vlc_table->huffbits;
        const uint32_t *table_codes = vlc_table->huffcodes;
        const uint16_t *levels_table = vlc_table->levels;
        uint16_t *run_table, *level_table;
        int i, l, j, k, level;

        init_vlc(vlc, VLCBITS, n, table_bits, table_codes, 4);

        run_table = para_malloc(n * sizeof(uint16_t));
        level_table = para_malloc(n * sizeof(uint16_t));
        i = 2;
        level = 1;
        k = 0;
        while (i < n) {
                l = levels_table[k++];
                for (j = 0; j < l; j++) {
                        run_table[i] = j;
                        level_table[i] = level;
                        i++;
                }
                level++;
        }
        *prun_table = run_table;
        *plevel_table = level_table;
}

/* compute the scale factor band sizes for each MDCT block size */
static void compute_scale_factor_band_sizes(struct private_wmadec_data *pwd,
        float high_freq)
{
        struct asf_header_info *ahi = &pwd->ahi;
        int a, b, pos, lpos, k, block_len, i, j, n;
        const uint8_t *table;

        for (k = 0; k < pwd->nb_block_sizes; k++) {
                block_len = pwd->frame_len >> k;

                table = NULL;
                a = pwd->frame_len_bits - BLOCK_MIN_BITS - k;
                if (a < 3) {
                        if (ahi->sample_rate >= 44100)
                                table = exponent_band_44100[a];
                        else if (ahi->sample_rate >= 32000)
                                table = exponent_band_32000[a];
                        else if (ahi->sample_rate >= 22050)
                                table = exponent_band_22050[a];
                }
                if (table) {
                        n = *table++;
                        for (i = 0; i < n; i++)
                                pwd->exponent_bands[k][i] = table[i];
                        pwd->exponent_sizes[k] = n;
                } else {
                        j = 0;
                        lpos = 0;
                        for (i = 0; i < 25; i++) {
                                a = wma_critical_freqs[i];
                                b = ahi->sample_rate;
                                pos = ((block_len * 2 * a) + (b << 1)) / (4 * b);
                                pos <<= 2;
                                if (pos > block_len)
                                        pos = block_len;
                                if (pos > lpos)
                                        pwd->exponent_bands[k][j++] = pos - lpos;
                                if (pos >= block_len)
                                        break;
                                lpos = pos;
                        }
                        pwd->exponent_sizes[k] = j;
                }

                /* max number of coefs */
                pwd->coefs_end[k] = (pwd->frame_len - ((pwd->frame_len * 9) / 100)) >> k;
                /* high freq computation */
                pwd->high_band_start[k] = (int) ((block_len * 2 * high_freq)
                        / ahi->sample_rate + 0.5);
                n = pwd->exponent_sizes[k];
                j = 0;
                pos = 0;
                for (i = 0; i < n; i++) {
                        int start, end;
                        start = pos;
                        pos += pwd->exponent_bands[k][i];
                        end = pos;
                        if (start < pwd->high_band_start[k])
                                start = pwd->high_band_start[k];
                        if (end > pwd->coefs_end[k])
                                end = pwd->coefs_end[k];
                        if (end > start)
                                pwd->exponent_high_bands[k][j++] = end - start;
                }
                pwd->exponent_high_sizes[k] = j;
        }
}

static int wma_init(struct private_wmadec_data *pwd)
{
        int i;
        float bps1, high_freq;
        volatile float bps;
        int sample_rate1;
        int coef_vlc_table;
        struct asf_header_info *ahi = &pwd->ahi;
        int flags2 = ahi->flags2;

        if (ahi->sample_rate <= 0 || ahi->sample_rate > 50000
                || ahi->channels <= 0 || ahi->channels > 8
                || ahi->bit_rate <= 0)
                return -E_WMA_BAD_PARAMS;

        /* compute MDCT block size */
        if (ahi->sample_rate <= 16000) {
                pwd->frame_len_bits = 9;
        } else if (ahi->sample_rate <= 22050) {
                pwd->frame_len_bits = 10;
        } else {
                pwd->frame_len_bits = 11;
        }
        pwd->frame_len = 1 << pwd->frame_len_bits;
        if (pwd->use_variable_block_len) {
                int nb_max, nb;
                nb = ((flags2 >> 3) & 3) + 1;
                if ((ahi->bit_rate / ahi->channels) >= 32000)
                        nb += 2;
                nb_max = pwd->frame_len_bits - BLOCK_MIN_BITS;
                if (nb > nb_max)
                        nb = nb_max;
                pwd->nb_block_sizes = nb + 1;
        } else
                pwd->nb_block_sizes = 1;

        /* init rate dependent parameters */
        pwd->use_noise_coding = 1;
        high_freq = ahi->sample_rate * 0.5;

        /* wma2 rates are normalized */
        sample_rate1 = ahi->sample_rate;
        if (sample_rate1 >= 44100)
                sample_rate1 = 44100;
        else if (sample_rate1 >= 22050)
                sample_rate1 = 22050;
        else if (sample_rate1 >= 16000)
                sample_rate1 = 16000;
        else if (sample_rate1 >= 11025)
                sample_rate1 = 11025;
        else if (sample_rate1 >= 8000)
                sample_rate1 = 8000;

        bps = (float) ahi->bit_rate / (float) (ahi->channels * ahi->sample_rate);
        pwd->byte_offset_bits = wma_log2((int) (bps * pwd->frame_len / 8.0 + 0.5)) + 2;
        /*
         * Compute high frequency value and choose if noise coding should be
         * activated.
         */
        bps1 = bps;
        if (ahi->channels == 2)
                bps1 = bps * 1.6;
        if (sample_rate1 == 44100) {
                if (bps1 >= 0.61)
                        pwd->use_noise_coding = 0;
                else
                        high_freq = high_freq * 0.4;
        } else if (sample_rate1 == 22050) {
                if (bps1 >= 1.16)
                        pwd->use_noise_coding = 0;
                else if (bps1 >= 0.72)
                        high_freq = high_freq * 0.7;
                else
                        high_freq = high_freq * 0.6;
        } else if (sample_rate1 == 16000) {
                if (bps > 0.5)
                        high_freq = high_freq * 0.5;
                else
                        high_freq = high_freq * 0.3;
        } else if (sample_rate1 == 11025) {
                high_freq = high_freq * 0.7;
        } else if (sample_rate1 == 8000) {
                if (bps <= 0.625) {
                        high_freq = high_freq * 0.5;
                } else if (bps > 0.75) {
                        pwd->use_noise_coding = 0;
                } else {
                        high_freq = high_freq * 0.65;
                }
        } else {
                if (bps >= 0.8) {
                        high_freq = high_freq * 0.75;
                } else if (bps >= 0.6) {
                        high_freq = high_freq * 0.6;
                } else {
                        high_freq = high_freq * 0.5;
                }
        }
        PARA_INFO_LOG("channels=%d sample_rate=%d "
                "bitrate=%d block_align=%d\n",
                ahi->channels, ahi->sample_rate,
                ahi->bit_rate, ahi->block_align);
        PARA_INFO_LOG("frame_len=%d, bps=%f bps1=%f "
                "high_freq=%f bitoffset=%d\n",
                pwd->frame_len, bps, bps1,
                high_freq, pwd->byte_offset_bits);
        PARA_INFO_LOG("use_noise_coding=%d use_exp_vlc=%d nb_block_sizes=%d\n",
                pwd->use_noise_coding, pwd->use_exp_vlc, pwd->nb_block_sizes);

        compute_scale_factor_band_sizes(pwd, high_freq);
        /* init MDCT windows : simple sinus window */
        for (i = 0; i < pwd->nb_block_sizes; i++) {
                int n;
                n = 1 << (pwd->frame_len_bits - i);
                sine_window_init(sine_windows[pwd->frame_len_bits - i - 7], n);
                pwd->windows[i] = sine_windows[pwd->frame_len_bits - i - 7];
        }

        pwd->reset_block_lengths = 1;

        if (pwd->use_noise_coding) {
                /* init the noise generator */
                if (pwd->use_exp_vlc)
                        pwd->noise_mult = 0.02;
                else
                        pwd->noise_mult = 0.04;

                {
                        unsigned int seed;
                        float norm;
                        seed = 1;
                        norm = (1.0 / (float) (1LL << 31)) * sqrt(3) * pwd->noise_mult;
                        for (i = 0; i < NOISE_TAB_SIZE; i++) {
                                seed = seed * 314159 + 1;
                                pwd->noise_table[i] = (float) ((int) seed) * norm;
                        }
                }
        }

        /* choose the VLC tables for the coefficients */
        coef_vlc_table = 2;
        if (ahi->sample_rate >= 32000) {
                if (bps1 < 0.72)
                        coef_vlc_table = 0;
                else if (bps1 < 1.16)
                        coef_vlc_table = 1;
        }
        pwd->coef_vlcs[0] = &coef_vlcs[coef_vlc_table * 2];
        pwd->coef_vlcs[1] = &coef_vlcs[coef_vlc_table * 2 + 1];
        init_coef_vlc(&pwd->coef_vlc[0], &pwd->run_table[0], &pwd->level_table[0],
                pwd->coef_vlcs[0]);
        init_coef_vlc(&pwd->coef_vlc[1], &pwd->run_table[1], &pwd->level_table[1],
                pwd->coef_vlcs[1]);
        return 0;
}

static void wma_lsp_to_curve_init(struct private_wmadec_data *pwd, int frame_len)
{
        float wdel, a, b;
        int i, e, m;

        wdel = M_PI / frame_len;
        for (i = 0; i < frame_len; i++)
                pwd->lsp_cos_table[i] = 2.0f * cos(wdel * i);

        /* tables for x^-0.25 computation */
        for (i = 0; i < 256; i++) {
                e = i - 126;
                pwd->lsp_pow_e_table[i] = pow(2.0, e * -0.25);
        }

        /* These two tables are needed to avoid two operations in pow_m1_4. */
        b = 1.0;
        for (i = (1 << LSP_POW_BITS) - 1; i >= 0; i--) {
                m = (1 << LSP_POW_BITS) + i;
                a = (float) m *(0.5 / (1 << LSP_POW_BITS));
                a = pow(a, -0.25);
                pwd->lsp_pow_m_table1[i] = 2 * a - b;
                pwd->lsp_pow_m_table2[i] = b - a;
                b = a;
        }
}

static int wma_decode_init(char *initial_buf, int len, struct private_wmadec_data **result)
{
        struct private_wmadec_data *pwd;
        int ret, i;

        PARA_NOTICE_LOG("initial buf: %d bytes\n", len);
        pwd = para_calloc(sizeof(*pwd));
        ret = read_asf_header(initial_buf, len, &pwd->ahi);
        if (ret <= 0) {
                free(pwd);
                return ret;
        }

        pwd->use_exp_vlc = pwd->ahi.flags2 & 0x0001;
        pwd->use_bit_reservoir = pwd->ahi.flags2 & 0x0002;
        pwd->use_variable_block_len = pwd->ahi.flags2 & 0x0004;

        ret = wma_init(pwd);
        if (ret < 0)
                return ret;
        /* init MDCT */
        for (i = 0; i < pwd->nb_block_sizes; i++) {
                ret = imdct_init(pwd->frame_len_bits - i + 1, &pwd->mdct_ctx[i]);
                if (ret < 0)
                        return ret;
        }
        if (pwd->use_noise_coding) {
                PARA_INFO_LOG("using noise coding\n");
                init_vlc(&pwd->hgain_vlc, HGAINVLCBITS,
                        sizeof(wma_hgain_huffbits), wma_hgain_huffbits,
                        wma_hgain_huffcodes, 2);
        }

        if (pwd->use_exp_vlc) {
                PARA_INFO_LOG("using exp_vlc\n");
                init_vlc(&pwd->exp_vlc, EXPVLCBITS,
                sizeof(wma_scale_huffbits), wma_scale_huffbits,
                wma_scale_huffcodes, 4);
        } else {
                PARA_INFO_LOG("using curve\n");
                wma_lsp_to_curve_init(pwd, pwd->frame_len);
        }
        *result = pwd;
        return pwd->ahi.header_len;
}

/**
 * compute x^-0.25 with an exponent and mantissa table. We use linear
 * interpolation to reduce the mantissa table size at a small speed
 * expense (linear interpolation approximately doubles the number of
 * bits of precision).
 */
static inline float pow_m1_4(struct private_wmadec_data *pwd, float x)
{
        union {
                float f;
                unsigned int v;
        } u, t;
        unsigned int e, m;
        float a, b;

        u.f = x;
        e = u.v >> 23;
        m = (u.v >> (23 - LSP_POW_BITS)) & ((1 << LSP_POW_BITS) - 1);
        /* build interpolation scale: 1 <= t < 2. */
        t.v = ((u.v << LSP_POW_BITS) & ((1 << 23) - 1)) | (127 << 23);
        a = pwd->lsp_pow_m_table1[m];
        b = pwd->lsp_pow_m_table2[m];
        return pwd->lsp_pow_e_table[e] * (a + b * t.f);
}

static void wma_lsp_to_curve(struct private_wmadec_data *pwd,
                float *out, float *val_max_ptr, int n, float *lsp)
{
        int i, j;
        float p, q, w, v, val_max;

        val_max = 0;
        for (i = 0; i < n; i++) {
                p = 0.5f;
                q = 0.5f;
                w = pwd->lsp_cos_table[i];
                for (j = 1; j < NB_LSP_COEFS; j += 2) {
                        q *= w - lsp[j - 1];
                        p *= w - lsp[j];
                }
                p *= p * (2.0f - w);
                q *= q * (2.0f + w);
                v = p + q;
                v = pow_m1_4(pwd, v);
                if (v > val_max)
                        val_max = v;
                out[i] = v;
        }
        *val_max_ptr = val_max;
}

/* Decode exponents coded with LSP coefficients (same idea as Vorbis). */
static void decode_exp_lsp(struct private_wmadec_data *pwd, int ch)
{
        float lsp_coefs[NB_LSP_COEFS];
        int val, i;

        for (i = 0; i < NB_LSP_COEFS; i++) {
                if (i == 0 || i >= 8)
                        val = get_bits(&pwd->gb, 3);
                else
                        val = get_bits(&pwd->gb, 4);
                lsp_coefs[i] = wma_lsp_codebook[i][val];
        }

        wma_lsp_to_curve(pwd, pwd->exponents[ch], &pwd->max_exponent[ch],
                pwd->block_len, lsp_coefs);
}

/* Decode exponents coded with VLC codes. */
static int decode_exp_vlc(struct private_wmadec_data *pwd, int ch)
{
        int last_exp, n, code;
        const uint16_t *ptr, *band_ptr;
        float v, *q, max_scale, *q_end;

        band_ptr = pwd->exponent_bands[pwd->frame_len_bits - pwd->block_len_bits];
        ptr = band_ptr;
        q = pwd->exponents[ch];
        q_end = q + pwd->block_len;
        max_scale = 0;
        last_exp = 36;

        while (q < q_end) {
                code = get_vlc(&pwd->gb, pwd->exp_vlc.table, EXPVLCBITS, EXPMAX);
                if (code < 0)
                        return -1;
                /* NOTE: this offset is the same as MPEG4 AAC ! */
                last_exp += code - 60;
                /* XXX: use a table */
                v = pow(10, last_exp * (1.0 / 16.0));
                if (v > max_scale)
                        max_scale = v;
                n = *ptr++;
                do {
                        *q++ = v;
                } while (--n);
        }
        pwd->max_exponent[ch] = max_scale;
        return 0;
}

/* compute src0 * src1 + src2 */
static inline void vector_mult_add(float *dst, const float *src0, const float *src1,
                const float *src2, int len)
{
        int i;

        for (i = 0; i < len; i++)
                dst[i] = src0[i] * src1[i] + src2[i];
}

static inline void vector_mult_reverse(float *dst, const float *src0,
                const float *src1, int len)
{
        int i;

        src1 += len - 1;
        for (i = 0; i < len; i++)
                dst[i] = src0[i] * src1[-i];
}

/**
 * Apply MDCT window and add into output.
 *
 * We ensure that when the windows overlap their squared sum
 * is always 1 (MDCT reconstruction rule).
 */
static void wma_window(struct private_wmadec_data *pwd, float *out)
{
        float *in = pwd->output;
        int block_len, bsize, n;

        /* left part */
        if (pwd->block_len_bits <= pwd->prev_block_len_bits) {
                block_len = pwd->block_len;
                bsize = pwd->frame_len_bits - pwd->block_len_bits;
                vector_mult_add(out, in, pwd->windows[bsize], out, block_len);
        } else {
                block_len = 1 << pwd->prev_block_len_bits;
                n = (pwd->block_len - block_len) / 2;
                bsize = pwd->frame_len_bits - pwd->prev_block_len_bits;
                vector_mult_add(out + n, in + n, pwd->windows[bsize], out + n,
                        block_len);
                memcpy(out + n + block_len, in + n + block_len,
                        n * sizeof(float));
        }
        out += pwd->block_len;
        in += pwd->block_len;
        /* right part */
        if (pwd->block_len_bits <= pwd->next_block_len_bits) {
                block_len = pwd->block_len;
                bsize = pwd->frame_len_bits - pwd->block_len_bits;
                vector_mult_reverse(out, in, pwd->windows[bsize], block_len);
        } else {
                block_len = 1 << pwd->next_block_len_bits;
                n = (pwd->block_len - block_len) / 2;
                bsize = pwd->frame_len_bits - pwd->next_block_len_bits;
                memcpy(out, in, n * sizeof(float));
                vector_mult_reverse(out + n, in + n, pwd->windows[bsize],
                        block_len);
                memset(out + n + block_len, 0, n * sizeof(float));
        }
}

static int wma_total_gain_to_bits(int total_gain)
{
        if (total_gain < 15)
                return 13;
        else if (total_gain < 32)
                return 12;
        else if (total_gain < 40)
                return 11;
        else if (total_gain < 45)
                return 10;
        else
                return 9;
}

static int compute_high_band_values(struct private_wmadec_data *pwd,
                int bsize, int nb_coefs[MAX_CHANNELS])
{
        int ch;

        if (!pwd->use_noise_coding)
                return 0;
        for (ch = 0; ch < pwd->ahi.channels; ch++) {
                int i, m, a;
                if (!pwd->channel_coded[ch])
                        continue;
                m = pwd->exponent_high_sizes[bsize];
                for (i = 0; i < m; i++) {
                        a = get_bit(&pwd->gb);
                        pwd->high_band_coded[ch][i] = a;
                        if (!a)
                                continue;
                        nb_coefs[ch] -= pwd->exponent_high_bands[bsize][i];
                }
        }
        for (ch = 0; ch < pwd->ahi.channels; ch++) {
                int i, n, val;
                if (!pwd->channel_coded[ch])
                        continue;
                n = pwd->exponent_high_sizes[bsize];
                val = (int)0x80000000;
                for (i = 0; i < n; i++) {
                        if (!pwd->high_band_coded[ch][i])
                                continue;
                        if (val == (int)0x80000000)
                                val = get_bits(&pwd->gb, 7) - 19;
                        else {
                                int code = get_vlc(&pwd->gb,
                                        pwd->hgain_vlc.table, HGAINVLCBITS,
                                        HGAINMAX);
                                if (code < 0)
                                        return -1;
                                val += code - 18;
                        }
                        pwd->high_band_values[ch][i] = val;
                }
        }
        return 1;
}

static void compute_mdct_coefficients(struct private_wmadec_data *pwd,
                int bsize, int total_gain, int nb_coefs[MAX_CHANNELS])
{
        int ch;
        float mdct_norm = 1.0 / (pwd->block_len / 2);

        for (ch = 0; ch < pwd->ahi.channels; ch++) {
                int16_t *coefs1;
                float *coefs, *exponents, mult, mult1, noise;
                int i, j, n, n1, last_high_band, esize;
                float exp_power[HIGH_BAND_MAX_SIZE];

                if (!pwd->channel_coded[ch])
                        continue;
                coefs1 = pwd->coefs1[ch];
                exponents = pwd->exponents[ch];
                esize = pwd->exponents_bsize[ch];
                mult = pow(10, total_gain * 0.05) / pwd->max_exponent[ch];
                mult *= mdct_norm;
                coefs = pwd->coefs[ch];
                if (!pwd->use_noise_coding) {
                        /* XXX: optimize more */
                        n = nb_coefs[ch];
                        for (i = 0; i < n; i++)
                                *coefs++ = coefs1[i] *
                                        exponents[i << bsize >> esize] * mult;
                        n = pwd->block_len - pwd->coefs_end[bsize];
                        for (i = 0; i < n; i++)
                                *coefs++ = 0.0;
                        continue;
                }
                mult1 = mult;
                n1 = pwd->exponent_high_sizes[bsize];
                /* compute power of high bands */
                exponents = pwd->exponents[ch] +
                        (pwd->high_band_start[bsize] << bsize);
                last_high_band = 0; /* avoid warning */
                for (j = 0; j < n1; j++) {
                        n = pwd->exponent_high_bands[
                                pwd->frame_len_bits - pwd->block_len_bits][j];
                        if (pwd->high_band_coded[ch][j]) {
                                float e2, val;
                                e2 = 0;
                                for (i = 0; i < n; i++) {
                                        val = exponents[i << bsize >> esize];
                                        e2 += val * val;
                                }
                                exp_power[j] = e2 / n;
                                last_high_band = j;
                        }
                        exponents += n << bsize;
                }
                /* main freqs and high freqs */
                exponents = pwd->exponents[ch];
                for (j = -1; j < n1; j++) {
                        if (j < 0)
                                n = pwd->high_band_start[bsize];
                        else
                                n = pwd->exponent_high_bands[pwd->frame_len_bits
                                        - pwd->block_len_bits][j];
                        if (j >= 0 && pwd->high_band_coded[ch][j]) {
                                /* use noise with specified power */
                                mult1 = sqrt(exp_power[j]
                                        / exp_power[last_high_band]);
                                /* XXX: use a table */
                                mult1 = mult1 * pow(10,
                                        pwd->high_band_values[ch][j] * 0.05);
                                mult1 /= (pwd->max_exponent[ch] * pwd->noise_mult);
                                mult1 *= mdct_norm;
                                for (i = 0; i < n; i++) {
                                        noise = pwd->noise_table[pwd->noise_index];
                                        pwd->noise_index = (pwd->noise_index + 1)
                                                & (NOISE_TAB_SIZE - 1);
                                        *coefs++ = noise * exponents[
                                                i << bsize >> esize] * mult1;
                                }
                                exponents += n << bsize;
                        } else {
                                /* coded values + small noise */
                                for (i = 0; i < n; i++) {
                                        noise = pwd->noise_table[pwd->noise_index];
                                        pwd->noise_index = (pwd->noise_index + 1)
                                                & (NOISE_TAB_SIZE - 1);
                                        *coefs++ = ((*coefs1++) + noise) *
                                                exponents[i << bsize >> esize]
                                                * mult;
                                }
                                exponents += n << bsize;
                        }
                }
                /* very high freqs: noise */
                n = pwd->block_len - pwd->coefs_end[bsize];
                mult1 = mult * exponents[((-1 << bsize)) >> esize];
                for (i = 0; i < n; i++) {
                        *coefs++ = pwd->noise_table[pwd->noise_index] * mult1;
                        pwd->noise_index = (pwd->noise_index + 1)
                                & (NOISE_TAB_SIZE - 1);
                }
        }
}

/**
 * @return 0 if OK. 1 if last block of frame. return -1 if
 * unrecorrable error.
 */
static int wma_decode_block(struct private_wmadec_data *pwd)
{
        int n, v, ch, code, bsize;
        int coef_nb_bits, total_gain;
        int nb_coefs[MAX_CHANNELS];

        /* compute current block length */
        if (pwd->use_variable_block_len) {
                n = wma_log2(pwd->nb_block_sizes - 1) + 1;

                if (pwd->reset_block_lengths) {
                        pwd->reset_block_lengths = 0;
                        v = get_bits(&pwd->gb, n);
                        if (v >= pwd->nb_block_sizes)
                                return -1;
                        pwd->prev_block_len_bits = pwd->frame_len_bits - v;
                        v = get_bits(&pwd->gb, n);
                        if (v >= pwd->nb_block_sizes)
                                return -1;
                        pwd->block_len_bits = pwd->frame_len_bits - v;
                } else {
                        /* update block lengths */
                        pwd->prev_block_len_bits = pwd->block_len_bits;
                        pwd->block_len_bits = pwd->next_block_len_bits;
                }
                v = get_bits(&pwd->gb, n);
                if (v >= pwd->nb_block_sizes)
                        return -1;
                pwd->next_block_len_bits = pwd->frame_len_bits - v;
        } else {
                /* fixed block len */
                pwd->next_block_len_bits = pwd->frame_len_bits;
                pwd->prev_block_len_bits = pwd->frame_len_bits;
                pwd->block_len_bits = pwd->frame_len_bits;
        }

        /* now check if the block length is coherent with the frame length */
        pwd->block_len = 1 << pwd->block_len_bits;
        if ((pwd->block_pos + pwd->block_len) > pwd->frame_len)
                return -E_INCOHERENT_BLOCK_LEN;

        if (pwd->ahi.channels == 2)
                pwd->ms_stereo = get_bit(&pwd->gb);
        v = 0;
        for (ch = 0; ch < pwd->ahi.channels; ch++) {
                int a = get_bit(&pwd->gb);
                pwd->channel_coded[ch] = a;
                v |= a;
        }

        bsize = pwd->frame_len_bits - pwd->block_len_bits;

        /* if no channel coded, no need to go further */
        /* XXX: fix potential framing problems */
        if (!v)
                goto next;

        /*
         * Read total gain and extract corresponding number of bits for coef
         * escape coding.
         */
        total_gain = 1;
        for (;;) {
                int a = get_bits(&pwd->gb, 7);
                total_gain += a;
                if (a != 127)
                        break;
        }

        coef_nb_bits = wma_total_gain_to_bits(total_gain);

        /* compute number of coefficients */
        n = pwd->coefs_end[bsize];
        for (ch = 0; ch < pwd->ahi.channels; ch++)
                nb_coefs[ch] = n;

        if (compute_high_band_values(pwd, bsize, nb_coefs) < 0)
                return -1;

        /* exponents can be reused in short blocks. */
        if ((pwd->block_len_bits == pwd->frame_len_bits) || get_bit(&pwd->gb)) {
                for (ch = 0; ch < pwd->ahi.channels; ch++) {
                        if (pwd->channel_coded[ch]) {
                                if (pwd->use_exp_vlc) {
                                        if (decode_exp_vlc(pwd, ch) < 0)
                                                return -1;
                                } else {
                                        decode_exp_lsp(pwd, ch);
                                }
                                pwd->exponents_bsize[ch] = bsize;
                        }
                }
        }

        /* parse spectral coefficients : just RLE encoding */
        for (ch = 0; ch < pwd->ahi.channels; ch++) {
                struct vlc *coef_vlc;
                int level, run, tindex;
                int16_t *ptr, *eptr;
                const uint16_t *level_table, *run_table;

                if (!pwd->channel_coded[ch])
                        continue;
                /*
                 * special VLC tables are used for ms stereo because there is
                 * potentially less energy there
                 */
                tindex = (ch == 1 && pwd->ms_stereo);
                coef_vlc = &pwd->coef_vlc[tindex];
                run_table = pwd->run_table[tindex];
                level_table = pwd->level_table[tindex];
                /* XXX: optimize */
                ptr = &pwd->coefs1[ch][0];
                eptr = ptr + nb_coefs[ch];
                memset(ptr, 0, pwd->block_len * sizeof(int16_t));
                for (;;) {
                        code = get_vlc(&pwd->gb, coef_vlc->table,
                                VLCBITS, VLCMAX);
                        if (code < 0)
                                return -1;
                        if (code == 1) /* EOB */
                                break;
                        if (code == 0) { /* escape */
                                level = get_bits(&pwd->gb, coef_nb_bits);
                                /* reading block_len_bits would be better */
                                run = get_bits(&pwd->gb, pwd->frame_len_bits);
                        } else { /* normal code */
                                run = run_table[code];
                                level = level_table[code];
                        }
                        if (!get_bit(&pwd->gb))
                                level = -level;
                        ptr += run;
                        if (ptr >= eptr) {
                                PARA_ERROR_LOG("overflow in spectral RLE, ignoring\n");
                                break;
                        }
                        *ptr++ = level;
                        if (ptr >= eptr) /* EOB can be omitted */
                                break;
                }
        }
        compute_mdct_coefficients(pwd, bsize, total_gain, nb_coefs);
        if (pwd->ms_stereo && pwd->channel_coded[1]) {
                float a, b;
                int i;
                /*
                 * Nominal case for ms stereo: we do it before mdct.
                 *
                 * No need to optimize this case because it should almost never
                 * happen.
                 */
                if (!pwd->channel_coded[0]) {
                        PARA_NOTICE_LOG("rare ms-stereo\n");
                        memset(pwd->coefs[0], 0, sizeof(float) * pwd->block_len);
                        pwd->channel_coded[0] = 1;
                }
                for (i = 0; i < pwd->block_len; i++) {
                        a = pwd->coefs[0][i];
                        b = pwd->coefs[1][i];
                        pwd->coefs[0][i] = a + b;
                        pwd->coefs[1][i] = a - b;
                }
        }
next:
        for (ch = 0; ch < pwd->ahi.channels; ch++) {
                int n4, index;

                n = pwd->block_len;
                n4 = pwd->block_len / 2;
                if (pwd->channel_coded[ch])
                        imdct(pwd->mdct_ctx[bsize], pwd->output, pwd->coefs[ch]);
                else if (!(pwd->ms_stereo && ch == 1))
                        memset(pwd->output, 0, sizeof(pwd->output));

                /* multiply by the window and add in the frame */
                index = (pwd->frame_len / 2) + pwd->block_pos - n4;
                wma_window(pwd, &pwd->frame_out[ch][index]);
        }

        /* update block number */
        pwd->block_pos += pwd->block_len;
        if (pwd->block_pos >= pwd->frame_len)
                return 1;
        else
                return 0;
}

/*
 * Clip a signed integer value into the -32768,32767 range.
 *
 * \param a The value to clip.
 *
 * \return The clipped value.
 */
static inline int16_t av_clip_int16(int a)
{
        if ((a + 32768) & ~65535)
                return (a >> 31) ^ 32767;
        else
                return a;
}

/* Decode a frame of frame_len samples. */
static int wma_decode_frame(struct private_wmadec_data *pwd, int16_t *samples)
{
        int ret, i, n, ch, incr;
        int16_t *ptr;
        float *iptr;

        /* read each block */
        pwd->block_pos = 0;
        for (;;) {
                ret = wma_decode_block(pwd);
                if (ret < 0)
                        return -1;
                if (ret)
                        break;
        }

        /* convert frame to integer */
        n = pwd->frame_len;
        incr = pwd->ahi.channels;
        for (ch = 0; ch < pwd->ahi.channels; ch++) {
                ptr = samples + ch;
                iptr = pwd->frame_out[ch];

                for (i = 0; i < n; i++) {
                        *ptr = av_clip_int16(lrintf(*iptr++));
                        ptr += incr;
                }
                /* prepare for next block */
                memmove(&pwd->frame_out[ch][0], &pwd->frame_out[ch][pwd->frame_len],
                        pwd->frame_len * sizeof(float));
        }
        return 0;
}

static int wma_decode_superframe(struct private_wmadec_data *pwd, void *data,
                int *data_size, const uint8_t *buf, int buf_size)
{
        int ret;
        int16_t *samples;
        static int frame_count;

        if (buf_size == 0) {
                pwd->last_superframe_len = 0;
                return 0;
        }
        if (buf_size < pwd->ahi.block_align)
                return 0;
        buf_size = pwd->ahi.block_align;
        samples = data;
        init_get_bits(&pwd->gb, buf, buf_size);
        if (pwd->use_bit_reservoir) {
                int i, nb_frames, bit_offset, pos, len;
                uint8_t *q;

                /* read super frame header */
                skip_bits(&pwd->gb, 4); /* super frame index */
                nb_frames = get_bits(&pwd->gb, 4) - 1;
                // PARA_DEBUG_LOG("have %d frames\n", nb_frames);
                ret = -E_WMA_OUTPUT_SPACE;
                if ((nb_frames + 1) * pwd->ahi.channels * pwd->frame_len
                                * sizeof(int16_t) > *data_size)
                        goto fail;

                bit_offset = get_bits(&pwd->gb, pwd->byte_offset_bits + 3);

                if (pwd->last_superframe_len > 0) {
                        /* add bit_offset bits to last frame */
                        ret = -E_WMA_BAD_SUPERFRAME;
                        if ((pwd->last_superframe_len + ((bit_offset + 7) >> 3)) >
                                        MAX_CODED_SUPERFRAME_SIZE)
                                goto fail;
                        q = pwd->last_superframe + pwd->last_superframe_len;
                        len = bit_offset;
                        while (len > 7) {
                                *q++ = get_bits(&pwd->gb, 8);
                                len -= 8;
                        }
                        if (len > 0)
                                *q++ = get_bits(&pwd->gb, len) << (8 - len);

                        /* XXX: bit_offset bits into last frame */
                        init_get_bits(&pwd->gb, pwd->last_superframe,
                                MAX_CODED_SUPERFRAME_SIZE);
                        /* skip unused bits */
                        if (pwd->last_bitoffset > 0)
                                skip_bits(&pwd->gb, pwd->last_bitoffset);
                        /*
                         * This frame is stored in the last superframe and in
                         * the current one.
                         */
                        ret = -E_WMA_DECODE;
                        if (wma_decode_frame(pwd, samples) < 0)
                                goto fail;
                        frame_count++;
                        samples += pwd->ahi.channels * pwd->frame_len;
                }

                /* read each frame starting from bit_offset */
                pos = bit_offset + 4 + 4 + pwd->byte_offset_bits + 3;
                init_get_bits(&pwd->gb, buf + (pos >> 3),
                        (MAX_CODED_SUPERFRAME_SIZE - (pos >> 3)));
                len = pos & 7;
                if (len > 0)
                        skip_bits(&pwd->gb, len);

                pwd->reset_block_lengths = 1;
                for (i = 0; i < nb_frames; i++) {
                        ret = -E_WMA_DECODE;
                        if (wma_decode_frame(pwd, samples) < 0)
                                goto fail;
                        frame_count++;
                        samples += pwd->ahi.channels * pwd->frame_len;
                }

                /* we copy the end of the frame in the last frame buffer */
                pos = get_bits_count(&pwd->gb) +
                        ((bit_offset + 4 + 4 + pwd->byte_offset_bits + 3) & ~7);
                pwd->last_bitoffset = pos & 7;
                pos >>= 3;
                len = buf_size - pos;
                ret = -E_WMA_BAD_SUPERFRAME;
                if (len > MAX_CODED_SUPERFRAME_SIZE || len < 0)
                        goto fail;
                pwd->last_superframe_len = len;
                memcpy(pwd->last_superframe, buf + pos, len);
        } else {
                PARA_DEBUG_LOG("not using bit reservoir\n");
                ret = -E_WMA_OUTPUT_SPACE;
                if (pwd->ahi.channels * pwd->frame_len * sizeof(int16_t) > *data_size)
                        goto fail;
                /* single frame decode */
                ret = -E_WMA_DECODE;
                if (wma_decode_frame(pwd, samples) < 0)
                        goto fail;
                frame_count++;
                samples += pwd->ahi.channels * pwd->frame_len;
        }
        PARA_DEBUG_LOG("frame_count: %d frame_len: %d, block_len: %d, "
                "outbytes: %zd, eaten: %d\n",
                frame_count, pwd->frame_len, pwd->block_len,
                (int8_t *) samples - (int8_t *) data, pwd->ahi.block_align);
        *data_size = (int8_t *)samples - (int8_t *)data;
        return pwd->ahi.block_align;
fail:
        /* reset the bit reservoir on errors */
        pwd->last_superframe_len = 0;
        return ret;
}

static ssize_t wmadec_convert(char *inbuffer, size_t len,
                struct filter_node *fn)
{
        int ret, converted = 0;
        struct private_wmadec_data *pwd = fn->private_data;

        if (len <= WMA_FRAME_SKIP)
                return 0;
        if (!pwd) {
                ret = wma_decode_init(inbuffer, len, &pwd);
                if (ret <= 0)
                        return ret;
                fn->private_data = pwd;
                fn->fc->channels = pwd->ahi.channels;
                fn->fc->samplerate = pwd->ahi.sample_rate;
                return pwd->ahi.header_len;
        }
        for (;;) {
                int out_size;
                if (converted + WMA_FRAME_SKIP + pwd->ahi.block_align > len)
                        break;
                out_size = fn->bufsize - fn->loaded;
                if (out_size < 128 * 1024)
                        break;
                ret = wma_decode_superframe(pwd, fn->buf + fn->loaded,
                        &out_size, (uint8_t *)inbuffer + converted + WMA_FRAME_SKIP,
                        len - WMA_FRAME_SKIP);
                if (ret < 0)
                        return ret;
                fn->loaded += out_size;
                converted += ret + WMA_FRAME_SKIP;
        }
        return converted;
}

static void wmadec_close(struct filter_node *fn)
{
        struct private_wmadec_data *pwd = fn->private_data;

        if (!pwd)
                return;
        wmadec_cleanup(pwd);
        free(fn->buf);
        fn->buf = NULL;
        free(fn->private_data);
        fn->private_data = NULL;
}

static void wmadec_open(struct filter_node *fn)
{
        fn->bufsize = 1024 * 1024;
        fn->buf = para_malloc(fn->bufsize);
        fn->private_data = NULL;
        fn->loaded = 0;
}

/**
 * The init function of the wma decoder.
 *
 * \param f Its fields are filled in by the function.
 */
void wmadec_filter_init(struct filter *f)
{
        f->open = wmadec_open;
        f->close = wmadec_close;
        f->convert = wmadec_convert;
}