libavcodec/ra288.c

   1 /*
   2  * RealAudio 2.0 (28.8K)
   3  * Copyright (c) 2003 the ffmpeg project
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "avcodec.h"
  23 #define ALT_BITSTREAM_READER_LE
  24 #include "bitstream.h"
  25 #include "ra288.h"
  26
  27 typedef struct {
  28     float history[8];
  29     float output[40];
  30     float pr1[36];
  31     float pr2[10];
  32     int   phase;
  33
  34     float st1a[111], st1b[37], st1[37];
  35     float st2a[38], st2b[11], st2[11];
  36     float sb[41];
  37     float lhist[10];
  38 } Real288_internal;
  39
  40 static inline float scalar_product_float(const float * v1, const float * v2,
  41                                          int size)
  42 {
  43     float res = 0.;
  44
  45     while (size--)
  46         res += *v1++ * *v2++;
  47
  48     return res;
  49 }
  50
  51 /* Decode and produce output */
  52 static void decode(Real288_internal *glob, float gain, int cb_coef)
  53 {
  54     int x, y;
  55     double sumsum;
  56     float sum, buffer[5];
  57
  58     memmove(glob->sb + 5, glob->sb, 36 * sizeof(*glob->sb));
  59
  60     for (x=4; x >= 0; x--)
  61         glob->sb[x] = -scalar_product_float(glob->sb + x + 1, glob->pr1, 36);
  62
  63     /* convert log and do rms */
  64     sum = 32. - scalar_product_float(glob->pr2, glob->lhist, 10);
  65
  66     sum = av_clipf(sum, 0, 60);
  67
  68     sumsum = exp(sum * 0.1151292546497) * gain;    /* pow(10.0,sum/20)*f */
  69
  70     for (x=0; x < 5; x++)
  71         buffer[x] = codetable[cb_coef][x] * sumsum;
  72
  73     sum = scalar_product_float(buffer, buffer, 5) / 5;
  74
  75     sum = FFMAX(sum, 1);
  76
  77     /* shift and store */
  78     memmove(glob->lhist, glob->lhist - 1, 10 * sizeof(*glob->lhist));
  79
  80     *glob->lhist = glob->history[glob->phase] = 10 * log10(sum) - 32;
  81
  82     for (x=1; x < 5; x++)
  83         for (y=x-1; y >= 0; y--)
  84             buffer[x] -= glob->pr1[x-y-1] * buffer[y];
  85
  86     /* output */
  87     for (x=0; x < 5; x++) {
  88         glob->output[glob->phase*5+x] = glob->sb[4-x] =
  89             av_clipf(glob->sb[4-x] + buffer[x], -4095, 4095);
  90     }
  91 }
  92
  93 /* column multiply */
  94 static void colmult(float *tgt, const float *m1, const float *m2, int n)
  95 {
  96     while (n--)
  97         *(tgt++) = (*(m1++)) * (*(m2++));
  98 }
  99
 100 static int pred(const float *in, float *tgt, int n)
 101 {
 102     int x, y;
 103     double f0, f1, f2;
 104
 105     if (in[n] == 0)
 106         return 0;
 107
 108     if ((f0 = *in) <= 0)
 109         return 0;
 110
 111     in--; // To avoid a -1 subtraction in the inner loop
 112
 113     for (x=1; x <= n; x++) {
 114         f1 = in[x+1];
 115
 116         for (y=0; y < x - 1; y++)
 117             f1 += in[x-y]*tgt[y];
 118
 119         tgt[x-1] = f2 = -f1/f0;
 120         for (y=0; y < x >> 1; y++) {
 121             float temp = tgt[y] + tgt[x-y-2]*f2;
 122             tgt[x-y-2] += tgt[y]*f2;
 123             tgt[y] = temp;
 124         }
 125         if ((f0 += f1*f2) < 0)
 126             return 0;
 127     }
 128
 129     return 1;
 130 }
 131
 132 /* product sum (lsf) */
 133 static void prodsum(float *tgt, const float *src, int len, int n)
 134 {
 135     for (; n >= 0; n--)
 136         tgt[n] = scalar_product_float(src, src - n, len);
 137
 138 }
 139
 140 static void co(int n, int i, int j, const float *in, float *out, float *st1,
 141                float *st2, const float *table)
 142 {
 143     unsigned int x;
 144     const float *fp;
 145     float buffer1[37];
 146     float buffer2[37];
 147     float work[111];
 148
 149     /* rotate and multiply */
 150     fp = st1 + i;
 151     for (x=0; x < n + i + j; x++) {
 152         if (x == n + j)
 153             fp=in;
 154         st1[x] = *(fp++);
 155         work[x] = table[x] * st1[x];
 156     }
 157
 158     prodsum(buffer1, work + n    , i, n);
 159     prodsum(buffer2, work + n + i, j, n);
 160
 161     for (x=0; x <= n; x++) {
 162         st2[x] = st2[x] * 0.5625 + buffer1[x];
 163         out[x] = st2[x]          + buffer2[x];
 164     }
 165     *out *= 1.00390625; /* to prevent clipping */
 166 }
 167
 168 static void update(Real288_internal *glob)
 169 {
 170     float buffer1[40], temp1[37];
 171     float buffer2[8], temp2[11];
 172
 173     memcpy(buffer1     , glob->output + 20, 20*sizeof(*buffer1));
 174     memcpy(buffer1 + 20, glob->output     , 20*sizeof(*buffer1));
 175
 176     co(36, 40, 35, buffer1, temp1, glob->st1a, glob->st1b, table1);
 177
 178     if (pred(temp1, glob->st1, 36))
 179         colmult(glob->pr1, glob->st1, table1a, 36);
 180
 181     memcpy(buffer2    , glob->history + 4, 4*sizeof(*buffer2));
 182     memcpy(buffer2 + 4, glob->history    , 4*sizeof(*buffer2));
 183
 184     co(10, 8, 20, buffer2, temp2, glob->st2a, glob->st2b, table2);
 185
 186     if (pred(temp2, glob->st2, 10))
 187         colmult(glob->pr2, glob->st2, table2a, 10);
 188 }
 189
 190 /* Decode a block (celp) */
 191 static int ra288_decode_frame(AVCodecContext * avctx, void *data,
 192                               int *data_size, const uint8_t * buf,
 193                               int buf_size)
 194 {
 195     int16_t *out = data;
 196     int x, y;
 197     Real288_internal *glob = avctx->priv_data;
 198     GetBitContext gb;
 199
 200     if (buf_size < avctx->block_align) {
 201         av_log(avctx, AV_LOG_ERROR,
 202                "Error! Input buffer is too small [%d<%d]\n",
 203                buf_size, avctx->block_align);
 204         return 0;
 205     }
 206
 207     init_get_bits(&gb, buf, avctx->block_align * 8);
 208
 209     for (x=0; x < 32; x++) {
 210         float gain = amptable[get_bits(&gb, 3)];
 211         int cb_coef = get_bits(&gb, 6 + (x&1));
 212         glob->phase = x & 7;
 213         decode(glob, gain, cb_coef);
 214
 215         for (y=0; y < 5; y++)
 216             *(out++) = 8 * glob->output[glob->phase*5 + y];
 217
 218         if (glob->phase == 3)
 219             update(glob);
 220     }
 221
 222     *data_size = (char *)out - (char *)data;
 223     return avctx->block_align;
 224 }
 225
 226 AVCodec ra_288_decoder =
 227 {
 228     "real_288",
 229     CODEC_TYPE_AUDIO,
 230     CODEC_ID_RA_288,
 231     sizeof(Real288_internal),
 232     NULL,
 233     NULL,
 234     NULL,
 235     ra288_decode_frame,
 236     .long_name = NULL_IF_CONFIG_SMALL("RealAudio 2.0 (28.8K)"),
 237 };