ra144.c 9.5 KB
Newer Older
1 2 3 4
/*
 * Real Audio 1.0 (14.4K)
 * Copyright (c) 2003 the ffmpeg project
 *
5 6 7
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
8 9
 * modify it under the terms of the GNU Lesser General Public
 * 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 14 15 16 17
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * 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
#include "bitstream.h"
24
#include "ra144.h"
25

26 27 28 29
#define NBLOCKS         4       /* number of segments within a block */
#define BLOCKSIZE       40      /* (quarter) block size in 16-bit words (80 bytes) */
#define HALFBLOCK       20      /* BLOCKSIZE/2 */
#define BUFFERSIZE      146     /* for do_output */
30 31 32 33


/* internal globals */
typedef struct {
34
    unsigned int     oldval;
35
    unsigned short   gbuf2[4][30];
36 37

    /* the swapped buffers */
38
    unsigned int     swapbuffers[4][10];
39 40 41 42 43 44 45
    unsigned int    *swapbuf1;
    unsigned int    *swapbuf2;
    unsigned int    *swapbuf1alt;
    unsigned int    *swapbuf2alt;

    unsigned int buffer[5];
    unsigned short int buffer_2[148];
46 47 48 49
} Real144_internal;

static int ra144_decode_init(AVCodecContext * avctx)
{
50
    Real144_internal *glob = avctx->priv_data;
51

52 53 54 55
    glob->swapbuf1    = glob->swapbuffers[0];
    glob->swapbuf2    = glob->swapbuffers[1];
    glob->swapbuf1alt = glob->swapbuffers[2];
    glob->swapbuf2alt = glob->swapbuffers[3];
56

57
    return 0;
58 59 60 61 62
}

/* lookup square roots in table */
static int t_sqrt(unsigned int x)
{
63 64 65 66 67 68
    int s = 0;
    while (x > 0xfff) {
        s++;
        x = x >> 2;
    }

69
    return (ff_sqrt(x << 20) << s) << 2;
70 71 72
}

/* do 'voice' */
73
static void do_voice(const int *a1, int *a2)
74
{
75
    int buffer[10];
Vitor Sessak's avatar
Vitor Sessak committed
76 77
    int *b1 = buffer;
    int *b2 = a2;
78
    int x, y;
79

80
    for (x=0; x < 10; x++) {
Vitor Sessak's avatar
Vitor Sessak committed
81 82 83
        b1[x] = a1[x] << 4;

        for (y=0; y < x; y++)
84
            b1[y] = ((a1[x] * b2[x-y-1]) >> 12) + b2[y];
85

86
        FFSWAP(int *, b1, b2);
87
    }
88

Vitor Sessak's avatar
Vitor Sessak committed
89 90
    for (x=0; x < 10; x++)
        a2[x] >>= 4;
91 92 93
}

/* rotate block */
94
static void rotate_block(const short *source, short *target, int offset)
95
{
Vitor Sessak's avatar
Vitor Sessak committed
96
    int i=0, k=0;
97
    source += BUFFERSIZE - offset;
Vitor Sessak's avatar
Vitor Sessak committed
98 99

    while (i<BLOCKSIZE) {
100
        target[i++] = source[k++];
Vitor Sessak's avatar
Vitor Sessak committed
101 102 103

        if (k == offset)
            k = 0;
104
    }
105 106 107
}

/* inverse root mean square */
108
static int irms(const short *data, int factor)
109
{
Vitor Sessak's avatar
Vitor Sessak committed
110
    unsigned int i, sum = 0;
111

Vitor Sessak's avatar
Vitor Sessak committed
112 113
    for (i=0; i < BLOCKSIZE; i++)
        sum += data[i] * data[i];
114 115 116 117 118

    if (sum == 0)
        return 0; /* OOPS - division by zero */

    return (0x20000000 / (t_sqrt(sum) >> 8)) * factor;
119 120 121
}

/* multiply/add wavetable */
122
static void add_wav(int n, int f, int m1, int m2, int m3, const short *s1,
123
                    const int8_t *s2, const int8_t *s3, short *dest)
124
{
Vitor Sessak's avatar
Vitor Sessak committed
125 126
    int a = 0;
    int b, c, i;
127
    const int16_t *ptr;
128
    const uint8_t *ptr2;
129

130 131
    ptr  = wavtable1[n];
    ptr2 = wavtable2[n];
132

Vitor Sessak's avatar
Vitor Sessak committed
133 134
    if (f)
        a = (ptr[0] * m1) >> (ptr2[0] + 1);
135

Vitor Sessak's avatar
Vitor Sessak committed
136 137
    b = (ptr[1] * m2) >> (ptr2[1] + 1);
    c = (ptr[2] * m3) >> (ptr2[2] + 1);
138

Vitor Sessak's avatar
Vitor Sessak committed
139 140
    for (i=0; i < BLOCKSIZE; i++)
        dest[i] = ((*(s1++)) * a + (*(s2++)) * b + (*(s3++)) * c) >> 12;
141 142 143
}


144
static void final(const short *i1, const short *i2,
145
                  void *out, int *statbuf, int len)
146
{
Vitor Sessak's avatar
Vitor Sessak committed
147
    int x, i;
148
    unsigned short int work[50];
Vitor Sessak's avatar
Vitor Sessak committed
149
    short *ptr = work;
150

151 152
    memcpy(work, statbuf,20);
    memcpy(work + 10, i2, len * 2);
153

Vitor Sessak's avatar
Vitor Sessak committed
154 155
    for (i=0; i<len; i++) {
        int sum = 0;
156
        int new_val;
157

Vitor Sessak's avatar
Vitor Sessak committed
158 159
        for(x=0; x<10; x++)
            sum += i1[9-x] * ptr[x];
160

Vitor Sessak's avatar
Vitor Sessak committed
161
        sum >>= 12;
162

163 164 165
        new_val = ptr[10] - sum;

        if (new_val < -32768 || new_val > 32767) {
166 167 168 169 170
            memset(out, 0, len * 2);
            memset(statbuf, 0, 20);
            return;
        }

171
        ptr[10] = new_val;
172
        ptr++;
173
    }
Vitor Sessak's avatar
Vitor Sessak committed
174 175 176

    memcpy(out, work+10, len * 2);
    memcpy(statbuf, work + 40, 20);
177 178
}

179
static unsigned int rms(const int *data, int f)
180
{
181
    int x;
Vitor Sessak's avatar
Vitor Sessak committed
182 183
    unsigned int res = 0x10000;
    int b = 0;
184 185

    for (x=0; x<10; x++) {
Vitor Sessak's avatar
Vitor Sessak committed
186
        res = (((0x1000000 - (*data) * (*data)) >> 12) * res) >> 12;
187 188 189 190

        if (res == 0)
            return 0;

Vitor Sessak's avatar
Indent  
Vitor Sessak committed
191 192
        if (res > 0x10000)
            return 0; /* We're screwed, might as well go out with a bang. :P */
Vitor Sessak's avatar
Vitor Sessak committed
193 194 195 196

        while (res <= 0x3fff) {
            b++;
            res <<= 2;
197
        }
Vitor Sessak's avatar
Vitor Sessak committed
198
        data++;
199 200
    }

201 202 203 204 205 206
    if (res > 0)
        res = t_sqrt(res);

    res >>= (b + 10);
    res = (res * f) >> 10;
    return res;
207 208
}

209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235
/* do quarter-block output */
static void do_output_subblock(Real144_internal *glob, const unsigned short  *gsp, unsigned int gval, signed short *output_buffer, GetBitContext *gb)
{
    unsigned short int buffer_a[40];
    unsigned short int *block;
    int e, f, g;
    int a = get_bits(gb, 7);
    int d = get_bits(gb, 8);
    int b = get_bits(gb, 7);
    int c = get_bits(gb, 7);

    if (a) {
        a += HALFBLOCK - 1;
        rotate_block(glob->buffer_2, buffer_a, a);
    }

    e = ((ftable1[b] >> 4) * gval) >> 8;
    f = ((ftable2[c] >> 4) * gval) >> 8;

    if (a)
        g = irms(buffer_a, gval) >> 12;
    else
        g = 0;

    memmove(glob->buffer_2, glob->buffer_2 + BLOCKSIZE, (BUFFERSIZE - BLOCKSIZE) * 2);
    block = glob->buffer_2 + BUFFERSIZE - BLOCKSIZE;

236 237
    add_wav(d, a, g, e, f, buffer_a, etable1[b],
            etable2[c], block);
238 239 240 241

    final(gsp, block, output_buffer, glob->buffer, BLOCKSIZE);
}

242
static int dec1(Real144_internal *glob, const int *data, const int *inp,
243
                 int f, int block_idx)
244
{
245
    short *ptr,*end;
246
    signed   short  *decsp = glob->gbuf2[block_idx];
247

248
    end = (ptr = decsp) + 30;
249

250 251
    while (ptr < end)
        *(ptr++) = *(inp++);
252 253

    return rms(data, f);
254 255
}

256
static int eq(const short *in, int *target)
257
{
Vitor Sessak's avatar
Vitor Sessak committed
258 259
    int retval = 0;
    int b, c, i;
260
    unsigned int u;
261 262
    int buffer1[10];
    int buffer2[10];
Vitor Sessak's avatar
Vitor Sessak committed
263 264
    int *bp1 = buffer1;
    int *bp2 = buffer2;
265

Vitor Sessak's avatar
Vitor Sessak committed
266 267
    for (i=0; i < 10; i++)
        buffer2[i] = in[i];
268

Vitor Sessak's avatar
Vitor Sessak committed
269
    u = target[9] = bp2[9];
270

Vitor Sessak's avatar
Vitor Sessak committed
271
    if (u + 0x1000 > 0x1fff)
272 273
        return 0; /* We're screwed, might as well go out with a bang. :P */

Vitor Sessak's avatar
Vitor Sessak committed
274
    for (c=8; c >= 0; c--) {
275 276 277 278 279 280 281 282 283 284 285 286
        if (u == 0x1000)
            u++;

        if (u == 0xfffff000)
            u--;

        b = 0x1000-((u * u) >> 12);

        if (b == 0)
            b++;

        for (u=0; u<=c; u++)
Vitor Sessak's avatar
Vitor Sessak committed
287
            bp1[u] = ((bp2[u] - ((target[c+1] * bp2[c-u]) >> 12)) * (0x1000000 / b)) >> 12;
288

Vitor Sessak's avatar
Vitor Sessak committed
289
        target[c] = u = bp1[c];
290 291 292 293

        if ((u + 0x1000) > 0x1fff)
            retval = 1;

294
        FFSWAP(int *, bp1, bp2);
295 296
    }
    return retval;
297 298
}

299
static int dec2(Real144_internal *glob, const int *data, const int *inp,
300
                 int f, const int *inp2, int l)
301
{
302
    unsigned const int *ptr1,*ptr2;
303 304 305 306
    int work[10];
    int a,b;
    int x;
    int result;
307
    signed   short *decsp = glob->gbuf2[l];
308
    unsigned short *sptr  = decsp;
309 310 311 312 313 314 315 316 317 318 319

    if(l + 1 < NBLOCKS / 2)
        a = NBLOCKS - (l + 1);
    else
        a = l + 1;

    b = NBLOCKS - a;

    ptr1 = inp;
    ptr2 = inp2;

320
    for (x=0; x<30; x++)
321
        *(sptr++) = (a * (*ptr1++) + b * (*ptr2++)) >> 2;
322

323
    result = eq(decsp, work);
324 325

    if (result == 1) {
326
        return dec1(glob, data, inp, f, l);
327
    } else {
328
        return rms(work, f);
329
    }
330 331 332 333
}

/* Uncompress one block (20 bytes -> 160*2 bytes) */
static int ra144_decode_frame(AVCodecContext * avctx,
334
            void *vdata, int *data_size,
Michael Niedermayer's avatar
const  
Michael Niedermayer committed
335
            const uint8_t * buf, int buf_size)
336
{
337
    static const uint8_t sizes[10] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2};
338
    unsigned int gbuf1[4];
339
    unsigned int a, c;
340
    int i;
341
    int16_t *data = vdata;
342 343
    unsigned int val;

344
    Real144_internal *glob = avctx->priv_data;
345
    GetBitContext gb;
346

347 348 349 350 351
    if(buf_size < 20) {
        av_log(avctx, AV_LOG_ERROR,
               "Frame too small (%d bytes). Truncated file?\n", buf_size);
        return buf_size;
    }
352
    init_get_bits(&gb, buf, 20 * 8);
353

354 355 356
    for (i=0; i<10; i++)
        // "<< 1"? Doesn't this make one value out of two of the table useless?
        glob->swapbuf1[i] = decodetable[i][get_bits(&gb, sizes[i]) << 1];
357

358
    do_voice(glob->swapbuf1, glob->swapbuf2);
359

360 361
    val = decodeval[get_bits(&gb, 5) << 1]; // Useless table entries?
    a = t_sqrt(val*glob->oldval) >> 12;
362

363
    gbuf1[0] = dec2(glob, glob->swapbuf1alt, glob->swapbuf2alt, glob->oldval, glob->swapbuf2, 0);
364
    if (glob->oldval < val) {
365
        gbuf1[1] = dec2(glob, glob->swapbuf1, glob->swapbuf2, a, glob->swapbuf2alt, 1);
366
    } else {
367
        gbuf1[1] = dec2(glob, glob->swapbuf1alt, glob->swapbuf2alt, a, glob->swapbuf2, 1);
368
    }
369 370
    gbuf1[2] = dec2(glob, glob->swapbuf1, glob->swapbuf2, val, glob->swapbuf2alt, 2);
    gbuf1[3] = dec1(glob, glob->swapbuf1, glob->swapbuf2, val, 3);
371 372

    /* do output */
373
    for (c=0; c<4; c++) {
374
        do_output_subblock(glob, glob->gbuf2[c], gbuf1[c], data, &gb);
375

376 377 378 379
        for (i=0; i<BLOCKSIZE; i++) {
            *data = av_clip_int16(*data << 2);
            data++;
        }
380 381
    }

382
    glob->oldval = val;
383 384 385 386

    FFSWAP(unsigned int *, glob->swapbuf1alt, glob->swapbuf1);
    FFSWAP(unsigned int *, glob->swapbuf2alt, glob->swapbuf2);

Vitor Sessak's avatar
Vitor Sessak committed
387
    *data_size = 2*160;
388
    return 20;
389 390 391 392 393 394 395 396 397 398 399 400 401
}


AVCodec ra_144_decoder =
{
    "real_144",
    CODEC_TYPE_AUDIO,
    CODEC_ID_RA_144,
    sizeof(Real144_internal),
    ra144_decode_init,
    NULL,
    NULL,
    ra144_decode_frame,
402
    .long_name = "RealAudio 1.0 (14.4K)",
403
};