2 * Real Audio 1.0 (14.4K)
3 * Copyright (c) 2003 the ffmpeg project
5 * This file is part of FFmpeg.
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.
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.
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
23 #include "bitstream.h"
26 #define NBLOCKS 4 /* number of segments within a block */
27 #define BLOCKSIZE 40 /* (quarter) block size in 16-bit words (80 bytes) */
28 #define HALFBLOCK 20 /* BLOCKSIZE/2 */
29 #define BUFFERSIZE 146 /* for do_output */
32 /* internal globals */
34 unsigned int old_energy; ///< previous frame energy
36 /* the swapped buffers */
37 unsigned int lpc_tables[4][10];
38 unsigned int *lpc_refl; ///< LPC reflection coefficients
39 unsigned int *lpc_coef; ///< LPC coefficients
40 unsigned int *lpc_refl_old; ///< previous frame LPC reflection coefs
41 unsigned int *lpc_coef_old; ///< previous frame LPC coefficients
43 unsigned int buffer[5];
44 uint16_t adapt_cb[148]; ///< adaptive codebook
47 static int ra144_decode_init(AVCodecContext * avctx)
49 RA144Context *ractx = avctx->priv_data;
51 ractx->lpc_refl = ractx->lpc_tables[0];
52 ractx->lpc_coef = ractx->lpc_tables[1];
53 ractx->lpc_refl_old = ractx->lpc_tables[2];
54 ractx->lpc_coef_old = ractx->lpc_tables[3];
60 * Evaluate sqrt(x << 24). x must fit in 20 bits. This value is evaluated in an
61 * odd way to make the output identical to the binary decoder.
63 static int t_sqrt(unsigned int x)
71 return (ff_sqrt(x << 20) << s) << 2;
75 static void do_voice(const int *a1, int *a2)
82 for (x=0; x < 10; x++) {
86 b1[y] = ((a1[x] * b2[x-y-1]) >> 12) + b2[y];
88 FFSWAP(int *, b1, b2);
91 for (x=0; x < 10; x++)
96 static void rotate_block(const int16_t *source, int16_t *target, int offset)
99 source += BUFFERSIZE - offset;
101 while (i<BLOCKSIZE) {
102 target[i++] = source[k++];
109 /* inverse root mean square */
110 static int irms(const int16_t *data, int factor)
112 unsigned int i, sum = 0;
114 for (i=0; i < BLOCKSIZE; i++)
115 sum += data[i] * data[i];
118 return 0; /* OOPS - division by zero */
120 return (0x20000000 / (t_sqrt(sum) >> 8)) * factor;
123 /* multiply/add wavetable */
124 static void add_wav(int n, int skip_first, int *m, const int16_t *s1,
125 const int8_t *s2, const int8_t *s3, int16_t *dest)
131 for (i=!skip_first; i<3; i++)
132 v[i] = (wavtable1[n][i] * m[i]) >> (wavtable2[n][i] + 1);
134 for (i=0; i < BLOCKSIZE; i++)
135 dest[i] = ((*(s1++))*v[0] + (*(s2++))*v[1] + (*(s3++))*v[2]) >> 12;
139 static void final(const int16_t *i1, const int16_t *i2,
140 void *out, int *statbuf, int len)
146 memcpy(work, statbuf,20);
147 memcpy(work + 10, i2, len * 2);
149 for (i=0; i<len; i++) {
154 sum += i1[9-x] * ptr[x];
158 new_val = ptr[10] - sum;
160 if (new_val < -32768 || new_val > 32767) {
161 memset(out, 0, len * 2);
162 memset(statbuf, 0, 20);
170 memcpy(out, work+10, len * 2);
171 memcpy(statbuf, work + 40, 20);
174 static unsigned int rms(const int *data, int f)
177 unsigned int res = 0x10000;
180 for (x=0; x<10; x++) {
181 res = (((0x1000000 - (*data) * (*data)) >> 12) * res) >> 12;
187 return 0; /* We're screwed, might as well go out with a bang. :P */
189 while (res <= 0x3fff) {
200 res = (res * f) >> 10;
204 /* do quarter-block output */
205 static void do_output_subblock(RA144Context *ractx,
206 const uint16_t *gsp, unsigned int gval,
207 int16_t *output_buffer, GetBitContext *gb)
209 uint16_t buffer_a[40];
211 int cba_idx = get_bits(gb, 7); // index of the adaptive CB, 0 if none
212 int gain = get_bits(gb, 8);
213 int cb1_idx = get_bits(gb, 7);
214 int cb2_idx = get_bits(gb, 7);
218 cba_idx += HALFBLOCK - 1;
219 rotate_block(ractx->adapt_cb, buffer_a, cba_idx);
220 m[0] = irms(buffer_a, gval) >> 12;
225 m[1] = ((ftable1[cb1_idx] >> 4) * gval) >> 8;
226 m[2] = ((ftable2[cb2_idx] >> 4) * gval) >> 8;
228 memmove(ractx->adapt_cb, ractx->adapt_cb + BLOCKSIZE,
229 (BUFFERSIZE - BLOCKSIZE) * 2);
231 block = ractx->adapt_cb + BUFFERSIZE - BLOCKSIZE;
233 add_wav(gain, cba_idx, m, buffer_a, etable1[cb1_idx], etable2[cb2_idx],
236 final(gsp, block, output_buffer, ractx->buffer, BLOCKSIZE);
239 static int dec1(int16_t *decsp, const int *data, const int *inp, int f)
244 *(decsp++) = *(inp++);
249 static int eq(const int16_t *in, int *target)
259 for (i=0; i < 10; i++)
262 u = target[9] = bp2[9];
264 if (u + 0x1000 > 0x1fff)
265 return 0; /* We're screwed, might as well go out with a bang. :P */
267 for (c=8; c >= 0; c--) {
274 b = 0x1000-((u * u) >> 12);
280 bp1[u] = ((bp2[u] - ((target[c+1] * bp2[c-u]) >> 12)) * (0x1000000 / b)) >> 12;
282 target[c] = u = bp1[c];
284 if ((u + 0x1000) > 0x1fff)
287 FFSWAP(int *, bp1, bp2);
292 static int dec2(RA144Context *ractx, int16_t *decsp, int block_num,
296 int a = block_num + 1;
300 // Interpolate block coefficients from the this frame forth block and
301 // last frame forth block
303 decsp[x] = (a * ractx->lpc_coef[x] + b * ractx->lpc_coef_old[x])>> 2;
305 if (eq(decsp, work)) {
306 // The interpolated coefficients are unstable, copy either new or old
309 return dec1(decsp, ractx->lpc_refl, ractx->lpc_coef, f);
311 return dec1(decsp, ractx->lpc_refl_old, ractx->lpc_coef_old, f);
317 /* Uncompress one block (20 bytes -> 160*2 bytes) */
318 static int ra144_decode_frame(AVCodecContext * avctx,
319 void *vdata, int *data_size,
320 const uint8_t * buf, int buf_size)
322 static const uint8_t sizes[10] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2};
323 unsigned int refl_rms[4]; // RMS of the reflection coefficients
324 uint16_t gbuf2[4][30];
327 int16_t *data = vdata;
330 RA144Context *ractx = avctx->priv_data;
334 av_log(avctx, AV_LOG_ERROR,
335 "Frame too small (%d bytes). Truncated file?\n", buf_size);
338 init_get_bits(&gb, buf, 20 * 8);
341 // "<< 1"? Doesn't this make one value out of two of the table useless?
342 ractx->lpc_refl[i] = decodetable[i][get_bits(&gb, sizes[i]) << 1];
344 do_voice(ractx->lpc_refl, ractx->lpc_coef);
346 energy = decodeval[get_bits(&gb, 5) << 1]; // Useless table entries?
348 refl_rms[0] = dec2(ractx, gbuf2[0], 0, 0, ractx->old_energy);
349 refl_rms[1] = dec2(ractx, gbuf2[1], 1, energy > ractx->old_energy,
350 t_sqrt(energy*ractx->old_energy) >> 12);
351 refl_rms[2] = dec2(ractx, gbuf2[2], 2, 1, energy);
352 refl_rms[3] = dec1(gbuf2[3], ractx->lpc_refl, ractx->lpc_coef, energy);
355 for (c=0; c<4; c++) {
356 do_output_subblock(ractx, gbuf2[c], refl_rms[c], data, &gb);
358 for (i=0; i<BLOCKSIZE; i++) {
359 *data = av_clip_int16(*data << 2);
364 ractx->old_energy = energy;
366 FFSWAP(unsigned int *, ractx->lpc_refl_old, ractx->lpc_refl);
367 FFSWAP(unsigned int *, ractx->lpc_coef_old, ractx->lpc_coef);
374 AVCodec ra_144_decoder =
379 sizeof(RA144Context),
384 .long_name = "RealAudio 1.0 (14.4K)",