ra288.c
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1 /*
2  * RealAudio 2.0 (28.8K)
3  * Copyright (c) 2003 the ffmpeg project
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; 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 "internal.h"
24 #define BITSTREAM_READER_LE
25 #include "get_bits.h"
26 #include "ra288.h"
27 #include "lpc.h"
28 #include "celp_math.h"
29 #include "celp_filters.h"
30 #include "dsputil.h"
31 
32 #define MAX_BACKWARD_FILTER_ORDER 36
33 #define MAX_BACKWARD_FILTER_LEN 40
34 #define MAX_BACKWARD_FILTER_NONREC 35
35 
36 #define RA288_BLOCK_SIZE 5
37 #define RA288_BLOCKS_PER_FRAME 32
38 
39 typedef struct {
42  DECLARE_ALIGNED(16, float, sp_lpc)[FFALIGN(36, 8)];
43  DECLARE_ALIGNED(16, float, gain_lpc)[FFALIGN(10, 8)];
44 
48  float sp_hist[111];
49 
51  float sp_rec[37];
52 
56  float gain_hist[38];
57 
59  float gain_rec[11];
60 } RA288Context;
61 
63 {
64  RA288Context *ractx = avctx->priv_data;
66  dsputil_init(&ractx->dsp, avctx);
67 
69  avctx->coded_frame = &ractx->frame;
70 
71  return 0;
72 }
73 
74 static void convolve(float *tgt, const float *src, int len, int n)
75 {
76  for (; n >= 0; n--)
77  tgt[n] = ff_dot_productf(src, src - n, len);
78 
79 }
80 
81 static void decode(RA288Context *ractx, float gain, int cb_coef)
82 {
83  int i;
84  double sumsum;
85  float sum, buffer[5];
86  float *block = ractx->sp_hist + 70 + 36; // current block
87  float *gain_block = ractx->gain_hist + 28;
88 
89  memmove(ractx->sp_hist + 70, ractx->sp_hist + 75, 36*sizeof(*block));
90 
91  /* block 46 of G.728 spec */
92  sum = 32.;
93  for (i=0; i < 10; i++)
94  sum -= gain_block[9-i] * ractx->gain_lpc[i];
95 
96  /* block 47 of G.728 spec */
97  sum = av_clipf(sum, 0, 60);
98 
99  /* block 48 of G.728 spec */
100  /* exp(sum * 0.1151292546497) == pow(10.0,sum/20) */
101  sumsum = exp(sum * 0.1151292546497) * gain * (1.0/(1<<23));
102 
103  for (i=0; i < 5; i++)
104  buffer[i] = codetable[cb_coef][i] * sumsum;
105 
106  sum = ff_dot_productf(buffer, buffer, 5) * ((1<<24)/5.);
107 
108  sum = FFMAX(sum, 1);
109 
110  /* shift and store */
111  memmove(gain_block, gain_block + 1, 9 * sizeof(*gain_block));
112 
113  gain_block[9] = 10 * log10(sum) - 32;
114 
115  ff_celp_lp_synthesis_filterf(block, ractx->sp_lpc, buffer, 5, 36);
116 }
117 
130 static void do_hybrid_window(RA288Context *ractx,
131  int order, int n, int non_rec, float *out,
132  float *hist, float *out2, const float *window)
133 {
134  int i;
135  float buffer1[MAX_BACKWARD_FILTER_ORDER + 1];
136  float buffer2[MAX_BACKWARD_FILTER_ORDER + 1];
140 
141  ractx->dsp.vector_fmul(work, window, hist, FFALIGN(order + n + non_rec, 8));
142 
143  convolve(buffer1, work + order , n , order);
144  convolve(buffer2, work + order + n, non_rec, order);
145 
146  for (i=0; i <= order; i++) {
147  out2[i] = out2[i] * 0.5625 + buffer1[i];
148  out [i] = out2[i] + buffer2[i];
149  }
150 
151  /* Multiply by the white noise correcting factor (WNCF). */
152  *out *= 257./256.;
153 }
154 
158 static void backward_filter(RA288Context *ractx,
159  float *hist, float *rec, const float *window,
160  float *lpc, const float *tab,
161  int order, int n, int non_rec, int move_size)
162 {
163  float temp[MAX_BACKWARD_FILTER_ORDER+1];
164 
165  do_hybrid_window(ractx, order, n, non_rec, temp, hist, rec, window);
166 
167  if (!compute_lpc_coefs(temp, order, lpc, 0, 1, 1))
168  ractx->dsp.vector_fmul(lpc, lpc, tab, FFALIGN(order, 8));
169 
170  memmove(hist, hist + n, move_size*sizeof(*hist));
171 }
172 
173 static int ra288_decode_frame(AVCodecContext * avctx, void *data,
174  int *got_frame_ptr, AVPacket *avpkt)
175 {
176  const uint8_t *buf = avpkt->data;
177  int buf_size = avpkt->size;
178  float *out;
179  int i, ret;
180  RA288Context *ractx = avctx->priv_data;
181  GetBitContext gb;
182 
183  if (buf_size < avctx->block_align) {
184  av_log(avctx, AV_LOG_ERROR,
185  "Error! Input buffer is too small [%d<%d]\n",
186  buf_size, avctx->block_align);
187  return AVERROR_INVALIDDATA;
188  }
189 
190  /* get output buffer */
192  if ((ret = ff_get_buffer(avctx, &ractx->frame)) < 0) {
193  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
194  return ret;
195  }
196  out = (float *)ractx->frame.data[0];
197 
198  init_get_bits(&gb, buf, avctx->block_align * 8);
199 
200  for (i=0; i < RA288_BLOCKS_PER_FRAME; i++) {
201  float gain = amptable[get_bits(&gb, 3)];
202  int cb_coef = get_bits(&gb, 6 + (i&1));
203 
204  decode(ractx, gain, cb_coef);
205 
206  memcpy(out, &ractx->sp_hist[70 + 36], RA288_BLOCK_SIZE * sizeof(*out));
207  out += RA288_BLOCK_SIZE;
208 
209  if ((i & 7) == 3) {
210  backward_filter(ractx, ractx->sp_hist, ractx->sp_rec, syn_window,
211  ractx->sp_lpc, syn_bw_tab, 36, 40, 35, 70);
212 
213  backward_filter(ractx, ractx->gain_hist, ractx->gain_rec, gain_window,
214  ractx->gain_lpc, gain_bw_tab, 10, 8, 20, 28);
215  }
216  }
217 
218  *got_frame_ptr = 1;
219  *(AVFrame *)data = ractx->frame;
220 
221  return avctx->block_align;
222 }
223 
225  .name = "real_288",
226  .type = AVMEDIA_TYPE_AUDIO,
227  .id = CODEC_ID_RA_288,
228  .priv_data_size = sizeof(RA288Context),
231  .capabilities = CODEC_CAP_DR1,
232  .long_name = NULL_IF_CONFIG_SMALL("RealAudio 2.0 (28.8K)"),
233 };