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 #define BITSTREAM_READER_LE
24 #include "get_bits.h"
25 #include "ra288.h"
26 #include "lpc.h"
27 #include "celp_math.h"
28 #include "celp_filters.h"
29 #include "dsputil.h"
30 
31 #define MAX_BACKWARD_FILTER_ORDER 36
32 #define MAX_BACKWARD_FILTER_LEN 40
33 #define MAX_BACKWARD_FILTER_NONREC 35
34 
35 #define RA288_BLOCK_SIZE 5
36 #define RA288_BLOCKS_PER_FRAME 32
37 
38 typedef struct {
41  DECLARE_ALIGNED(16, float, sp_lpc)[FFALIGN(36, 8)];
42  DECLARE_ALIGNED(16, float, gain_lpc)[FFALIGN(10, 8)];
43 
47  float sp_hist[111];
48 
50  float sp_rec[37];
51 
55  float gain_hist[38];
56 
58  float gain_rec[11];
59 } RA288Context;
60 
62 {
63  RA288Context *ractx = avctx->priv_data;
65  dsputil_init(&ractx->dsp, avctx);
66 
68  avctx->coded_frame = &ractx->frame;
69 
70  return 0;
71 }
72 
73 static void convolve(float *tgt, const float *src, int len, int n)
74 {
75  for (; n >= 0; n--)
76  tgt[n] = ff_dot_productf(src, src - n, len);
77 
78 }
79 
80 static void decode(RA288Context *ractx, float gain, int cb_coef)
81 {
82  int i;
83  double sumsum;
84  float sum, buffer[5];
85  float *block = ractx->sp_hist + 70 + 36; // current block
86  float *gain_block = ractx->gain_hist + 28;
87 
88  memmove(ractx->sp_hist + 70, ractx->sp_hist + 75, 36*sizeof(*block));
89 
90  /* block 46 of G.728 spec */
91  sum = 32.;
92  for (i=0; i < 10; i++)
93  sum -= gain_block[9-i] * ractx->gain_lpc[i];
94 
95  /* block 47 of G.728 spec */
96  sum = av_clipf(sum, 0, 60);
97 
98  /* block 48 of G.728 spec */
99  /* exp(sum * 0.1151292546497) == pow(10.0,sum/20) */
100  sumsum = exp(sum * 0.1151292546497) * gain * (1.0/(1<<23));
101 
102  for (i=0; i < 5; i++)
103  buffer[i] = codetable[cb_coef][i] * sumsum;
104 
105  sum = ff_dot_productf(buffer, buffer, 5) * ((1<<24)/5.);
106 
107  sum = FFMAX(sum, 1);
108 
109  /* shift and store */
110  memmove(gain_block, gain_block + 1, 9 * sizeof(*gain_block));
111 
112  gain_block[9] = 10 * log10(sum) - 32;
113 
114  ff_celp_lp_synthesis_filterf(block, ractx->sp_lpc, buffer, 5, 36);
115 }
116 
129 static void do_hybrid_window(RA288Context *ractx,
130  int order, int n, int non_rec, float *out,
131  float *hist, float *out2, const float *window)
132 {
133  int i;
134  float buffer1[MAX_BACKWARD_FILTER_ORDER + 1];
135  float buffer2[MAX_BACKWARD_FILTER_ORDER + 1];
139 
140  ractx->dsp.vector_fmul(work, window, hist, FFALIGN(order + n + non_rec, 8));
141 
142  convolve(buffer1, work + order , n , order);
143  convolve(buffer2, work + order + n, non_rec, order);
144 
145  for (i=0; i <= order; i++) {
146  out2[i] = out2[i] * 0.5625 + buffer1[i];
147  out [i] = out2[i] + buffer2[i];
148  }
149 
150  /* Multiply by the white noise correcting factor (WNCF). */
151  *out *= 257./256.;
152 }
153 
157 static void backward_filter(RA288Context *ractx,
158  float *hist, float *rec, const float *window,
159  float *lpc, const float *tab,
160  int order, int n, int non_rec, int move_size)
161 {
162  float temp[MAX_BACKWARD_FILTER_ORDER+1];
163 
164  do_hybrid_window(ractx, order, n, non_rec, temp, hist, rec, window);
165 
166  if (!compute_lpc_coefs(temp, order, lpc, 0, 1, 1))
167  ractx->dsp.vector_fmul(lpc, lpc, tab, FFALIGN(order, 8));
168 
169  memmove(hist, hist + n, move_size*sizeof(*hist));
170 }
171 
172 static int ra288_decode_frame(AVCodecContext * avctx, void *data,
173  int *got_frame_ptr, AVPacket *avpkt)
174 {
175  const uint8_t *buf = avpkt->data;
176  int buf_size = avpkt->size;
177  float *out;
178  int i, ret;
179  RA288Context *ractx = avctx->priv_data;
180  GetBitContext gb;
181 
182  if (buf_size < avctx->block_align) {
183  av_log(avctx, AV_LOG_ERROR,
184  "Error! Input buffer is too small [%d<%d]\n",
185  buf_size, avctx->block_align);
186  return AVERROR_INVALIDDATA;
187  }
188 
189  /* get output buffer */
191  if ((ret = avctx->get_buffer(avctx, &ractx->frame)) < 0) {
192  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
193  return ret;
194  }
195  out = (float *)ractx->frame.data[0];
196 
197  init_get_bits(&gb, buf, avctx->block_align * 8);
198 
199  for (i=0; i < RA288_BLOCKS_PER_FRAME; i++) {
200  float gain = amptable[get_bits(&gb, 3)];
201  int cb_coef = get_bits(&gb, 6 + (i&1));
202 
203  decode(ractx, gain, cb_coef);
204 
205  memcpy(out, &ractx->sp_hist[70 + 36], RA288_BLOCK_SIZE * sizeof(*out));
206  out += RA288_BLOCK_SIZE;
207 
208  if ((i & 7) == 3) {
209  backward_filter(ractx, ractx->sp_hist, ractx->sp_rec, syn_window,
210  ractx->sp_lpc, syn_bw_tab, 36, 40, 35, 70);
211 
212  backward_filter(ractx, ractx->gain_hist, ractx->gain_rec, gain_window,
213  ractx->gain_lpc, gain_bw_tab, 10, 8, 20, 28);
214  }
215  }
216 
217  *got_frame_ptr = 1;
218  *(AVFrame *)data = ractx->frame;
219 
220  return avctx->block_align;
221 }
222 
224  .name = "real_288",
225  .type = AVMEDIA_TYPE_AUDIO,
226  .id = CODEC_ID_RA_288,
227  .priv_data_size = sizeof(RA288Context),
230  .capabilities = CODEC_CAP_DR1,
231  .long_name = NULL_IF_CONFIG_SMALL("RealAudio 2.0 (28.8K)"),
232 };