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 
23 #include "libavutil/float_dsp.h"
24 #include "avcodec.h"
25 #include "internal.h"
26 #define BITSTREAM_READER_LE
27 #include "get_bits.h"
28 #include "ra288.h"
29 #include "lpc.h"
30 #include "celp_filters.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 {
43  DECLARE_ALIGNED(32, float, sp_lpc)[FFALIGN(36, 16)];
44  DECLARE_ALIGNED(32, float, gain_lpc)[FFALIGN(10, 16)];
45 
49  float sp_hist[111];
50 
52  float sp_rec[37];
53 
57  float gain_hist[38];
58 
60  float gain_rec[11];
61 } RA288Context;
62 
64 {
65  RA288Context *ractx = avctx->priv_data;
66 
67  avctx->channels = 1;
70 
72 
74  avctx->coded_frame = &ractx->frame;
75 
76  return 0;
77 }
78 
79 static void convolve(float *tgt, const float *src, int len, int n)
80 {
81  for (; n >= 0; n--)
82  tgt[n] = ff_scalarproduct_float_c(src, src - n, len);
83 
84 }
85 
86 static void decode(RA288Context *ractx, float gain, int cb_coef)
87 {
88  int i;
89  double sumsum;
90  float sum, buffer[5];
91  float *block = ractx->sp_hist + 70 + 36; // current block
92  float *gain_block = ractx->gain_hist + 28;
93 
94  memmove(ractx->sp_hist + 70, ractx->sp_hist + 75, 36*sizeof(*block));
95 
96  /* block 46 of G.728 spec */
97  sum = 32.;
98  for (i=0; i < 10; i++)
99  sum -= gain_block[9-i] * ractx->gain_lpc[i];
100 
101  /* block 47 of G.728 spec */
102  sum = av_clipf(sum, 0, 60);
103 
104  /* block 48 of G.728 spec */
105  /* exp(sum * 0.1151292546497) == pow(10.0,sum/20) */
106  sumsum = exp(sum * 0.1151292546497) * gain * (1.0/(1<<23));
107 
108  for (i=0; i < 5; i++)
109  buffer[i] = codetable[cb_coef][i] * sumsum;
110 
111  sum = ff_scalarproduct_float_c(buffer, buffer, 5) * ((1 << 24) / 5.);
112 
113  sum = FFMAX(sum, 1);
114 
115  /* shift and store */
116  memmove(gain_block, gain_block + 1, 9 * sizeof(*gain_block));
117 
118  gain_block[9] = 10 * log10(sum) - 32;
119 
120  ff_celp_lp_synthesis_filterf(block, ractx->sp_lpc, buffer, 5, 36);
121 }
122 
135 static void do_hybrid_window(RA288Context *ractx,
136  int order, int n, int non_rec, float *out,
137  float *hist, float *out2, const float *window)
138 {
139  int i;
140  float buffer1[MAX_BACKWARD_FILTER_ORDER + 1];
141  float buffer2[MAX_BACKWARD_FILTER_ORDER + 1];
145 
146  ractx->fdsp.vector_fmul(work, window, hist, FFALIGN(order + n + non_rec, 16));
147 
148  convolve(buffer1, work + order , n , order);
149  convolve(buffer2, work + order + n, non_rec, order);
150 
151  for (i=0; i <= order; i++) {
152  out2[i] = out2[i] * 0.5625 + buffer1[i];
153  out [i] = out2[i] + buffer2[i];
154  }
155 
156  /* Multiply by the white noise correcting factor (WNCF). */
157  *out *= 257./256.;
158 }
159 
163 static void backward_filter(RA288Context *ractx,
164  float *hist, float *rec, const float *window,
165  float *lpc, const float *tab,
166  int order, int n, int non_rec, int move_size)
167 {
168  float temp[MAX_BACKWARD_FILTER_ORDER+1];
169 
170  do_hybrid_window(ractx, order, n, non_rec, temp, hist, rec, window);
171 
172  if (!compute_lpc_coefs(temp, order, lpc, 0, 1, 1))
173  ractx->fdsp.vector_fmul(lpc, lpc, tab, FFALIGN(order, 16));
174 
175  memmove(hist, hist + n, move_size*sizeof(*hist));
176 }
177 
178 static int ra288_decode_frame(AVCodecContext * avctx, void *data,
179  int *got_frame_ptr, AVPacket *avpkt)
180 {
181  const uint8_t *buf = avpkt->data;
182  int buf_size = avpkt->size;
183  float *out;
184  int i, ret;
185  RA288Context *ractx = avctx->priv_data;
186  GetBitContext gb;
187 
188  if (buf_size < avctx->block_align) {
189  av_log(avctx, AV_LOG_ERROR,
190  "Error! Input buffer is too small [%d<%d]\n",
191  buf_size, avctx->block_align);
192  return AVERROR_INVALIDDATA;
193  }
194 
195  /* get output buffer */
197  if ((ret = ff_get_buffer(avctx, &ractx->frame)) < 0) {
198  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
199  return ret;
200  }
201  out = (float *)ractx->frame.data[0];
202 
203  init_get_bits(&gb, buf, avctx->block_align * 8);
204 
205  for (i=0; i < RA288_BLOCKS_PER_FRAME; i++) {
206  float gain = amptable[get_bits(&gb, 3)];
207  int cb_coef = get_bits(&gb, 6 + (i&1));
208 
209  decode(ractx, gain, cb_coef);
210 
211  memcpy(out, &ractx->sp_hist[70 + 36], RA288_BLOCK_SIZE * sizeof(*out));
212  out += RA288_BLOCK_SIZE;
213 
214  if ((i & 7) == 3) {
215  backward_filter(ractx, ractx->sp_hist, ractx->sp_rec, syn_window,
216  ractx->sp_lpc, syn_bw_tab, 36, 40, 35, 70);
217 
218  backward_filter(ractx, ractx->gain_hist, ractx->gain_rec, gain_window,
219  ractx->gain_lpc, gain_bw_tab, 10, 8, 20, 28);
220  }
221  }
222 
223  *got_frame_ptr = 1;
224  *(AVFrame *)data = ractx->frame;
225 
226  return avctx->block_align;
227 }
228 
230  .name = "real_288",
231  .type = AVMEDIA_TYPE_AUDIO,
232  .id = AV_CODEC_ID_RA_288,
233  .priv_data_size = sizeof(RA288Context),
236  .capabilities = CODEC_CAP_DR1,
237  .long_name = NULL_IF_CONFIG_SMALL("RealAudio 2.0 (28.8K)"),
238 };