Libav
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 "libavutil/internal.h"
25 #include "avcodec.h"
26 #include "internal.h"
27 #define BITSTREAM_READER_LE
28 #include "get_bits.h"
29 #include "ra288.h"
30 #include "lpc.h"
31 #include "celp_filters.h"
32 
33 #define MAX_BACKWARD_FILTER_ORDER 36
34 #define MAX_BACKWARD_FILTER_LEN 40
35 #define MAX_BACKWARD_FILTER_NONREC 35
36 
37 #define RA288_BLOCK_SIZE 5
38 #define RA288_BLOCKS_PER_FRAME 32
39 
40 typedef struct {
42  DECLARE_ALIGNED(32, float, sp_lpc)[FFALIGN(36, 16)];
43  DECLARE_ALIGNED(32, float, gain_lpc)[FFALIGN(10, 16)];
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;
65 
66  avctx->channels = 1;
69 
71 
72  return 0;
73 }
74 
75 static void convolve(float *tgt, const float *src, int len, int n)
76 {
77  for (; n >= 0; n--)
78  tgt[n] = avpriv_scalarproduct_float_c(src, src - n, len);
79 
80 }
81 
82 static void decode(RA288Context *ractx, float gain, int cb_coef)
83 {
84  int i;
85  double sumsum;
86  float sum, buffer[5];
87  float *block = ractx->sp_hist + 70 + 36; // current block
88  float *gain_block = ractx->gain_hist + 28;
89 
90  memmove(ractx->sp_hist + 70, ractx->sp_hist + 75, 36*sizeof(*block));
91 
92  /* block 46 of G.728 spec */
93  sum = 32.0;
94  for (i=0; i < 10; i++)
95  sum -= gain_block[9-i] * ractx->gain_lpc[i];
96 
97  /* block 47 of G.728 spec */
98  sum = av_clipf(sum, 0, 60);
99 
100  /* block 48 of G.728 spec */
101  /* exp(sum * 0.1151292546497) == pow(10.0,sum/20) */
102  sumsum = exp(sum * 0.1151292546497) * gain * (1.0/(1<<23));
103 
104  for (i=0; i < 5; i++)
105  buffer[i] = codetable[cb_coef][i] * sumsum;
106 
107  sum = avpriv_scalarproduct_float_c(buffer, buffer, 5) * ((1 << 24) / 5.0);
108 
109  sum = FFMAX(sum, 1);
110 
111  /* shift and store */
112  memmove(gain_block, gain_block + 1, 9 * sizeof(*gain_block));
113 
114  gain_block[9] = 10 * log10(sum) - 32;
115 
116  ff_celp_lp_synthesis_filterf(block, ractx->sp_lpc, buffer, 5, 36);
117 }
118 
131 static void do_hybrid_window(RA288Context *ractx,
132  int order, int n, int non_rec, float *out,
133  float *hist, float *out2, const float *window)
134 {
135  int i;
136  float buffer1[MAX_BACKWARD_FILTER_ORDER + 1];
137  float buffer2[MAX_BACKWARD_FILTER_ORDER + 1];
141 
142  ractx->fdsp.vector_fmul(work, window, hist, FFALIGN(order + n + non_rec, 16));
143 
144  convolve(buffer1, work + order , n , order);
145  convolve(buffer2, work + order + n, non_rec, order);
146 
147  for (i=0; i <= order; i++) {
148  out2[i] = out2[i] * 0.5625 + buffer1[i];
149  out [i] = out2[i] + buffer2[i];
150  }
151 
152  /* Multiply by the white noise correcting factor (WNCF). */
153  *out *= 257.0 / 256.0;
154 }
155 
159 static void backward_filter(RA288Context *ractx,
160  float *hist, float *rec, const float *window,
161  float *lpc, const float *tab,
162  int order, int n, int non_rec, int move_size)
163 {
164  float temp[MAX_BACKWARD_FILTER_ORDER+1];
165 
166  do_hybrid_window(ractx, order, n, non_rec, temp, hist, rec, window);
167 
168  if (!compute_lpc_coefs(temp, order, lpc, 0, 1, 1))
169  ractx->fdsp.vector_fmul(lpc, lpc, tab, FFALIGN(order, 16));
170 
171  memmove(hist, hist + n, move_size*sizeof(*hist));
172 }
173 
174 static int ra288_decode_frame(AVCodecContext * avctx, void *data,
175  int *got_frame_ptr, AVPacket *avpkt)
176 {
177  AVFrame *frame = data;
178  const uint8_t *buf = avpkt->data;
179  int buf_size = avpkt->size;
180  float *out;
181  int i, ret;
182  RA288Context *ractx = avctx->priv_data;
183  GetBitContext gb;
184 
185  if (buf_size < avctx->block_align) {
186  av_log(avctx, AV_LOG_ERROR,
187  "Error! Input buffer is too small [%d<%d]\n",
188  buf_size, avctx->block_align);
189  return AVERROR_INVALIDDATA;
190  }
191 
192  /* get output buffer */
194  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
195  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
196  return ret;
197  }
198  out = (float *)frame->data[0];
199 
200  init_get_bits(&gb, buf, avctx->block_align * 8);
201 
202  for (i=0; i < RA288_BLOCKS_PER_FRAME; i++) {
203  float gain = amptable[get_bits(&gb, 3)];
204  int cb_coef = get_bits(&gb, 6 + (i&1));
205 
206  decode(ractx, gain, cb_coef);
207 
208  memcpy(out, &ractx->sp_hist[70 + 36], RA288_BLOCK_SIZE * sizeof(*out));
209  out += RA288_BLOCK_SIZE;
210 
211  if ((i & 7) == 3) {
212  backward_filter(ractx, ractx->sp_hist, ractx->sp_rec, syn_window,
213  ractx->sp_lpc, syn_bw_tab, 36, 40, 35, 70);
214 
215  backward_filter(ractx, ractx->gain_hist, ractx->gain_rec, gain_window,
216  ractx->gain_lpc, gain_bw_tab, 10, 8, 20, 28);
217  }
218  }
219 
220  *got_frame_ptr = 1;
221 
222  return avctx->block_align;
223 }
224 
226  .name = "real_288",
227  .long_name = NULL_IF_CONFIG_SMALL("RealAudio 2.0 (28.8K)"),
228  .type = AVMEDIA_TYPE_AUDIO,
229  .id = AV_CODEC_ID_RA_288,
230  .priv_data_size = sizeof(RA288Context),
233  .capabilities = CODEC_CAP_DR1,
234 };