nellymoserdec.c
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1 /*
2  * NellyMoser audio decoder
3  * Copyright (c) 2007 a840bda5870ba11f19698ff6eb9581dfb0f95fa5,
4  * 539459aeb7d425140b62a3ec7dbf6dc8e408a306, and
5  * 520e17cd55896441042b14df2566a6eb610ed444
6  * Copyright (c) 2007 Loic Minier <lool at dooz.org>
7  * Benjamin Larsson
8  *
9  * Permission is hereby granted, free of charge, to any person obtaining a
10  * copy of this software and associated documentation files (the "Software"),
11  * to deal in the Software without restriction, including without limitation
12  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13  * and/or sell copies of the Software, and to permit persons to whom the
14  * Software is furnished to do so, subject to the following conditions:
15  *
16  * The above copyright notice and this permission notice shall be included in
17  * all copies or substantial portions of the Software.
18  *
19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
24  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
25  * DEALINGS IN THE SOFTWARE.
26  */
27 
35 #include "libavutil/float_dsp.h"
36 #include "libavutil/lfg.h"
37 #include "libavutil/random_seed.h"
38 #include "avcodec.h"
39 #include "dsputil.h"
40 #include "fft.h"
41 #include "fmtconvert.h"
42 #include "internal.h"
43 #include "nellymoser.h"
44 #include "sinewin.h"
45 
46 #define BITSTREAM_READER_LE
47 #include "get_bits.h"
48 
49 
50 typedef struct NellyMoserDecodeContext {
55  float scale_bias;
59  float *imdct_out;
60  float *imdct_prev;
62 
64  const unsigned char block[NELLY_BLOCK_LEN],
65  float audio[NELLY_SAMPLES])
66 {
67  int i,j;
68  float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN];
69  float *aptr, *bptr, *pptr, val, pval;
70  int bits[NELLY_BUF_LEN];
71  unsigned char v;
72 
73  init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
74 
75  bptr = buf;
76  pptr = pows;
77  val = ff_nelly_init_table[get_bits(&s->gb, 6)];
78  for (i=0 ; i<NELLY_BANDS ; i++) {
79  if (i > 0)
80  val += ff_nelly_delta_table[get_bits(&s->gb, 5)];
81  pval = -pow(2, val/2048) * s->scale_bias;
82  for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) {
83  *bptr++ = val;
84  *pptr++ = pval;
85  }
86 
87  }
88 
89  ff_nelly_get_sample_bits(buf, bits);
90 
91  for (i = 0; i < 2; i++) {
92  aptr = audio + i * NELLY_BUF_LEN;
93 
94  init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
96 
97  for (j = 0; j < NELLY_FILL_LEN; j++) {
98  if (bits[j] <= 0) {
99  aptr[j] = M_SQRT1_2*pows[j];
100  if (av_lfg_get(&s->random_state) & 1)
101  aptr[j] *= -1.0;
102  } else {
103  v = get_bits(&s->gb, bits[j]);
104  aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j];
105  }
106  }
107  memset(&aptr[NELLY_FILL_LEN], 0,
108  (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float));
109 
110  s->imdct_ctx.imdct_half(&s->imdct_ctx, s->imdct_out, aptr);
111  s->fdsp.vector_fmul_window(aptr, s->imdct_prev + NELLY_BUF_LEN / 2,
112  s->imdct_out, ff_sine_128,
113  NELLY_BUF_LEN / 2);
114  FFSWAP(float *, s->imdct_out, s->imdct_prev);
115  }
116 }
117 
118 static av_cold int decode_init(AVCodecContext * avctx) {
120 
121  s->avctx = avctx;
122  s->imdct_out = s->imdct_buf[0];
123  s->imdct_prev = s->imdct_buf[1];
124  av_lfg_init(&s->random_state, 0);
125  ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0);
126 
128 
129  s->scale_bias = 1.0/(32768*8);
130  avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
131 
132  /* Generate overlap window */
133  if (!ff_sine_128[127])
135 
136  avctx->channels = 1;
138 
140  avctx->coded_frame = &s->frame;
141 
142  return 0;
143 }
144 
145 static int decode_tag(AVCodecContext *avctx, void *data,
146  int *got_frame_ptr, AVPacket *avpkt)
147 {
148  const uint8_t *buf = avpkt->data;
149  int buf_size = avpkt->size;
151  int blocks, i, ret;
152  float *samples_flt;
153 
154  blocks = buf_size / NELLY_BLOCK_LEN;
155  if (blocks <= 0) {
156  av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
157  return AVERROR_INVALIDDATA;
158  }
159  if (buf_size % NELLY_BLOCK_LEN) {
160  av_log(avctx, AV_LOG_WARNING, "Leftover bytes: %d.\n",
161  buf_size % NELLY_BLOCK_LEN);
162  }
163  /* Normal numbers of blocks for sample rates:
164  * 8000 Hz - 1
165  * 11025 Hz - 2
166  * 16000 Hz - 3
167  * 22050 Hz - 4
168  * 44100 Hz - 8
169  */
170 
171  /* get output buffer */
172  s->frame.nb_samples = NELLY_SAMPLES * blocks;
173  if ((ret = ff_get_buffer(avctx, &s->frame)) < 0) {
174  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
175  return ret;
176  }
177  samples_flt = (float *)s->frame.data[0];
178 
179  for (i=0 ; i<blocks ; i++) {
180  nelly_decode_block(s, buf, samples_flt);
181  samples_flt += NELLY_SAMPLES;
182  buf += NELLY_BLOCK_LEN;
183  }
184 
185  *got_frame_ptr = 1;
186  *(AVFrame *)data = s->frame;
187 
188  return buf_size;
189 }
190 
191 static av_cold int decode_end(AVCodecContext * avctx) {
193 
194  ff_mdct_end(&s->imdct_ctx);
195 
196  return 0;
197 }
198 
200  .name = "nellymoser",
201  .type = AVMEDIA_TYPE_AUDIO,
203  .priv_data_size = sizeof(NellyMoserDecodeContext),
204  .init = decode_init,
205  .close = decode_end,
206  .decode = decode_tag,
207  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_PARAM_CHANGE,
208  .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),
209  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,
211 };