nellymoserdec.c
Go to the documentation of this file.
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 
34 #include "nellymoser.h"
35 #include "libavutil/lfg.h"
36 #include "libavutil/random_seed.h"
37 #include "libavutil/audioconvert.h"
38 #include "avcodec.h"
39 #include "dsputil.h"
40 #include "fft.h"
41 #include "fmtconvert.h"
42 #include "sinewin.h"
43 
44 #define BITSTREAM_READER_LE
45 #include "get_bits.h"
46 
47 
48 typedef struct NellyMoserDecodeContext {
51  float *float_buf;
55  float scale_bias;
61 
63  const unsigned char block[NELLY_BLOCK_LEN],
64  float audio[NELLY_SAMPLES])
65 {
66  int i,j;
67  float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN];
68  float *aptr, *bptr, *pptr, val, pval;
69  int bits[NELLY_BUF_LEN];
70  unsigned char v;
71 
72  init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
73 
74  bptr = buf;
75  pptr = pows;
76  val = ff_nelly_init_table[get_bits(&s->gb, 6)];
77  for (i=0 ; i<NELLY_BANDS ; i++) {
78  if (i > 0)
79  val += ff_nelly_delta_table[get_bits(&s->gb, 5)];
80  pval = -pow(2, val/2048) * s->scale_bias;
81  for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) {
82  *bptr++ = val;
83  *pptr++ = pval;
84  }
85 
86  }
87 
88  ff_nelly_get_sample_bits(buf, bits);
89 
90  for (i = 0; i < 2; i++) {
91  aptr = audio + i * NELLY_BUF_LEN;
92 
93  init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
95 
96  for (j = 0; j < NELLY_FILL_LEN; j++) {
97  if (bits[j] <= 0) {
98  aptr[j] = M_SQRT1_2*pows[j];
99  if (av_lfg_get(&s->random_state) & 1)
100  aptr[j] *= -1.0;
101  } else {
102  v = get_bits(&s->gb, bits[j]);
103  aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j];
104  }
105  }
106  memset(&aptr[NELLY_FILL_LEN], 0,
107  (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float));
108 
109  s->imdct_ctx.imdct_calc(&s->imdct_ctx, s->imdct_out, aptr);
110  /* XXX: overlapping and windowing should be part of a more
111  generic imdct function */
112  s->dsp.vector_fmul_reverse(s->state, s->state, ff_sine_128, NELLY_BUF_LEN);
113  s->dsp.vector_fmul_add(aptr, s->imdct_out, ff_sine_128, s->state, NELLY_BUF_LEN);
114  memcpy(s->state, s->imdct_out + NELLY_BUF_LEN, sizeof(float)*NELLY_BUF_LEN);
115  }
116 }
117 
118 static av_cold int decode_init(AVCodecContext * avctx) {
120 
121  s->avctx = avctx;
122  av_lfg_init(&s->random_state, 0);
123  ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0);
124 
125  dsputil_init(&s->dsp, avctx);
126 
127  if (avctx->request_sample_fmt == AV_SAMPLE_FMT_FLT) {
128  s->scale_bias = 1.0/(32768*8);
129  avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
130  } else {
131  s->scale_bias = 1.0/(1*8);
132  avctx->sample_fmt = AV_SAMPLE_FMT_S16;
133  ff_fmt_convert_init(&s->fmt_conv, avctx);
134  s->float_buf = av_mallocz(NELLY_SAMPLES * sizeof(*s->float_buf));
135  if (!s->float_buf) {
136  av_log(avctx, AV_LOG_ERROR, "error allocating float buffer\n");
137  return AVERROR(ENOMEM);
138  }
139  }
140 
141  /* Generate overlap window */
142  if (!ff_sine_128[127])
144 
146 
148  avctx->coded_frame = &s->frame;
149 
150  return 0;
151 }
152 
153 static int decode_tag(AVCodecContext *avctx, void *data,
154  int *got_frame_ptr, AVPacket *avpkt)
155 {
156  const uint8_t *buf = avpkt->data;
157  int buf_size = avpkt->size;
159  int blocks, i, ret;
160  int16_t *samples_s16;
161  float *samples_flt;
162 
163  blocks = buf_size / NELLY_BLOCK_LEN;
164  if (blocks <= 0) {
165  av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
166  return AVERROR_INVALIDDATA;
167  }
168  if (buf_size % NELLY_BLOCK_LEN) {
169  av_log(avctx, AV_LOG_WARNING, "Leftover bytes: %d.\n",
170  buf_size % NELLY_BLOCK_LEN);
171  }
172  /* Normal numbers of blocks for sample rates:
173  * 8000 Hz - 1
174  * 11025 Hz - 2
175  * 16000 Hz - 3
176  * 22050 Hz - 4
177  * 44100 Hz - 8
178  */
179 
180  /* get output buffer */
181  s->frame.nb_samples = NELLY_SAMPLES * blocks;
182  if ((ret = avctx->get_buffer(avctx, &s->frame)) < 0) {
183  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
184  return ret;
185  }
186  samples_s16 = (int16_t *)s->frame.data[0];
187  samples_flt = (float *)s->frame.data[0];
188 
189  for (i=0 ; i<blocks ; i++) {
190  if (avctx->sample_fmt == AV_SAMPLE_FMT_FLT) {
191  nelly_decode_block(s, buf, samples_flt);
192  samples_flt += NELLY_SAMPLES;
193  } else {
194  nelly_decode_block(s, buf, s->float_buf);
195  s->fmt_conv.float_to_int16(samples_s16, s->float_buf, NELLY_SAMPLES);
196  samples_s16 += NELLY_SAMPLES;
197  }
198  buf += NELLY_BLOCK_LEN;
199  }
200 
201  *got_frame_ptr = 1;
202  *(AVFrame *)data = s->frame;
203 
204  return buf_size;
205 }
206 
207 static av_cold int decode_end(AVCodecContext * avctx) {
209 
210  av_freep(&s->float_buf);
211  ff_mdct_end(&s->imdct_ctx);
212 
213  return 0;
214 }
215 
217  .name = "nellymoser",
218  .type = AVMEDIA_TYPE_AUDIO,
219  .id = CODEC_ID_NELLYMOSER,
220  .priv_data_size = sizeof(NellyMoserDecodeContext),
221  .init = decode_init,
222  .close = decode_end,
223  .decode = decode_tag,
224  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_PARAM_CHANGE,
225  .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),
226  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,
229 };
230