atrac1.c
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1 /*
2  * Atrac 1 compatible decoder
3  * Copyright (c) 2009 Maxim Poliakovski
4  * Copyright (c) 2009 Benjamin Larsson
5  *
6  * This file is part of Libav.
7  *
8  * Libav is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * Libav is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with Libav; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
29 /* Many thanks to Tim Craig for all the help! */
30 
31 #include <math.h>
32 #include <stddef.h>
33 #include <stdio.h>
34 
35 #include "avcodec.h"
36 #include "get_bits.h"
37 #include "dsputil.h"
38 #include "fft.h"
39 #include "fmtconvert.h"
40 #include "sinewin.h"
41 
42 #include "atrac.h"
43 #include "atrac1data.h"
44 
45 #define AT1_MAX_BFU 52
46 #define AT1_SU_SIZE 212
47 #define AT1_SU_SAMPLES 512
48 #define AT1_FRAME_SIZE AT1_SU_SIZE * 2
49 #define AT1_SU_MAX_BITS AT1_SU_SIZE * 8
50 #define AT1_MAX_CHANNELS 2
51 
52 #define AT1_QMF_BANDS 3
53 #define IDX_LOW_BAND 0
54 #define IDX_MID_BAND 1
55 #define IDX_HIGH_BAND 2
56 
60 typedef struct {
61  int log2_block_count[AT1_QMF_BANDS];
62  int num_bfus;
63  float* spectrum[2];
64  DECLARE_ALIGNED(32, float, spec1)[AT1_SU_SAMPLES];
65  DECLARE_ALIGNED(32, float, spec2)[AT1_SU_SAMPLES];
66  DECLARE_ALIGNED(32, float, fst_qmf_delay)[46];
67  DECLARE_ALIGNED(32, float, snd_qmf_delay)[46];
68  DECLARE_ALIGNED(32, float, last_qmf_delay)[256+23];
69 } AT1SUCtx;
70 
74 typedef struct {
77  DECLARE_ALIGNED(32, float, spec)[AT1_SU_SAMPLES];
78 
79  DECLARE_ALIGNED(32, float, low)[256];
80  DECLARE_ALIGNED(32, float, mid)[256];
81  DECLARE_ALIGNED(32, float, high)[512];
82  float* bands[3];
83  float *out_samples[AT1_MAX_CHANNELS];
84  FFTContext mdct_ctx[3];
85  int channels;
88 } AT1Ctx;
89 
91 static const uint16_t samples_per_band[3] = {128, 128, 256};
92 static const uint8_t mdct_long_nbits[3] = {7, 7, 8};
93 
94 
95 static void at1_imdct(AT1Ctx *q, float *spec, float *out, int nbits,
96  int rev_spec)
97 {
98  FFTContext* mdct_context = &q->mdct_ctx[nbits - 5 - (nbits > 6)];
99  int transf_size = 1 << nbits;
100 
101  if (rev_spec) {
102  int i;
103  for (i = 0; i < transf_size / 2; i++)
104  FFSWAP(float, spec[i], spec[transf_size - 1 - i]);
105  }
106  mdct_context->imdct_half(mdct_context, out, spec);
107 }
108 
109 
110 static int at1_imdct_block(AT1SUCtx* su, AT1Ctx *q)
111 {
112  int band_num, band_samples, log2_block_count, nbits, num_blocks, block_size;
113  unsigned int start_pos, ref_pos = 0, pos = 0;
114 
115  for (band_num = 0; band_num < AT1_QMF_BANDS; band_num++) {
116  float *prev_buf;
117  int j;
118 
119  band_samples = samples_per_band[band_num];
120  log2_block_count = su->log2_block_count[band_num];
121 
122  /* number of mdct blocks in the current QMF band: 1 - for long mode */
123  /* 4 for short mode(low/middle bands) and 8 for short mode(high band)*/
124  num_blocks = 1 << log2_block_count;
125 
126  if (num_blocks == 1) {
127  /* mdct block size in samples: 128 (long mode, low & mid bands), */
128  /* 256 (long mode, high band) and 32 (short mode, all bands) */
129  block_size = band_samples >> log2_block_count;
130 
131  /* calc transform size in bits according to the block_size_mode */
132  nbits = mdct_long_nbits[band_num] - log2_block_count;
133 
134  if (nbits != 5 && nbits != 7 && nbits != 8)
135  return AVERROR_INVALIDDATA;
136  } else {
137  block_size = 32;
138  nbits = 5;
139  }
140 
141  start_pos = 0;
142  prev_buf = &su->spectrum[1][ref_pos + band_samples - 16];
143  for (j=0; j < num_blocks; j++) {
144  at1_imdct(q, &q->spec[pos], &su->spectrum[0][ref_pos + start_pos], nbits, band_num);
145 
146  /* overlap and window */
147  q->dsp.vector_fmul_window(&q->bands[band_num][start_pos], prev_buf,
148  &su->spectrum[0][ref_pos + start_pos], ff_sine_32, 16);
149 
150  prev_buf = &su->spectrum[0][ref_pos+start_pos + 16];
151  start_pos += block_size;
152  pos += block_size;
153  }
154 
155  if (num_blocks == 1)
156  memcpy(q->bands[band_num] + 32, &su->spectrum[0][ref_pos + 16], 240 * sizeof(float));
157 
158  ref_pos += band_samples;
159  }
160 
161  /* Swap buffers so the mdct overlap works */
162  FFSWAP(float*, su->spectrum[0], su->spectrum[1]);
163 
164  return 0;
165 }
166 
171 static int at1_parse_bsm(GetBitContext* gb, int log2_block_cnt[AT1_QMF_BANDS])
172 {
173  int log2_block_count_tmp, i;
174 
175  for (i = 0; i < 2; i++) {
176  /* low and mid band */
177  log2_block_count_tmp = get_bits(gb, 2);
178  if (log2_block_count_tmp & 1)
179  return AVERROR_INVALIDDATA;
180  log2_block_cnt[i] = 2 - log2_block_count_tmp;
181  }
182 
183  /* high band */
184  log2_block_count_tmp = get_bits(gb, 2);
185  if (log2_block_count_tmp != 0 && log2_block_count_tmp != 3)
186  return AVERROR_INVALIDDATA;
187  log2_block_cnt[IDX_HIGH_BAND] = 3 - log2_block_count_tmp;
188 
189  skip_bits(gb, 2);
190  return 0;
191 }
192 
193 
195  float spec[AT1_SU_SAMPLES])
196 {
197  int bits_used, band_num, bfu_num, i;
198  uint8_t idwls[AT1_MAX_BFU];
199  uint8_t idsfs[AT1_MAX_BFU];
200 
201  /* parse the info byte (2nd byte) telling how much BFUs were coded */
202  su->num_bfus = bfu_amount_tab1[get_bits(gb, 3)];
203 
204  /* calc number of consumed bits:
205  num_BFUs * (idwl(4bits) + idsf(6bits)) + log2_block_count(8bits) + info_byte(8bits)
206  + info_byte_copy(8bits) + log2_block_count_copy(8bits) */
207  bits_used = su->num_bfus * 10 + 32 +
208  bfu_amount_tab2[get_bits(gb, 2)] +
209  (bfu_amount_tab3[get_bits(gb, 3)] << 1);
210 
211  /* get word length index (idwl) for each BFU */
212  for (i = 0; i < su->num_bfus; i++)
213  idwls[i] = get_bits(gb, 4);
214 
215  /* get scalefactor index (idsf) for each BFU */
216  for (i = 0; i < su->num_bfus; i++)
217  idsfs[i] = get_bits(gb, 6);
218 
219  /* zero idwl/idsf for empty BFUs */
220  for (i = su->num_bfus; i < AT1_MAX_BFU; i++)
221  idwls[i] = idsfs[i] = 0;
222 
223  /* read in the spectral data and reconstruct MDCT spectrum of this channel */
224  for (band_num = 0; band_num < AT1_QMF_BANDS; band_num++) {
225  for (bfu_num = bfu_bands_t[band_num]; bfu_num < bfu_bands_t[band_num+1]; bfu_num++) {
226  int pos;
227 
228  int num_specs = specs_per_bfu[bfu_num];
229  int word_len = !!idwls[bfu_num] + idwls[bfu_num];
230  float scale_factor = ff_atrac_sf_table[idsfs[bfu_num]];
231  bits_used += word_len * num_specs; /* add number of bits consumed by current BFU */
232 
233  /* check for bitstream overflow */
234  if (bits_used > AT1_SU_MAX_BITS)
235  return AVERROR_INVALIDDATA;
236 
237  /* get the position of the 1st spec according to the block size mode */
238  pos = su->log2_block_count[band_num] ? bfu_start_short[bfu_num] : bfu_start_long[bfu_num];
239 
240  if (word_len) {
241  float max_quant = 1.0 / (float)((1 << (word_len - 1)) - 1);
242 
243  for (i = 0; i < num_specs; i++) {
244  /* read in a quantized spec and convert it to
245  * signed int and then inverse quantization
246  */
247  spec[pos+i] = get_sbits(gb, word_len) * scale_factor * max_quant;
248  }
249  } else { /* word_len = 0 -> empty BFU, zero all specs in the emty BFU */
250  memset(&spec[pos], 0, num_specs * sizeof(float));
251  }
252  }
253  }
254 
255  return 0;
256 }
257 
258 
259 static void at1_subband_synthesis(AT1Ctx *q, AT1SUCtx* su, float *pOut)
260 {
261  float temp[256];
262  float iqmf_temp[512 + 46];
263 
264  /* combine low and middle bands */
265  atrac_iqmf(q->bands[0], q->bands[1], 128, temp, su->fst_qmf_delay, iqmf_temp);
266 
267  /* delay the signal of the high band by 23 samples */
268  memcpy( su->last_qmf_delay, &su->last_qmf_delay[256], sizeof(float) * 23);
269  memcpy(&su->last_qmf_delay[23], q->bands[2], sizeof(float) * 256);
270 
271  /* combine (low + middle) and high bands */
272  atrac_iqmf(temp, su->last_qmf_delay, 256, pOut, su->snd_qmf_delay, iqmf_temp);
273 }
274 
275 
276 static int atrac1_decode_frame(AVCodecContext *avctx, void *data,
277  int *got_frame_ptr, AVPacket *avpkt)
278 {
279  const uint8_t *buf = avpkt->data;
280  int buf_size = avpkt->size;
281  AT1Ctx *q = avctx->priv_data;
282  int ch, ret;
283  GetBitContext gb;
284  float *samples;
285 
286 
287  if (buf_size < 212 * q->channels) {
288  av_log(avctx, AV_LOG_ERROR, "Not enough data to decode!\n");
289  return AVERROR_INVALIDDATA;
290  }
291 
292  /* get output buffer */
294  if ((ret = avctx->get_buffer(avctx, &q->frame)) < 0) {
295  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
296  return ret;
297  }
298  samples = (float *)q->frame.data[0];
299 
300  for (ch = 0; ch < q->channels; ch++) {
301  AT1SUCtx* su = &q->SUs[ch];
302 
303  init_get_bits(&gb, &buf[212 * ch], 212 * 8);
304 
305  /* parse block_size_mode, 1st byte */
306  ret = at1_parse_bsm(&gb, su->log2_block_count);
307  if (ret < 0)
308  return ret;
309 
310  ret = at1_unpack_dequant(&gb, su, q->spec);
311  if (ret < 0)
312  return ret;
313 
314  ret = at1_imdct_block(su, q);
315  if (ret < 0)
316  return ret;
317  at1_subband_synthesis(q, su, q->channels == 1 ? samples : q->out_samples[ch]);
318  }
319 
320  /* interleave */
321  if (q->channels == 2) {
322  q->fmt_conv.float_interleave(samples, (const float **)q->out_samples,
323  AT1_SU_SAMPLES, 2);
324  }
325 
326  *got_frame_ptr = 1;
327  *(AVFrame *)data = q->frame;
328 
329  return avctx->block_align;
330 }
331 
332 
334 {
335  AT1Ctx *q = avctx->priv_data;
336 
337  av_freep(&q->out_samples[0]);
338 
339  ff_mdct_end(&q->mdct_ctx[0]);
340  ff_mdct_end(&q->mdct_ctx[1]);
341  ff_mdct_end(&q->mdct_ctx[2]);
342 
343  return 0;
344 }
345 
346 
348 {
349  AT1Ctx *q = avctx->priv_data;
350  int ret;
351 
352  avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
353 
354  if (avctx->channels < 1 || avctx->channels > AT1_MAX_CHANNELS) {
355  av_log(avctx, AV_LOG_ERROR, "Unsupported number of channels: %d\n",
356  avctx->channels);
357  return AVERROR(EINVAL);
358  }
359  q->channels = avctx->channels;
360 
361  if (avctx->channels == 2) {
362  q->out_samples[0] = av_malloc(2 * AT1_SU_SAMPLES * sizeof(*q->out_samples[0]));
363  q->out_samples[1] = q->out_samples[0] + AT1_SU_SAMPLES;
364  if (!q->out_samples[0]) {
365  av_freep(&q->out_samples[0]);
366  return AVERROR(ENOMEM);
367  }
368  }
369 
370  /* Init the mdct transforms */
371  if ((ret = ff_mdct_init(&q->mdct_ctx[0], 6, 1, -1.0/ (1 << 15))) ||
372  (ret = ff_mdct_init(&q->mdct_ctx[1], 8, 1, -1.0/ (1 << 15))) ||
373  (ret = ff_mdct_init(&q->mdct_ctx[2], 9, 1, -1.0/ (1 << 15)))) {
374  av_log(avctx, AV_LOG_ERROR, "Error initializing MDCT\n");
375  atrac1_decode_end(avctx);
376  return ret;
377  }
378 
380 
382 
383  dsputil_init(&q->dsp, avctx);
384  ff_fmt_convert_init(&q->fmt_conv, avctx);
385 
386  q->bands[0] = q->low;
387  q->bands[1] = q->mid;
388  q->bands[2] = q->high;
389 
390  /* Prepare the mdct overlap buffers */
391  q->SUs[0].spectrum[0] = q->SUs[0].spec1;
392  q->SUs[0].spectrum[1] = q->SUs[0].spec2;
393  q->SUs[1].spectrum[0] = q->SUs[1].spec1;
394  q->SUs[1].spectrum[1] = q->SUs[1].spec2;
395 
397  avctx->coded_frame = &q->frame;
398 
399  return 0;
400 }
401 
402 
404  .name = "atrac1",
405  .type = AVMEDIA_TYPE_AUDIO,
406  .id = CODEC_ID_ATRAC1,
407  .priv_data_size = sizeof(AT1Ctx),
411  .capabilities = CODEC_CAP_DR1,
412  .long_name = NULL_IF_CONFIG_SMALL("Atrac 1 (Adaptive TRansform Acoustic Coding)"),
413 };