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 "libavutil/float_dsp.h"
36 #include "avcodec.h"
37 #include "get_bits.h"
38 #include "dsputil.h"
39 #include "fft.h"
40 #include "internal.h"
41 #include "sinewin.h"
42 
43 #include "atrac.h"
44 #include "atrac1data.h"
45 
46 #define AT1_MAX_BFU 52
47 #define AT1_SU_SIZE 212
48 #define AT1_SU_SAMPLES 512
49 #define AT1_FRAME_SIZE AT1_SU_SIZE * 2
50 #define AT1_SU_MAX_BITS AT1_SU_SIZE * 8
51 #define AT1_MAX_CHANNELS 2
52 
53 #define AT1_QMF_BANDS 3
54 #define IDX_LOW_BAND 0
55 #define IDX_MID_BAND 1
56 #define IDX_HIGH_BAND 2
57 
61 typedef struct {
62  int log2_block_count[AT1_QMF_BANDS];
63  int num_bfus;
64  float* spectrum[2];
65  DECLARE_ALIGNED(32, float, spec1)[AT1_SU_SAMPLES];
66  DECLARE_ALIGNED(32, float, spec2)[AT1_SU_SAMPLES];
67  DECLARE_ALIGNED(32, float, fst_qmf_delay)[46];
68  DECLARE_ALIGNED(32, float, snd_qmf_delay)[46];
69  DECLARE_ALIGNED(32, float, last_qmf_delay)[256+23];
70 } AT1SUCtx;
71 
75 typedef struct {
78  DECLARE_ALIGNED(32, float, spec)[AT1_SU_SAMPLES];
79 
80  DECLARE_ALIGNED(32, float, low)[256];
81  DECLARE_ALIGNED(32, float, mid)[256];
82  DECLARE_ALIGNED(32, float, high)[512];
83  float* bands[3];
84  FFTContext mdct_ctx[3];
86 } AT1Ctx;
87 
89 static const uint16_t samples_per_band[3] = {128, 128, 256};
90 static const uint8_t mdct_long_nbits[3] = {7, 7, 8};
91 
92 
93 static void at1_imdct(AT1Ctx *q, float *spec, float *out, int nbits,
94  int rev_spec)
95 {
96  FFTContext* mdct_context = &q->mdct_ctx[nbits - 5 - (nbits > 6)];
97  int transf_size = 1 << nbits;
98 
99  if (rev_spec) {
100  int i;
101  for (i = 0; i < transf_size / 2; i++)
102  FFSWAP(float, spec[i], spec[transf_size - 1 - i]);
103  }
104  mdct_context->imdct_half(mdct_context, out, spec);
105 }
106 
107 
108 static int at1_imdct_block(AT1SUCtx* su, AT1Ctx *q)
109 {
110  int band_num, band_samples, log2_block_count, nbits, num_blocks, block_size;
111  unsigned int start_pos, ref_pos = 0, pos = 0;
112 
113  for (band_num = 0; band_num < AT1_QMF_BANDS; band_num++) {
114  float *prev_buf;
115  int j;
116 
117  band_samples = samples_per_band[band_num];
118  log2_block_count = su->log2_block_count[band_num];
119 
120  /* number of mdct blocks in the current QMF band: 1 - for long mode */
121  /* 4 for short mode(low/middle bands) and 8 for short mode(high band)*/
122  num_blocks = 1 << log2_block_count;
123 
124  if (num_blocks == 1) {
125  /* mdct block size in samples: 128 (long mode, low & mid bands), */
126  /* 256 (long mode, high band) and 32 (short mode, all bands) */
127  block_size = band_samples >> log2_block_count;
128 
129  /* calc transform size in bits according to the block_size_mode */
130  nbits = mdct_long_nbits[band_num] - log2_block_count;
131 
132  if (nbits != 5 && nbits != 7 && nbits != 8)
133  return AVERROR_INVALIDDATA;
134  } else {
135  block_size = 32;
136  nbits = 5;
137  }
138 
139  start_pos = 0;
140  prev_buf = &su->spectrum[1][ref_pos + band_samples - 16];
141  for (j=0; j < num_blocks; j++) {
142  at1_imdct(q, &q->spec[pos], &su->spectrum[0][ref_pos + start_pos], nbits, band_num);
143 
144  /* overlap and window */
145  q->fdsp.vector_fmul_window(&q->bands[band_num][start_pos], prev_buf,
146  &su->spectrum[0][ref_pos + start_pos], ff_sine_32, 16);
147 
148  prev_buf = &su->spectrum[0][ref_pos+start_pos + 16];
149  start_pos += block_size;
150  pos += block_size;
151  }
152 
153  if (num_blocks == 1)
154  memcpy(q->bands[band_num] + 32, &su->spectrum[0][ref_pos + 16], 240 * sizeof(float));
155 
156  ref_pos += band_samples;
157  }
158 
159  /* Swap buffers so the mdct overlap works */
160  FFSWAP(float*, su->spectrum[0], su->spectrum[1]);
161 
162  return 0;
163 }
164 
169 static int at1_parse_bsm(GetBitContext* gb, int log2_block_cnt[AT1_QMF_BANDS])
170 {
171  int log2_block_count_tmp, i;
172 
173  for (i = 0; i < 2; i++) {
174  /* low and mid band */
175  log2_block_count_tmp = get_bits(gb, 2);
176  if (log2_block_count_tmp & 1)
177  return AVERROR_INVALIDDATA;
178  log2_block_cnt[i] = 2 - log2_block_count_tmp;
179  }
180 
181  /* high band */
182  log2_block_count_tmp = get_bits(gb, 2);
183  if (log2_block_count_tmp != 0 && log2_block_count_tmp != 3)
184  return AVERROR_INVALIDDATA;
185  log2_block_cnt[IDX_HIGH_BAND] = 3 - log2_block_count_tmp;
186 
187  skip_bits(gb, 2);
188  return 0;
189 }
190 
191 
193  float spec[AT1_SU_SAMPLES])
194 {
195  int bits_used, band_num, bfu_num, i;
196  uint8_t idwls[AT1_MAX_BFU];
197  uint8_t idsfs[AT1_MAX_BFU];
198 
199  /* parse the info byte (2nd byte) telling how much BFUs were coded */
200  su->num_bfus = bfu_amount_tab1[get_bits(gb, 3)];
201 
202  /* calc number of consumed bits:
203  num_BFUs * (idwl(4bits) + idsf(6bits)) + log2_block_count(8bits) + info_byte(8bits)
204  + info_byte_copy(8bits) + log2_block_count_copy(8bits) */
205  bits_used = su->num_bfus * 10 + 32 +
206  bfu_amount_tab2[get_bits(gb, 2)] +
207  (bfu_amount_tab3[get_bits(gb, 3)] << 1);
208 
209  /* get word length index (idwl) for each BFU */
210  for (i = 0; i < su->num_bfus; i++)
211  idwls[i] = get_bits(gb, 4);
212 
213  /* get scalefactor index (idsf) for each BFU */
214  for (i = 0; i < su->num_bfus; i++)
215  idsfs[i] = get_bits(gb, 6);
216 
217  /* zero idwl/idsf for empty BFUs */
218  for (i = su->num_bfus; i < AT1_MAX_BFU; i++)
219  idwls[i] = idsfs[i] = 0;
220 
221  /* read in the spectral data and reconstruct MDCT spectrum of this channel */
222  for (band_num = 0; band_num < AT1_QMF_BANDS; band_num++) {
223  for (bfu_num = bfu_bands_t[band_num]; bfu_num < bfu_bands_t[band_num+1]; bfu_num++) {
224  int pos;
225 
226  int num_specs = specs_per_bfu[bfu_num];
227  int word_len = !!idwls[bfu_num] + idwls[bfu_num];
228  float scale_factor = ff_atrac_sf_table[idsfs[bfu_num]];
229  bits_used += word_len * num_specs; /* add number of bits consumed by current BFU */
230 
231  /* check for bitstream overflow */
232  if (bits_used > AT1_SU_MAX_BITS)
233  return AVERROR_INVALIDDATA;
234 
235  /* get the position of the 1st spec according to the block size mode */
236  pos = su->log2_block_count[band_num] ? bfu_start_short[bfu_num] : bfu_start_long[bfu_num];
237 
238  if (word_len) {
239  float max_quant = 1.0 / (float)((1 << (word_len - 1)) - 1);
240 
241  for (i = 0; i < num_specs; i++) {
242  /* read in a quantized spec and convert it to
243  * signed int and then inverse quantization
244  */
245  spec[pos+i] = get_sbits(gb, word_len) * scale_factor * max_quant;
246  }
247  } else { /* word_len = 0 -> empty BFU, zero all specs in the emty BFU */
248  memset(&spec[pos], 0, num_specs * sizeof(float));
249  }
250  }
251  }
252 
253  return 0;
254 }
255 
256 
257 static void at1_subband_synthesis(AT1Ctx *q, AT1SUCtx* su, float *pOut)
258 {
259  float temp[256];
260  float iqmf_temp[512 + 46];
261 
262  /* combine low and middle bands */
263  ff_atrac_iqmf(q->bands[0], q->bands[1], 128, temp, su->fst_qmf_delay, iqmf_temp);
264 
265  /* delay the signal of the high band by 23 samples */
266  memcpy( su->last_qmf_delay, &su->last_qmf_delay[256], sizeof(float) * 23);
267  memcpy(&su->last_qmf_delay[23], q->bands[2], sizeof(float) * 256);
268 
269  /* combine (low + middle) and high bands */
270  ff_atrac_iqmf(temp, su->last_qmf_delay, 256, pOut, su->snd_qmf_delay, iqmf_temp);
271 }
272 
273 
274 static int atrac1_decode_frame(AVCodecContext *avctx, void *data,
275  int *got_frame_ptr, AVPacket *avpkt)
276 {
277  const uint8_t *buf = avpkt->data;
278  int buf_size = avpkt->size;
279  AT1Ctx *q = avctx->priv_data;
280  int ch, ret;
281  GetBitContext gb;
282 
283 
284  if (buf_size < 212 * avctx->channels) {
285  av_log(avctx, AV_LOG_ERROR, "Not enough data to decode!\n");
286  return AVERROR_INVALIDDATA;
287  }
288 
289  /* get output buffer */
291  if ((ret = ff_get_buffer(avctx, &q->frame)) < 0) {
292  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
293  return ret;
294  }
295 
296  for (ch = 0; ch < avctx->channels; ch++) {
297  AT1SUCtx* su = &q->SUs[ch];
298 
299  init_get_bits(&gb, &buf[212 * ch], 212 * 8);
300 
301  /* parse block_size_mode, 1st byte */
302  ret = at1_parse_bsm(&gb, su->log2_block_count);
303  if (ret < 0)
304  return ret;
305 
306  ret = at1_unpack_dequant(&gb, su, q->spec);
307  if (ret < 0)
308  return ret;
309 
310  ret = at1_imdct_block(su, q);
311  if (ret < 0)
312  return ret;
313  at1_subband_synthesis(q, su, (float *)q->frame.extended_data[ch]);
314  }
315 
316  *got_frame_ptr = 1;
317  *(AVFrame *)data = q->frame;
318 
319  return avctx->block_align;
320 }
321 
322 
324 {
325  AT1Ctx *q = avctx->priv_data;
326 
327  ff_mdct_end(&q->mdct_ctx[0]);
328  ff_mdct_end(&q->mdct_ctx[1]);
329  ff_mdct_end(&q->mdct_ctx[2]);
330 
331  return 0;
332 }
333 
334 
336 {
337  AT1Ctx *q = avctx->priv_data;
338  int ret;
339 
341 
342  if (avctx->channels < 1 || avctx->channels > AT1_MAX_CHANNELS) {
343  av_log(avctx, AV_LOG_ERROR, "Unsupported number of channels: %d\n",
344  avctx->channels);
345  return AVERROR(EINVAL);
346  }
347 
348  /* Init the mdct transforms */
349  if ((ret = ff_mdct_init(&q->mdct_ctx[0], 6, 1, -1.0/ (1 << 15))) ||
350  (ret = ff_mdct_init(&q->mdct_ctx[1], 8, 1, -1.0/ (1 << 15))) ||
351  (ret = ff_mdct_init(&q->mdct_ctx[2], 9, 1, -1.0/ (1 << 15)))) {
352  av_log(avctx, AV_LOG_ERROR, "Error initializing MDCT\n");
353  atrac1_decode_end(avctx);
354  return ret;
355  }
356 
358 
360 
362 
363  q->bands[0] = q->low;
364  q->bands[1] = q->mid;
365  q->bands[2] = q->high;
366 
367  /* Prepare the mdct overlap buffers */
368  q->SUs[0].spectrum[0] = q->SUs[0].spec1;
369  q->SUs[0].spectrum[1] = q->SUs[0].spec2;
370  q->SUs[1].spectrum[0] = q->SUs[1].spec1;
371  q->SUs[1].spectrum[1] = q->SUs[1].spec2;
372 
374  avctx->coded_frame = &q->frame;
375 
376  return 0;
377 }
378 
379 
381  .name = "atrac1",
382  .type = AVMEDIA_TYPE_AUDIO,
383  .id = AV_CODEC_ID_ATRAC1,
384  .priv_data_size = sizeof(AT1Ctx),
388  .capabilities = CODEC_CAP_DR1,
389  .long_name = NULL_IF_CONFIG_SMALL("Atrac 1 (Adaptive TRansform Acoustic Coding)"),
390  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
392 };