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 "internal.h"
37 #include "get_bits.h"
38 #include "dsputil.h"
39 #include "fft.h"
40 #include "fmtconvert.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  float *out_samples[AT1_MAX_CHANNELS];
85  FFTContext mdct_ctx[3];
86  int channels;
89 } AT1Ctx;
90 
92 static const uint16_t samples_per_band[3] = {128, 128, 256};
93 static const uint8_t mdct_long_nbits[3] = {7, 7, 8};
94 
95 
96 static void at1_imdct(AT1Ctx *q, float *spec, float *out, int nbits,
97  int rev_spec)
98 {
99  FFTContext* mdct_context = &q->mdct_ctx[nbits - 5 - (nbits > 6)];
100  int transf_size = 1 << nbits;
101 
102  if (rev_spec) {
103  int i;
104  for (i = 0; i < transf_size / 2; i++)
105  FFSWAP(float, spec[i], spec[transf_size - 1 - i]);
106  }
107  mdct_context->imdct_half(mdct_context, out, spec);
108 }
109 
110 
111 static int at1_imdct_block(AT1SUCtx* su, AT1Ctx *q)
112 {
113  int band_num, band_samples, log2_block_count, nbits, num_blocks, block_size;
114  unsigned int start_pos, ref_pos = 0, pos = 0;
115 
116  for (band_num = 0; band_num < AT1_QMF_BANDS; band_num++) {
117  float *prev_buf;
118  int j;
119 
120  band_samples = samples_per_band[band_num];
121  log2_block_count = su->log2_block_count[band_num];
122 
123  /* number of mdct blocks in the current QMF band: 1 - for long mode */
124  /* 4 for short mode(low/middle bands) and 8 for short mode(high band)*/
125  num_blocks = 1 << log2_block_count;
126 
127  if (num_blocks == 1) {
128  /* mdct block size in samples: 128 (long mode, low & mid bands), */
129  /* 256 (long mode, high band) and 32 (short mode, all bands) */
130  block_size = band_samples >> log2_block_count;
131 
132  /* calc transform size in bits according to the block_size_mode */
133  nbits = mdct_long_nbits[band_num] - log2_block_count;
134 
135  if (nbits != 5 && nbits != 7 && nbits != 8)
136  return AVERROR_INVALIDDATA;
137  } else {
138  block_size = 32;
139  nbits = 5;
140  }
141 
142  start_pos = 0;
143  prev_buf = &su->spectrum[1][ref_pos + band_samples - 16];
144  for (j=0; j < num_blocks; j++) {
145  at1_imdct(q, &q->spec[pos], &su->spectrum[0][ref_pos + start_pos], nbits, band_num);
146 
147  /* overlap and window */
148  q->dsp.vector_fmul_window(&q->bands[band_num][start_pos], prev_buf,
149  &su->spectrum[0][ref_pos + start_pos], ff_sine_32, 16);
150 
151  prev_buf = &su->spectrum[0][ref_pos+start_pos + 16];
152  start_pos += block_size;
153  pos += block_size;
154  }
155 
156  if (num_blocks == 1)
157  memcpy(q->bands[band_num] + 32, &su->spectrum[0][ref_pos + 16], 240 * sizeof(float));
158 
159  ref_pos += band_samples;
160  }
161 
162  /* Swap buffers so the mdct overlap works */
163  FFSWAP(float*, su->spectrum[0], su->spectrum[1]);
164 
165  return 0;
166 }
167 
172 static int at1_parse_bsm(GetBitContext* gb, int log2_block_cnt[AT1_QMF_BANDS])
173 {
174  int log2_block_count_tmp, i;
175 
176  for (i = 0; i < 2; i++) {
177  /* low and mid band */
178  log2_block_count_tmp = get_bits(gb, 2);
179  if (log2_block_count_tmp & 1)
180  return AVERROR_INVALIDDATA;
181  log2_block_cnt[i] = 2 - log2_block_count_tmp;
182  }
183 
184  /* high band */
185  log2_block_count_tmp = get_bits(gb, 2);
186  if (log2_block_count_tmp != 0 && log2_block_count_tmp != 3)
187  return AVERROR_INVALIDDATA;
188  log2_block_cnt[IDX_HIGH_BAND] = 3 - log2_block_count_tmp;
189 
190  skip_bits(gb, 2);
191  return 0;
192 }
193 
194 
196  float spec[AT1_SU_SAMPLES])
197 {
198  int bits_used, band_num, bfu_num, i;
199  uint8_t idwls[AT1_MAX_BFU];
200  uint8_t idsfs[AT1_MAX_BFU];
201 
202  /* parse the info byte (2nd byte) telling how much BFUs were coded */
203  su->num_bfus = bfu_amount_tab1[get_bits(gb, 3)];
204 
205  /* calc number of consumed bits:
206  num_BFUs * (idwl(4bits) + idsf(6bits)) + log2_block_count(8bits) + info_byte(8bits)
207  + info_byte_copy(8bits) + log2_block_count_copy(8bits) */
208  bits_used = su->num_bfus * 10 + 32 +
209  bfu_amount_tab2[get_bits(gb, 2)] +
210  (bfu_amount_tab3[get_bits(gb, 3)] << 1);
211 
212  /* get word length index (idwl) for each BFU */
213  for (i = 0; i < su->num_bfus; i++)
214  idwls[i] = get_bits(gb, 4);
215 
216  /* get scalefactor index (idsf) for each BFU */
217  for (i = 0; i < su->num_bfus; i++)
218  idsfs[i] = get_bits(gb, 6);
219 
220  /* zero idwl/idsf for empty BFUs */
221  for (i = su->num_bfus; i < AT1_MAX_BFU; i++)
222  idwls[i] = idsfs[i] = 0;
223 
224  /* read in the spectral data and reconstruct MDCT spectrum of this channel */
225  for (band_num = 0; band_num < AT1_QMF_BANDS; band_num++) {
226  for (bfu_num = bfu_bands_t[band_num]; bfu_num < bfu_bands_t[band_num+1]; bfu_num++) {
227  int pos;
228 
229  int num_specs = specs_per_bfu[bfu_num];
230  int word_len = !!idwls[bfu_num] + idwls[bfu_num];
231  float scale_factor = ff_atrac_sf_table[idsfs[bfu_num]];
232  bits_used += word_len * num_specs; /* add number of bits consumed by current BFU */
233 
234  /* check for bitstream overflow */
235  if (bits_used > AT1_SU_MAX_BITS)
236  return AVERROR_INVALIDDATA;
237 
238  /* get the position of the 1st spec according to the block size mode */
239  pos = su->log2_block_count[band_num] ? bfu_start_short[bfu_num] : bfu_start_long[bfu_num];
240 
241  if (word_len) {
242  float max_quant = 1.0 / (float)((1 << (word_len - 1)) - 1);
243 
244  for (i = 0; i < num_specs; i++) {
245  /* read in a quantized spec and convert it to
246  * signed int and then inverse quantization
247  */
248  spec[pos+i] = get_sbits(gb, word_len) * scale_factor * max_quant;
249  }
250  } else { /* word_len = 0 -> empty BFU, zero all specs in the emty BFU */
251  memset(&spec[pos], 0, num_specs * sizeof(float));
252  }
253  }
254  }
255 
256  return 0;
257 }
258 
259 
260 static void at1_subband_synthesis(AT1Ctx *q, AT1SUCtx* su, float *pOut)
261 {
262  float temp[256];
263  float iqmf_temp[512 + 46];
264 
265  /* combine low and middle bands */
266  atrac_iqmf(q->bands[0], q->bands[1], 128, temp, su->fst_qmf_delay, iqmf_temp);
267 
268  /* delay the signal of the high band by 23 samples */
269  memcpy( su->last_qmf_delay, &su->last_qmf_delay[256], sizeof(float) * 23);
270  memcpy(&su->last_qmf_delay[23], q->bands[2], sizeof(float) * 256);
271 
272  /* combine (low + middle) and high bands */
273  atrac_iqmf(temp, su->last_qmf_delay, 256, pOut, su->snd_qmf_delay, iqmf_temp);
274 }
275 
276 
277 static int atrac1_decode_frame(AVCodecContext *avctx, void *data,
278  int *got_frame_ptr, AVPacket *avpkt)
279 {
280  const uint8_t *buf = avpkt->data;
281  int buf_size = avpkt->size;
282  AT1Ctx *q = avctx->priv_data;
283  int ch, ret;
284  GetBitContext gb;
285  float *samples;
286 
287 
288  if (buf_size < 212 * q->channels) {
289  av_log(avctx, AV_LOG_ERROR, "Not enough data to decode!\n");
290  return AVERROR_INVALIDDATA;
291  }
292 
293  /* get output buffer */
295  if ((ret = ff_get_buffer(avctx, &q->frame)) < 0) {
296  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
297  return ret;
298  }
299  samples = (float *)q->frame.data[0];
300 
301  for (ch = 0; ch < q->channels; ch++) {
302  AT1SUCtx* su = &q->SUs[ch];
303 
304  init_get_bits(&gb, &buf[212 * ch], 212 * 8);
305 
306  /* parse block_size_mode, 1st byte */
307  ret = at1_parse_bsm(&gb, su->log2_block_count);
308  if (ret < 0)
309  return ret;
310 
311  ret = at1_unpack_dequant(&gb, su, q->spec);
312  if (ret < 0)
313  return ret;
314 
315  ret = at1_imdct_block(su, q);
316  if (ret < 0)
317  return ret;
318  at1_subband_synthesis(q, su, q->channels == 1 ? samples : q->out_samples[ch]);
319  }
320 
321  /* interleave */
322  if (q->channels == 2) {
323  q->fmt_conv.float_interleave(samples, (const float **)q->out_samples,
324  AT1_SU_SAMPLES, 2);
325  }
326 
327  *got_frame_ptr = 1;
328  *(AVFrame *)data = q->frame;
329 
330  return avctx->block_align;
331 }
332 
333 
335 {
336  AT1Ctx *q = avctx->priv_data;
337 
338  av_freep(&q->out_samples[0]);
339 
340  ff_mdct_end(&q->mdct_ctx[0]);
341  ff_mdct_end(&q->mdct_ctx[1]);
342  ff_mdct_end(&q->mdct_ctx[2]);
343 
344  return 0;
345 }
346 
347 
349 {
350  AT1Ctx *q = avctx->priv_data;
351  int ret;
352 
353  avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
354 
355  if (avctx->channels < 1 || avctx->channels > AT1_MAX_CHANNELS) {
356  av_log(avctx, AV_LOG_ERROR, "Unsupported number of channels: %d\n",
357  avctx->channels);
358  return AVERROR(EINVAL);
359  }
360  q->channels = avctx->channels;
361 
362  if (avctx->channels == 2) {
363  q->out_samples[0] = av_malloc(2 * AT1_SU_SAMPLES * sizeof(*q->out_samples[0]));
364  q->out_samples[1] = q->out_samples[0] + AT1_SU_SAMPLES;
365  if (!q->out_samples[0]) {
366  av_freep(&q->out_samples[0]);
367  return AVERROR(ENOMEM);
368  }
369  }
370 
371  /* Init the mdct transforms */
372  if ((ret = ff_mdct_init(&q->mdct_ctx[0], 6, 1, -1.0/ (1 << 15))) ||
373  (ret = ff_mdct_init(&q->mdct_ctx[1], 8, 1, -1.0/ (1 << 15))) ||
374  (ret = ff_mdct_init(&q->mdct_ctx[2], 9, 1, -1.0/ (1 << 15)))) {
375  av_log(avctx, AV_LOG_ERROR, "Error initializing MDCT\n");
376  atrac1_decode_end(avctx);
377  return ret;
378  }
379 
381 
383 
384  dsputil_init(&q->dsp, avctx);
385  ff_fmt_convert_init(&q->fmt_conv, avctx);
386 
387  q->bands[0] = q->low;
388  q->bands[1] = q->mid;
389  q->bands[2] = q->high;
390 
391  /* Prepare the mdct overlap buffers */
392  q->SUs[0].spectrum[0] = q->SUs[0].spec1;
393  q->SUs[0].spectrum[1] = q->SUs[0].spec2;
394  q->SUs[1].spectrum[0] = q->SUs[1].spec1;
395  q->SUs[1].spectrum[1] = q->SUs[1].spec2;
396 
398  avctx->coded_frame = &q->frame;
399 
400  return 0;
401 }
402 
403 
405  .name = "atrac1",
406  .type = AVMEDIA_TYPE_AUDIO,
407  .id = CODEC_ID_ATRAC1,
408  .priv_data_size = sizeof(AT1Ctx),
412  .capabilities = CODEC_CAP_DR1,
413  .long_name = NULL_IF_CONFIG_SMALL("Atrac 1 (Adaptive TRansform Acoustic Coding)"),
414 };