FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
mpc7.c
Go to the documentation of this file.
1 /*
2  * Musepack SV7 decoder
3  * Copyright (c) 2006 Konstantin Shishkov
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * MPEG Audio Layer 1/2 -like codec with frames of 1152 samples
25  * divided into 32 subbands.
26  */
27 
28 #include "libavutil/channel_layout.h"
29 #include "libavutil/internal.h"
30 #include "libavutil/lfg.h"
31 #include "avcodec.h"
32 #include "get_bits.h"
33 #include "internal.h"
34 #include "mpegaudiodsp.h"
35 
36 #include "mpc.h"
37 #include "mpc7data.h"
38 
39 static VLC scfi_vlc, dscf_vlc, hdr_vlc, quant_vlc[MPC7_QUANT_VLC_TABLES][2];
40 
41 static const uint16_t quant_offsets[MPC7_QUANT_VLC_TABLES*2 + 1] =
42 {
43  0, 512, 1024, 1536, 2052, 2564, 3076, 3588, 4100, 4612, 5124,
44  5636, 6164, 6676, 7224
45 };
46 
47 
48 static av_cold int mpc7_decode_init(AVCodecContext * avctx)
49 {
50  int i, j;
51  MPCContext *c = avctx->priv_data;
52  GetBitContext gb;
53  LOCAL_ALIGNED_16(uint8_t, buf, [16]);
54  static int vlc_initialized = 0;
55 
56  static VLC_TYPE scfi_table[1 << MPC7_SCFI_BITS][2];
57  static VLC_TYPE dscf_table[1 << MPC7_DSCF_BITS][2];
58  static VLC_TYPE hdr_table[1 << MPC7_HDR_BITS][2];
59  static VLC_TYPE quant_tables[7224][2];
60 
61  /* Musepack SV7 is always stereo */
62  if (avctx->channels != 2) {
63  avpriv_request_sample(avctx, "%d channels", avctx->channels);
64  return AVERROR_PATCHWELCOME;
65  }
66 
67  if(avctx->extradata_size < 16){
68  av_log(avctx, AV_LOG_ERROR, "Too small extradata size (%i)!\n", avctx->extradata_size);
69  return -1;
70  }
71  memset(c->oldDSCF, 0, sizeof(c->oldDSCF));
72  av_lfg_init(&c->rnd, 0xDEADBEEF);
73  ff_bswapdsp_init(&c->bdsp);
74  ff_mpadsp_init(&c->mpadsp);
75  c->bdsp.bswap_buf((uint32_t *) buf, (const uint32_t *) avctx->extradata, 4);
76  ff_mpc_init();
77  init_get_bits(&gb, buf, 128);
78 
79  c->IS = get_bits1(&gb);
80  c->MSS = get_bits1(&gb);
81  c->maxbands = get_bits(&gb, 6);
82  if(c->maxbands >= BANDS){
83  av_log(avctx, AV_LOG_ERROR, "Too many bands: %i\n", c->maxbands);
84  return -1;
85  }
86  skip_bits_long(&gb, 88);
87  c->gapless = get_bits1(&gb);
88  c->lastframelen = get_bits(&gb, 11);
89  av_log(avctx, AV_LOG_DEBUG, "IS: %d, MSS: %d, TG: %d, LFL: %d, bands: %d\n",
90  c->IS, c->MSS, c->gapless, c->lastframelen, c->maxbands);
91  c->frames_to_skip = 0;
92 
93  avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
94  avctx->channel_layout = AV_CH_LAYOUT_STEREO;
95 
96  if(vlc_initialized) return 0;
97  av_log(avctx, AV_LOG_DEBUG, "Initing VLC\n");
98  scfi_vlc.table = scfi_table;
99  scfi_vlc.table_allocated = 1 << MPC7_SCFI_BITS;
100  if(init_vlc(&scfi_vlc, MPC7_SCFI_BITS, MPC7_SCFI_SIZE,
101  &mpc7_scfi[1], 2, 1,
102  &mpc7_scfi[0], 2, 1, INIT_VLC_USE_NEW_STATIC)){
103  av_log(avctx, AV_LOG_ERROR, "Cannot init SCFI VLC\n");
104  return -1;
105  }
106  dscf_vlc.table = dscf_table;
107  dscf_vlc.table_allocated = 1 << MPC7_DSCF_BITS;
108  if(init_vlc(&dscf_vlc, MPC7_DSCF_BITS, MPC7_DSCF_SIZE,
109  &mpc7_dscf[1], 2, 1,
110  &mpc7_dscf[0], 2, 1, INIT_VLC_USE_NEW_STATIC)){
111  av_log(avctx, AV_LOG_ERROR, "Cannot init DSCF VLC\n");
112  return -1;
113  }
114  hdr_vlc.table = hdr_table;
115  hdr_vlc.table_allocated = 1 << MPC7_HDR_BITS;
116  if(init_vlc(&hdr_vlc, MPC7_HDR_BITS, MPC7_HDR_SIZE,
117  &mpc7_hdr[1], 2, 1,
118  &mpc7_hdr[0], 2, 1, INIT_VLC_USE_NEW_STATIC)){
119  av_log(avctx, AV_LOG_ERROR, "Cannot init HDR VLC\n");
120  return -1;
121  }
122  for(i = 0; i < MPC7_QUANT_VLC_TABLES; i++){
123  for(j = 0; j < 2; j++){
124  quant_vlc[i][j].table = &quant_tables[quant_offsets[i*2 + j]];
125  quant_vlc[i][j].table_allocated = quant_offsets[i*2 + j + 1] - quant_offsets[i*2 + j];
126  if(init_vlc(&quant_vlc[i][j], 9, mpc7_quant_vlc_sizes[i],
127  &mpc7_quant_vlc[i][j][1], 4, 2,
128  &mpc7_quant_vlc[i][j][0], 4, 2, INIT_VLC_USE_NEW_STATIC)){
129  av_log(avctx, AV_LOG_ERROR, "Cannot init QUANT VLC %i,%i\n",i,j);
130  return -1;
131  }
132  }
133  }
134  vlc_initialized = 1;
135 
136  return 0;
137 }
138 
139 /**
140  * Fill samples for given subband
141  */
142 static inline void idx_to_quant(MPCContext *c, GetBitContext *gb, int idx, int *dst)
143 {
144  int i, i1, t;
145  switch(idx){
146  case -1:
147  for(i = 0; i < SAMPLES_PER_BAND; i++){
148  *dst++ = (av_lfg_get(&c->rnd) & 0x3FC) - 510;
149  }
150  break;
151  case 1:
152  i1 = get_bits1(gb);
153  for(i = 0; i < SAMPLES_PER_BAND/3; i++){
154  t = get_vlc2(gb, quant_vlc[0][i1].table, 9, 2);
155  *dst++ = mpc7_idx30[t];
156  *dst++ = mpc7_idx31[t];
157  *dst++ = mpc7_idx32[t];
158  }
159  break;
160  case 2:
161  i1 = get_bits1(gb);
162  for(i = 0; i < SAMPLES_PER_BAND/2; i++){
163  t = get_vlc2(gb, quant_vlc[1][i1].table, 9, 2);
164  *dst++ = mpc7_idx50[t];
165  *dst++ = mpc7_idx51[t];
166  }
167  break;
168  case 3: case 4: case 5: case 6: case 7:
169  i1 = get_bits1(gb);
170  for(i = 0; i < SAMPLES_PER_BAND; i++)
171  *dst++ = get_vlc2(gb, quant_vlc[idx-1][i1].table, 9, 2) - mpc7_quant_vlc_off[idx-1];
172  break;
173  case 8: case 9: case 10: case 11: case 12:
174  case 13: case 14: case 15: case 16: case 17:
175  t = (1 << (idx - 2)) - 1;
176  for(i = 0; i < SAMPLES_PER_BAND; i++)
177  *dst++ = get_bits(gb, idx - 1) - t;
178  break;
179  default: // case 0 and -2..-17
180  return;
181  }
182 }
183 
184 static int get_scale_idx(GetBitContext *gb, int ref)
185 {
186  int t = get_vlc2(gb, dscf_vlc.table, MPC7_DSCF_BITS, 1) - 7;
187  if (t == 8)
188  return get_bits(gb, 6);
189  return ref + t;
190 }
191 
192 static int mpc7_decode_frame(AVCodecContext * avctx, void *data,
193  int *got_frame_ptr, AVPacket *avpkt)
194 {
195  AVFrame *frame = data;
196  const uint8_t *buf = avpkt->data;
197  int buf_size;
198  MPCContext *c = avctx->priv_data;
199  GetBitContext gb;
200  int i, ch;
201  int mb = -1;
202  Band *bands = c->bands;
203  int off, ret, last_frame, skip;
204  int bits_used, bits_avail;
205 
206  memset(bands, 0, sizeof(*bands) * (c->maxbands + 1));
207 
208  buf_size = avpkt->size & ~3;
209  if (buf_size <= 0) {
210  av_log(avctx, AV_LOG_ERROR, "packet size is too small (%i bytes)\n",
211  avpkt->size);
212  return AVERROR_INVALIDDATA;
213  }
214  if (buf_size != avpkt->size) {
215  av_log(avctx, AV_LOG_WARNING, "packet size is not a multiple of 4. "
216  "extra bytes at the end will be skipped.\n");
217  }
218 
219  skip = buf[0];
220  last_frame = buf[1];
221  buf += 4;
222  buf_size -= 4;
223 
224  /* get output buffer */
225  frame->nb_samples = MPC_FRAME_SIZE;
226  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
227  return ret;
228 
229  av_fast_padded_malloc(&c->bits, &c->buf_size, buf_size);
230  if (!c->bits)
231  return AVERROR(ENOMEM);
232  c->bdsp.bswap_buf((uint32_t *) c->bits, (const uint32_t *) buf,
233  buf_size >> 2);
234  init_get_bits(&gb, c->bits, buf_size * 8);
235  skip_bits_long(&gb, skip);
236 
237  /* read subband indexes */
238  for(i = 0; i <= c->maxbands; i++){
239  for(ch = 0; ch < 2; ch++){
240  int t = 4;
241  if(i) t = get_vlc2(&gb, hdr_vlc.table, MPC7_HDR_BITS, 1) - 5;
242  if(t == 4) bands[i].res[ch] = get_bits(&gb, 4);
243  else bands[i].res[ch] = bands[i-1].res[ch] + t;
244  if (bands[i].res[ch] < -1 || bands[i].res[ch] > 17) {
245  av_log(avctx, AV_LOG_ERROR, "subband index invalid\n");
246  return AVERROR_INVALIDDATA;
247  }
248  }
249 
250  if(bands[i].res[0] || bands[i].res[1]){
251  mb = i;
252  if(c->MSS) bands[i].msf = get_bits1(&gb);
253  }
254  }
255  /* get scale indexes coding method */
256  for(i = 0; i <= mb; i++)
257  for(ch = 0; ch < 2; ch++)
258  if(bands[i].res[ch]) bands[i].scfi[ch] = get_vlc2(&gb, scfi_vlc.table, MPC7_SCFI_BITS, 1);
259  /* get scale indexes */
260  for(i = 0; i <= mb; i++){
261  for(ch = 0; ch < 2; ch++){
262  if(bands[i].res[ch]){
263  bands[i].scf_idx[ch][2] = c->oldDSCF[ch][i];
264  bands[i].scf_idx[ch][0] = get_scale_idx(&gb, bands[i].scf_idx[ch][2]);
265  switch(bands[i].scfi[ch]){
266  case 0:
267  bands[i].scf_idx[ch][1] = get_scale_idx(&gb, bands[i].scf_idx[ch][0]);
268  bands[i].scf_idx[ch][2] = get_scale_idx(&gb, bands[i].scf_idx[ch][1]);
269  break;
270  case 1:
271  bands[i].scf_idx[ch][1] = get_scale_idx(&gb, bands[i].scf_idx[ch][0]);
272  bands[i].scf_idx[ch][2] = bands[i].scf_idx[ch][1];
273  break;
274  case 2:
275  bands[i].scf_idx[ch][1] = bands[i].scf_idx[ch][0];
276  bands[i].scf_idx[ch][2] = get_scale_idx(&gb, bands[i].scf_idx[ch][1]);
277  break;
278  case 3:
279  bands[i].scf_idx[ch][2] = bands[i].scf_idx[ch][1] = bands[i].scf_idx[ch][0];
280  break;
281  }
282  c->oldDSCF[ch][i] = bands[i].scf_idx[ch][2];
283  }
284  }
285  }
286  /* get quantizers */
287  memset(c->Q, 0, sizeof(c->Q));
288  off = 0;
289  for(i = 0; i < BANDS; i++, off += SAMPLES_PER_BAND)
290  for(ch = 0; ch < 2; ch++)
291  idx_to_quant(c, &gb, bands[i].res[ch], c->Q[ch] + off);
292 
293  ff_mpc_dequantize_and_synth(c, mb, (int16_t **)frame->extended_data, 2);
294  if(last_frame)
295  frame->nb_samples = c->lastframelen;
296 
297  bits_used = get_bits_count(&gb);
298  bits_avail = buf_size * 8;
299  if (!last_frame && ((bits_avail < bits_used) || (bits_used + 32 <= bits_avail))) {
300  av_log(avctx, AV_LOG_ERROR, "Error decoding frame: used %i of %i bits\n", bits_used, bits_avail);
301  return -1;
302  }
303  if(c->frames_to_skip){
304  c->frames_to_skip--;
305  *got_frame_ptr = 0;
306  return avpkt->size;
307  }
308 
309  *got_frame_ptr = 1;
310 
311  return avpkt->size;
312 }
313 
314 static void mpc7_decode_flush(AVCodecContext *avctx)
315 {
316  MPCContext *c = avctx->priv_data;
317 
318  memset(c->oldDSCF, 0, sizeof(c->oldDSCF));
319  c->frames_to_skip = 32;
320 }
321 
322 static av_cold int mpc7_decode_close(AVCodecContext *avctx)
323 {
324  MPCContext *c = avctx->priv_data;
325  av_freep(&c->bits);
326  c->buf_size = 0;
327  return 0;
328 }
329 
330 AVCodec ff_mpc7_decoder = {
331  .name = "mpc7",
332  .long_name = NULL_IF_CONFIG_SMALL("Musepack SV7"),
333  .type = AVMEDIA_TYPE_AUDIO,
334  .id = AV_CODEC_ID_MUSEPACK7,
335  .priv_data_size = sizeof(MPCContext),
336  .init = mpc7_decode_init,
337  .close = mpc7_decode_close,
338  .decode = mpc7_decode_frame,
339  .flush = mpc7_decode_flush,
340  .capabilities = CODEC_CAP_DR1,
341  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
342  AV_SAMPLE_FMT_NONE },
343 };
Generated on Sun Jul 20 2014 23:05:51 for FFmpeg by   doxygen 1.8.2