pcm-mpeg.c
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1 /*
2  * LPCM codecs for PCM formats found in MPEG streams
3  * Copyright (c) 2009 Christian Schmidt
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
27 #include "libavutil/audioconvert.h"
28 #include "avcodec.h"
29 #include "bytestream.h"
30 
31 /*
32  * Channel Mapping according to
33  * Blu-ray Disc Read-Only Format Version 1
34  * Part 3: Audio Visual Basic Specifications
35  * mono M1 X
36  * stereo L R
37  * 3/0 L R C X
38  * 2/1 L R S X
39  * 3/1 L R C S
40  * 2/2 L R LS RS
41  * 3/2 L R C LS RS X
42  * 3/2+lfe L R C LS RS lfe
43  * 3/4 L R C LS Rls Rrs RS X
44  * 3/4+lfe L R C LS Rls Rrs RS lfe
45  */
46 
53  const uint8_t *header)
54 {
55  static const uint8_t bits_per_samples[4] = { 0, 16, 20, 24 };
56  static const uint32_t channel_layouts[16] = {
60  };
61  static const uint8_t channels[16] = {
62  0, 1, 0, 2, 3, 3, 4, 4, 5, 6, 7, 8, 0, 0, 0, 0
63  };
64  uint8_t channel_layout = header[2] >> 4;
65 
66  if (avctx->debug & FF_DEBUG_PICT_INFO)
67  av_dlog(avctx, "pcm_bluray_parse_header: header = %02x%02x%02x%02x\n",
68  header[0], header[1], header[2], header[3]);
69 
70  /* get the sample depth and derive the sample format from it */
71  avctx->bits_per_coded_sample = bits_per_samples[header[3] >> 6];
72  if (!avctx->bits_per_coded_sample) {
73  av_log(avctx, AV_LOG_ERROR, "unsupported sample depth (0)\n");
74  return -1;
75  }
76  avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? AV_SAMPLE_FMT_S16 :
78 
79  /* get the sample rate. Not all values are known or exist. */
80  switch (header[2] & 0x0f) {
81  case 1:
82  avctx->sample_rate = 48000;
83  break;
84  case 4:
85  avctx->sample_rate = 96000;
86  break;
87  case 5:
88  avctx->sample_rate = 192000;
89  break;
90  default:
91  avctx->sample_rate = 0;
92  av_log(avctx, AV_LOG_ERROR, "unsupported sample rate (%d)\n",
93  header[2] & 0x0f);
94  return -1;
95  }
96 
97  /*
98  * get the channel number (and mapping). Not all values are known or exist.
99  * It must be noted that the number of channels in the MPEG stream can
100  * differ from the actual meaningful number, e.g. mono audio still has two
101  * channels, one being empty.
102  */
103  avctx->channel_layout = channel_layouts[channel_layout];
104  avctx->channels = channels[channel_layout];
105  if (!avctx->channels) {
106  av_log(avctx, AV_LOG_ERROR, "unsupported channel configuration (%d)\n",
107  channel_layout);
108  return -1;
109  }
110 
111  avctx->bit_rate = avctx->channels * avctx->sample_rate *
112  avctx->bits_per_coded_sample;
113 
114  if (avctx->debug & FF_DEBUG_PICT_INFO)
115  av_dlog(avctx,
116  "pcm_bluray_parse_header: %d channels, %d bits per sample, %d kHz, %d kbit\n",
117  avctx->channels, avctx->bits_per_coded_sample,
118  avctx->sample_rate, avctx->bit_rate);
119  return 0;
120 }
121 
122 typedef struct PCMBRDecode {
124 } PCMBRDecode;
125 
127 {
128  PCMBRDecode *s = avctx->priv_data;
129 
131  avctx->coded_frame = &s->frame;
132 
133  return 0;
134 }
135 
136 static int pcm_bluray_decode_frame(AVCodecContext *avctx, void *data,
137  int *got_frame_ptr, AVPacket *avpkt)
138 {
139  const uint8_t *src = avpkt->data;
140  int buf_size = avpkt->size;
141  PCMBRDecode *s = avctx->priv_data;
142  int num_source_channels, channel, retval;
143  int sample_size, samples;
144  int16_t *dst16;
145  int32_t *dst32;
146 
147  if (buf_size < 4) {
148  av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n");
149  return -1;
150  }
151 
152  if (pcm_bluray_parse_header(avctx, src))
153  return -1;
154  src += 4;
155  buf_size -= 4;
156 
157  /* There's always an even number of channels in the source */
158  num_source_channels = FFALIGN(avctx->channels, 2);
159  sample_size = (num_source_channels * (avctx->sample_fmt == AV_SAMPLE_FMT_S16 ? 16 : 24)) >> 3;
160  samples = buf_size / sample_size;
161 
162  /* get output buffer */
163  s->frame.nb_samples = samples;
164  if ((retval = avctx->get_buffer(avctx, &s->frame)) < 0) {
165  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
166  return retval;
167  }
168  dst16 = (int16_t *)s->frame.data[0];
169  dst32 = (int32_t *)s->frame.data[0];
170 
171  if (samples) {
172  switch (avctx->channel_layout) {
173  /* cases with same number of source and coded channels */
174  case AV_CH_LAYOUT_STEREO:
176  case AV_CH_LAYOUT_2_2:
177  samples *= num_source_channels;
178  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
179 #if HAVE_BIGENDIAN
180  memcpy(dst16, src, buf_size);
181 #else
182  do {
183  *dst16++ = bytestream_get_be16(&src);
184  } while (--samples);
185 #endif
186  } else {
187  do {
188  *dst32++ = bytestream_get_be24(&src) << 8;
189  } while (--samples);
190  }
191  break;
192  /* cases where number of source channels = coded channels + 1 */
193  case AV_CH_LAYOUT_MONO:
195  case AV_CH_LAYOUT_2_1:
197  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
198  do {
199 #if HAVE_BIGENDIAN
200  memcpy(dst16, src, avctx->channels * 2);
201  dst16 += avctx->channels;
202  src += sample_size;
203 #else
204  channel = avctx->channels;
205  do {
206  *dst16++ = bytestream_get_be16(&src);
207  } while (--channel);
208  src += 2;
209 #endif
210  } while (--samples);
211  } else {
212  do {
213  channel = avctx->channels;
214  do {
215  *dst32++ = bytestream_get_be24(&src) << 8;
216  } while (--channel);
217  src += 3;
218  } while (--samples);
219  }
220  break;
221  /* remapping: L, R, C, LBack, RBack, LF */
223  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
224  do {
225  dst16[0] = bytestream_get_be16(&src);
226  dst16[1] = bytestream_get_be16(&src);
227  dst16[2] = bytestream_get_be16(&src);
228  dst16[4] = bytestream_get_be16(&src);
229  dst16[5] = bytestream_get_be16(&src);
230  dst16[3] = bytestream_get_be16(&src);
231  dst16 += 6;
232  } while (--samples);
233  } else {
234  do {
235  dst32[0] = bytestream_get_be24(&src) << 8;
236  dst32[1] = bytestream_get_be24(&src) << 8;
237  dst32[2] = bytestream_get_be24(&src) << 8;
238  dst32[4] = bytestream_get_be24(&src) << 8;
239  dst32[5] = bytestream_get_be24(&src) << 8;
240  dst32[3] = bytestream_get_be24(&src) << 8;
241  dst32 += 6;
242  } while (--samples);
243  }
244  break;
245  /* remapping: L, R, C, LSide, LBack, RBack, RSide, <unused> */
247  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
248  do {
249  dst16[0] = bytestream_get_be16(&src);
250  dst16[1] = bytestream_get_be16(&src);
251  dst16[2] = bytestream_get_be16(&src);
252  dst16[5] = bytestream_get_be16(&src);
253  dst16[3] = bytestream_get_be16(&src);
254  dst16[4] = bytestream_get_be16(&src);
255  dst16[6] = bytestream_get_be16(&src);
256  dst16 += 7;
257  src += 2;
258  } while (--samples);
259  } else {
260  do {
261  dst32[0] = bytestream_get_be24(&src) << 8;
262  dst32[1] = bytestream_get_be24(&src) << 8;
263  dst32[2] = bytestream_get_be24(&src) << 8;
264  dst32[5] = bytestream_get_be24(&src) << 8;
265  dst32[3] = bytestream_get_be24(&src) << 8;
266  dst32[4] = bytestream_get_be24(&src) << 8;
267  dst32[6] = bytestream_get_be24(&src) << 8;
268  dst32 += 7;
269  src += 3;
270  } while (--samples);
271  }
272  break;
273  /* remapping: L, R, C, LSide, LBack, RBack, RSide, LF */
275  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
276  do {
277  dst16[0] = bytestream_get_be16(&src);
278  dst16[1] = bytestream_get_be16(&src);
279  dst16[2] = bytestream_get_be16(&src);
280  dst16[6] = bytestream_get_be16(&src);
281  dst16[4] = bytestream_get_be16(&src);
282  dst16[5] = bytestream_get_be16(&src);
283  dst16[7] = bytestream_get_be16(&src);
284  dst16[3] = bytestream_get_be16(&src);
285  dst16 += 8;
286  } while (--samples);
287  } else {
288  do {
289  dst32[0] = bytestream_get_be24(&src) << 8;
290  dst32[1] = bytestream_get_be24(&src) << 8;
291  dst32[2] = bytestream_get_be24(&src) << 8;
292  dst32[6] = bytestream_get_be24(&src) << 8;
293  dst32[4] = bytestream_get_be24(&src) << 8;
294  dst32[5] = bytestream_get_be24(&src) << 8;
295  dst32[7] = bytestream_get_be24(&src) << 8;
296  dst32[3] = bytestream_get_be24(&src) << 8;
297  dst32 += 8;
298  } while (--samples);
299  }
300  break;
301  }
302  }
303 
304  *got_frame_ptr = 1;
305  *(AVFrame *)data = s->frame;
306 
307  retval = src - avpkt->data;
308  if (avctx->debug & FF_DEBUG_BITSTREAM)
309  av_dlog(avctx, "pcm_bluray_decode_frame: decoded %d -> %d bytes\n",
310  retval, buf_size);
311  return retval;
312 }
313 
315  .name = "pcm_bluray",
316  .type = AVMEDIA_TYPE_AUDIO,
317  .id = CODEC_ID_PCM_BLURAY,
318  .priv_data_size = sizeof(PCMBRDecode),
321  .capabilities = CODEC_CAP_DR1,
322  .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32,
324  .long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for Blu-ray media"),
325 };