FFmpeg: libavcodec/pcm-mpeg.c Source File

FFmpeg
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 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  * PCM codecs for encodings found in MPEG streams (DVD/Blu-ray)
25  */
26 
27 #include "libavutil/channel_layout.h"
28 #include "avcodec.h"
29 #include "bytestream.h"
30 #include "internal.h"
31 
32 /*
33  * Channel Mapping according to
34  * Blu-ray Disc Read-Only Format Version 1
35  * Part 3: Audio Visual Basic Specifications
36  * mono M1 X
37  * stereo L R
38  * 3/0 L R C X
39  * 2/1 L R S X
40  * 3/1 L R C S
41  * 2/2 L R LS RS
42  * 3/2 L R C LS RS X
43  * 3/2+lfe L R C LS RS lfe
44  * 3/4 L R C LS Rls Rrs RS X
45  * 3/4+lfe L R C LS Rls Rrs RS lfe
46  */
47 
48 /**
49  * Parse the header of a LPCM frame read from a MPEG-TS stream
50  * @param avctx the codec context
51  * @param header pointer to the first four bytes of the data packet
52  */
53  static int pcm_bluray_parse_header(AVCodecContext *avctx,
54  const uint8_t *header)
55 {
56  static const uint8_t bits_per_samples[4] = { 0, 16, 20, 24 };
57  static const uint32_t channel_layouts[16] = {
58  0, AV_CH_LAYOUT_MONO, 0, AV_CH_LAYOUT_STEREO, AV_CH_LAYOUT_SURROUND,
59  AV_CH_LAYOUT_2_1, AV_CH_LAYOUT_4POINT0, AV_CH_LAYOUT_2_2, AV_CH_LAYOUT_5POINT0,
60  AV_CH_LAYOUT_5POINT1, AV_CH_LAYOUT_7POINT0, AV_CH_LAYOUT_7POINT1, 0, 0, 0, 0
61  };
62  static const uint8_t channels[16] = {
63  0, 1, 0, 2, 3, 3, 4, 4, 5, 6, 7, 8, 0, 0, 0, 0
64  };
65  uint8_t channel_layout = header[2] >> 4;
66 
67  if (avctx->debug & FF_DEBUG_PICT_INFO)
68  av_dlog(avctx, "pcm_bluray_parse_header: header = %02x%02x%02x%02x\n",
69  header[0], header[1], header[2], header[3]);
70 
71  /* get the sample depth and derive the sample format from it */
72  avctx->bits_per_coded_sample = bits_per_samples[header[3] >> 6];
73  if (!(avctx->bits_per_coded_sample == 16 || avctx->bits_per_coded_sample == 24)) {
74  av_log(avctx, AV_LOG_ERROR, "unsupported sample depth (%d)\n", avctx->bits_per_coded_sample);
75  return -1;
76  }
77  avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? AV_SAMPLE_FMT_S16 :
78  AV_SAMPLE_FMT_S32;
79  if (avctx->sample_fmt == AV_SAMPLE_FMT_S32)
80  avctx->bits_per_raw_sample = avctx->bits_per_coded_sample;
81 
82  /* get the sample rate. Not all values are used. */
83  switch (header[2] & 0x0f) {
84  case 1:
85  avctx->sample_rate = 48000;
86  break;
87  case 4:
88  avctx->sample_rate = 96000;
89  break;
90  case 5:
91  avctx->sample_rate = 192000;
92  break;
93  default:
94  avctx->sample_rate = 0;
95  av_log(avctx, AV_LOG_ERROR, "reserved sample rate (%d)\n",
96  header[2] & 0x0f);
97  return -1;
98  }
99 
100  /*
101  * get the channel number (and mapping). Not all values are used.
102  * It must be noted that the number of channels in the MPEG stream can
103  * differ from the actual meaningful number, e.g. mono audio still has two
104  * channels, one being empty.
105  */
106  avctx->channel_layout = channel_layouts[channel_layout];
107  avctx->channels = channels[channel_layout];
108  if (!avctx->channels) {
109  av_log(avctx, AV_LOG_ERROR, "reserved channel configuration (%d)\n",
110  channel_layout);
111  return -1;
112  }
113 
114  avctx->bit_rate = FFALIGN(avctx->channels, 2) * avctx->sample_rate *
115  avctx->bits_per_coded_sample;
116 
117  if (avctx->debug & FF_DEBUG_PICT_INFO)
118  av_dlog(avctx,
119  "pcm_bluray_parse_header: %d channels, %d bits per sample, %d Hz, %d bit/s\n",
120  avctx->channels, avctx->bits_per_coded_sample,
121  avctx->sample_rate, avctx->bit_rate);
122  return 0;
123 }
124 
125  typedef struct PCMBRDecode {
126   AVFrame frame;
127 } PCMBRDecode;
128 
129  static av_cold int pcm_bluray_decode_init(AVCodecContext * avctx)
130 {
131  PCMBRDecode *s = avctx->priv_data;
132 
133  avcodec_get_frame_defaults(&s->frame);
134  avctx->coded_frame = &s->frame;
135 
136  return 0;
137 }
138 
139  static int pcm_bluray_decode_frame(AVCodecContext *avctx, void *data,
140  int *got_frame_ptr, AVPacket *avpkt)
141 {
142  const uint8_t *src = avpkt->data;
143  int buf_size = avpkt->size;
144  PCMBRDecode *s = avctx->priv_data;
145  GetByteContext gb;
146  int num_source_channels, channel, retval;
147  int sample_size, samples;
148  int16_t *dst16;
149  int32_t *dst32;
150 
151  if (buf_size < 4) {
152  av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n");
153  return -1;
154  }
155 
156  if (pcm_bluray_parse_header(avctx, src))
157  return -1;
158  src += 4;
159  buf_size -= 4;
160 
161  bytestream2_init(&gb, src, buf_size);
162 
163  /* There's always an even number of channels in the source */
164  num_source_channels = FFALIGN(avctx->channels, 2);
165  sample_size = (num_source_channels * (avctx->sample_fmt == AV_SAMPLE_FMT_S16 ? 16 : 24)) >> 3;
166  samples = buf_size / sample_size;
167 
168  /* get output buffer */
169  s->frame.nb_samples = samples;
170  if ((retval = ff_get_buffer(avctx, &s->frame)) < 0) {
171  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
172  return retval;
173  }
174  dst16 = (int16_t *)s->frame.data[0];
175  dst32 = (int32_t *)s->frame.data[0];
176 
177  if (samples) {
178  switch (avctx->channel_layout) {
179  /* cases with same number of source and coded channels */
180  case AV_CH_LAYOUT_STEREO:
181  case AV_CH_LAYOUT_4POINT0:
182  case AV_CH_LAYOUT_2_2:
183  samples *= num_source_channels;
184  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
185 #if HAVE_BIGENDIAN
186  bytestream2_get_buffer(&gb, dst16, buf_size);
187 #else
188  do {
189  *dst16++ = bytestream2_get_be16u(&gb);
190  } while (--samples);
191 #endif
192  } else {
193  do {
194  *dst32++ = bytestream2_get_be24u(&gb) << 8;
195  } while (--samples);
196  }
197  break;
198  /* cases where number of source channels = coded channels + 1 */
199  case AV_CH_LAYOUT_MONO:
200  case AV_CH_LAYOUT_SURROUND:
201  case AV_CH_LAYOUT_2_1:
202  case AV_CH_LAYOUT_5POINT0:
203  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
204  do {
205 #if HAVE_BIGENDIAN
206  bytestream2_get_buffer(&gb, dst16, avctx->channels * 2);
207  dst16 += avctx->channels;
208 #else
209  channel = avctx->channels;
210  do {
211  *dst16++ = bytestream2_get_be16u(&gb);
212  } while (--channel);
213 #endif
214  bytestream2_skip(&gb, 2);
215  } while (--samples);
216  } else {
217  do {
218  channel = avctx->channels;
219  do {
220  *dst32++ = bytestream2_get_be24u(&gb) << 8;
221  } while (--channel);
222  bytestream2_skip(&gb, 3);
223  } while (--samples);
224  }
225  break;
226  /* remapping: L, R, C, LBack, RBack, LF */
227  case AV_CH_LAYOUT_5POINT1:
228  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
229  do {
230  dst16[0] = bytestream2_get_be16u(&gb);
231  dst16[1] = bytestream2_get_be16u(&gb);
232  dst16[2] = bytestream2_get_be16u(&gb);
233  dst16[4] = bytestream2_get_be16u(&gb);
234  dst16[5] = bytestream2_get_be16u(&gb);
235  dst16[3] = bytestream2_get_be16u(&gb);
236  dst16 += 6;
237  } while (--samples);
238  } else {
239  do {
240  dst32[0] = bytestream2_get_be24u(&gb) << 8;
241  dst32[1] = bytestream2_get_be24u(&gb) << 8;
242  dst32[2] = bytestream2_get_be24u(&gb) << 8;
243  dst32[4] = bytestream2_get_be24u(&gb) << 8;
244  dst32[5] = bytestream2_get_be24u(&gb) << 8;
245  dst32[3] = bytestream2_get_be24u(&gb) << 8;
246  dst32 += 6;
247  } while (--samples);
248  }
249  break;
250  /* remapping: L, R, C, LSide, LBack, RBack, RSide, <unused> */
251  case AV_CH_LAYOUT_7POINT0:
252  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
253  do {
254  dst16[0] = bytestream2_get_be16u(&gb);
255  dst16[1] = bytestream2_get_be16u(&gb);
256  dst16[2] = bytestream2_get_be16u(&gb);
257  dst16[5] = bytestream2_get_be16u(&gb);
258  dst16[3] = bytestream2_get_be16u(&gb);
259  dst16[4] = bytestream2_get_be16u(&gb);
260  dst16[6] = bytestream2_get_be16u(&gb);
261  dst16 += 7;
262  bytestream2_skip(&gb, 2);
263  } while (--samples);
264  } else {
265  do {
266  dst32[0] = bytestream2_get_be24u(&gb) << 8;
267  dst32[1] = bytestream2_get_be24u(&gb) << 8;
268  dst32[2] = bytestream2_get_be24u(&gb) << 8;
269  dst32[5] = bytestream2_get_be24u(&gb) << 8;
270  dst32[3] = bytestream2_get_be24u(&gb) << 8;
271  dst32[4] = bytestream2_get_be24u(&gb) << 8;
272  dst32[6] = bytestream2_get_be24u(&gb) << 8;
273  dst32 += 7;
274  bytestream2_skip(&gb, 3);
275  } while (--samples);
276  }
277  break;
278  /* remapping: L, R, C, LSide, LBack, RBack, RSide, LF */
279  case AV_CH_LAYOUT_7POINT1:
280  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
281  do {
282  dst16[0] = bytestream2_get_be16u(&gb);
283  dst16[1] = bytestream2_get_be16u(&gb);
284  dst16[2] = bytestream2_get_be16u(&gb);
285  dst16[6] = bytestream2_get_be16u(&gb);
286  dst16[4] = bytestream2_get_be16u(&gb);
287  dst16[5] = bytestream2_get_be16u(&gb);
288  dst16[7] = bytestream2_get_be16u(&gb);
289  dst16[3] = bytestream2_get_be16u(&gb);
290  dst16 += 8;
291  } while (--samples);
292  } else {
293  do {
294  dst32[0] = bytestream2_get_be24u(&gb) << 8;
295  dst32[1] = bytestream2_get_be24u(&gb) << 8;
296  dst32[2] = bytestream2_get_be24u(&gb) << 8;
297  dst32[6] = bytestream2_get_be24u(&gb) << 8;
298  dst32[4] = bytestream2_get_be24u(&gb) << 8;
299  dst32[5] = bytestream2_get_be24u(&gb) << 8;
300  dst32[7] = bytestream2_get_be24u(&gb) << 8;
301  dst32[3] = bytestream2_get_be24u(&gb) << 8;
302  dst32 += 8;
303  } while (--samples);
304  }
305  break;
306  }
307  }
308 
309  *got_frame_ptr = 1;
310  *(AVFrame *)data = s->frame;
311 
312  retval = bytestream2_tell(&gb);
313  if (avctx->debug & FF_DEBUG_BITSTREAM)
314  av_dlog(avctx, "pcm_bluray_decode_frame: decoded %d -> %d bytes\n",
315  retval, buf_size);
316  return retval + 4;
317 }
318 
319  AVCodec ff_pcm_bluray_decoder = {
320  .name = "pcm_bluray",
321  .type = AVMEDIA_TYPE_AUDIO,
322  .id = AV_CODEC_ID_PCM_BLURAY,
323  .priv_data_size = sizeof(PCMBRDecode),
324  .init = pcm_bluray_decode_init,
325  .decode = pcm_bluray_decode_frame,
326  .capabilities = CODEC_CAP_DR1,
327  .sample_fmts = (const enum AVSampleFormat[]){
328  AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_NONE
329  },
330  .long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for Blu-ray media"),
331 };
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