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  static int pcm_bluray_decode_frame(AVCodecContext *avctx, void *data,
126  int *got_frame_ptr, AVPacket *avpkt)
127 {
128  AVFrame *frame = data;
129  const uint8_t *src = avpkt->data;
130  int buf_size = avpkt->size;
131  GetByteContext gb;
132  int num_source_channels, channel, retval;
133  int sample_size, samples;
134  int16_t *dst16;
135  int32_t *dst32;
136 
137  if (buf_size < 4) {
138  av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n");
139  return -1;
140  }
141 
142  if (pcm_bluray_parse_header(avctx, src))
143  return -1;
144  src += 4;
145  buf_size -= 4;
146 
147  bytestream2_init(&gb, src, buf_size);
148 
149  /* There's always an even number of channels in the source */
150  num_source_channels = FFALIGN(avctx->channels, 2);
151  sample_size = (num_source_channels * (avctx->sample_fmt == AV_SAMPLE_FMT_S16 ? 16 : 24)) >> 3;
152  samples = buf_size / sample_size;
153 
154  /* get output buffer */
155  frame->nb_samples = samples;
156  if ((retval = ff_get_buffer(avctx, frame, 0)) < 0)
157  return retval;
158  dst16 = (int16_t *)frame->data[0];
159  dst32 = (int32_t *)frame->data[0];
160 
161  if (samples) {
162  switch (avctx->channel_layout) {
163  /* cases with same number of source and coded channels */
164  case AV_CH_LAYOUT_STEREO:
165  case AV_CH_LAYOUT_4POINT0:
166  case AV_CH_LAYOUT_2_2:
167  samples *= num_source_channels;
168  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
169 #if HAVE_BIGENDIAN
170  bytestream2_get_buffer(&gb, dst16, buf_size);
171 #else
172  do {
173  *dst16++ = bytestream2_get_be16u(&gb);
174  } while (--samples);
175 #endif
176  } else {
177  do {
178  *dst32++ = bytestream2_get_be24u(&gb) << 8;
179  } while (--samples);
180  }
181  break;
182  /* cases where number of source channels = coded channels + 1 */
183  case AV_CH_LAYOUT_MONO:
184  case AV_CH_LAYOUT_SURROUND:
185  case AV_CH_LAYOUT_2_1:
186  case AV_CH_LAYOUT_5POINT0:
187  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
188  do {
189 #if HAVE_BIGENDIAN
190  bytestream2_get_buffer(&gb, dst16, avctx->channels * 2);
191  dst16 += avctx->channels;
192 #else
193  channel = avctx->channels;
194  do {
195  *dst16++ = bytestream2_get_be16u(&gb);
196  } while (--channel);
197 #endif
198  bytestream2_skip(&gb, 2);
199  } while (--samples);
200  } else {
201  do {
202  channel = avctx->channels;
203  do {
204  *dst32++ = bytestream2_get_be24u(&gb) << 8;
205  } while (--channel);
206  bytestream2_skip(&gb, 3);
207  } while (--samples);
208  }
209  break;
210  /* remapping: L, R, C, LBack, RBack, LF */
211  case AV_CH_LAYOUT_5POINT1:
212  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
213  do {
214  dst16[0] = bytestream2_get_be16u(&gb);
215  dst16[1] = bytestream2_get_be16u(&gb);
216  dst16[2] = bytestream2_get_be16u(&gb);
217  dst16[4] = bytestream2_get_be16u(&gb);
218  dst16[5] = bytestream2_get_be16u(&gb);
219  dst16[3] = bytestream2_get_be16u(&gb);
220  dst16 += 6;
221  } while (--samples);
222  } else {
223  do {
224  dst32[0] = bytestream2_get_be24u(&gb) << 8;
225  dst32[1] = bytestream2_get_be24u(&gb) << 8;
226  dst32[2] = bytestream2_get_be24u(&gb) << 8;
227  dst32[4] = bytestream2_get_be24u(&gb) << 8;
228  dst32[5] = bytestream2_get_be24u(&gb) << 8;
229  dst32[3] = bytestream2_get_be24u(&gb) << 8;
230  dst32 += 6;
231  } while (--samples);
232  }
233  break;
234  /* remapping: L, R, C, LSide, LBack, RBack, RSide, <unused> */
235  case AV_CH_LAYOUT_7POINT0:
236  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
237  do {
238  dst16[0] = bytestream2_get_be16u(&gb);
239  dst16[1] = bytestream2_get_be16u(&gb);
240  dst16[2] = bytestream2_get_be16u(&gb);
241  dst16[5] = bytestream2_get_be16u(&gb);
242  dst16[3] = bytestream2_get_be16u(&gb);
243  dst16[4] = bytestream2_get_be16u(&gb);
244  dst16[6] = bytestream2_get_be16u(&gb);
245  dst16 += 7;
246  bytestream2_skip(&gb, 2);
247  } while (--samples);
248  } else {
249  do {
250  dst32[0] = bytestream2_get_be24u(&gb) << 8;
251  dst32[1] = bytestream2_get_be24u(&gb) << 8;
252  dst32[2] = bytestream2_get_be24u(&gb) << 8;
253  dst32[5] = bytestream2_get_be24u(&gb) << 8;
254  dst32[3] = bytestream2_get_be24u(&gb) << 8;
255  dst32[4] = bytestream2_get_be24u(&gb) << 8;
256  dst32[6] = bytestream2_get_be24u(&gb) << 8;
257  dst32 += 7;
258  bytestream2_skip(&gb, 3);
259  } while (--samples);
260  }
261  break;
262  /* remapping: L, R, C, LSide, LBack, RBack, RSide, LF */
263  case AV_CH_LAYOUT_7POINT1:
264  if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
265  do {
266  dst16[0] = bytestream2_get_be16u(&gb);
267  dst16[1] = bytestream2_get_be16u(&gb);
268  dst16[2] = bytestream2_get_be16u(&gb);
269  dst16[6] = bytestream2_get_be16u(&gb);
270  dst16[4] = bytestream2_get_be16u(&gb);
271  dst16[5] = bytestream2_get_be16u(&gb);
272  dst16[7] = bytestream2_get_be16u(&gb);
273  dst16[3] = bytestream2_get_be16u(&gb);
274  dst16 += 8;
275  } while (--samples);
276  } else {
277  do {
278  dst32[0] = bytestream2_get_be24u(&gb) << 8;
279  dst32[1] = bytestream2_get_be24u(&gb) << 8;
280  dst32[2] = bytestream2_get_be24u(&gb) << 8;
281  dst32[6] = bytestream2_get_be24u(&gb) << 8;
282  dst32[4] = bytestream2_get_be24u(&gb) << 8;
283  dst32[5] = bytestream2_get_be24u(&gb) << 8;
284  dst32[7] = bytestream2_get_be24u(&gb) << 8;
285  dst32[3] = bytestream2_get_be24u(&gb) << 8;
286  dst32 += 8;
287  } while (--samples);
288  }
289  break;
290  }
291  }
292 
293  *got_frame_ptr = 1;
294 
295  retval = bytestream2_tell(&gb);
296  if (avctx->debug & FF_DEBUG_BITSTREAM)
297  av_dlog(avctx, "pcm_bluray_decode_frame: decoded %d -> %d bytes\n",
298  retval, buf_size);
299  return retval + 4;
300 }
301 
302  AVCodec ff_pcm_bluray_decoder = {
303  .name = "pcm_bluray",
304  .type = AVMEDIA_TYPE_AUDIO,
305  .id = AV_CODEC_ID_PCM_BLURAY,
306  .decode = pcm_bluray_decode_frame,
307  .capabilities = CODEC_CAP_DR1,
308  .sample_fmts = (const enum AVSampleFormat[]){
309  AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_NONE
310  },
311  .long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for Blu-ray media"),
312 };
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