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spdifdec.c
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1 /*
2  * IEC 61937 demuxer
3  * Copyright (c) 2010 Anssi Hannula <anssi.hannula at iki.fi>
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  * IEC 61937 demuxer, used for compressed data in S/PDIF
25  * @author Anssi Hannula
26  */
27 
28 #include "avformat.h"
29 #include "spdif.h"
30 #include "libavcodec/ac3.h"
31 #include "libavcodec/aacadtsdec.h"
32 
34  enum IEC61937DataType data_type,
35  const char *buf, int *offset,
36  enum AVCodecID *codec)
37 {
38  AACADTSHeaderInfo aac_hdr;
39  GetBitContext gbc;
40 
41  switch (data_type & 0xff) {
42  case IEC61937_AC3:
43  *offset = AC3_FRAME_SIZE << 2;
44  *codec = AV_CODEC_ID_AC3;
45  break;
47  *offset = spdif_mpeg_pkt_offset[1][0];
48  *codec = AV_CODEC_ID_MP1;
49  break;
51  *offset = spdif_mpeg_pkt_offset[1][0];
52  *codec = AV_CODEC_ID_MP3;
53  break;
54  case IEC61937_MPEG2_EXT:
55  *offset = 4608;
56  *codec = AV_CODEC_ID_MP3;
57  break;
58  case IEC61937_MPEG2_AAC:
59  init_get_bits(&gbc, buf, AAC_ADTS_HEADER_SIZE * 8);
60  if (avpriv_aac_parse_header(&gbc, &aac_hdr) < 0) {
61  if (s) /* be silent during a probe */
62  av_log(s, AV_LOG_ERROR, "Invalid AAC packet in IEC 61937\n");
63  return AVERROR_INVALIDDATA;
64  }
65  *offset = aac_hdr.samples << 2;
66  *codec = AV_CODEC_ID_AAC;
67  break;
69  *offset = spdif_mpeg_pkt_offset[0][0];
70  *codec = AV_CODEC_ID_MP1;
71  break;
73  *offset = spdif_mpeg_pkt_offset[0][1];
74  *codec = AV_CODEC_ID_MP2;
75  break;
77  *offset = spdif_mpeg_pkt_offset[0][2];
78  *codec = AV_CODEC_ID_MP3;
79  break;
80  case IEC61937_DTS1:
81  *offset = 2048;
82  *codec = AV_CODEC_ID_DTS;
83  break;
84  case IEC61937_DTS2:
85  *offset = 4096;
86  *codec = AV_CODEC_ID_DTS;
87  break;
88  case IEC61937_DTS3:
89  *offset = 8192;
90  *codec = AV_CODEC_ID_DTS;
91  break;
92  default:
93  if (s) { /* be silent during a probe */
94  avpriv_request_sample(s, "Data type 0x%04x in IEC 61937",
95  data_type);
96  }
97  return AVERROR_PATCHWELCOME;
98  }
99  return 0;
100 }
101 
102 /* Largest offset between bursts we currently handle, i.e. AAC with
103  aac_hdr.samples = 4096 */
104 #define SPDIF_MAX_OFFSET 16384
105 
106 static int spdif_probe(AVProbeData *p)
107 {
108  enum AVCodecID codec;
109  return ff_spdif_probe (p->buf, p->buf_size, &codec);
110 }
111 
112 int ff_spdif_probe(const uint8_t *p_buf, int buf_size, enum AVCodecID *codec)
113 {
114  const uint8_t *buf = p_buf;
115  const uint8_t *probe_end = p_buf + FFMIN(2 * SPDIF_MAX_OFFSET, buf_size - 1);
116  const uint8_t *expected_code = buf + 7;
117  uint32_t state = 0;
118  int sync_codes = 0;
119  int consecutive_codes = 0;
120  int offset;
121 
122  for (; buf < probe_end; buf++) {
123  state = (state << 8) | *buf;
124 
125  if (state == (AV_BSWAP16C(SYNCWORD1) << 16 | AV_BSWAP16C(SYNCWORD2))
126  && buf[1] < 0x37) {
127  sync_codes++;
128 
129  if (buf == expected_code) {
130  if (++consecutive_codes >= 2)
131  return AVPROBE_SCORE_MAX;
132  } else
133  consecutive_codes = 0;
134 
135  if (buf + 4 + AAC_ADTS_HEADER_SIZE > p_buf + buf_size)
136  break;
137 
138  /* continue probing to find more sync codes */
139  probe_end = FFMIN(buf + SPDIF_MAX_OFFSET, p_buf + buf_size - 1);
140 
141  /* skip directly to the next sync code */
142  if (!spdif_get_offset_and_codec(NULL, (buf[2] << 8) | buf[1],
143  &buf[5], &offset, codec)) {
144  if (buf + offset >= p_buf + buf_size)
145  break;
146  expected_code = buf + offset;
147  buf = expected_code - 7;
148  }
149  }
150  }
151 
152  if (!sync_codes)
153  return 0;
154 
155  if (sync_codes >= 6)
156  /* good amount of sync codes but with unexpected offsets */
158 
159  /* some sync codes were found */
160  return AVPROBE_SCORE_EXTENSION / 4;
161 }
162 
164 {
166  return 0;
167 }
168 
170 {
171  AVIOContext *pb = s->pb;
172  enum IEC61937DataType data_type;
173  enum AVCodecID codec_id;
174  uint32_t state = 0;
175  int pkt_size_bits, offset, ret;
176 
177  while (state != (AV_BSWAP16C(SYNCWORD1) << 16 | AV_BSWAP16C(SYNCWORD2))) {
178  state = (state << 8) | avio_r8(pb);
179  if (avio_feof(pb))
180  return AVERROR_EOF;
181  }
182 
183  data_type = avio_rl16(pb);
184  pkt_size_bits = avio_rl16(pb);
185 
186  if (pkt_size_bits % 16)
187  avpriv_request_sample(s, "Packet not ending at a 16-bit boundary");
188 
189  ret = av_new_packet(pkt, FFALIGN(pkt_size_bits, 16) >> 3);
190  if (ret)
191  return ret;
192 
193  pkt->pos = avio_tell(pb) - BURST_HEADER_SIZE;
194 
195  if (avio_read(pb, pkt->data, pkt->size) < pkt->size) {
196  av_packet_unref(pkt);
197  return AVERROR_EOF;
198  }
199  ff_spdif_bswap_buf16((uint16_t *)pkt->data, (uint16_t *)pkt->data, pkt->size >> 1);
200 
201  ret = spdif_get_offset_and_codec(s, data_type, pkt->data,
202  &offset, &codec_id);
203  if (ret) {
204  av_packet_unref(pkt);
205  return ret;
206  }
207 
208  /* skip over the padding to the beginning of the next frame */
209  avio_skip(pb, offset - pkt->size - BURST_HEADER_SIZE);
210 
211  if (!s->nb_streams) {
212  /* first packet, create a stream */
214  if (!st) {
215  av_packet_unref(pkt);
216  return AVERROR(ENOMEM);
217  }
219  st->codecpar->codec_id = codec_id;
220  } else if (codec_id != s->streams[0]->codecpar->codec_id) {
221  avpriv_report_missing_feature(s, "Codec change in IEC 61937");
222  return AVERROR_PATCHWELCOME;
223  }
224 
225  if (!s->bit_rate && s->streams[0]->codecpar->sample_rate)
226  /* stream bitrate matches 16-bit stereo PCM bitrate for currently
227  supported codecs */
228  s->bit_rate = 2 * 16 * s->streams[0]->codecpar->sample_rate;
229 
230  return 0;
231 }
232 
234  .name = "spdif",
235  .long_name = NULL_IF_CONFIG_SMALL("IEC 61937 (compressed data in S/PDIF)"),
236  .read_probe = spdif_probe,
237  .read_header = spdif_read_header,
238  .read_packet = ff_spdif_read_packet,
239  .flags = AVFMT_GENERIC_INDEX,
240 };
static int spdif_get_offset_and_codec(AVFormatContext *s, enum IEC61937DataType data_type, const char *buf, int *offset, enum AVCodecID *codec)
Definition: spdifdec.c:33
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:631
Bytestream IO Context.
Definition: avio.h:147
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
enum AVCodecID codec_id
Definition: ffmpeg_vaapi.c:149
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1608
#define BURST_HEADER_SIZE
Definition: spdif.h:30
MPEG-2, layer-1 low sampling frequency.
Definition: spdif.h:38
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3939
int size
Definition: avcodec.h:1589
static int spdif_read_header(AVFormatContext *s)
Definition: spdifdec.c:163
int64_t bit_rate
Total stream bitrate in bit/s, 0 if not available.
Definition: avformat.h:1427
IEC61937DataType
Definition: spdif.h:32
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:304
static AVPacket pkt
void ff_spdif_bswap_buf16(uint16_t *dst, const uint16_t *src, int w)
Definition: spdif.c:26
int ctx_flags
Flags signalling stream properties.
Definition: avformat.h:1374
int ff_spdif_probe(const uint8_t *p_buf, int buf_size, enum AVCodecID *codec)
Definition: spdifdec.c:112
Format I/O context.
Definition: avformat.h:1325
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
MPEG-2 AAC ADTS.
Definition: spdif.h:37
uint8_t
static int spdif_probe(AVProbeData *p)
Definition: spdifdec.c:106
#define AVFMTCTX_NOHEADER
signal that no header is present (streams are added dynamically)
Definition: avformat.h:1278
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4131
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1393
uint8_t * data
Definition: avcodec.h:1588
#define AVERROR_EOF
End of file.
Definition: error.h:55
DTS type II (1024 samples)
Definition: spdif.h:42
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:511
#define FFALIGN(x, a)
Definition: macros.h:48
#define av_log(a,...)
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:598
#define AV_BSWAP16C(x)
Definition: bswap.h:51
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:86
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: avcodec.h:189
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
DTS type III (2048 samples)
Definition: spdif.h:43
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
preferred ID for decoding MPEG audio layer 1, 2 or 3
Definition: avcodec.h:515
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3935
MPEG-1 layer 2 or 3 data or MPEG-2 without extension.
Definition: spdif.h:35
MPEG-2, layer-3 low sampling frequency.
Definition: spdif.h:40
static const uint8_t offset[127][2]
Definition: vf_spp.c:92
MPEG-1 layer 1.
Definition: spdif.h:34
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:589
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:462
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:461
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1381
#define FFMIN(a, b)
Definition: common.h:96
#define SPDIF_MAX_OFFSET
Definition: spdifdec.c:104
uint32_t samples
Definition: aacadtsdec.h:33
#define SYNCWORD2
Definition: spdif.h:29
Stream structure.
Definition: avformat.h:876
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
#define AAC_ADTS_HEADER_SIZE
Definition: aacadtsdec.h:29
AVIOContext * pb
I/O context.
Definition: avformat.h:1367
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:563
int avpriv_aac_parse_header(GetBitContext *gbc, AACADTSHeaderInfo *hdr)
Parse AAC frame header.
Definition: aacadtsdec.c:29
void * buf
Definition: avisynth_c.h:553
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:485
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:406
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:469
DTS type I (512 samples)
Definition: spdif.h:41
This structure contains the data a format has to probe a file.
Definition: avformat.h:459
void avpriv_report_missing_feature(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
MPEG-2, layer-2 low sampling frequency.
Definition: spdif.h:39
int sample_rate
Audio only.
Definition: avcodec.h:4049
#define AC3_FRAME_SIZE
Definition: ac3.h:37
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:471
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:704
Main libavformat public API header.
MPEG-2 data with extension.
Definition: spdif.h:36
static const uint16_t spdif_mpeg_pkt_offset[2][3]
Definition: spdif.h:55
#define SYNCWORD1
Definition: spdif.h:28
AC-3 data.
Definition: spdif.h:33
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:660
AVCodecParameters * codecpar
Definition: avformat.h:1228
int avio_feof(AVIOContext *s)
feof() equivalent for AVIOContext.
Definition: aviobuf.c:328
static struct @230 state
int ff_spdif_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: spdifdec.c:169
This structure stores compressed data.
Definition: avcodec.h:1565
Common code between the AC-3 encoder and decoder.
AVInputFormat ff_spdif_demuxer
Definition: spdifdec.c:233