FFmpeg
dtsdec.c
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1 /*
2  * RAW DTS demuxer
3  * Copyright (c) 2008 Benjamin Larsson
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 #include "libavutil/crc.h"
23 
24 #include "libavcodec/bytestream.h"
25 #include "libavcodec/dca.h"
27 #include "libavcodec/get_bits.h"
28 
29 #include "avformat.h"
30 #include "demux.h"
31 #include "rawdec.h"
32 
33 static int dts_probe(const AVProbeData *p)
34 {
35  const uint8_t *buf, *bufp;
36  uint32_t state = -1;
37  int markers[4*16] = {0};
38  int exss_markers = 0, exss_nextpos = 0;
39  int sum, max, pos, ret, i;
40  int64_t diff = 0;
41  int diffcount = 1;
43 
44  for (pos = FFMIN(4096, p->buf_size); pos < p->buf_size - 2; pos += 2) {
45  int marker, wide_hdr, hdr_size, framesize;
47  GetBitContext gb;
48 
49  bufp = buf = p->buf + pos;
50  state = (state << 16) | bytestream_get_be16(&bufp);
51 
52  if (pos >= 4) {
53  if (AV_RL16(buf) || AV_RL16(buf-4)) {
54  diff += FFABS(((int16_t)AV_RL16(buf)) - (int16_t)AV_RL16(buf-4));
55  diffcount ++;
56  }
57  }
58 
59  /* extension substream (EXSS) */
61  if (pos < exss_nextpos)
62  continue;
63 
64  init_get_bits(&gb, buf - 2, 96);
65  skip_bits_long(&gb, 42);
66 
67  wide_hdr = get_bits1(&gb);
68  hdr_size = get_bits(&gb, 8 + 4 * wide_hdr) + 1;
69  framesize = get_bits(&gb, 16 + 4 * wide_hdr) + 1;
70  if (hdr_size & 3 || framesize & 3)
71  continue;
72  if (hdr_size < 16 || framesize < hdr_size)
73  continue;
74  if (pos - 2 + hdr_size > p->buf_size)
75  continue;
76  if (av_crc(av_crc_get_table(AV_CRC_16_CCITT), 0xffff, buf + 3, hdr_size - 5))
77  continue;
78 
79  if (pos == exss_nextpos)
80  exss_markers++;
81  else
82  exss_markers = FFMAX(1, exss_markers - 1);
83  exss_nextpos = pos + framesize;
84  continue;
85  }
86 
87  /* regular bitstream */
88  if (state == DCA_SYNCWORD_CORE_BE &&
89  (bytestream_get_be16(&bufp) & 0xFC00) == 0xFC00)
90  marker = 0;
91  else if (state == DCA_SYNCWORD_CORE_LE &&
92  (bytestream_get_be16(&bufp) & 0x00FC) == 0x00FC)
93  marker = 1;
94 
95  /* 14 bits big-endian bitstream */
96  else if (state == DCA_SYNCWORD_CORE_14B_BE &&
97  (bytestream_get_be16(&bufp) & 0xFFF0) == 0x07F0)
98  marker = 2;
99 
100  /* 14 bits little-endian bitstream */
101  else if (state == DCA_SYNCWORD_CORE_14B_LE &&
102  (bytestream_get_be16(&bufp) & 0xF0FF) == 0xF007)
103  marker = 3;
104  else
105  continue;
106 
108  hdr, DCA_CORE_FRAME_HEADER_SIZE)) < 0)
109  continue;
110  if (avpriv_dca_parse_core_frame_header(&h, hdr, ret) < 0)
111  continue;
112 
113  marker += 4 * h.sr_code;
114 
115  markers[marker] ++;
116  }
117 
118  if (exss_markers > 3)
119  return AVPROBE_SCORE_EXTENSION + 1;
120 
121  sum = max = 0;
122  for (i=0; i<FF_ARRAY_ELEMS(markers); i++) {
123  sum += markers[i];
124  if (markers[max] < markers[i])
125  max = i;
126  }
127 
128  if (markers[max] > 3 && p->buf_size / markers[max] < 32*1024 &&
129  markers[max] * 4 > sum * 3 &&
130  diff / diffcount > 600)
131  return AVPROBE_SCORE_EXTENSION + 1;
132 
133  return 0;
134 }
135 
137  .p.name = "dts",
138  .p.long_name = NULL_IF_CONFIG_SMALL("raw DTS"),
139  .p.flags = AVFMT_GENERIC_INDEX,
140  .p.extensions = "dts",
141  .p.priv_class = &ff_raw_demuxer_class,
142  .read_probe = dts_probe,
143  .read_header = ff_raw_audio_read_header,
144  .read_packet = ff_raw_read_partial_packet,
145  .raw_codec_id = AV_CODEC_ID_DTS,
146  .priv_data_size = sizeof(FFRawDemuxerContext),
147 };
ff_dts_demuxer
const FFInputFormat ff_dts_demuxer
Definition: dtsdec.c:136
skip_bits_long
static void skip_bits_long(GetBitContext *s, int n)
Skips the specified number of bits.
Definition: get_bits.h:278
dca.h
DCA_SYNCWORD_CORE_14B_BE
#define DCA_SYNCWORD_CORE_14B_BE
Definition: dca_syncwords.h:24
dts_probe
static int dts_probe(const AVProbeData *p)
Definition: dtsdec.c:33
max
#define max(a, b)
Definition: cuda_runtime.h:33
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:454
FFMAX
#define FFMAX(a, b)
Definition: macros.h:47
init_get_bits
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:514
crc.h
get_bits
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:335
avpriv_dca_convert_bitstream
int avpriv_dca_convert_bitstream(const uint8_t *src, int src_size, uint8_t *dst, int max_size)
Convert bitstream to one representation based on sync marker.
Definition: dca.c:49
GetBitContext
Definition: get_bits.h:108
FFRawDemuxerContext
Definition: rawdec.h:37
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:480
FF_ARRAY_ELEMS
#define FF_ARRAY_ELEMS(a)
Definition: sinewin_tablegen.c:29
ff_raw_read_partial_packet
int ff_raw_read_partial_packet(AVFormatContext *s, AVPacket *pkt)
Definition: rawdec.c:33
state
static struct @382 state
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:553
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:453
get_bits.h
AV_RL16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:94
dca_syncwords.h
FFABS
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
Definition: common.h:72
ff_raw_demuxer_class
const AVClass ff_raw_demuxer_class
Definition: rawdec.c:141
rawdec.h
get_bits1
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:388
ff_raw_audio_read_header
int ff_raw_audio_read_header(AVFormatContext *s)
Definition: rawdec.c:54
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:451
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:461
DCA_SYNCWORD_CORE_BE
#define DCA_SYNCWORD_CORE_BE
Definition: dca_syncwords.h:22
DCACoreFrameHeader
Definition: dca.h:50
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:106
AV_CODEC_ID_DTS
@ AV_CODEC_ID_DTS
Definition: codec_id.h:444
DCA_SYNCWORD_CORE_14B_LE
#define DCA_SYNCWORD_CORE_14B_LE
Definition: dca_syncwords.h:25
FFInputFormat::p
AVInputFormat p
The public AVInputFormat.
Definition: demux.h:35
diff
static av_always_inline int diff(const struct color_info *a, const struct color_info *b, const int trans_thresh)
Definition: vf_paletteuse.c:164
av_crc_get_table
const AVCRC * av_crc_get_table(AVCRCId crc_id)
Get an initialized standard CRC table.
Definition: crc.c:374
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:255
AV_CRC_16_CCITT
@ AV_CRC_16_CCITT
Definition: crc.h:51
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
demux.h
DCA_SYNCWORD_SUBSTREAM
#define DCA_SYNCWORD_SUBSTREAM
Definition: dca_syncwords.h:32
ret
ret
Definition: filter_design.txt:187
DCA_CORE_FRAME_HEADER_SIZE
#define DCA_CORE_FRAME_HEADER_SIZE
Definition: dca.h:36
pos
unsigned int pos
Definition: spdifenc.c:413
avformat.h
AV_INPUT_BUFFER_PADDING_SIZE
#define AV_INPUT_BUFFER_PADDING_SIZE
Definition: defs.h:40
av_crc
uint32_t av_crc(const AVCRC *ctx, uint32_t crc, const uint8_t *buffer, size_t length)
Calculate the CRC of a block.
Definition: crc.c:392
DCA_SYNCWORD_CORE_LE
#define DCA_SYNCWORD_CORE_LE
Definition: dca_syncwords.h:23
avpriv_dca_parse_core_frame_header
int avpriv_dca_parse_core_frame_header(DCACoreFrameHeader *h, const uint8_t *buf, int size)
Parse and validate core frame header.
Definition: dca.c:144
FFInputFormat
Definition: demux.h:31
bytestream.h
h
h
Definition: vp9dsp_template.c:2038