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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 "libavcodec/bytestream.h" | |
23 | #include "libavcodec/get_bits.h" | |
24 | #include "libavcodec/dca.h" | |
25 | #include "avformat.h" | |
26 | #include "rawdec.h" | |
27 | ||
28 | #define DCA_MARKER_14B_BE 0x1FFFE800 | |
29 | #define DCA_MARKER_14B_LE 0xFF1F00E8 | |
30 | #define DCA_MARKER_RAW_BE 0x7FFE8001 | |
31 | #define DCA_MARKER_RAW_LE 0xFE7F0180 | |
32 | ||
33 | static int dts_probe(AVProbeData *p) | |
34 | { | |
35 | const uint8_t *buf, *bufp; | |
36 | uint32_t state = -1; | |
37 | int markers[4] = {0}; | |
38 | int sum, max, i; | |
39 | int64_t diff = 0; | |
40 | uint8_t hdr[12 + FF_INPUT_BUFFER_PADDING_SIZE] = { 0 }; | |
41 | ||
42 | buf = p->buf + FFMIN(4096, p->buf_size); | |
43 | ||
44 | for(; buf < (p->buf+p->buf_size)-2; buf+=2) { | |
45 | int marker, sample_blocks, sample_rate, sr_code, framesize; | |
46 | GetBitContext gb; | |
47 | ||
48 | bufp = buf; | |
49 | state = (state << 16) | bytestream_get_be16(&bufp); | |
50 | ||
51 | if (buf - p->buf >= 4) | |
52 | diff += FFABS(((int16_t)AV_RL16(buf)) - (int16_t)AV_RL16(buf-4)); | |
53 | ||
54 | /* regular bitstream */ | |
55 | if (state == DCA_MARKER_RAW_BE) | |
56 | marker = 0; | |
57 | else if (state == DCA_MARKER_RAW_LE) | |
58 | marker = 1; | |
59 | ||
60 | /* 14 bits big-endian bitstream */ | |
61 | else if (state == DCA_MARKER_14B_BE && | |
62 | (bytestream_get_be16(&bufp) & 0xFFF0) == 0x07F0) | |
63 | marker = 2; | |
64 | ||
65 | /* 14 bits little-endian bitstream */ | |
66 | else if (state == DCA_MARKER_14B_LE && | |
67 | (bytestream_get_be16(&bufp) & 0xF0FF) == 0xF007) | |
68 | marker = 3; | |
69 | else | |
70 | continue; | |
71 | ||
72 | if (avpriv_dca_convert_bitstream(buf-2, 12, hdr, 12) < 0) | |
73 | continue; | |
74 | ||
75 | init_get_bits(&gb, hdr, 96); | |
76 | skip_bits_long(&gb, 39); | |
77 | ||
78 | sample_blocks = get_bits(&gb, 7) + 1; | |
79 | if (sample_blocks < 8) | |
80 | continue; | |
81 | ||
82 | framesize = get_bits(&gb, 14) + 1; | |
83 | if (framesize < 95) | |
84 | continue; | |
85 | ||
86 | skip_bits(&gb, 6); | |
87 | sr_code = get_bits(&gb, 4); | |
88 | sample_rate = avpriv_dca_sample_rates[sr_code]; | |
89 | if (sample_rate == 0) | |
90 | continue; | |
91 | ||
92 | markers[marker] ++; | |
93 | } | |
94 | sum = markers[0] + markers[1] + markers[2] + markers[3]; | |
95 | max = 0; | |
96 | for (i=1; i<4; i++) | |
97 | if (markers[max] < markers[i]) | |
98 | max = i; | |
99 | if (markers[max] > 3 && p->buf_size / markers[max] < 32*1024 && | |
100 | markers[max] * 4 > sum * 3 && | |
101 | diff / p->buf_size > 200) | |
102 | return AVPROBE_SCORE_EXTENSION + 1; | |
103 | ||
104 | return 0; | |
105 | } | |
106 | ||
107 | AVInputFormat ff_dts_demuxer = { | |
108 | .name = "dts", | |
109 | .long_name = NULL_IF_CONFIG_SMALL("raw DTS"), | |
110 | .read_probe = dts_probe, | |
111 | .read_header = ff_raw_audio_read_header, | |
112 | .read_packet = ff_raw_read_partial_packet, | |
113 | .flags = AVFMT_GENERIC_INDEX, | |
114 | .extensions = "dts", | |
115 | .raw_codec_id = AV_CODEC_ID_DTS, | |
116 | }; |