blob: 8c985b887736becf6e67783ac7937a16e4b2f5e0
| 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" |
| 26 | #include "libavcodec/dca_syncwords.h" |
| 27 | #include "libavcodec/get_bits.h" |
| 28 | |
| 29 | #include "avformat.h" |
| 30 | #include "rawdec.h" |
| 31 | |
| 32 | static int dts_probe(AVProbeData *p) |
| 33 | { |
| 34 | const uint8_t *buf, *bufp; |
| 35 | uint32_t state = -1; |
| 36 | int markers[4*16] = {0}; |
| 37 | int exss_markers = 0, exss_nextpos = 0; |
| 38 | int sum, max, pos, i; |
| 39 | int64_t diff = 0; |
| 40 | uint8_t hdr[12 + AV_INPUT_BUFFER_PADDING_SIZE] = { 0 }; |
| 41 | |
| 42 | for (pos = FFMIN(4096, p->buf_size); pos < p->buf_size - 2; pos += 2) { |
| 43 | int marker, sample_blocks, sample_rate, sr_code, framesize; |
| 44 | int lfe, wide_hdr, hdr_size; |
| 45 | GetBitContext gb; |
| 46 | |
| 47 | bufp = buf = p->buf + pos; |
| 48 | state = (state << 16) | bytestream_get_be16(&bufp); |
| 49 | |
| 50 | if (pos >= 4) |
| 51 | diff += FFABS(((int16_t)AV_RL16(buf)) - (int16_t)AV_RL16(buf-4)); |
| 52 | |
| 53 | /* extension substream (EXSS) */ |
| 54 | if (state == DCA_SYNCWORD_SUBSTREAM) { |
| 55 | if (pos < exss_nextpos) |
| 56 | continue; |
| 57 | |
| 58 | init_get_bits(&gb, buf - 2, 96); |
| 59 | skip_bits_long(&gb, 42); |
| 60 | |
| 61 | wide_hdr = get_bits1(&gb); |
| 62 | hdr_size = get_bits(&gb, 8 + 4 * wide_hdr) + 1; |
| 63 | framesize = get_bits(&gb, 16 + 4 * wide_hdr) + 1; |
| 64 | if (hdr_size & 3 || framesize & 3) |
| 65 | continue; |
| 66 | if (hdr_size < 16 || framesize < hdr_size) |
| 67 | continue; |
| 68 | if (pos - 2 + hdr_size > p->buf_size) |
| 69 | continue; |
| 70 | if (av_crc(av_crc_get_table(AV_CRC_16_CCITT), 0xffff, buf + 3, hdr_size - 5)) |
| 71 | continue; |
| 72 | |
| 73 | if (pos == exss_nextpos) |
| 74 | exss_markers++; |
| 75 | else |
| 76 | exss_markers = FFMAX(1, exss_markers - 1); |
| 77 | exss_nextpos = pos + framesize; |
| 78 | continue; |
| 79 | } |
| 80 | |
| 81 | /* regular bitstream */ |
| 82 | if (state == DCA_SYNCWORD_CORE_BE && |
| 83 | (bytestream_get_be16(&bufp) & 0xFC00) == 0xFC00) |
| 84 | marker = 0; |
| 85 | else if (state == DCA_SYNCWORD_CORE_LE && |
| 86 | (bytestream_get_be16(&bufp) & 0x00FC) == 0x00FC) |
| 87 | marker = 1; |
| 88 | |
| 89 | /* 14 bits big-endian bitstream */ |
| 90 | else if (state == DCA_SYNCWORD_CORE_14B_BE && |
| 91 | (bytestream_get_be16(&bufp) & 0xFFF0) == 0x07F0) |
| 92 | marker = 2; |
| 93 | |
| 94 | /* 14 bits little-endian bitstream */ |
| 95 | else if (state == DCA_SYNCWORD_CORE_14B_LE && |
| 96 | (bytestream_get_be16(&bufp) & 0xF0FF) == 0xF007) |
| 97 | marker = 3; |
| 98 | else |
| 99 | continue; |
| 100 | |
| 101 | if (avpriv_dca_convert_bitstream(buf-2, 12, hdr, 12) < 0) |
| 102 | continue; |
| 103 | |
| 104 | init_get_bits(&gb, hdr, 96); |
| 105 | skip_bits_long(&gb, 39); |
| 106 | |
| 107 | sample_blocks = get_bits(&gb, 7) + 1; |
| 108 | if (sample_blocks < 8) |
| 109 | continue; |
| 110 | |
| 111 | framesize = get_bits(&gb, 14) + 1; |
| 112 | if (framesize < 95) |
| 113 | continue; |
| 114 | |
| 115 | skip_bits(&gb, 6); |
| 116 | sr_code = get_bits(&gb, 4); |
| 117 | sample_rate = avpriv_dca_sample_rates[sr_code]; |
| 118 | if (sample_rate == 0) |
| 119 | continue; |
| 120 | |
| 121 | get_bits(&gb, 5); |
| 122 | if (get_bits(&gb, 1)) |
| 123 | continue; |
| 124 | |
| 125 | skip_bits_long(&gb, 9); |
| 126 | lfe = get_bits(&gb, 2); |
| 127 | if (lfe > 2) |
| 128 | continue; |
| 129 | |
| 130 | marker += 4* sr_code; |
| 131 | |
| 132 | markers[marker] ++; |
| 133 | } |
| 134 | |
| 135 | if (exss_markers > 3) |
| 136 | return AVPROBE_SCORE_EXTENSION + 1; |
| 137 | |
| 138 | sum = max = 0; |
| 139 | for (i=0; i<FF_ARRAY_ELEMS(markers); i++) { |
| 140 | sum += markers[i]; |
| 141 | if (markers[max] < markers[i]) |
| 142 | max = i; |
| 143 | } |
| 144 | |
| 145 | if (markers[max] > 3 && p->buf_size / markers[max] < 32*1024 && |
| 146 | markers[max] * 4 > sum * 3 && |
| 147 | diff / p->buf_size > 200) |
| 148 | return AVPROBE_SCORE_EXTENSION + 1; |
| 149 | |
| 150 | return 0; |
| 151 | } |
| 152 | |
| 153 | AVInputFormat ff_dts_demuxer = { |
| 154 | .name = "dts", |
| 155 | .long_name = NULL_IF_CONFIG_SMALL("raw DTS"), |
| 156 | .read_probe = dts_probe, |
| 157 | .read_header = ff_raw_audio_read_header, |
| 158 | .read_packet = ff_raw_read_partial_packet, |
| 159 | .flags = AVFMT_GENERIC_INDEX, |
| 160 | .extensions = "dts", |
| 161 | .raw_codec_id = AV_CODEC_ID_DTS, |
| 162 | }; |
| 163 |