| 1 | /* |
| 2 | * RAW AC-3 and E-AC-3 demuxer |
| 3 | * Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com> |
| 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 | #include "libavcodec/ac3_parser.h" |
| 24 | #include "avformat.h" |
| 25 | #include "rawdec.h" |
| 26 | |
| 27 | static int ac3_eac3_probe(AVProbeData *p, enum AVCodecID expected_codec_id) |
| 28 | { |
| 29 | int max_frames, first_frames = 0, frames; |
| 30 | const uint8_t *buf, *buf2, *end; |
| 31 | AC3HeaderInfo *phdr = NULL; |
| 32 | GetBitContext gbc; |
| 33 | enum AVCodecID codec_id = AV_CODEC_ID_AC3; |
| 34 | |
| 35 | max_frames = 0; |
| 36 | buf = p->buf; |
| 37 | end = buf + p->buf_size; |
| 38 | |
| 39 | for(; buf < end; buf++) { |
| 40 | if(buf > p->buf && !(buf[0] == 0x0B && buf[1] == 0x77) |
| 41 | && !(buf[0] == 0x77 && buf[1] == 0x0B) ) |
| 42 | continue; |
| 43 | buf2 = buf; |
| 44 | |
| 45 | for(frames = 0; buf2 < end; frames++) { |
| 46 | uint8_t buf3[4096]; |
| 47 | int i; |
| 48 | if(!memcmp(buf2, "\x1\x10\0\0\0\0\0\0", 8)) |
| 49 | buf2+=16; |
| 50 | if (buf[0] == 0x77 && buf[1] == 0x0B) { |
| 51 | for(i=0; i<8; i+=2) { |
| 52 | buf3[i ] = buf[i+1]; |
| 53 | buf3[i+1] = buf[i ]; |
| 54 | } |
| 55 | init_get_bits(&gbc, buf3, 54); |
| 56 | }else |
| 57 | init_get_bits(&gbc, buf2, 54); |
| 58 | if(avpriv_ac3_parse_header2(&gbc, &phdr) < 0) |
| 59 | break; |
| 60 | if(buf2 + phdr->frame_size > end) |
| 61 | break; |
| 62 | if (buf[0] == 0x77 && buf[1] == 0x0B) { |
| 63 | av_assert0(phdr->frame_size <= sizeof(buf3)); |
| 64 | for(i=8; i<phdr->frame_size; i+=2) { |
| 65 | buf3[i ] = buf[i+1]; |
| 66 | buf3[i+1] = buf[i ]; |
| 67 | } |
| 68 | } |
| 69 | if(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, gbc.buffer + 2, phdr->frame_size - 2)) |
| 70 | break; |
| 71 | if (phdr->bitstream_id > 10) |
| 72 | codec_id = AV_CODEC_ID_EAC3; |
| 73 | buf2 += phdr->frame_size; |
| 74 | } |
| 75 | max_frames = FFMAX(max_frames, frames); |
| 76 | if(buf == p->buf) |
| 77 | first_frames = frames; |
| 78 | } |
| 79 | av_freep(&phdr); |
| 80 | if(codec_id != expected_codec_id) return 0; |
| 81 | // keep this in sync with mp3 probe, both need to avoid |
| 82 | // issues with MPEG-files! |
| 83 | if (first_frames>=4) return AVPROBE_SCORE_EXTENSION + 1; |
| 84 | else if(max_frames>200)return AVPROBE_SCORE_EXTENSION; |
| 85 | else if(max_frames>=4) return AVPROBE_SCORE_EXTENSION/2; |
| 86 | else if(max_frames>=1) return 1; |
| 87 | else return 0; |
| 88 | } |
| 89 | |
| 90 | #if CONFIG_AC3_DEMUXER |
| 91 | static int ac3_probe(AVProbeData *p) |
| 92 | { |
| 93 | return ac3_eac3_probe(p, AV_CODEC_ID_AC3); |
| 94 | } |
| 95 | |
| 96 | AVInputFormat ff_ac3_demuxer = { |
| 97 | .name = "ac3", |
| 98 | .long_name = NULL_IF_CONFIG_SMALL("raw AC-3"), |
| 99 | .read_probe = ac3_probe, |
| 100 | .read_header = ff_raw_audio_read_header, |
| 101 | .read_packet = ff_raw_read_partial_packet, |
| 102 | .flags= AVFMT_GENERIC_INDEX, |
| 103 | .extensions = "ac3", |
| 104 | .raw_codec_id = AV_CODEC_ID_AC3, |
| 105 | }; |
| 106 | #endif |
| 107 | |
| 108 | #if CONFIG_EAC3_DEMUXER |
| 109 | static int eac3_probe(AVProbeData *p) |
| 110 | { |
| 111 | return ac3_eac3_probe(p, AV_CODEC_ID_EAC3); |
| 112 | } |
| 113 | |
| 114 | AVInputFormat ff_eac3_demuxer = { |
| 115 | .name = "eac3", |
| 116 | .long_name = NULL_IF_CONFIG_SMALL("raw E-AC-3"), |
| 117 | .read_probe = eac3_probe, |
| 118 | .read_header = ff_raw_audio_read_header, |
| 119 | .read_packet = ff_raw_read_partial_packet, |
| 120 | .flags = AVFMT_GENERIC_INDEX, |
| 121 | .extensions = "eac3", |
| 122 | .raw_codec_id = AV_CODEC_ID_EAC3, |
| 123 | }; |
| 124 | #endif |