1/* 2 * Copyright (C) 2017 foo86 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21#include "libavutil/intreadwrite.h" 22#include "avformat.h" 23#include "internal.h" 24#include "spdif.h" 25 26#define MARKER_16LE 0x72F81F4E 27#define MARKER_20LE 0x20876FF0E154 28#define MARKER_24LE 0x72F8961F4EA5 29 30#define IS_16LE_MARKER(state) ((state & 0xFFFFFFFF) == MARKER_16LE) 31#define IS_20LE_MARKER(state) ((state & 0xF0FFFFF0FFFF) == MARKER_20LE) 32#define IS_24LE_MARKER(state) ((state & 0xFFFFFFFFFFFF) == MARKER_24LE) 33#define IS_LE_MARKER(state) (IS_16LE_MARKER(state) || IS_20LE_MARKER(state) || IS_24LE_MARKER(state)) 34 35static int s337m_get_offset_and_codec(void *avc, 36 uint64_t state, 37 int data_type, int data_size, 38 int *offset, enum AVCodecID *codec) 39{ 40 int word_bits; 41 42 if (IS_16LE_MARKER(state)) { 43 word_bits = 16; 44 } else if (IS_20LE_MARKER(state)) { 45 data_type >>= 8; 46 data_size >>= 4; 47 word_bits = 20; 48 } else { 49 data_type >>= 8; 50 word_bits = 24; 51 } 52 53 if ((data_type & 0x1F) != 0x1C) { 54 if (avc) 55 avpriv_report_missing_feature(avc, "Data type %#x in SMPTE 337M", data_type & 0x1F); 56 return AVERROR_PATCHWELCOME; 57 } 58 59 if (codec) 60 *codec = AV_CODEC_ID_DOLBY_E; 61 62 switch (data_size / word_bits) { 63 case 3648: 64 *offset = 1920; 65 break; 66 case 3644: 67 *offset = 2002; 68 break; 69 case 3640: 70 *offset = 2000; 71 break; 72 case 3040: 73 *offset = 1601; 74 break; 75 default: 76 if (avc) 77 avpriv_report_missing_feature(avc, "Dolby E data size %d in SMPTE 337M", data_size); 78 return AVERROR_PATCHWELCOME; 79 } 80 81 *offset -= 4; 82 *offset *= (word_bits + 7 >> 3) * 2; 83 return 0; 84} 85 86static int s337m_probe(const AVProbeData *p) 87{ 88 uint64_t state = 0; 89 int markers[3] = { 0 }; 90 int i, pos, sum, max, data_type, data_size, offset; 91 uint8_t *buf; 92 93 for (pos = 0; pos < p->buf_size; pos++) { 94 state = (state << 8) | p->buf[pos]; 95 if (!IS_LE_MARKER(state)) 96 continue; 97 98 buf = p->buf + pos + 1; 99 if (IS_16LE_MARKER(state)) { 100 data_type = AV_RL16(buf ); 101 data_size = AV_RL16(buf + 2); 102 } else { 103 data_type = AV_RL24(buf ); 104 data_size = AV_RL24(buf + 3); 105 } 106 107 if (s337m_get_offset_and_codec(NULL, state, data_type, data_size, &offset, NULL)) 108 continue; 109 110 i = IS_16LE_MARKER(state) ? 0 : IS_20LE_MARKER(state) ? 1 : 2; 111 markers[i]++; 112 113 pos += IS_16LE_MARKER(state) ? 4 : 6; 114 pos += offset; 115 state = 0; 116 } 117 118 sum = max = 0; 119 for (i = 0; i < FF_ARRAY_ELEMS(markers); i++) { 120 sum += markers[i]; 121 if (markers[max] < markers[i]) 122 max = i; 123 } 124 125 if (markers[max] > 3 && markers[max] * 4 > sum * 3) 126 return AVPROBE_SCORE_EXTENSION + 1; 127 128 return 0; 129} 130 131static int s337m_read_header(AVFormatContext *s) 132{ 133 s->ctx_flags |= AVFMTCTX_NOHEADER; 134 return 0; 135} 136 137static void bswap_buf24(uint8_t *data, int size) 138{ 139 int i; 140 141 for (i = 0; i < size / 3; i++, data += 3) 142 FFSWAP(uint8_t, data[0], data[2]); 143} 144 145static int s337m_read_packet(AVFormatContext *s, AVPacket *pkt) 146{ 147 AVIOContext *pb = s->pb; 148 uint64_t state = 0; 149 int ret, data_type, data_size, offset; 150 enum AVCodecID codec; 151 152 while (!IS_LE_MARKER(state)) { 153 state = (state << 8) | avio_r8(pb); 154 if (avio_feof(pb)) 155 return AVERROR_EOF; 156 } 157 158 if (IS_16LE_MARKER(state)) { 159 data_type = avio_rl16(pb); 160 data_size = avio_rl16(pb); 161 } else { 162 data_type = avio_rl24(pb); 163 data_size = avio_rl24(pb); 164 } 165 166 if ((ret = s337m_get_offset_and_codec(s, state, data_type, data_size, &offset, &codec)) < 0) 167 return ret; 168 169 if ((ret = av_get_packet(pb, pkt, offset)) != offset) 170 return ret < 0 ? ret : AVERROR_EOF; 171 172 if (IS_16LE_MARKER(state)) 173 ff_spdif_bswap_buf16((uint16_t *)pkt->data, (uint16_t *)pkt->data, pkt->size >> 1); 174 else 175 bswap_buf24(pkt->data, pkt->size); 176 177 if (!s->nb_streams) { 178 AVStream *st = avformat_new_stream(s, NULL); 179 if (!st) { 180 return AVERROR(ENOMEM); 181 } 182 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO; 183 st->codecpar->codec_id = codec; 184 ffstream(st)->need_parsing = AVSTREAM_PARSE_HEADERS; 185 } 186 187 return 0; 188} 189 190const AVInputFormat ff_s337m_demuxer = { 191 .name = "s337m", 192 .long_name = NULL_IF_CONFIG_SMALL("SMPTE 337M"), 193 .read_probe = s337m_probe, 194 .read_header = s337m_read_header, 195 .read_packet = s337m_read_packet, 196 .flags = AVFMT_GENERIC_INDEX, 197}; 198