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
s337m_get_offset_and_codec(void * avc,uint64_t state,int data_type,int data_size,int * offset,enum AVCodecID * codec)35 static 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
s337m_probe(const AVProbeData * p)86 static 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
s337m_read_header(AVFormatContext * s)131 static int s337m_read_header(AVFormatContext *s)
132 {
133 s->ctx_flags |= AVFMTCTX_NOHEADER;
134 return 0;
135 }
136
bswap_buf24(uint8_t * data,int size)137 static 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
s337m_read_packet(AVFormatContext * s,AVPacket * pkt)145 static 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
190 const 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