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 "spdif.h"
24
25 #define MARKER_16LE 0x72F81F4E
26 #define MARKER_20LE 0x20876FF0E154
27 #define MARKER_24LE 0x72F8961F4EA5
28
29 #define IS_16LE_MARKER(state) ((state & 0xFFFFFFFF) == MARKER_16LE)
30 #define IS_20LE_MARKER(state) ((state & 0xF0FFFFF0FFFF) == MARKER_20LE)
31 #define IS_24LE_MARKER(state) ((state & 0xFFFFFFFFFFFF) == MARKER_24LE)
32 #define IS_LE_MARKER(state) (IS_16LE_MARKER(state) || IS_20LE_MARKER(state) || IS_24LE_MARKER(state))
33
s337m_get_offset_and_codec(void * avc,uint64_t state,int data_type,int data_size,int * offset,enum AVCodecID * codec)34 static int s337m_get_offset_and_codec(void *avc,
35 uint64_t state,
36 int data_type, int data_size,
37 int *offset, enum AVCodecID *codec)
38 {
39 int word_bits;
40
41 if (IS_16LE_MARKER(state)) {
42 word_bits = 16;
43 } else if (IS_20LE_MARKER(state)) {
44 data_type >>= 8;
45 data_size >>= 4;
46 word_bits = 20;
47 } else {
48 data_type >>= 8;
49 word_bits = 24;
50 }
51
52 if ((data_type & 0x1F) != 0x1C) {
53 if (avc)
54 avpriv_report_missing_feature(avc, "Data type %#x in SMPTE 337M", data_type & 0x1F);
55 return AVERROR_PATCHWELCOME;
56 }
57
58 if (codec)
59 *codec = AV_CODEC_ID_DOLBY_E;
60
61 switch (data_size / word_bits) {
62 case 3648:
63 *offset = 1920;
64 break;
65 case 3644:
66 *offset = 2002;
67 break;
68 case 3640:
69 *offset = 2000;
70 break;
71 case 3040:
72 *offset = 1601;
73 break;
74 default:
75 if (avc)
76 avpriv_report_missing_feature(avc, "Dolby E data size %d in SMPTE 337M", data_size);
77 return AVERROR_PATCHWELCOME;
78 }
79
80 *offset -= 4;
81 *offset *= (word_bits + 7 >> 3) * 2;
82 return 0;
83 }
84
s337m_probe(const AVProbeData * p)85 static int s337m_probe(const AVProbeData *p)
86 {
87 uint64_t state = 0;
88 int markers[3] = { 0 };
89 int i, pos, sum, max, data_type, data_size, offset;
90 uint8_t *buf;
91
92 for (pos = 0; pos < p->buf_size; pos++) {
93 state = (state << 8) | p->buf[pos];
94 if (!IS_LE_MARKER(state))
95 continue;
96
97 buf = p->buf + pos + 1;
98 if (IS_16LE_MARKER(state)) {
99 data_type = AV_RL16(buf );
100 data_size = AV_RL16(buf + 2);
101 } else {
102 data_type = AV_RL24(buf );
103 data_size = AV_RL24(buf + 3);
104 }
105
106 if (s337m_get_offset_and_codec(NULL, state, data_type, data_size, &offset, NULL))
107 continue;
108
109 i = IS_16LE_MARKER(state) ? 0 : IS_20LE_MARKER(state) ? 1 : 2;
110 markers[i]++;
111
112 pos += IS_16LE_MARKER(state) ? 4 : 6;
113 pos += offset;
114 state = 0;
115 }
116
117 sum = max = 0;
118 for (i = 0; i < FF_ARRAY_ELEMS(markers); i++) {
119 sum += markers[i];
120 if (markers[max] < markers[i])
121 max = i;
122 }
123
124 if (markers[max] > 3 && markers[max] * 4 > sum * 3)
125 return AVPROBE_SCORE_EXTENSION + 1;
126
127 return 0;
128 }
129
s337m_read_header(AVFormatContext * s)130 static int s337m_read_header(AVFormatContext *s)
131 {
132 s->ctx_flags |= AVFMTCTX_NOHEADER;
133 return 0;
134 }
135
bswap_buf24(uint8_t * data,int size)136 static void bswap_buf24(uint8_t *data, int size)
137 {
138 int i;
139
140 for (i = 0; i < size / 3; i++, data += 3)
141 FFSWAP(uint8_t, data[0], data[2]);
142 }
143
s337m_read_packet(AVFormatContext * s,AVPacket * pkt)144 static int s337m_read_packet(AVFormatContext *s, AVPacket *pkt)
145 {
146 AVIOContext *pb = s->pb;
147 uint64_t state = 0;
148 int ret, data_type, data_size, offset;
149 enum AVCodecID codec;
150 int64_t pos;
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 pos = avio_tell(pb);
167
168 if ((ret = s337m_get_offset_and_codec(s, state, data_type, data_size, &offset, &codec)) < 0)
169 return ret;
170
171 if ((ret = av_new_packet(pkt, offset)) < 0)
172 return ret;
173
174 pkt->pos = pos;
175
176 if (avio_read(pb, pkt->data, pkt->size) < pkt->size) {
177 return AVERROR_EOF;
178 }
179
180 if (IS_16LE_MARKER(state))
181 ff_spdif_bswap_buf16((uint16_t *)pkt->data, (uint16_t *)pkt->data, pkt->size >> 1);
182 else
183 bswap_buf24(pkt->data, pkt->size);
184
185 if (!s->nb_streams) {
186 AVStream *st = avformat_new_stream(s, NULL);
187 if (!st) {
188 return AVERROR(ENOMEM);
189 }
190 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
191 st->codecpar->codec_id = codec;
192 }
193
194 return 0;
195 }
196
197 AVInputFormat ff_s337m_demuxer = {
198 .name = "s337m",
199 .long_name = NULL_IF_CONFIG_SMALL("SMPTE 337M"),
200 .read_probe = s337m_probe,
201 .read_header = s337m_read_header,
202 .read_packet = s337m_read_packet,
203 .flags = AVFMT_GENERIC_INDEX,
204 };
205