Commit | Line | Data |
---|---|---|
2ba45a60 DM |
1 | /* |
2 | * IEC 61937 demuxer | |
3 | * Copyright (c) 2010 Anssi Hannula <anssi.hannula at iki.fi> | |
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 | /** | |
23 | * @file | |
24 | * IEC 61937 demuxer, used for compressed data in S/PDIF | |
25 | * @author Anssi Hannula | |
26 | */ | |
27 | ||
28 | #include "avformat.h" | |
29 | #include "spdif.h" | |
30 | #include "libavcodec/ac3.h" | |
31 | #include "libavcodec/aacadtsdec.h" | |
32 | ||
33 | static int spdif_get_offset_and_codec(AVFormatContext *s, | |
34 | enum IEC61937DataType data_type, | |
35 | const char *buf, int *offset, | |
36 | enum AVCodecID *codec) | |
37 | { | |
38 | AACADTSHeaderInfo aac_hdr; | |
39 | GetBitContext gbc; | |
40 | ||
41 | switch (data_type & 0xff) { | |
42 | case IEC61937_AC3: | |
43 | *offset = AC3_FRAME_SIZE << 2; | |
44 | *codec = AV_CODEC_ID_AC3; | |
45 | break; | |
46 | case IEC61937_MPEG1_LAYER1: | |
47 | *offset = spdif_mpeg_pkt_offset[1][0]; | |
48 | *codec = AV_CODEC_ID_MP1; | |
49 | break; | |
50 | case IEC61937_MPEG1_LAYER23: | |
51 | *offset = spdif_mpeg_pkt_offset[1][0]; | |
52 | *codec = AV_CODEC_ID_MP3; | |
53 | break; | |
54 | case IEC61937_MPEG2_EXT: | |
55 | *offset = 4608; | |
56 | *codec = AV_CODEC_ID_MP3; | |
57 | break; | |
58 | case IEC61937_MPEG2_AAC: | |
59 | init_get_bits(&gbc, buf, AAC_ADTS_HEADER_SIZE * 8); | |
60 | if (avpriv_aac_parse_header(&gbc, &aac_hdr) < 0) { | |
61 | if (s) /* be silent during a probe */ | |
62 | av_log(s, AV_LOG_ERROR, "Invalid AAC packet in IEC 61937\n"); | |
63 | return AVERROR_INVALIDDATA; | |
64 | } | |
65 | *offset = aac_hdr.samples << 2; | |
66 | *codec = AV_CODEC_ID_AAC; | |
67 | break; | |
68 | case IEC61937_MPEG2_LAYER1_LSF: | |
69 | *offset = spdif_mpeg_pkt_offset[0][0]; | |
70 | *codec = AV_CODEC_ID_MP1; | |
71 | break; | |
72 | case IEC61937_MPEG2_LAYER2_LSF: | |
73 | *offset = spdif_mpeg_pkt_offset[0][1]; | |
74 | *codec = AV_CODEC_ID_MP2; | |
75 | break; | |
76 | case IEC61937_MPEG2_LAYER3_LSF: | |
77 | *offset = spdif_mpeg_pkt_offset[0][2]; | |
78 | *codec = AV_CODEC_ID_MP3; | |
79 | break; | |
80 | case IEC61937_DTS1: | |
81 | *offset = 2048; | |
82 | *codec = AV_CODEC_ID_DTS; | |
83 | break; | |
84 | case IEC61937_DTS2: | |
85 | *offset = 4096; | |
86 | *codec = AV_CODEC_ID_DTS; | |
87 | break; | |
88 | case IEC61937_DTS3: | |
89 | *offset = 8192; | |
90 | *codec = AV_CODEC_ID_DTS; | |
91 | break; | |
92 | default: | |
93 | if (s) { /* be silent during a probe */ | |
94 | avpriv_request_sample(s, "Data type 0x%04x in IEC 61937", | |
95 | data_type); | |
96 | } | |
97 | return AVERROR_PATCHWELCOME; | |
98 | } | |
99 | return 0; | |
100 | } | |
101 | ||
102 | /* Largest offset between bursts we currently handle, i.e. AAC with | |
103 | aac_hdr.samples = 4096 */ | |
104 | #define SPDIF_MAX_OFFSET 16384 | |
105 | ||
106 | static int spdif_probe(AVProbeData *p) | |
107 | { | |
108 | enum AVCodecID codec; | |
109 | return ff_spdif_probe (p->buf, p->buf_size, &codec); | |
110 | } | |
111 | ||
112 | int ff_spdif_probe(const uint8_t *p_buf, int buf_size, enum AVCodecID *codec) | |
113 | { | |
114 | const uint8_t *buf = p_buf; | |
115 | const uint8_t *probe_end = p_buf + FFMIN(2 * SPDIF_MAX_OFFSET, buf_size - 1); | |
116 | const uint8_t *expected_code = buf + 7; | |
117 | uint32_t state = 0; | |
118 | int sync_codes = 0; | |
119 | int consecutive_codes = 0; | |
120 | int offset; | |
121 | ||
122 | for (; buf < probe_end; buf++) { | |
123 | state = (state << 8) | *buf; | |
124 | ||
125 | if (state == (AV_BSWAP16C(SYNCWORD1) << 16 | AV_BSWAP16C(SYNCWORD2)) | |
126 | && buf[1] < 0x37) { | |
127 | sync_codes++; | |
128 | ||
129 | if (buf == expected_code) { | |
130 | if (++consecutive_codes >= 2) | |
131 | return AVPROBE_SCORE_MAX; | |
132 | } else | |
133 | consecutive_codes = 0; | |
134 | ||
135 | if (buf + 4 + AAC_ADTS_HEADER_SIZE > p_buf + buf_size) | |
136 | break; | |
137 | ||
138 | /* continue probing to find more sync codes */ | |
139 | probe_end = FFMIN(buf + SPDIF_MAX_OFFSET, p_buf + buf_size - 1); | |
140 | ||
141 | /* skip directly to the next sync code */ | |
142 | if (!spdif_get_offset_and_codec(NULL, (buf[2] << 8) | buf[1], | |
143 | &buf[5], &offset, codec)) { | |
144 | if (buf + offset >= p_buf + buf_size) | |
145 | break; | |
146 | expected_code = buf + offset; | |
147 | buf = expected_code - 7; | |
148 | } | |
149 | } | |
150 | } | |
151 | ||
152 | if (!sync_codes) | |
153 | return 0; | |
154 | ||
155 | if (sync_codes >= 6) | |
156 | /* good amount of sync codes but with unexpected offsets */ | |
157 | return AVPROBE_SCORE_EXTENSION; | |
158 | ||
159 | /* some sync codes were found */ | |
160 | return AVPROBE_SCORE_EXTENSION / 4; | |
161 | } | |
162 | ||
163 | static int spdif_read_header(AVFormatContext *s) | |
164 | { | |
165 | s->ctx_flags |= AVFMTCTX_NOHEADER; | |
166 | return 0; | |
167 | } | |
168 | ||
169 | int ff_spdif_read_packet(AVFormatContext *s, AVPacket *pkt) | |
170 | { | |
171 | AVIOContext *pb = s->pb; | |
172 | enum IEC61937DataType data_type; | |
173 | enum AVCodecID codec_id; | |
174 | uint32_t state = 0; | |
175 | int pkt_size_bits, offset, ret; | |
176 | ||
177 | while (state != (AV_BSWAP16C(SYNCWORD1) << 16 | AV_BSWAP16C(SYNCWORD2))) { | |
178 | state = (state << 8) | avio_r8(pb); | |
179 | if (avio_feof(pb)) | |
180 | return AVERROR_EOF; | |
181 | } | |
182 | ||
183 | data_type = avio_rl16(pb); | |
184 | pkt_size_bits = avio_rl16(pb); | |
185 | ||
186 | if (pkt_size_bits % 16) | |
187 | avpriv_request_sample(s, "Packet not ending at a 16-bit boundary"); | |
188 | ||
189 | ret = av_new_packet(pkt, FFALIGN(pkt_size_bits, 16) >> 3); | |
190 | if (ret) | |
191 | return ret; | |
192 | ||
193 | pkt->pos = avio_tell(pb) - BURST_HEADER_SIZE; | |
194 | ||
195 | if (avio_read(pb, pkt->data, pkt->size) < pkt->size) { | |
196 | av_free_packet(pkt); | |
197 | return AVERROR_EOF; | |
198 | } | |
199 | ff_spdif_bswap_buf16((uint16_t *)pkt->data, (uint16_t *)pkt->data, pkt->size >> 1); | |
200 | ||
201 | ret = spdif_get_offset_and_codec(s, data_type, pkt->data, | |
202 | &offset, &codec_id); | |
203 | if (ret) { | |
204 | av_free_packet(pkt); | |
205 | return ret; | |
206 | } | |
207 | ||
208 | /* skip over the padding to the beginning of the next frame */ | |
209 | avio_skip(pb, offset - pkt->size - BURST_HEADER_SIZE); | |
210 | ||
211 | if (!s->nb_streams) { | |
212 | /* first packet, create a stream */ | |
213 | AVStream *st = avformat_new_stream(s, NULL); | |
214 | if (!st) { | |
215 | av_free_packet(pkt); | |
216 | return AVERROR(ENOMEM); | |
217 | } | |
218 | st->codec->codec_type = AVMEDIA_TYPE_AUDIO; | |
219 | st->codec->codec_id = codec_id; | |
220 | } else if (codec_id != s->streams[0]->codec->codec_id) { | |
221 | avpriv_report_missing_feature(s, "Codec change in IEC 61937"); | |
222 | return AVERROR_PATCHWELCOME; | |
223 | } | |
224 | ||
225 | if (!s->bit_rate && s->streams[0]->codec->sample_rate) | |
226 | /* stream bitrate matches 16-bit stereo PCM bitrate for currently | |
227 | supported codecs */ | |
228 | s->bit_rate = 2 * 16 * s->streams[0]->codec->sample_rate; | |
229 | ||
230 | return 0; | |
231 | } | |
232 | ||
233 | AVInputFormat ff_spdif_demuxer = { | |
234 | .name = "spdif", | |
235 | .long_name = NULL_IF_CONFIG_SMALL("IEC 61937 (compressed data in S/PDIF)"), | |
236 | .read_probe = spdif_probe, | |
237 | .read_header = spdif_read_header, | |
238 | .read_packet = ff_spdif_read_packet, | |
239 | .flags = AVFMT_GENERIC_INDEX, | |
240 | }; |