1 /*
2 * ADTS muxer.
3 * Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com>
4 * Mans Rullgard <mans@mansr.com>
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include "libavcodec/get_bits.h"
24 #include "libavcodec/put_bits.h"
25 #include "libavcodec/codec_id.h"
26 #include "libavcodec/codec_par.h"
27 #include "libavcodec/packet.h"
28 #include "libavcodec/mpeg4audio.h"
29 #include "libavutil/opt.h"
30 #include "avformat.h"
31 #include "apetag.h"
32 #include "id3v2.h"
33
34 #define ADTS_HEADER_SIZE 7
35
36 typedef struct ADTSContext {
37 AVClass *class;
38 int write_adts;
39 int objecttype;
40 int sample_rate_index;
41 int channel_conf;
42 int pce_size;
43 int apetag;
44 int id3v2tag;
45 int mpeg_id;
46 uint8_t pce_data[MAX_PCE_SIZE];
47 } ADTSContext;
48
49 #define ADTS_MAX_FRAME_BYTES ((1 << 14) - 1)
50
adts_decode_extradata(AVFormatContext * s,ADTSContext * adts,const uint8_t * buf,int size)51 static int adts_decode_extradata(AVFormatContext *s, ADTSContext *adts, const uint8_t *buf, int size)
52 {
53 GetBitContext gb;
54 PutBitContext pb;
55 MPEG4AudioConfig m4ac;
56 int off, ret;
57
58 ret = init_get_bits8(&gb, buf, size);
59 if (ret < 0)
60 return ret;
61 off = avpriv_mpeg4audio_get_config2(&m4ac, buf, size, 1, s);
62 if (off < 0)
63 return off;
64 skip_bits_long(&gb, off);
65 adts->objecttype = m4ac.object_type - 1;
66 adts->sample_rate_index = m4ac.sampling_index;
67 adts->channel_conf = m4ac.chan_config;
68
69 if (adts->objecttype > 3U) {
70 av_log(s, AV_LOG_ERROR, "MPEG-4 AOT %d is not allowed in ADTS\n", adts->objecttype+1);
71 return AVERROR_INVALIDDATA;
72 }
73 if (adts->sample_rate_index == 15) {
74 av_log(s, AV_LOG_ERROR, "Escape sample rate index illegal in ADTS\n");
75 return AVERROR_INVALIDDATA;
76 }
77 if (get_bits(&gb, 1)) {
78 av_log(s, AV_LOG_ERROR, "960/120 MDCT window is not allowed in ADTS\n");
79 return AVERROR_INVALIDDATA;
80 }
81 if (get_bits(&gb, 1)) {
82 av_log(s, AV_LOG_ERROR, "Scalable configurations are not allowed in ADTS\n");
83 return AVERROR_INVALIDDATA;
84 }
85 if (get_bits(&gb, 1)) {
86 av_log(s, AV_LOG_ERROR, "Extension flag is not allowed in ADTS\n");
87 return AVERROR_INVALIDDATA;
88 }
89 if (!adts->channel_conf) {
90 init_put_bits(&pb, adts->pce_data, MAX_PCE_SIZE);
91
92 put_bits(&pb, 3, 5); //ID_PCE
93 adts->pce_size = (ff_copy_pce_data(&pb, &gb) + 3) / 8;
94 flush_put_bits(&pb);
95 }
96
97 adts->write_adts = 1;
98
99 return 0;
100 }
101
adts_init(AVFormatContext * s)102 static int adts_init(AVFormatContext *s)
103 {
104 ADTSContext *adts = s->priv_data;
105 AVCodecParameters *par = s->streams[0]->codecpar;
106
107 if (par->codec_id != AV_CODEC_ID_AAC) {
108 av_log(s, AV_LOG_ERROR, "Only AAC streams can be muxed by the ADTS muxer\n");
109 return AVERROR(EINVAL);
110 }
111 if (par->extradata_size > 0)
112 return adts_decode_extradata(s, adts, par->extradata,
113 par->extradata_size);
114
115 return 0;
116 }
117
adts_write_header(AVFormatContext * s)118 static int adts_write_header(AVFormatContext *s)
119 {
120 ADTSContext *adts = s->priv_data;
121
122 if (adts->id3v2tag)
123 ff_id3v2_write_simple(s, 4, ID3v2_DEFAULT_MAGIC);
124
125 return 0;
126 }
127
adts_write_frame_header(ADTSContext * ctx,uint8_t * buf,int size,int pce_size)128 static int adts_write_frame_header(ADTSContext *ctx,
129 uint8_t *buf, int size, int pce_size)
130 {
131 PutBitContext pb;
132
133 unsigned full_frame_size = (unsigned)ADTS_HEADER_SIZE + size + pce_size;
134 if (full_frame_size > ADTS_MAX_FRAME_BYTES) {
135 av_log(NULL, AV_LOG_ERROR, "ADTS frame size too large: %u (max %d)\n",
136 full_frame_size, ADTS_MAX_FRAME_BYTES);
137 return AVERROR_INVALIDDATA;
138 }
139
140 init_put_bits(&pb, buf, ADTS_HEADER_SIZE);
141
142 /* adts_fixed_header */
143 put_bits(&pb, 12, 0xfff); /* syncword */
144 put_bits(&pb, 1, ctx->mpeg_id); /* ID */
145 put_bits(&pb, 2, 0); /* layer */
146 put_bits(&pb, 1, 1); /* protection_absent */
147 put_bits(&pb, 2, ctx->objecttype); /* profile_objecttype */
148 put_bits(&pb, 4, ctx->sample_rate_index);
149 put_bits(&pb, 1, 0); /* private_bit */
150 put_bits(&pb, 3, ctx->channel_conf); /* channel_configuration */
151 put_bits(&pb, 1, 0); /* original_copy */
152 put_bits(&pb, 1, 0); /* home */
153
154 /* adts_variable_header */
155 put_bits(&pb, 1, 0); /* copyright_identification_bit */
156 put_bits(&pb, 1, 0); /* copyright_identification_start */
157 put_bits(&pb, 13, full_frame_size); /* aac_frame_length */
158 put_bits(&pb, 11, 0x7ff); /* adts_buffer_fullness */
159 put_bits(&pb, 2, 0); /* number_of_raw_data_blocks_in_frame */
160
161 flush_put_bits(&pb);
162
163 return 0;
164 }
165
adts_write_packet(AVFormatContext * s,AVPacket * pkt)166 static int adts_write_packet(AVFormatContext *s, AVPacket *pkt)
167 {
168 ADTSContext *adts = s->priv_data;
169 AVCodecParameters *par = s->streams[0]->codecpar;
170 AVIOContext *pb = s->pb;
171 uint8_t buf[ADTS_HEADER_SIZE];
172
173 if (!pkt->size)
174 return 0;
175 if (!par->extradata_size) {
176 uint8_t *side_data;
177 size_t side_data_size;
178 int ret;
179
180 side_data = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
181 &side_data_size);
182 if (side_data_size) {
183 ret = adts_decode_extradata(s, adts, side_data, side_data_size);
184 if (ret < 0)
185 return ret;
186 ret = ff_alloc_extradata(par, side_data_size);
187 if (ret < 0)
188 return ret;
189 memcpy(par->extradata, side_data, side_data_size);
190 }
191 }
192 if (adts->write_adts) {
193 int err = adts_write_frame_header(adts, buf, pkt->size,
194 adts->pce_size);
195 if (err < 0)
196 return err;
197 avio_write(pb, buf, ADTS_HEADER_SIZE);
198 if (adts->pce_size) {
199 avio_write(pb, adts->pce_data, adts->pce_size);
200 adts->pce_size = 0;
201 }
202 }
203 avio_write(pb, pkt->data, pkt->size);
204
205 return 0;
206 }
207
adts_write_trailer(AVFormatContext * s)208 static int adts_write_trailer(AVFormatContext *s)
209 {
210 ADTSContext *adts = s->priv_data;
211
212 if (adts->apetag)
213 ff_ape_write_tag(s);
214
215 return 0;
216 }
217
218 #define ENC AV_OPT_FLAG_ENCODING_PARAM
219 #define OFFSET(obj) offsetof(ADTSContext, obj)
220 static const AVOption options[] = {
221 { "write_id3v2", "Enable ID3v2 tag writing", OFFSET(id3v2tag), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, ENC},
222 { "write_apetag", "Enable APE tag writing", OFFSET(apetag), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, ENC},
223 { "write_mpeg2", "Set MPEG version to MPEG-2", OFFSET(mpeg_id), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, ENC},
224 { NULL },
225 };
226
227 static const AVClass adts_muxer_class = {
228 .class_name = "ADTS muxer",
229 .item_name = av_default_item_name,
230 .option = options,
231 .version = LIBAVUTIL_VERSION_INT,
232 };
233
234 const AVOutputFormat ff_adts_muxer = {
235 .name = "adts",
236 .long_name = NULL_IF_CONFIG_SMALL("ADTS AAC (Advanced Audio Coding)"),
237 .mime_type = "audio/aac",
238 .extensions = "aac,adts",
239 .priv_data_size = sizeof(ADTSContext),
240 .audio_codec = AV_CODEC_ID_AAC,
241 .video_codec = AV_CODEC_ID_NONE,
242 .init = adts_init,
243 .write_header = adts_write_header,
244 .write_packet = adts_write_packet,
245 .write_trailer = adts_write_trailer,
246 .priv_class = &adts_muxer_class,
247 .flags = AVFMT_NOTIMESTAMPS,
248 };
249