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/avcodec.h"
26 #include "libavcodec/mpeg4audio.h"
27 #include "libavutil/opt.h"
28 #include "avformat.h"
29 #include "apetag.h"
30 #include "id3v2.h"
31
32 #define ADTS_HEADER_SIZE 7
33
34 typedef struct ADTSContext {
35 AVClass *class;
36 int write_adts;
37 int objecttype;
38 int sample_rate_index;
39 int channel_conf;
40 int pce_size;
41 int apetag;
42 int id3v2tag;
43 uint8_t pce_data[MAX_PCE_SIZE];
44 } ADTSContext;
45
46 #define ADTS_MAX_FRAME_BYTES ((1 << 13) - 1)
47
adts_decode_extradata(AVFormatContext * s,ADTSContext * adts,const uint8_t * buf,int size)48 static int adts_decode_extradata(AVFormatContext *s, ADTSContext *adts, const uint8_t *buf, int size)
49 {
50 GetBitContext gb;
51 PutBitContext pb;
52 MPEG4AudioConfig m4ac;
53 int off;
54
55 init_get_bits(&gb, buf, size * 8);
56 off = avpriv_mpeg4audio_get_config2(&m4ac, buf, size, 1, s);
57 if (off < 0)
58 return off;
59 skip_bits_long(&gb, off);
60 adts->objecttype = m4ac.object_type - 1;
61 adts->sample_rate_index = m4ac.sampling_index;
62 adts->channel_conf = m4ac.chan_config;
63
64 if (adts->objecttype > 3U) {
65 av_log(s, AV_LOG_ERROR, "MPEG-4 AOT %d is not allowed in ADTS\n", adts->objecttype+1);
66 return AVERROR_INVALIDDATA;
67 }
68 if (adts->sample_rate_index == 15) {
69 av_log(s, AV_LOG_ERROR, "Escape sample rate index illegal in ADTS\n");
70 return AVERROR_INVALIDDATA;
71 }
72 if (get_bits(&gb, 1)) {
73 av_log(s, AV_LOG_ERROR, "960/120 MDCT window is not allowed in ADTS\n");
74 return AVERROR_INVALIDDATA;
75 }
76 if (get_bits(&gb, 1)) {
77 av_log(s, AV_LOG_ERROR, "Scalable configurations are not allowed in ADTS\n");
78 return AVERROR_INVALIDDATA;
79 }
80 if (get_bits(&gb, 1)) {
81 av_log(s, AV_LOG_ERROR, "Extension flag is not allowed in ADTS\n");
82 return AVERROR_INVALIDDATA;
83 }
84 if (!adts->channel_conf) {
85 init_put_bits(&pb, adts->pce_data, MAX_PCE_SIZE);
86
87 put_bits(&pb, 3, 5); //ID_PCE
88 adts->pce_size = (ff_copy_pce_data(&pb, &gb) + 3) / 8;
89 flush_put_bits(&pb);
90 }
91
92 adts->write_adts = 1;
93
94 return 0;
95 }
96
adts_init(AVFormatContext * s)97 static int adts_init(AVFormatContext *s)
98 {
99 ADTSContext *adts = s->priv_data;
100 AVCodecParameters *par = s->streams[0]->codecpar;
101
102 if (par->codec_id != AV_CODEC_ID_AAC) {
103 av_log(s, AV_LOG_ERROR, "Only AAC streams can be muxed by the ADTS muxer\n");
104 return AVERROR(EINVAL);
105 }
106 if (par->extradata_size > 0)
107 return adts_decode_extradata(s, adts, par->extradata,
108 par->extradata_size);
109
110 return 0;
111 }
112
adts_write_header(AVFormatContext * s)113 static int adts_write_header(AVFormatContext *s)
114 {
115 ADTSContext *adts = s->priv_data;
116
117 if (adts->id3v2tag)
118 ff_id3v2_write_simple(s, 4, ID3v2_DEFAULT_MAGIC);
119
120 return 0;
121 }
122
adts_write_frame_header(ADTSContext * ctx,uint8_t * buf,int size,int pce_size)123 static int adts_write_frame_header(ADTSContext *ctx,
124 uint8_t *buf, int size, int pce_size)
125 {
126 PutBitContext pb;
127
128 unsigned full_frame_size = (unsigned)ADTS_HEADER_SIZE + size + pce_size;
129 if (full_frame_size > ADTS_MAX_FRAME_BYTES) {
130 av_log(NULL, AV_LOG_ERROR, "ADTS frame size too large: %u (max %d)\n",
131 full_frame_size, ADTS_MAX_FRAME_BYTES);
132 return AVERROR_INVALIDDATA;
133 }
134
135 init_put_bits(&pb, buf, ADTS_HEADER_SIZE);
136
137 /* adts_fixed_header */
138 put_bits(&pb, 12, 0xfff); /* syncword */
139 put_bits(&pb, 1, 0); /* ID */
140 put_bits(&pb, 2, 0); /* layer */
141 put_bits(&pb, 1, 1); /* protection_absent */
142 put_bits(&pb, 2, ctx->objecttype); /* profile_objecttype */
143 put_bits(&pb, 4, ctx->sample_rate_index);
144 put_bits(&pb, 1, 0); /* private_bit */
145 put_bits(&pb, 3, ctx->channel_conf); /* channel_configuration */
146 put_bits(&pb, 1, 0); /* original_copy */
147 put_bits(&pb, 1, 0); /* home */
148
149 /* adts_variable_header */
150 put_bits(&pb, 1, 0); /* copyright_identification_bit */
151 put_bits(&pb, 1, 0); /* copyright_identification_start */
152 put_bits(&pb, 13, full_frame_size); /* aac_frame_length */
153 put_bits(&pb, 11, 0x7ff); /* adts_buffer_fullness */
154 put_bits(&pb, 2, 0); /* number_of_raw_data_blocks_in_frame */
155
156 flush_put_bits(&pb);
157
158 return 0;
159 }
160
adts_write_packet(AVFormatContext * s,AVPacket * pkt)161 static int adts_write_packet(AVFormatContext *s, AVPacket *pkt)
162 {
163 ADTSContext *adts = s->priv_data;
164 AVCodecParameters *par = s->streams[0]->codecpar;
165 AVIOContext *pb = s->pb;
166 uint8_t buf[ADTS_HEADER_SIZE];
167
168 if (!pkt->size)
169 return 0;
170 if (!par->extradata_size) {
171 uint8_t *side_data;
172 int side_data_size = 0, ret;
173
174 side_data = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
175 &side_data_size);
176 if (side_data_size) {
177 ret = adts_decode_extradata(s, adts, side_data, side_data_size);
178 if (ret < 0)
179 return ret;
180 ret = ff_alloc_extradata(par, side_data_size);
181 if (ret < 0)
182 return ret;
183 memcpy(par->extradata, side_data, side_data_size);
184 }
185 }
186 if (adts->write_adts) {
187 int err = adts_write_frame_header(adts, buf, pkt->size,
188 adts->pce_size);
189 if (err < 0)
190 return err;
191 avio_write(pb, buf, ADTS_HEADER_SIZE);
192 if (adts->pce_size) {
193 avio_write(pb, adts->pce_data, adts->pce_size);
194 adts->pce_size = 0;
195 }
196 }
197 avio_write(pb, pkt->data, pkt->size);
198
199 return 0;
200 }
201
adts_write_trailer(AVFormatContext * s)202 static int adts_write_trailer(AVFormatContext *s)
203 {
204 ADTSContext *adts = s->priv_data;
205
206 if (adts->apetag)
207 ff_ape_write_tag(s);
208
209 return 0;
210 }
211
212 #define ENC AV_OPT_FLAG_ENCODING_PARAM
213 #define OFFSET(obj) offsetof(ADTSContext, obj)
214 static const AVOption options[] = {
215 { "write_id3v2", "Enable ID3v2 tag writing", OFFSET(id3v2tag), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, ENC},
216 { "write_apetag", "Enable APE tag writing", OFFSET(apetag), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, ENC},
217 { NULL },
218 };
219
220 static const AVClass adts_muxer_class = {
221 .class_name = "ADTS muxer",
222 .item_name = av_default_item_name,
223 .option = options,
224 .version = LIBAVUTIL_VERSION_INT,
225 };
226
227 AVOutputFormat ff_adts_muxer = {
228 .name = "adts",
229 .long_name = NULL_IF_CONFIG_SMALL("ADTS AAC (Advanced Audio Coding)"),
230 .mime_type = "audio/aac",
231 .extensions = "aac,adts",
232 .priv_data_size = sizeof(ADTSContext),
233 .audio_codec = AV_CODEC_ID_AAC,
234 .video_codec = AV_CODEC_ID_NONE,
235 .init = adts_init,
236 .write_header = adts_write_header,
237 .write_packet = adts_write_packet,
238 .write_trailer = adts_write_trailer,
239 .priv_class = &adts_muxer_class,
240 .flags = AVFMT_NOTIMESTAMPS,
241 };
242