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 int mpeg_id;
44 uint8_t pce_data[MAX_PCE_SIZE];
45 } ADTSContext;
46
47 #define ADTS_MAX_FRAME_BYTES ((1 << 13) - 1)
48
adts_decode_extradata(AVFormatContext * s,ADTSContext * adts,const uint8_t * buf,int size)49 static int adts_decode_extradata(AVFormatContext *s, ADTSContext *adts, const uint8_t *buf, int size)
50 {
51 GetBitContext gb;
52 PutBitContext pb;
53 MPEG4AudioConfig m4ac;
54 int off, ret;
55
56 ret = init_get_bits8(&gb, buf, size);
57 if (ret < 0)
58 return ret;
59 off = avpriv_mpeg4audio_get_config2(&m4ac, buf, size, 1, s);
60 if (off < 0)
61 return off;
62 skip_bits_long(&gb, off);
63 adts->objecttype = m4ac.object_type - 1;
64 adts->sample_rate_index = m4ac.sampling_index;
65 adts->channel_conf = m4ac.chan_config;
66
67 if (adts->objecttype > 3U) {
68 av_log(s, AV_LOG_ERROR, "MPEG-4 AOT %d is not allowed in ADTS\n", adts->objecttype+1);
69 return AVERROR_INVALIDDATA;
70 }
71 if (adts->sample_rate_index == 15) {
72 av_log(s, AV_LOG_ERROR, "Escape sample rate index illegal in ADTS\n");
73 return AVERROR_INVALIDDATA;
74 }
75 if (get_bits(&gb, 1)) {
76 av_log(s, AV_LOG_ERROR, "960/120 MDCT window is not allowed in ADTS\n");
77 return AVERROR_INVALIDDATA;
78 }
79 if (get_bits(&gb, 1)) {
80 av_log(s, AV_LOG_ERROR, "Scalable configurations are not allowed in ADTS\n");
81 return AVERROR_INVALIDDATA;
82 }
83 if (get_bits(&gb, 1)) {
84 av_log(s, AV_LOG_ERROR, "Extension flag is not allowed in ADTS\n");
85 return AVERROR_INVALIDDATA;
86 }
87 if (!adts->channel_conf) {
88 init_put_bits(&pb, adts->pce_data, MAX_PCE_SIZE);
89
90 put_bits(&pb, 3, 5); //ID_PCE
91 adts->pce_size = (ff_copy_pce_data(&pb, &gb) + 3) / 8;
92 flush_put_bits(&pb);
93 }
94
95 adts->write_adts = 1;
96
97 return 0;
98 }
99
adts_init(AVFormatContext * s)100 static int adts_init(AVFormatContext *s)
101 {
102 ADTSContext *adts = s->priv_data;
103 AVCodecParameters *par = s->streams[0]->codecpar;
104
105 if (par->codec_id != AV_CODEC_ID_AAC) {
106 av_log(s, AV_LOG_ERROR, "Only AAC streams can be muxed by the ADTS muxer\n");
107 return AVERROR(EINVAL);
108 }
109 if (par->extradata_size > 0)
110 return adts_decode_extradata(s, adts, par->extradata,
111 par->extradata_size);
112
113 return 0;
114 }
115
adts_write_header(AVFormatContext * s)116 static int adts_write_header(AVFormatContext *s)
117 {
118 ADTSContext *adts = s->priv_data;
119
120 if (adts->id3v2tag)
121 ff_id3v2_write_simple(s, 4, ID3v2_DEFAULT_MAGIC);
122
123 return 0;
124 }
125
adts_write_frame_header(ADTSContext * ctx,uint8_t * buf,int size,int pce_size)126 static int adts_write_frame_header(ADTSContext *ctx,
127 uint8_t *buf, int size, int pce_size)
128 {
129 PutBitContext pb;
130
131 unsigned full_frame_size = (unsigned)ADTS_HEADER_SIZE + size + pce_size;
132 if (full_frame_size > ADTS_MAX_FRAME_BYTES) {
133 av_log(NULL, AV_LOG_ERROR, "ADTS frame size too large: %u (max %d)\n",
134 full_frame_size, ADTS_MAX_FRAME_BYTES);
135 return AVERROR_INVALIDDATA;
136 }
137
138 init_put_bits(&pb, buf, ADTS_HEADER_SIZE);
139
140 /* adts_fixed_header */
141 put_bits(&pb, 12, 0xfff); /* syncword */
142 put_bits(&pb, 1, ctx->mpeg_id); /* ID */
143 put_bits(&pb, 2, 0); /* layer */
144 put_bits(&pb, 1, 1); /* protection_absent */
145 put_bits(&pb, 2, ctx->objecttype); /* profile_objecttype */
146 put_bits(&pb, 4, ctx->sample_rate_index);
147 put_bits(&pb, 1, 0); /* private_bit */
148 put_bits(&pb, 3, ctx->channel_conf); /* channel_configuration */
149 put_bits(&pb, 1, 0); /* original_copy */
150 put_bits(&pb, 1, 0); /* home */
151
152 /* adts_variable_header */
153 put_bits(&pb, 1, 0); /* copyright_identification_bit */
154 put_bits(&pb, 1, 0); /* copyright_identification_start */
155 put_bits(&pb, 13, full_frame_size); /* aac_frame_length */
156 put_bits(&pb, 11, 0x7ff); /* adts_buffer_fullness */
157 put_bits(&pb, 2, 0); /* number_of_raw_data_blocks_in_frame */
158
159 flush_put_bits(&pb);
160
161 return 0;
162 }
163
adts_write_packet(AVFormatContext * s,AVPacket * pkt)164 static int adts_write_packet(AVFormatContext *s, AVPacket *pkt)
165 {
166 ADTSContext *adts = s->priv_data;
167 AVCodecParameters *par = s->streams[0]->codecpar;
168 AVIOContext *pb = s->pb;
169 uint8_t buf[ADTS_HEADER_SIZE];
170
171 if (!pkt->size)
172 return 0;
173 if (!par->extradata_size) {
174 uint8_t *side_data;
175 buffer_size_t side_data_size;
176 int ret;
177
178 side_data = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
179 &side_data_size);
180 if (side_data_size) {
181 ret = adts_decode_extradata(s, adts, side_data, side_data_size);
182 if (ret < 0)
183 return ret;
184 ret = ff_alloc_extradata(par, side_data_size);
185 if (ret < 0)
186 return ret;
187 memcpy(par->extradata, side_data, side_data_size);
188 }
189 }
190 if (adts->write_adts) {
191 int err = adts_write_frame_header(adts, buf, pkt->size,
192 adts->pce_size);
193 if (err < 0)
194 return err;
195 avio_write(pb, buf, ADTS_HEADER_SIZE);
196 if (adts->pce_size) {
197 avio_write(pb, adts->pce_data, adts->pce_size);
198 adts->pce_size = 0;
199 }
200 }
201 avio_write(pb, pkt->data, pkt->size);
202
203 return 0;
204 }
205
adts_write_trailer(AVFormatContext * s)206 static int adts_write_trailer(AVFormatContext *s)
207 {
208 ADTSContext *adts = s->priv_data;
209
210 if (adts->apetag)
211 ff_ape_write_tag(s);
212
213 return 0;
214 }
215
216 #define ENC AV_OPT_FLAG_ENCODING_PARAM
217 #define OFFSET(obj) offsetof(ADTSContext, obj)
218 static const AVOption options[] = {
219 { "write_id3v2", "Enable ID3v2 tag writing", OFFSET(id3v2tag), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, ENC},
220 { "write_apetag", "Enable APE tag writing", OFFSET(apetag), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, ENC},
221 { "write_mpeg2", "Use MPE2 ID when writing", OFFSET(mpeg_id), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, ENC, "mpeg_id"},
222 { NULL },
223 };
224
225 static const AVClass adts_muxer_class = {
226 .class_name = "ADTS muxer",
227 .item_name = av_default_item_name,
228 .option = options,
229 .version = LIBAVUTIL_VERSION_INT,
230 };
231
232 AVOutputFormat ff_adts_muxer = {
233 .name = "adts",
234 .long_name = NULL_IF_CONFIG_SMALL("ADTS AAC (Advanced Audio Coding)"),
235 .mime_type = "audio/aac",
236 .extensions = "aac,adts",
237 .priv_data_size = sizeof(ADTSContext),
238 .audio_codec = AV_CODEC_ID_AAC,
239 .video_codec = AV_CODEC_ID_NONE,
240 .init = adts_init,
241 .write_header = adts_write_header,
242 .write_packet = adts_write_packet,
243 .write_trailer = adts_write_trailer,
244 .priv_class = &adts_muxer_class,
245 .flags = AVFMT_NOTIMESTAMPS,
246 };
247