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adtsenc.c
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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 
31 #define ADTS_HEADER_SIZE 7
32 
33 typedef struct {
34  AVClass *class;
39  int pce_size;
40  int apetag;
41  uint8_t pce_data[MAX_PCE_SIZE];
42 } ADTSContext;
43 
44 #define ADTS_MAX_FRAME_BYTES ((1 << 13) - 1)
45 
47 {
48  GetBitContext gb;
49  PutBitContext pb;
50  MPEG4AudioConfig m4ac;
51  int off;
52 
53  init_get_bits(&gb, buf, size * 8);
54  off = avpriv_mpeg4audio_get_config(&m4ac, buf, size * 8, 1);
55  if (off < 0)
56  return off;
57  skip_bits_long(&gb, off);
58  adts->objecttype = m4ac.object_type - 1;
59  adts->sample_rate_index = m4ac.sampling_index;
60  adts->channel_conf = m4ac.chan_config;
61 
62  if (adts->objecttype > 3U) {
63  av_log(s, AV_LOG_ERROR, "MPEG-4 AOT %d is not allowed in ADTS\n", adts->objecttype+1);
64  return -1;
65  }
66  if (adts->sample_rate_index == 15) {
67  av_log(s, AV_LOG_ERROR, "Escape sample rate index illegal in ADTS\n");
68  return -1;
69  }
70  if (get_bits(&gb, 1)) {
71  av_log(s, AV_LOG_ERROR, "960/120 MDCT window is not allowed in ADTS\n");
72  return -1;
73  }
74  if (get_bits(&gb, 1)) {
75  av_log(s, AV_LOG_ERROR, "Scalable configurations are not allowed in ADTS\n");
76  return -1;
77  }
78  if (get_bits(&gb, 1)) {
79  av_log(s, AV_LOG_ERROR, "Extension flag is not allowed in ADTS\n");
80  return -1;
81  }
82  if (!adts->channel_conf) {
83  init_put_bits(&pb, adts->pce_data, MAX_PCE_SIZE);
84 
85  put_bits(&pb, 3, 5); //ID_PCE
86  adts->pce_size = (avpriv_copy_pce_data(&pb, &gb) + 3) / 8;
87  flush_put_bits(&pb);
88  }
89 
90  adts->write_adts = 1;
91 
92  return 0;
93 }
94 
96 {
97  ADTSContext *adts = s->priv_data;
98  AVCodecContext *avc = s->streams[0]->codec;
99 
100  if (avc->extradata_size > 0 &&
101  adts_decode_extradata(s, adts, avc->extradata, avc->extradata_size) < 0)
102  return -1;
103 
104  return 0;
105 }
106 
108  uint8_t *buf, int size, int pce_size)
109 {
110  PutBitContext pb;
111 
112  unsigned full_frame_size = (unsigned)ADTS_HEADER_SIZE + size + pce_size;
113  if (full_frame_size > ADTS_MAX_FRAME_BYTES) {
114  av_log(NULL, AV_LOG_ERROR, "ADTS frame size too large: %u (max %d)\n",
115  full_frame_size, ADTS_MAX_FRAME_BYTES);
116  return AVERROR_INVALIDDATA;
117  }
118 
119  init_put_bits(&pb, buf, ADTS_HEADER_SIZE);
120 
121  /* adts_fixed_header */
122  put_bits(&pb, 12, 0xfff); /* syncword */
123  put_bits(&pb, 1, 0); /* ID */
124  put_bits(&pb, 2, 0); /* layer */
125  put_bits(&pb, 1, 1); /* protection_absent */
126  put_bits(&pb, 2, ctx->objecttype); /* profile_objecttype */
127  put_bits(&pb, 4, ctx->sample_rate_index);
128  put_bits(&pb, 1, 0); /* private_bit */
129  put_bits(&pb, 3, ctx->channel_conf); /* channel_configuration */
130  put_bits(&pb, 1, 0); /* original_copy */
131  put_bits(&pb, 1, 0); /* home */
132 
133  /* adts_variable_header */
134  put_bits(&pb, 1, 0); /* copyright_identification_bit */
135  put_bits(&pb, 1, 0); /* copyright_identification_start */
136  put_bits(&pb, 13, full_frame_size); /* aac_frame_length */
137  put_bits(&pb, 11, 0x7ff); /* adts_buffer_fullness */
138  put_bits(&pb, 2, 0); /* number_of_raw_data_blocks_in_frame */
139 
140  flush_put_bits(&pb);
141 
142  return 0;
143 }
144 
146 {
147  ADTSContext *adts = s->priv_data;
148  AVIOContext *pb = s->pb;
150 
151  if (!pkt->size)
152  return 0;
153  if (adts->write_adts) {
154  int err = adts_write_frame_header(adts, buf, pkt->size,
155  adts->pce_size);
156  if (err < 0)
157  return err;
158  avio_write(pb, buf, ADTS_HEADER_SIZE);
159  if (adts->pce_size) {
160  avio_write(pb, adts->pce_data, adts->pce_size);
161  adts->pce_size = 0;
162  }
163  }
164  avio_write(pb, pkt->data, pkt->size);
165 
166  return 0;
167 }
168 
170 {
171  ADTSContext *adts = s->priv_data;
172 
173  if (adts->apetag)
174  ff_ape_write_tag(s);
175 
176  return 0;
177 }
178 
179 #define ENC AV_OPT_FLAG_ENCODING_PARAM
180 #define OFFSET(obj) offsetof(ADTSContext, obj)
181 static const AVOption options[] = {
182  { "write_apetag", "Enable APE tag writing", OFFSET(apetag), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, ENC},
183  { NULL },
184 };
185 
186 static const AVClass adts_muxer_class = {
187  .class_name = "ADTS muxer",
188  .item_name = av_default_item_name,
189  .option = options,
190  .version = LIBAVUTIL_VERSION_INT,
191 };
192 
194  .name = "adts",
195  .long_name = NULL_IF_CONFIG_SMALL("ADTS AAC (Advanced Audio Coding)"),
196  .mime_type = "audio/aac",
197  .extensions = "aac,adts",
198  .priv_data_size = sizeof(ADTSContext),
199  .audio_codec = AV_CODEC_ID_AAC,
200  .video_codec = AV_CODEC_ID_NONE,
204  .priv_class = &adts_muxer_class,
205 };