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 33typedef struct { 34 AVClass *class; 35 int write_adts; 36 int objecttype; 37 int sample_rate_index; 38 int channel_conf; 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 46static int adts_decode_extradata(AVFormatContext *s, ADTSContext *adts, uint8_t *buf, int size) 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 95static int adts_write_header(AVFormatContext *s) 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 107static int adts_write_frame_header(ADTSContext *ctx, 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 145static int adts_write_packet(AVFormatContext *s, AVPacket *pkt) 146{ 147 ADTSContext *adts = s->priv_data; 148 AVIOContext *pb = s->pb; 149 uint8_t buf[ADTS_HEADER_SIZE]; 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 169static int adts_write_trailer(AVFormatContext *s) 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) 181static 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 186static 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 193AVOutputFormat ff_adts_muxer = { 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, 201 .write_header = adts_write_header, 202 .write_packet = adts_write_packet, 203 .write_trailer = adts_write_trailer, 204 .priv_class = &adts_muxer_class, 205 .flags = AVFMT_NOTIMESTAMPS, 206}; 207