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/bitstream.h" 24#include "libavcodec/internal.h" 25#include "avformat.h" 26 27#define ADTS_HEADER_SIZE 7 28 29typedef struct { 30 int write_adts; 31 int objecttype; 32 int sample_rate_index; 33 int channel_conf; 34} ADTSContext; 35 36static int decode_extradata(AVFormatContext *s, ADTSContext *adts, uint8_t *buf, int size) 37{ 38 GetBitContext gb; 39 40 init_get_bits(&gb, buf, size * 8); 41 adts->objecttype = get_bits(&gb, 5) - 1; 42 adts->sample_rate_index = get_bits(&gb, 4); 43 adts->channel_conf = get_bits(&gb, 4); 44 45 if (adts->objecttype > 3) { 46 av_log(s, AV_LOG_ERROR, "MPEG-4 AOT %d is not allowed in ADTS\n", adts->objecttype+1); 47 return -1; 48 } 49 if (adts->sample_rate_index == 15) { 50 av_log(s, AV_LOG_ERROR, "Escape sample rate index illegal in ADTS\n"); 51 return -1; 52 } 53 if (adts->channel_conf == 0) { 54 ff_log_missing_feature(s, "PCE based channel configuration", 0); 55 return -1; 56 } 57 58 adts->write_adts = 1; 59 60 return 0; 61} 62 63static int adts_write_header(AVFormatContext *s) 64{ 65 ADTSContext *adts = s->priv_data; 66 AVCodecContext *avc = s->streams[0]->codec; 67 68 if(avc->extradata_size > 0 && 69 decode_extradata(s, adts, avc->extradata, avc->extradata_size) < 0) 70 return -1; 71 72 return 0; 73} 74 75static int adts_write_frame_header(AVFormatContext *s, int size) 76{ 77 ADTSContext *ctx = s->priv_data; 78 PutBitContext pb; 79 uint8_t buf[ADTS_HEADER_SIZE]; 80 81 init_put_bits(&pb, buf, ADTS_HEADER_SIZE); 82 83 /* adts_fixed_header */ 84 put_bits(&pb, 12, 0xfff); /* syncword */ 85 put_bits(&pb, 1, 0); /* ID */ 86 put_bits(&pb, 2, 0); /* layer */ 87 put_bits(&pb, 1, 1); /* protection_absent */ 88 put_bits(&pb, 2, ctx->objecttype); /* profile_objecttype */ 89 put_bits(&pb, 4, ctx->sample_rate_index); 90 put_bits(&pb, 1, 0); /* private_bit */ 91 put_bits(&pb, 3, ctx->channel_conf); /* channel_configuration */ 92 put_bits(&pb, 1, 0); /* original_copy */ 93 put_bits(&pb, 1, 0); /* home */ 94 95 /* adts_variable_header */ 96 put_bits(&pb, 1, 0); /* copyright_identification_bit */ 97 put_bits(&pb, 1, 0); /* copyright_identification_start */ 98 put_bits(&pb, 13, ADTS_HEADER_SIZE + size); /* aac_frame_length */ 99 put_bits(&pb, 11, 0x7ff); /* adts_buffer_fullness */ 100 put_bits(&pb, 2, 0); /* number_of_raw_data_blocks_in_frame */ 101 102 flush_put_bits(&pb); 103 put_buffer(s->pb, buf, ADTS_HEADER_SIZE); 104 105 return 0; 106} 107 108static int adts_write_packet(AVFormatContext *s, AVPacket *pkt) 109{ 110 ADTSContext *adts = s->priv_data; 111 ByteIOContext *pb = s->pb; 112 113 if (!pkt->size) 114 return 0; 115 if(adts->write_adts) 116 adts_write_frame_header(s, pkt->size); 117 put_buffer(pb, pkt->data, pkt->size); 118 put_flush_packet(pb); 119 120 return 0; 121} 122 123AVOutputFormat adts_muxer = { 124 "adts", 125 NULL_IF_CONFIG_SMALL("ADTS AAC"), 126 "audio/aac", 127 "aac", 128 sizeof(ADTSContext), 129 CODEC_ID_AAC, 130 CODEC_ID_NONE, 131 adts_write_header, 132 adts_write_packet, 133}; 134