1/* 2 * LATM/LOAS muxer 3 * Copyright (c) 2011 Kieran Kunhya <kieran@kunhya.com> 4 * 5 * This file is part of Libav. 6 * 7 * Libav is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * Libav is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with Libav; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22#include "libavcodec/get_bits.h" 23#include "libavcodec/put_bits.h" 24#include "libavcodec/avcodec.h" 25#include "libavcodec/mpeg4audio.h" 26#include "libavutil/opt.h" 27#include "avformat.h" 28 29typedef struct { 30 AVClass *av_class; 31 int off; 32 int channel_conf; 33 int object_type; 34 int counter; 35 int mod; 36} LATMContext; 37 38static const AVOption options[] = { 39 {"smc-interval", "StreamMuxConfig interval.", 40 offsetof(LATMContext, mod), AV_OPT_TYPE_INT, {.dbl = 0x0014}, 0x0001, 0xffff, AV_OPT_FLAG_ENCODING_PARAM}, 41 {NULL}, 42}; 43 44static const AVClass latm_muxer_class = { 45 .class_name = "LATM/LOAS muxer", 46 .item_name = av_default_item_name, 47 .option = options, 48 .version = LIBAVUTIL_VERSION_INT, 49}; 50 51static int latm_decode_extradata(LATMContext *ctx, uint8_t *buf, int size) 52{ 53 GetBitContext gb; 54 MPEG4AudioConfig m4ac; 55 56 init_get_bits(&gb, buf, size * 8); 57 ctx->off = avpriv_mpeg4audio_get_config(&m4ac, buf, size * 8, 1); 58 if (ctx->off < 0) 59 return ctx->off; 60 skip_bits_long(&gb, ctx->off); 61 62 /* FIXME: are any formats not allowed in LATM? */ 63 64 if (m4ac.object_type > AOT_SBR && m4ac.object_type != AOT_ALS) { 65 av_log(ctx, AV_LOG_ERROR, "Muxing MPEG-4 AOT %d in LATM is not supported\n", m4ac.object_type); 66 return AVERROR_INVALIDDATA; 67 } 68 ctx->channel_conf = m4ac.chan_config; 69 ctx->object_type = m4ac.object_type; 70 71 return 0; 72} 73 74static int latm_write_header(AVFormatContext *s) 75{ 76 LATMContext *ctx = s->priv_data; 77 AVCodecContext *avctx = s->streams[0]->codec; 78 79 if (avctx->extradata_size > 0 && 80 latm_decode_extradata(ctx, avctx->extradata, avctx->extradata_size) < 0) 81 return AVERROR_INVALIDDATA; 82 83 return 0; 84} 85 86static int latm_write_frame_header(AVFormatContext *s, PutBitContext *bs) 87{ 88 LATMContext *ctx = s->priv_data; 89 AVCodecContext *avctx = s->streams[0]->codec; 90 GetBitContext gb; 91 int header_size; 92 93 /* AudioMuxElement */ 94 put_bits(bs, 1, !!ctx->counter); 95 96 if (!ctx->counter) { 97 init_get_bits(&gb, avctx->extradata, avctx->extradata_size * 8); 98 99 /* StreamMuxConfig */ 100 put_bits(bs, 1, 0); /* audioMuxVersion */ 101 put_bits(bs, 1, 1); /* allStreamsSameTimeFraming */ 102 put_bits(bs, 6, 0); /* numSubFrames */ 103 put_bits(bs, 4, 0); /* numProgram */ 104 put_bits(bs, 3, 0); /* numLayer */ 105 106 /* AudioSpecificConfig */ 107 if (ctx->object_type == AOT_ALS) { 108 header_size = avctx->extradata_size-(ctx->off + 7) >> 3; 109 avpriv_copy_bits(bs, &avctx->extradata[ctx->off], header_size); 110 } else { 111 avpriv_copy_bits(bs, avctx->extradata, ctx->off + 3); 112 113 if (!ctx->channel_conf) { 114 avpriv_copy_pce_data(bs, &gb); 115 } 116 } 117 118 put_bits(bs, 3, 0); /* frameLengthType */ 119 put_bits(bs, 8, 0xff); /* latmBufferFullness */ 120 121 put_bits(bs, 1, 0); /* otherDataPresent */ 122 put_bits(bs, 1, 0); /* crcCheckPresent */ 123 } 124 125 ctx->counter++; 126 ctx->counter %= ctx->mod; 127 128 return 0; 129} 130 131static int latm_write_packet(AVFormatContext *s, AVPacket *pkt) 132{ 133 AVIOContext *pb = s->pb; 134 PutBitContext bs; 135 int i, len; 136 uint8_t loas_header[] = "\x56\xe0\x00"; 137 uint8_t *buf; 138 139 if (pkt->size > 2 && pkt->data[0] == 0xff && (pkt->data[1] >> 4) == 0xf) { 140 av_log(s, AV_LOG_ERROR, "ADTS header detected - ADTS will not be incorrectly muxed into LATM\n"); 141 return AVERROR_INVALIDDATA; 142 } 143 144 buf = av_malloc(pkt->size+1024); 145 if (!buf) 146 return AVERROR(ENOMEM); 147 148 init_put_bits(&bs, buf, pkt->size+1024); 149 150 latm_write_frame_header(s, &bs); 151 152 /* PayloadLengthInfo() */ 153 for (i = 0; i <= pkt->size-255; i+=255) 154 put_bits(&bs, 8, 255); 155 156 put_bits(&bs, 8, pkt->size-i); 157 158 /* The LATM payload is written unaligned */ 159 160 /* PayloadMux() */ 161 for (i = 0; i < pkt->size; i++) 162 put_bits(&bs, 8, pkt->data[i]); 163 164 avpriv_align_put_bits(&bs); 165 flush_put_bits(&bs); 166 167 len = put_bits_count(&bs) >> 3; 168 169 loas_header[1] |= (len >> 8) & 0x1f; 170 loas_header[2] |= len & 0xff; 171 172 avio_write(pb, loas_header, 3); 173 avio_write(pb, buf, len); 174 175 av_free(buf); 176 177 return 0; 178} 179 180AVOutputFormat ff_latm_muxer = { 181 .name = "latm", 182 .long_name = NULL_IF_CONFIG_SMALL("LOAS/LATM"), 183 .mime_type = "audio/MP4A-LATM", 184 .extensions = "latm", 185 .priv_data_size = sizeof(LATMContext), 186 .audio_codec = CODEC_ID_AAC, 187 .video_codec = CODEC_ID_NONE, 188 .write_header = latm_write_header, 189 .write_packet = latm_write_packet, 190 .priv_class = &latm_muxer_class, 191}; 192