/* * LATM/LOAS muxer * Copyright (c) 2011 Kieran Kunhya <kieran@kunhya.com> * * This file is part of Libav. * * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "libavcodec/get_bits.h" #include "libavcodec/put_bits.h" #include "libavcodec/avcodec.h" #include "libavcodec/mpeg4audio.h" #include "libavutil/opt.h" #include "avformat.h" typedef struct { AVClass *av_class; int off; int channel_conf; int object_type; int counter; int mod; } LATMContext; static const AVOption options[] = { {"smc-interval", "StreamMuxConfig interval.", offsetof(LATMContext, mod), AV_OPT_TYPE_INT, {.i64 = 0x0014}, 0x0001, 0xffff, AV_OPT_FLAG_ENCODING_PARAM}, {NULL}, }; static const AVClass latm_muxer_class = { .class_name = "LATM/LOAS muxer", .item_name = av_default_item_name, .option = options, .version = LIBAVUTIL_VERSION_INT, }; static int latm_decode_extradata(LATMContext *ctx, uint8_t *buf, int size) { GetBitContext gb; MPEG4AudioConfig m4ac; init_get_bits(&gb, buf, size * 8); ctx->off = avpriv_mpeg4audio_get_config(&m4ac, buf, size * 8, 1); if (ctx->off < 0) return ctx->off; skip_bits_long(&gb, ctx->off); /* FIXME: are any formats not allowed in LATM? */ if (m4ac.object_type > AOT_SBR && m4ac.object_type != AOT_ALS) { av_log(ctx, AV_LOG_ERROR, "Muxing MPEG-4 AOT %d in LATM is not supported\n", m4ac.object_type); return AVERROR_INVALIDDATA; } ctx->channel_conf = m4ac.chan_config; ctx->object_type = m4ac.object_type; return 0; } static int latm_write_header(AVFormatContext *s) { LATMContext *ctx = s->priv_data; AVCodecContext *avctx = s->streams[0]->codec; if (avctx->extradata_size > 0 && latm_decode_extradata(ctx, avctx->extradata, avctx->extradata_size) < 0) return AVERROR_INVALIDDATA; return 0; } static int latm_write_frame_header(AVFormatContext *s, PutBitContext *bs) { LATMContext *ctx = s->priv_data; AVCodecContext *avctx = s->streams[0]->codec; GetBitContext gb; int header_size; /* AudioMuxElement */ put_bits(bs, 1, !!ctx->counter); if (!ctx->counter) { init_get_bits(&gb, avctx->extradata, avctx->extradata_size * 8); /* StreamMuxConfig */ put_bits(bs, 1, 0); /* audioMuxVersion */ put_bits(bs, 1, 1); /* allStreamsSameTimeFraming */ put_bits(bs, 6, 0); /* numSubFrames */ put_bits(bs, 4, 0); /* numProgram */ put_bits(bs, 3, 0); /* numLayer */ /* AudioSpecificConfig */ if (ctx->object_type == AOT_ALS) { header_size = avctx->extradata_size-(ctx->off + 7) >> 3; avpriv_copy_bits(bs, &avctx->extradata[ctx->off], header_size); } else { avpriv_copy_bits(bs, avctx->extradata, ctx->off + 3); if (!ctx->channel_conf) { avpriv_copy_pce_data(bs, &gb); } } put_bits(bs, 3, 0); /* frameLengthType */ put_bits(bs, 8, 0xff); /* latmBufferFullness */ put_bits(bs, 1, 0); /* otherDataPresent */ put_bits(bs, 1, 0); /* crcCheckPresent */ } ctx->counter++; ctx->counter %= ctx->mod; return 0; } static int latm_write_packet(AVFormatContext *s, AVPacket *pkt) { AVIOContext *pb = s->pb; PutBitContext bs; int i, len; uint8_t loas_header[] = "\x56\xe0\x00"; uint8_t *buf; if (pkt->size > 2 && pkt->data[0] == 0xff && (pkt->data[1] >> 4) == 0xf) { av_log(s, AV_LOG_ERROR, "ADTS header detected - ADTS will not be incorrectly muxed into LATM\n"); return AVERROR_INVALIDDATA; } buf = av_malloc(pkt->size+1024); if (!buf) return AVERROR(ENOMEM); init_put_bits(&bs, buf, pkt->size+1024); latm_write_frame_header(s, &bs); /* PayloadLengthInfo() */ for (i = 0; i <= pkt->size-255; i+=255) put_bits(&bs, 8, 255); put_bits(&bs, 8, pkt->size-i); /* The LATM payload is written unaligned */ /* PayloadMux() */ for (i = 0; i < pkt->size; i++) put_bits(&bs, 8, pkt->data[i]); avpriv_align_put_bits(&bs); flush_put_bits(&bs); len = put_bits_count(&bs) >> 3; loas_header[1] |= (len >> 8) & 0x1f; loas_header[2] |= len & 0xff; avio_write(pb, loas_header, 3); avio_write(pb, buf, len); av_free(buf); return 0; } AVOutputFormat ff_latm_muxer = { .name = "latm", .long_name = NULL_IF_CONFIG_SMALL("LOAS/LATM"), .mime_type = "audio/MP4A-LATM", .extensions = "latm", .priv_data_size = sizeof(LATMContext), .audio_codec = AV_CODEC_ID_AAC, .video_codec = AV_CODEC_ID_NONE, .write_header = latm_write_header, .write_packet = latm_write_packet, .priv_class = &latm_muxer_class, };