/* * ADTS muxer. * Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com> * Mans Rullgard <mans@mansr.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 "avformat.h" #define ADTS_HEADER_SIZE 7 typedef struct { int write_adts; int objecttype; int sample_rate_index; int channel_conf; int pce_size; uint8_t pce_data[MAX_PCE_SIZE]; } ADTSContext; #define ADTS_MAX_FRAME_BYTES ((1 << 13) - 1) static int adts_decode_extradata(AVFormatContext *s, ADTSContext *adts, uint8_t *buf, int size) { GetBitContext gb; PutBitContext pb; MPEG4AudioConfig m4ac; int off; init_get_bits(&gb, buf, size * 8); off = avpriv_mpeg4audio_get_config(&m4ac, buf, size * 8, 1); if (off < 0) return off; skip_bits_long(&gb, off); adts->objecttype = m4ac.object_type - 1; adts->sample_rate_index = m4ac.sampling_index; adts->channel_conf = m4ac.chan_config; if (adts->objecttype > 3U) { av_log(s, AV_LOG_ERROR, "MPEG-4 AOT %d is not allowed in ADTS\n", adts->objecttype+1); return -1; } if (adts->sample_rate_index == 15) { av_log(s, AV_LOG_ERROR, "Escape sample rate index illegal in ADTS\n"); return -1; } if (get_bits(&gb, 1)) { av_log(s, AV_LOG_ERROR, "960/120 MDCT window is not allowed in ADTS\n"); return -1; } if (get_bits(&gb, 1)) { av_log(s, AV_LOG_ERROR, "Scalable configurations are not allowed in ADTS\n"); return -1; } if (get_bits(&gb, 1)) { av_log(s, AV_LOG_ERROR, "Extension flag is not allowed in ADTS\n"); return -1; } if (!adts->channel_conf) { init_put_bits(&pb, adts->pce_data, MAX_PCE_SIZE); put_bits(&pb, 3, 5); //ID_PCE adts->pce_size = (avpriv_copy_pce_data(&pb, &gb) + 3) / 8; flush_put_bits(&pb); } adts->write_adts = 1; return 0; } static int adts_write_header(AVFormatContext *s) { ADTSContext *adts = s->priv_data; AVCodecContext *avc = s->streams[0]->codec; if (avc->extradata_size > 0 && adts_decode_extradata(s, adts, avc->extradata, avc->extradata_size) < 0) return -1; return 0; } static int adts_write_frame_header(ADTSContext *ctx, uint8_t *buf, int size, int pce_size) { PutBitContext pb; unsigned full_frame_size = (unsigned)ADTS_HEADER_SIZE + size + pce_size; if (full_frame_size > ADTS_MAX_FRAME_BYTES) { av_log(NULL, AV_LOG_ERROR, "ADTS frame size too large: %u (max %d)\n", full_frame_size, ADTS_MAX_FRAME_BYTES); return AVERROR_INVALIDDATA; } init_put_bits(&pb, buf, ADTS_HEADER_SIZE); /* adts_fixed_header */ put_bits(&pb, 12, 0xfff); /* syncword */ put_bits(&pb, 1, 0); /* ID */ put_bits(&pb, 2, 0); /* layer */ put_bits(&pb, 1, 1); /* protection_absent */ put_bits(&pb, 2, ctx->objecttype); /* profile_objecttype */ put_bits(&pb, 4, ctx->sample_rate_index); put_bits(&pb, 1, 0); /* private_bit */ put_bits(&pb, 3, ctx->channel_conf); /* channel_configuration */ put_bits(&pb, 1, 0); /* original_copy */ put_bits(&pb, 1, 0); /* home */ /* adts_variable_header */ put_bits(&pb, 1, 0); /* copyright_identification_bit */ put_bits(&pb, 1, 0); /* copyright_identification_start */ put_bits(&pb, 13, full_frame_size); /* aac_frame_length */ put_bits(&pb, 11, 0x7ff); /* adts_buffer_fullness */ put_bits(&pb, 2, 0); /* number_of_raw_data_blocks_in_frame */ flush_put_bits(&pb); return 0; } static int adts_write_packet(AVFormatContext *s, AVPacket *pkt) { ADTSContext *adts = s->priv_data; AVIOContext *pb = s->pb; uint8_t buf[ADTS_HEADER_SIZE]; if (!pkt->size) return 0; if (adts->write_adts) { int err = adts_write_frame_header(adts, buf, pkt->size, adts->pce_size); if (err < 0) return err; avio_write(pb, buf, ADTS_HEADER_SIZE); if (adts->pce_size) { avio_write(pb, adts->pce_data, adts->pce_size); adts->pce_size = 0; } } avio_write(pb, pkt->data, pkt->size); avio_flush(pb); return 0; } AVOutputFormat ff_adts_muxer = { .name = "adts", .long_name = NULL_IF_CONFIG_SMALL("ADTS AAC (Advanced Audio Coding)"), .mime_type = "audio/aac", .extensions = "aac,adts", .priv_data_size = sizeof(ADTSContext), .audio_codec = AV_CODEC_ID_AAC, .video_codec = AV_CODEC_ID_NONE, .write_header = adts_write_header, .write_packet = adts_write_packet, };