| /* |
| * ADTS muxer. |
| * Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com> |
| * Mans Rullgard <mans@mansr.com> |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg 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. |
| * |
| * FFmpeg 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 FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include "libavcodec/bitstream.h" |
| #include "libavcodec/internal.h" |
| #include "avformat.h" |
| |
| #define ADTS_HEADER_SIZE 7 |
| |
| typedef struct { |
| int write_adts; |
| int objecttype; |
| int sample_rate_index; |
| int channel_conf; |
| } ADTSContext; |
| |
| static int decode_extradata(AVFormatContext *s, ADTSContext *adts, uint8_t *buf, int size) |
| { |
| GetBitContext gb; |
| |
| init_get_bits(&gb, buf, size * 8); |
| adts->objecttype = get_bits(&gb, 5) - 1; |
| adts->sample_rate_index = get_bits(&gb, 4); |
| adts->channel_conf = get_bits(&gb, 4); |
| |
| if (adts->objecttype > 3) { |
| 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 (adts->channel_conf == 0) { |
| ff_log_missing_feature(s, "PCE based channel configuration", 0); |
| return -1; |
| } |
| |
| 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 && |
| decode_extradata(s, adts, avc->extradata, avc->extradata_size) < 0) |
| return -1; |
| |
| return 0; |
| } |
| |
| static int adts_write_frame_header(AVFormatContext *s, int size) |
| { |
| ADTSContext *ctx = s->priv_data; |
| PutBitContext pb; |
| uint8_t buf[ADTS_HEADER_SIZE]; |
| |
| 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, ADTS_HEADER_SIZE + 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); |
| put_buffer(s->pb, buf, ADTS_HEADER_SIZE); |
| |
| return 0; |
| } |
| |
| static int adts_write_packet(AVFormatContext *s, AVPacket *pkt) |
| { |
| ADTSContext *adts = s->priv_data; |
| ByteIOContext *pb = s->pb; |
| |
| if (!pkt->size) |
| return 0; |
| if(adts->write_adts) |
| adts_write_frame_header(s, pkt->size); |
| put_buffer(pb, pkt->data, pkt->size); |
| put_flush_packet(pb); |
| |
| return 0; |
| } |
| |
| AVOutputFormat adts_muxer = { |
| "adts", |
| NULL_IF_CONFIG_SMALL("ADTS AAC"), |
| "audio/aac", |
| "aac", |
| sizeof(ADTSContext), |
| CODEC_ID_AAC, |
| CODEC_ID_NONE, |
| adts_write_header, |
| adts_write_packet, |
| }; |