3 * Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com>
4 * Mans Rullgard <mans@mansr.com>
6 * This file is part of FFmpeg.
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.
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.
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
23 #include "libavcodec/bitstream.h"
26 #define ADTS_HEADER_SIZE 7
31 int sample_rate_index;
35 static int decode_extradata(ADTSContext *adts, uint8_t *buf, int size)
39 init_get_bits(&gb, buf, size * 8);
40 adts->objecttype = get_bits(&gb, 5) - 1;
41 adts->sample_rate_index = get_bits(&gb, 4);
42 adts->channel_conf = get_bits(&gb, 4);
49 static int adts_write_header(AVFormatContext *s)
51 ADTSContext *adts = s->priv_data;
52 AVCodecContext *avc = s->streams[0]->codec;
54 if(avc->extradata_size > 0)
55 decode_extradata(adts, avc->extradata, avc->extradata_size);
60 static int adts_write_frame_header(AVFormatContext *s, int size)
62 ADTSContext *ctx = s->priv_data;
64 uint8_t buf[ADTS_HEADER_SIZE];
66 init_put_bits(&pb, buf, ADTS_HEADER_SIZE);
68 /* adts_fixed_header */
69 put_bits(&pb, 12, 0xfff); /* syncword */
70 put_bits(&pb, 1, 0); /* ID */
71 put_bits(&pb, 2, 0); /* layer */
72 put_bits(&pb, 1, 1); /* protection_absent */
73 put_bits(&pb, 2, ctx->objecttype); /* profile_objecttype */
74 put_bits(&pb, 4, ctx->sample_rate_index);
75 put_bits(&pb, 1, 0); /* private_bit */
76 put_bits(&pb, 3, ctx->channel_conf); /* channel_configuration */
77 put_bits(&pb, 1, 0); /* original_copy */
78 put_bits(&pb, 1, 0); /* home */
80 /* adts_variable_header */
81 put_bits(&pb, 1, 0); /* copyright_identification_bit */
82 put_bits(&pb, 1, 0); /* copyright_identification_start */
83 put_bits(&pb, 13, ADTS_HEADER_SIZE + size); /* aac_frame_length */
84 put_bits(&pb, 11, 0x7ff); /* adts_buffer_fullness */
85 put_bits(&pb, 2, 0); /* number_of_raw_data_blocks_in_frame */
88 put_buffer(s->pb, buf, ADTS_HEADER_SIZE);
93 static int adts_write_packet(AVFormatContext *s, AVPacket *pkt)
95 ADTSContext *adts = s->priv_data;
96 ByteIOContext *pb = s->pb;
101 adts_write_frame_header(s, pkt->size);
102 put_buffer(pb, pkt->data, pkt->size);
103 put_flush_packet(pb);
108 AVOutputFormat adts_muxer = {
110 NULL_IF_CONFIG_SMALL("ADTS AAC"),