From a283db3962c07f9dfab87dc7553b61cbc4e6efb8 Mon Sep 17 00:00:00 2001 From: Måns Rullgård Date: Fri, 10 Feb 2006 01:24:32 +0000 Subject: generate adts frame headers if required Originally committed as revision 4970 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavformat/adtsenc.c | 128 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 128 insertions(+) create mode 100644 libavformat/adtsenc.c (limited to 'libavformat/adtsenc.c') diff --git a/libavformat/adtsenc.c b/libavformat/adtsenc.c new file mode 100644 index 0000000000..55f8831af1 --- /dev/null +++ b/libavformat/adtsenc.c @@ -0,0 +1,128 @@ +/* + * ADTS muxer. + * Copyright (c) 2006 Baptiste Coudurier + * Mans Rullgard + * + * This library 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 of the License, or (at your option) any later version. + * + * This library 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 this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ +#include "avformat.h" +#include "bitstream.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(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); + + 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(adts, avc->extradata, avc->extradata_size); + + 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_trailer(AVFormatContext *s) +{ + return 0; +} + +static int adts_write_packet(AVFormatContext *s, AVPacket *pkt) +{ + ADTSContext *adts = s->priv_data; + ByteIOContext *pb = &s->pb; + + if(adts->write_adts) + adts_write_frame_header(s, pkt->size); + put_buffer(pb, pkt->data, pkt->size); + + return 0; +} + +#ifdef CONFIG_MUXERS +static AVOutputFormat adts_oformat = { + "adts", + "ADTS AAC", + "audio/aac", + "aac", + sizeof(ADTSContext), + CODEC_ID_AAC, + CODEC_ID_NONE, + adts_write_header, + adts_write_packet, + adts_write_trailer, +}; +#endif //CONFIG_MUXERS + +int ff_adts_init(void) +{ +#ifdef CONFIG_MUXERS + av_register_output_format(&adts_oformat); +#endif //CONFIG_MUXERS + return 0; +} -- cgit v1.2.3