Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

177 lines (152 sloc) 5.659 kB
/*
* 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/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,
};
Jump to Line
Something went wrong with that request. Please try again.