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/*
* MPEG-2/4 AAC ADTS to MPEG-4 Audio Specific Configuration bitstream filter
* Copyright (c) 2009 Alex Converse <alex.converse@gmail.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 "avcodec.h"
#include "aacadtsdec.h"
#include "put_bits.h"
#include "get_bits.h"
#include "mpeg4audio.h"
#include "internal.h"
typedef struct AACBSFContext {
int first_frame_done;
} AACBSFContext;
/**
* This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4
* ADTS header and removes the ADTS header.
*/
static int aac_adtstoasc_filter(AVBitStreamFilterContext *bsfc,
AVCodecContext *avctx, const char *args,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size,
int keyframe)
{
GetBitContext gb;
PutBitContext pb;
AACADTSHeaderInfo hdr;
AACBSFContext *ctx = bsfc->priv_data;
init_get_bits(&gb, buf, AAC_ADTS_HEADER_SIZE*8);
*poutbuf = (uint8_t*) buf;
*poutbuf_size = buf_size;
if (avctx->extradata)
if (show_bits(&gb, 12) != 0xfff)
return 0;
if (avpriv_aac_parse_header(&gb, &hdr) < 0) {
av_log(avctx, AV_LOG_ERROR, "Error parsing ADTS frame header!\n");
return -1;
}
if (!hdr.crc_absent && hdr.num_aac_frames > 1) {
av_log_missing_feature(avctx, "Multiple RDBs per frame with CRC", 0);
return -1;
}
buf += AAC_ADTS_HEADER_SIZE + 2*!hdr.crc_absent;
buf_size -= AAC_ADTS_HEADER_SIZE + 2*!hdr.crc_absent;
if (!ctx->first_frame_done) {
int pce_size = 0;
uint8_t pce_data[MAX_PCE_SIZE];
if (!hdr.chan_config) {
init_get_bits(&gb, buf, buf_size * 8);
if (get_bits(&gb, 3) != 5) {
av_log_missing_feature(avctx, "PCE based channel configuration, where the PCE is not the first syntax element", 0);
return -1;
}
init_put_bits(&pb, pce_data, MAX_PCE_SIZE);
pce_size = avpriv_copy_pce_data(&pb, &gb)/8;
flush_put_bits(&pb);
buf_size -= get_bits_count(&gb)/8;
buf += get_bits_count(&gb)/8;
}
avctx->extradata_size = 2 + pce_size;
avctx->extradata = av_mallocz(avctx->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
init_put_bits(&pb, avctx->extradata, avctx->extradata_size);
put_bits(&pb, 5, hdr.object_type);
put_bits(&pb, 4, hdr.sampling_index);
put_bits(&pb, 4, hdr.chan_config);
put_bits(&pb, 1, 0); //frame length - 1024 samples
put_bits(&pb, 1, 0); //does not depend on core coder
put_bits(&pb, 1, 0); //is not extension
flush_put_bits(&pb);
if (pce_size) {
memcpy(avctx->extradata + 2, pce_data, pce_size);
}
ctx->first_frame_done = 1;
}
*poutbuf = (uint8_t*) buf;
*poutbuf_size = buf_size;
return 0;
}
AVBitStreamFilter ff_aac_adtstoasc_bsf = {
"aac_adtstoasc",
sizeof(AACBSFContext),
aac_adtstoasc_filter,
};
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