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120 lines
4.1 KiB
C
120 lines
4.1 KiB
C
/*
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* MPEG-2/4 AAC ADTS to MPEG-4 Audio Specific Configuration bitstream filter
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* Copyright (c) 2009 Alex Converse <alex.converse@gmail.com>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avcodec.h"
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#include "aacadtsdec.h"
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#include "put_bits.h"
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#include "get_bits.h"
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#include "mpeg4audio.h"
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#include "internal.h"
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typedef struct AACBSFContext {
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int first_frame_done;
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} AACBSFContext;
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/**
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* This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4
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* ADTS header and removes the ADTS header.
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*/
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static int aac_adtstoasc_filter(AVBitStreamFilterContext *bsfc,
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AVCodecContext *avctx, const char *args,
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uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size,
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int keyframe)
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{
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GetBitContext gb;
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PutBitContext pb;
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AACADTSHeaderInfo hdr;
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AACBSFContext *ctx = bsfc->priv_data;
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init_get_bits(&gb, buf, AAC_ADTS_HEADER_SIZE*8);
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*poutbuf = (uint8_t*) buf;
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*poutbuf_size = buf_size;
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if (avctx->extradata)
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if (show_bits(&gb, 12) != 0xfff)
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return 0;
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if (avpriv_aac_parse_header(&gb, &hdr) < 0) {
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av_log(avctx, AV_LOG_ERROR, "Error parsing ADTS frame header!\n");
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return -1;
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}
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if (!hdr.crc_absent && hdr.num_aac_frames > 1) {
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avpriv_report_missing_feature(avctx,
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"Multiple RDBs per frame with CRC");
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return AVERROR_PATCHWELCOME;
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}
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buf += AAC_ADTS_HEADER_SIZE + 2*!hdr.crc_absent;
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buf_size -= AAC_ADTS_HEADER_SIZE + 2*!hdr.crc_absent;
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if (!ctx->first_frame_done) {
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int pce_size = 0;
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uint8_t pce_data[MAX_PCE_SIZE];
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if (!hdr.chan_config) {
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init_get_bits(&gb, buf, buf_size * 8);
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if (get_bits(&gb, 3) != 5) {
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avpriv_report_missing_feature(avctx,
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"PCE-based channel configuration "
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"without PCE as first syntax "
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"element");
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return AVERROR_PATCHWELCOME;
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}
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init_put_bits(&pb, pce_data, MAX_PCE_SIZE);
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pce_size = avpriv_copy_pce_data(&pb, &gb)/8;
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flush_put_bits(&pb);
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buf_size -= get_bits_count(&gb)/8;
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buf += get_bits_count(&gb)/8;
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}
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av_free(avctx->extradata);
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avctx->extradata_size = 2 + pce_size;
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avctx->extradata = av_mallocz(avctx->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
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init_put_bits(&pb, avctx->extradata, avctx->extradata_size);
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put_bits(&pb, 5, hdr.object_type);
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put_bits(&pb, 4, hdr.sampling_index);
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put_bits(&pb, 4, hdr.chan_config);
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put_bits(&pb, 1, 0); //frame length - 1024 samples
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put_bits(&pb, 1, 0); //does not depend on core coder
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put_bits(&pb, 1, 0); //is not extension
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flush_put_bits(&pb);
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if (pce_size) {
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memcpy(avctx->extradata + 2, pce_data, pce_size);
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}
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ctx->first_frame_done = 1;
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}
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*poutbuf = (uint8_t*) buf;
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*poutbuf_size = buf_size;
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return 0;
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}
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AVBitStreamFilter ff_aac_adtstoasc_bsf = {
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.name = "aac_adtstoasc",
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.priv_data_size = sizeof(AACBSFContext),
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.filter = aac_adtstoasc_filter,
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};
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