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114 lines
3.8 KiB
114 lines
3.8 KiB
/* |
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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 Libav. |
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* |
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* Libav 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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* Libav 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 Libav; 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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av_log_missing_feature(avctx, "Multiple RDBs per frame with CRC", 0); |
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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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av_log_missing_feature(avctx, "PCE based channel configuration, where the PCE is not the first syntax element", 0); |
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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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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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"aac_adtstoasc", |
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sizeof(AACBSFContext), |
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aac_adtstoasc_filter, |
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};
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