ffmpeg / libavcodec / mp3_header_compress_bsf.c @ d36beb3f
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/*
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* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
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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 "mpegaudio.h" |
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static int mp3_header_compress(AVBitStreamFilterContext *bsfc, 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, int keyframe){ |
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uint32_t header, extraheader; |
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int mode_extension, header_size;
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if(avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL){
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av_log(avctx, AV_LOG_ERROR, "not standards compliant\n");
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return -1; |
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} |
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header = AV_RB32(buf); |
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mode_extension= (header>>4)&3; |
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if(ff_mpa_check_header(header) < 0 || (header&0x60000) != 0x20000){ |
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output_unchanged:
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*poutbuf= (uint8_t *) buf; |
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*poutbuf_size= buf_size; |
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av_log(avctx, AV_LOG_INFO, "cannot compress %08X\n", header);
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return 0; |
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} |
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if(avctx->extradata_size == 0){ |
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avctx->extradata_size=15;
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avctx->extradata= av_malloc(avctx->extradata_size); |
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strcpy(avctx->extradata, "FFCMP3 0.0");
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memcpy(avctx->extradata+11, buf, 4); |
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} |
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if(avctx->extradata_size != 15){ |
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av_log(avctx, AV_LOG_ERROR, "Extradata invalid\n");
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return -1; |
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} |
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extraheader = AV_RB32(avctx->extradata+11);
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if((extraheader&MP3_MASK) != (header&MP3_MASK))
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goto output_unchanged;
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header_size= (header&0x10000) ? 4 : 6; |
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*poutbuf_size= buf_size - header_size; |
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*poutbuf= av_malloc(buf_size - header_size + FF_INPUT_BUFFER_PADDING_SIZE); |
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memcpy(*poutbuf, buf + header_size, buf_size - header_size + FF_INPUT_BUFFER_PADDING_SIZE); |
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if(avctx->channels==2){ |
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if((header & (3<<19)) != 3<<19){ |
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(*poutbuf)[1] &= 0x3F; |
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(*poutbuf)[1] |= mode_extension<<6; |
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FFSWAP(int, (*poutbuf)[1], (*poutbuf)[2]); |
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}else{
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(*poutbuf)[1] &= 0x8F; |
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(*poutbuf)[1] |= mode_extension<<4; |
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} |
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} |
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return 1; |
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} |
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AVBitStreamFilter ff_mp3_header_compress_bsf={
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"mp3comp",
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0,
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mp3_header_compress, |
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}; |