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63 lines
2.1 KiB
63 lines
2.1 KiB
/*****************************************************************************
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* opus.h : Opus demux helpers
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*****************************************************************************
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* Copyright (C) 2012 VLC authors and VideoLAN
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* $Id$
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*
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* Authors: Timothy B. Terriberry <tterribe@xiph.org>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* GNU 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 License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
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*****************************************************************************/
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/* Returns Opus frame duration in samples */
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static inline unsigned opus_frame_duration(unsigned char *data, long len)
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{
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static const int silk_fs_div[4] = { 6000, 3000, 1500, 1000 };
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unsigned toc;
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unsigned nframes;
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unsigned frame_size;
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unsigned nsamples;
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unsigned i_rate;
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if( len < 1 )
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return 0;
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toc = data[0];
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switch( toc&3 )
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{
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case 0:
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nframes = 1;
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break;
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case 1:
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case 2:
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nframes = 2;
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break;
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default:
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if( len < 2 )
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return 0;
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nframes = data[1]&0x3F;
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break;
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}
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i_rate = 48000;
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if( toc&0x80 )
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frame_size = (i_rate << (toc >> 3 & 3)) / 400;
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else if( ( toc&0x60 ) == 0x60 )
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frame_size = i_rate/(100 >> (toc >> 3 & 1));
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else
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frame_size = i_rate*60 / silk_fs_div[toc >> 3 & 3];
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nsamples = nframes*frame_size;
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if( nsamples*25 > i_rate*3 )
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return 0;
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return nsamples;
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}
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