mirror of
https://github.com/cookiengineer/audacity
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80 lines
2.2 KiB
C
80 lines
2.2 KiB
C
/*
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* TwoLAME: an optimized MPEG Audio Layer Two encoder
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*
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* Copyright (C) 2001-2004 Michael Cheng
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* Copyright (C) 2004-2006 The TwoLAME Project
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*
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* This library 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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* This library 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 this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* $Id: availbits.c,v 1.3 2008-02-01 19:44:27 richardash1981 Exp $
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*
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*/
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#include <stdio.h>
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#include "twolame.h"
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#include "common.h"
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#include "availbits.h"
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struct slotinfo {
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FLOAT average;
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FLOAT frac;
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int whole;
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FLOAT lag;
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int extra;
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} slots;
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/* function returns the number of available bits */
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int available_bits ( twolame_options * glopts )
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{
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frame_header *header = &glopts->header;
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int adb;
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slots.extra = 0; /* be default, no extra slots */
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slots.average =
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(1152.0/ ((FLOAT)glopts->samplerate_out/1000.0) )
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* ((FLOAT)glopts->bitrate / 8.0);
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//fprintf(stdout,"availbits says: sampling freq is %i. version %i. bitrateindex %i slots %f\n",header->sampling_frequency, header->version, header->bitrate_index, slots.average);
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slots.whole = (int) slots.average;
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slots.frac = slots.average - (FLOAT) slots.whole;
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/* never allow padding for a VBR frame.
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Don't ask me why, I've forgotten why I set this */
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if (slots.frac != 0 && glopts->padding && glopts->vbr == FALSE) {
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if (slots.lag > (slots.frac - 1.0)) { /* no padding for this frame */
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slots.lag -= slots.frac;
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slots.extra = 0;
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header->padding = 0;
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} else { /* padding */
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slots.extra = 1;
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header->padding = 1;
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slots.lag += (1 - slots.frac);
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}
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}
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adb = (slots.whole + slots.extra) * 8;
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return adb;
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}
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// vim:ts=4:sw=4:nowrap:
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