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/*
* toolame - an optimized mpeg 1/2 layer 2 audio encoder
* Copyright (C) 2001 Michael Cheng
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <stdio.h>
#include "common.h"
#include "encoder.h"
#include "musicin.h"
#include "options.h"
#include "availbits.h"
struct slotinfo {
double average;
double frac;
int whole;
double lag;
int extra;
} slots;
/* function returns the number of available bits */
int available_bits (frame_header *header, options * glopts)
{
int adb;
slots.extra = 0; /* be default, no extra slots */
slots.average =
(1152.0 / s_freq[header->version][header->sampling_frequency]) *
((double) bitrate[header->version][header->bitrate_index] / 8.0);
slots.whole = (int) slots.average;
slots.frac = slots.average - (double) slots.whole;
/* never allow padding for a VBR frame.
Don't ask me why, I've forgotten why I set this */
if (slots.frac != 0 && glopts->usepadbit && glopts->vbr == FALSE) {
if (slots.lag > (slots.frac - 1.0)) { /* no padding for this frame */
slots.lag -= slots.frac;
slots.extra = 0;
header->padding = 0;
} else { /* padding */
slots.extra = 1;
header->padding = 1;
slots.lag += (1 - slots.frac);
}
}
adb = (slots.whole + slots.extra) * 8;
return adb;
}
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