Andreas Grün / Mbed 2 deprecated madplayer

MP3 Player without external hardware MP3 Player without external hardware. A software based MP3 player based on a modified version of libmad. Mono output (at the moment) via AnalogOut. Files are read from an USB drive. This is a demo program, it plays only one file at the moment. Documentation is in "main.cpp" and "config.h"

Dependencies:   mbed

fixed.cpp@2:f28cf0afd021, 2010-11-27 (annotated)

Committer:
Gruenfrosch
Date:
Sat Nov 27 17:27:33 2010 +0000
Revision:
2:f28cf0afd021
Parent:
0:7627c79db971 
Version 3:

 * moved another memory block into AHB RAM, giving more room for

 * stereo buffer.

 * moved content of decode() to main()

 * decoding	is now safe to be called multiple times (bug in older versions)

 * Output routine now fills stereo buffer, DAC output sums channels,

 * just for demonstration that stereo output could go here

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Gruenfrosch 0:7627c79db971 1 /*
Gruenfrosch 0:7627c79db971 2 * libmad - MPEG audio decoder library
Gruenfrosch 0:7627c79db971 3 * Copyright (C) 2000-2004 Underbit Technologies, Inc.
Gruenfrosch 0:7627c79db971 4 *
Gruenfrosch 0:7627c79db971 5 * This program is free software; you can redistribute it and/or modify
Gruenfrosch 0:7627c79db971 6 * it under the terms of the GNU General Public License as published by
Gruenfrosch 0:7627c79db971 7 * the Free Software Foundation; either version 2 of the License, or
Gruenfrosch 0:7627c79db971 8 * (at your option) any later version.
Gruenfrosch 0:7627c79db971 9 *
Gruenfrosch 0:7627c79db971 10 * This program is distributed in the hope that it will be useful,
Gruenfrosch 0:7627c79db971 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
Gruenfrosch 0:7627c79db971 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
Gruenfrosch 0:7627c79db971 13 * GNU General Public License for more details.
Gruenfrosch 0:7627c79db971 14 *
Gruenfrosch 0:7627c79db971 15 * You should have received a copy of the GNU General Public License
Gruenfrosch 0:7627c79db971 16 * along with this program; if not, write to the Free Software
Gruenfrosch 0:7627c79db971 17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Gruenfrosch 0:7627c79db971 18 *
Gruenfrosch 0:7627c79db971 19 * $Id: fixed.c,v 1.1 2010/11/23 20:12:57 andy Exp $
Gruenfrosch 0:7627c79db971 20 */
Gruenfrosch 0:7627c79db971 21
Gruenfrosch 0:7627c79db971 22 # include "config.h"
Gruenfrosch 0:7627c79db971 23
Gruenfrosch 0:7627c79db971 24 # include "global.h"
Gruenfrosch 0:7627c79db971 25
Gruenfrosch 0:7627c79db971 26 # include "fixed.h"
Gruenfrosch 0:7627c79db971 27
Gruenfrosch 0:7627c79db971 28 /*
Gruenfrosch 0:7627c79db971 29 * NAME: fixed->abs()
Gruenfrosch 0:7627c79db971 30 * DESCRIPTION: return absolute value of a fixed-point number
Gruenfrosch 0:7627c79db971 31 */
Gruenfrosch 0:7627c79db971 32 mad_fixed_t mad_f_abs(mad_fixed_t x)
Gruenfrosch 0:7627c79db971 33 {
Gruenfrosch 0:7627c79db971 34 return x < 0 ? -x : x;
Gruenfrosch 0:7627c79db971 35 }
Gruenfrosch 0:7627c79db971 36
Gruenfrosch 0:7627c79db971 37 /*
Gruenfrosch 0:7627c79db971 38 * NAME: fixed->div()
Gruenfrosch 0:7627c79db971 39 * DESCRIPTION: perform division using fixed-point math
Gruenfrosch 0:7627c79db971 40 */
Gruenfrosch 0:7627c79db971 41 mad_fixed_t mad_f_div(mad_fixed_t x, mad_fixed_t y)
Gruenfrosch 0:7627c79db971 42 {
Gruenfrosch 0:7627c79db971 43 mad_fixed_t q, r;
Gruenfrosch 0:7627c79db971 44 unsigned int bits;
Gruenfrosch 0:7627c79db971 45
Gruenfrosch 0:7627c79db971 46 q = mad_f_abs(x / y);
Gruenfrosch 0:7627c79db971 47
Gruenfrosch 0:7627c79db971 48 if (x < 0) {
Gruenfrosch 0:7627c79db971 49 x = -x;
Gruenfrosch 0:7627c79db971 50 y = -y;
Gruenfrosch 0:7627c79db971 51 }
Gruenfrosch 0:7627c79db971 52
Gruenfrosch 0:7627c79db971 53 r = x % y;
Gruenfrosch 0:7627c79db971 54
Gruenfrosch 0:7627c79db971 55 if (y < 0) {
Gruenfrosch 0:7627c79db971 56 x = -x;
Gruenfrosch 0:7627c79db971 57 y = -y;
Gruenfrosch 0:7627c79db971 58 }
Gruenfrosch 0:7627c79db971 59
Gruenfrosch 0:7627c79db971 60 if (q > mad_f_intpart(MAD_F_MAX) &&
Gruenfrosch 0:7627c79db971 61 !(q == -mad_f_intpart(MAD_F_MIN) && r == 0 && (x < 0) != (y < 0)))
Gruenfrosch 0:7627c79db971 62 return 0;
Gruenfrosch 0:7627c79db971 63
Gruenfrosch 0:7627c79db971 64 for (bits = MAD_F_FRACBITS; bits && r; --bits) {
Gruenfrosch 0:7627c79db971 65 q <<= 1, r <<= 1;
Gruenfrosch 0:7627c79db971 66 if (r >= y)
Gruenfrosch 0:7627c79db971 67 r -= y, ++q;
Gruenfrosch 0:7627c79db971 68 }
Gruenfrosch 0:7627c79db971 69
Gruenfrosch 0:7627c79db971 70 /* round */
Gruenfrosch 0:7627c79db971 71 if (2 * r >= y)
Gruenfrosch 0:7627c79db971 72 ++q;
Gruenfrosch 0:7627c79db971 73
Gruenfrosch 0:7627c79db971 74 /* fix sign */
Gruenfrosch 0:7627c79db971 75 if ((x < 0) != (y < 0))
Gruenfrosch 0:7627c79db971 76 q = -q;
Gruenfrosch 0:7627c79db971 77
Gruenfrosch 0:7627c79db971 78 return q << bits;
Gruenfrosch 0:7627c79db971 79 }