6a9a8197b3
Patch by Thomas Jarosch. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@28892 a1c6a512-1295-4272-9138-f99709370657
103 lines
3.1 KiB
C
103 lines
3.1 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2005 Dave Chapman
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include <stdio.h>
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#include "metadata.h"
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#include "logf.h"
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#include "metadata_parsers.h"
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static const unsigned short a52_bitrates[] =
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{
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32, 40, 48, 56, 64, 80, 96, 112, 128, 160,
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192, 224, 256, 320, 384, 448, 512, 576, 640
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};
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/* Only store frame sizes for 44.1KHz - others are simply multiples
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of the bitrate */
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static const unsigned short a52_441framesizes[] =
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{
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69 * 2, 70 * 2, 87 * 2, 88 * 2, 104 * 2, 105 * 2, 121 * 2,
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122 * 2, 139 * 2, 140 * 2, 174 * 2, 175 * 2, 208 * 2, 209 * 2,
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243 * 2, 244 * 2, 278 * 2, 279 * 2, 348 * 2, 349 * 2, 417 * 2,
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418 * 2, 487 * 2, 488 * 2, 557 * 2, 558 * 2, 696 * 2, 697 * 2,
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835 * 2, 836 * 2, 975 * 2, 976 * 2, 1114 * 2, 1115 * 2, 1253 * 2,
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1254 * 2, 1393 * 2, 1394 * 2
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};
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bool get_a52_metadata(int fd, struct mp3entry *id3)
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{
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/* Use the trackname part of the id3 structure as a temporary buffer */
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unsigned char* buf = (unsigned char *)id3->path;
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unsigned long totalsamples;
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int i;
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if ((lseek(fd, 0, SEEK_SET) < 0) || (read(fd, buf, 5) < 5))
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{
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return false;
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}
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if ((buf[0] != 0x0b) || (buf[1] != 0x77))
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{
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logf("not an A52/AC3 file\n");
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return false;
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}
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i = buf[4] & 0x3e;
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if (i > 36)
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{
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logf("A52: Invalid frmsizecod: %d\n",i);
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return false;
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}
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id3->bitrate = a52_bitrates[i >> 1];
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id3->vbr = false;
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id3->filesize = filesize(fd);
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switch (buf[4] & 0xc0)
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{
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case 0x00:
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id3->frequency = 48000;
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id3->bytesperframe=id3->bitrate * 2 * 2;
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break;
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case 0x40:
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id3->frequency = 44100;
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id3->bytesperframe = a52_441framesizes[i];
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break;
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case 0x80:
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id3->frequency = 32000;
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id3->bytesperframe = id3->bitrate * 3 * 2;
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break;
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default:
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logf("A52: Invalid samplerate code: 0x%02x\n", buf[4] & 0xc0);
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return false;
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break;
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}
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/* One A52 frame contains 6 blocks, each containing 256 samples */
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totalsamples = id3->filesize / id3->bytesperframe * 6 * 256;
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id3->length = totalsamples / id3->frequency * 1000;
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return true;
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}
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