99 lines
3 KiB
C
99 lines
3 KiB
C
|
/***************************************************************************
|
||
|
|
* __________ __ ___.
|
||
|
|
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
|
||
|
|
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
|
||
|
|
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
|
||
|
|
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
|
||
|
|
* \/ \/ \/ \/ \/
|
||
|
|
* $Id: metadata.c 15859 2007-11-30 18:48:07Z lostlogic $
|
||
|
|
*
|
||
|
|
* Copyright (C) 2005 Magnus Holmgren
|
||
|
|
*
|
||
|
|
* All files in this archive are subject to the GNU General Public License.
|
||
|
|
* See the file COPYING in the source tree root for full license agreement.
|
||
|
|
*
|
||
|
|
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
|
||
|
|
* KIND, either express or implied.
|
||
|
|
*
|
||
|
|
****************************************************************************/
|
||
|
|
|
||
|
|
#include "id3.h"
|
||
|
|
#include "logf.h"
|
||
|
|
|
||
|
|
static const unsigned short a52_bitrates[] =
|
||
|
|
{
|
||
|
|
32, 40, 48, 56, 64, 80, 96, 112, 128, 160,
|
||
|
|
192, 224, 256, 320, 384, 448, 512, 576, 640
|
||
|
|
};
|
||
|
|
|
||
|
|
/* Only store frame sizes for 44.1KHz - others are simply multiples
|
||
|
|
of the bitrate */
|
||
|
|
static const unsigned short a52_441framesizes[] =
|
||
|
|
{
|
||
|
|
69 * 2, 70 * 2, 87 * 2, 88 * 2, 104 * 2, 105 * 2, 121 * 2,
|
||
|
|
122 * 2, 139 * 2, 140 * 2, 174 * 2, 175 * 2, 208 * 2, 209 * 2,
|
||
|
|
243 * 2, 244 * 2, 278 * 2, 279 * 2, 348 * 2, 349 * 2, 417 * 2,
|
||
|
|
418 * 2, 487 * 2, 488 * 2, 557 * 2, 558 * 2, 696 * 2, 697 * 2,
|
||
|
|
835 * 2, 836 * 2, 975 * 2, 976 * 2, 1114 * 2, 1115 * 2, 1253 * 2,
|
||
|
|
1254 * 2, 1393 * 2, 1394 * 2
|
||
|
|
};
|
||
|
|
|
||
|
|
bool get_a52_metadata(int fd, struct mp3entry *id3)
|
||
|
|
{
|
||
|
|
/* Use the trackname part of the id3 structure as a temporary buffer */
|
||
|
|
unsigned char* buf = (unsigned char *)id3->path;
|
||
|
|
unsigned long totalsamples;
|
||
|
|
int i;
|
||
|
|
|
||
|
|
if ((lseek(fd, 0, SEEK_SET) < 0) || (read(fd, buf, 5) < 5))
|
||
|
|
{
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
if ((buf[0] != 0x0b) || (buf[1] != 0x77))
|
||
|
|
{
|
||
|
|
logf("%s is not an A52/AC3 file\n",trackname);
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
i = buf[4] & 0x3e;
|
||
|
|
|
||
|
|
if (i > 36)
|
||
|
|
{
|
||
|
|
logf("A52: Invalid frmsizecod: %d\n",i);
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
id3->bitrate = a52_bitrates[i >> 1];
|
||
|
|
id3->vbr = false;
|
||
|
|
id3->filesize = filesize(fd);
|
||
|
|
|
||
|
|
switch (buf[4] & 0xc0)
|
||
|
|
{
|
||
|
|
case 0x00:
|
||
|
|
id3->frequency = 48000;
|
||
|
|
id3->bytesperframe=id3->bitrate * 2 * 2;
|
||
|
|
break;
|
||
|
|
|
||
|
|
case 0x40:
|
||
|
|
id3->frequency = 44100;
|
||
|
|
id3->bytesperframe = a52_441framesizes[i];
|
||
|
|
break;
|
||
|
|
|
||
|
|
case 0x80:
|
||
|
|
id3->frequency = 32000;
|
||
|
|
id3->bytesperframe = id3->bitrate * 3 * 2;
|
||
|
|
break;
|
||
|
|
|
||
|
|
default:
|
||
|
|
logf("A52: Invalid samplerate code: 0x%02x\n", buf[4] & 0xc0);
|
||
|
|
return false;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* One A52 frame contains 6 blocks, each containing 256 samples */
|
||
|
|
totalsamples = id3->filesize / id3->bytesperframe * 6 * 256;
|
||
|
|
id3->length = totalsamples / id3->frequency * 1000;
|
||
|
|
return true;
|
||
|
|
}
|