mirror of
https://github.com/Rockbox/rockbox.git
synced 2025-11-09 13:12:37 -05:00
144 lines
4.3 KiB
C
144 lines
4.3 KiB
C
/***************************************************************************
|
|
* __________ __ ___.
|
|
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
|
|
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
|
|
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
|
|
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
|
|
* \/ \/ \/ \/ \/
|
|
* $Id$
|
|
*
|
|
* Parsing ADTS and ADIF headers
|
|
*
|
|
* Written by Igor B. Poretsky
|
|
*
|
|
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
|
|
* KIND, either express or implied.
|
|
*
|
|
****************************************************************************/
|
|
|
|
#include <stdlib.h>
|
|
#include <stdbool.h>
|
|
#include <string.h>
|
|
|
|
#include "platform.h"
|
|
|
|
#include "metadata.h"
|
|
#include "metadata_common.h"
|
|
#include "metadata_parsers.h"
|
|
|
|
static const int sample_rates[] =
|
|
{
|
|
96000, 88200, 64000, 48000,
|
|
44100, 32000, 24000, 22050,
|
|
16000, 12000, 11025, 8000,
|
|
7350, 0, 0, 0
|
|
};
|
|
|
|
static bool check_adts_syncword(int fd)
|
|
{
|
|
uint16_t syncword = 0;
|
|
|
|
read_uint16be(fd, &syncword);
|
|
return (syncword & 0xFFF6) == 0xFFF0;
|
|
}
|
|
|
|
static bool find_adts_keyword(int fd, struct mp3entry *entry)
|
|
{
|
|
/* logic is copied from adts_fixed_header libfaad/syntax.c:
|
|
* try to recover from sync errors */
|
|
for (int i = 0; i < 768; ++i)
|
|
{
|
|
if (-1 == lseek(fd, entry->first_frame_offset + i, SEEK_SET))
|
|
return false;
|
|
|
|
if (check_adts_syncword(fd))
|
|
{
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool get_aac_metadata(int fd, struct mp3entry *entry)
|
|
{
|
|
unsigned char buf[5];
|
|
|
|
entry->title = NULL;
|
|
entry->tracknum = 0;
|
|
entry->discnum = 0;
|
|
entry->id3v1len = 0;
|
|
entry->id3v2len = getid3v2len(fd);
|
|
entry->first_frame_offset = entry->id3v2len;
|
|
entry->filesize = filesize(fd) - entry->first_frame_offset;
|
|
entry->needs_upsampling_correction = false;
|
|
|
|
if (entry->id3v2len)
|
|
setid3v2title(fd, entry);
|
|
|
|
if (-1 == lseek(fd, entry->first_frame_offset, SEEK_SET))
|
|
return false;
|
|
if (read(fd, buf, 5) != 5)
|
|
return false;
|
|
if (!memcmp(buf, "ADIF", 4))
|
|
{
|
|
if (-1 == lseek(fd, (buf[4] & 0x80) ? (entry->first_frame_offset + 9) : entry->first_frame_offset, SEEK_SET))
|
|
return false;
|
|
|
|
uint32_t bitrate;
|
|
read_uint32be(fd, &bitrate);
|
|
entry->vbr = (bitrate & 0x10000000) != 0;
|
|
entry->bitrate = ((bitrate & 0xFFFFFE0) + 16000) / 32000;
|
|
read_uint32be(fd, (uint32_t*)(&(entry->frequency)));
|
|
entry->frequency = sample_rates[(entry->frequency >> (entry->vbr ? 23 : 3)) & 0x0F];
|
|
}
|
|
else if (find_adts_keyword(fd, entry))
|
|
{
|
|
int frames;
|
|
int stat_length;
|
|
uint64_t total;
|
|
if (read(fd, buf, 5) != 5)
|
|
return false;
|
|
entry->frequency = sample_rates[(buf[0] >> 2) & 0x0F];
|
|
entry->vbr = ((buf[3] & 0x1F) == 0x1F)
|
|
&& ((buf[4] & 0xFC) == 0xFC);
|
|
stat_length = entry->frequency >> ((entry->vbr) ? 5 : 7);
|
|
for (frames = 1, total = 0; frames < stat_length; frames++)
|
|
{
|
|
unsigned int frame_length = (((unsigned int)buf[1] & 0x3) << 11)
|
|
| ((unsigned int)buf[2] << 3)
|
|
| ((unsigned int)buf[3] >> 5);
|
|
total += frame_length;
|
|
if (frame_length < 7)
|
|
break;
|
|
if (-1 == lseek(fd, frame_length - 7, SEEK_CUR))
|
|
break;
|
|
if (!check_adts_syncword(fd))
|
|
break;
|
|
if (read(fd, buf, 5) != 5)
|
|
break;
|
|
}
|
|
entry->bitrate = (unsigned int)((total * entry->frequency / frames + 64000) / 128000);
|
|
#ifdef CODEC_AAC_SBR_DEC
|
|
if (entry->frequency <= 24000)
|
|
{
|
|
entry->frequency <<= 1;
|
|
entry->needs_upsampling_correction = true;
|
|
}
|
|
#endif
|
|
}
|
|
else
|
|
{
|
|
lseek(fd, 0, SEEK_SET);
|
|
return get_mp4_metadata(fd, entry);
|
|
}
|
|
|
|
entry->length = (unsigned long)((entry->filesize * 8LL + (entry->bitrate >> 1)) / entry->bitrate);
|
|
|
|
return true;
|
|
}
|