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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Daniel Stenberg
*
* 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.
*
****************************************************************************/
/*
* Parts of this code has been stolen from the Ample project and was written
* by David H�deman. It has since been extended and enhanced pretty much by
* all sorts of friendly Rockbox people.
*
*/
/* tagResolver and associated code copyright 2003 Thomas Paul Diffenbach
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include "string-extra.h"
#include "config.h"
#include "file.h"
#include "logf.h"
#include "system.h"
#include "metadata.h"
#include "mp3data.h"
#include "metadata_common.h"
#include "metadata_parsers.h"
/*
* Calculates the length (in milliseconds) of an MP3 file.
*
* Modified to only use integers.
*
* Arguments: file - the file to calculate the length upon
* entry - the entry to update with the length
*
* Returns: the song length in milliseconds,
* 0 means that it couldn't be calculated
*/
static int getsonglength(int fd, struct mp3entry *entry)
{
unsigned long filetime = 0;
struct mp3info info;
long bytecount;
/* Start searching after ID3v2 header */
if(-1 == lseek(fd, entry->id3v2len, SEEK_SET))
return 0;
bytecount = get_mp3file_info(fd, &info);
logf("Space between ID3V2 tag and first audio frame: 0x%lx bytes",
bytecount);
if(bytecount < 0)
return -1;
bytecount += entry->id3v2len;
/* Validate byte count, in case the file has been edited without
* updating the header.
*/
if (info.byte_count)
{
const unsigned long expected = entry->filesize - entry->id3v1len
- entry->id3v2len;
const unsigned long diff = MAX(10240, info.byte_count / 20);
if ((info.byte_count > expected + diff)
|| (info.byte_count < expected - diff))
{
logf("Note: info.byte_count differs from expected value by "
"%ld bytes", labs((long) (expected - info.byte_count)));
info.byte_count = 0;
info.frame_count = 0;
info.file_time = 0;
info.enc_padding = 0;
/* Even if the bitrate was based on "known bad" values, it
* should still be better for VBR files than using the bitrate
* of the first audio frame.
*/
}
}
entry->bitrate = info.bitrate;
entry->frequency = info.frequency;
entry->version = info.version;
entry->layer = info.layer;
switch(entry->layer) {
#if CONFIG_CODEC==SWCODEC
case 0:
entry->codectype=AFMT_MPA_L1;
break;
#endif
case 1:
entry->codectype=AFMT_MPA_L2;
break;
case 2:
entry->codectype=AFMT_MPA_L3;
break;
}
/* If the file time hasn't been established, this may be a fixed
rate MP3, so just use the default formula */
filetime = info.file_time;
if(filetime == 0)
{
/* Prevent a division by zero */
if (info.bitrate < 8)
filetime = 0;
else
filetime = (entry->filesize - bytecount) / (info.bitrate / 8);
/* bitrate is in kbps so this delivers milliseconds. Doing bitrate / 8
* instead of filesize * 8 is exact, because mpeg audio bitrates are
* always multiples of 8, and it avoids overflows. */
}
entry->frame_count = info.frame_count;
entry->vbr = info.is_vbr;
entry->has_toc = info.has_toc;
#if CONFIG_CODEC==SWCODEC
if (!entry->lead_trim)
entry->lead_trim = info.enc_delay;
if (!entry->tail_trim)
entry->tail_trim = info.enc_padding;
#endif
memcpy(entry->toc, info.toc, sizeof(info.toc));
entry->vbr_header_pos = info.vbr_header_pos;
/* Update the seek point for the first playable frame */
entry->first_frame_offset = bytecount;
logf("First frame is at %lx", entry->first_frame_offset);
return filetime;
}
/*
* Checks all relevant information (such as ID3v1 tag, ID3v2 tag, length etc)
* about an MP3 file and updates it's entry accordingly.
*
Note, that this returns true for successful, false for error! */
bool get_mp3_metadata(int fd, struct mp3entry *entry)
{
entry->title = NULL;
entry->filesize = filesize(fd);
entry->id3v2len = getid3v2len(fd);
entry->tracknum = 0;
entry->discnum = 0;
if (entry->id3v2len)
setid3v2title(fd, entry);
int len = getsonglength(fd, entry);
if (len < 0)
return false;
entry->length = len;
/* Subtract the meta information from the file size to get
the true size of the MP3 stream */
entry->filesize -= entry->first_frame_offset;
/* only seek to end of file if no id3v2 tags were found */
if (!entry->id3v2len) {
setid3v1title(fd, entry);
}
if(!entry->length || (entry->filesize < 8 ))
/* no song length or less than 8 bytes is hereby considered to be an
invalid mp3 and won't be played by us! */
return false;
return true;
}
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