apps/metadata/mpc.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2005 Thom Johansen
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 #include <string.h>
  23 #include <inttypes.h>
  24 #include "system.h"
  25 #include "metadata.h"
  26 #include "metadata_common.h"
  27 #include "metadata_parsers.h"
  28 #include "logf.h"
  29 #include "replaygain.h"
  30
  31 static int set_replaygain(struct mp3entry* id3, bool album, long value,
  32     long used)
  33 {
  34     long gain = (int16_t) ((value >> 16) & 0xffff);
  35     long peak = (uint16_t) (value & 0xffff);
  36
  37     /* We use a peak value of 0 to indicate a given gain type isn't used. */
  38     if (peak != 0)
  39     {
  40         /* Use the Xing TOC field to store ReplayGain strings for use in the
  41          * ID3 screen, since Musepack files shouldn't need to use it in any
  42          * other way.
  43          */
  44         used += parse_replaygain_int(album, gain * 512 / 100, peak << 9,
  45             id3, id3->toc + used, sizeof(id3->toc) - used);
  46     }
  47
  48     return used;
  49 }
  50
  51 bool get_musepack_metadata(int fd, struct mp3entry *id3)
  52 {
  53     static const int32_t sfreqs_sv7[4] = { 44100, 48000, 37800, 32000 };
  54     uint32_t header[8];
  55     uint64_t samples = 0;
  56     int i;
  57
  58     if (!skip_id3v2(fd, id3))
  59         return false;
  60     if (read(fd, header, 4*8) != 4*8) return false;
  61     /* Musepack files are little endian, might need swapping */
  62     for (i = 1; i < 8; i++)
  63        header[i] = letoh32(header[i]);
  64     if (!memcmp(header, "MP+", 3)) { /* Compare to sig "MP+" */
  65         unsigned int streamversion;
  66
  67         header[0] = letoh32(header[0]);
  68         streamversion = (header[0] >> 24) & 15;
  69         if (streamversion >= 8) {
  70             return false; /* SV8 or higher don't exist yet, so no support */
  71         } else if (streamversion == 7) {
  72             unsigned int gapless = (header[5] >> 31) & 0x0001;
  73             unsigned int last_frame_samples = (header[5] >> 20) & 0x07ff;
  74             unsigned int bufused = 0;
  75
  76             id3->frequency = sfreqs_sv7[(header[2] >> 16) & 0x0003];
  77             samples = (uint64_t)header[1]*1152; /* 1152 is mpc frame size */
  78             if (gapless)
  79                 samples -= 1152 - last_frame_samples;
  80             else
  81                 samples -= 481; /* Musepack subband synth filter delay */
  82
  83             bufused = set_replaygain(id3, false, header[3], bufused);
  84             bufused = set_replaygain(id3, true, header[4], bufused);
  85         }
  86     } else {
  87         return false; /* SV4-6 is not supported anymore */
  88     }
  89
  90     id3->vbr = true;
  91     /* Estimate bitrate, we should probably subtract the various header sizes
  92        here for super-accurate results */
  93     id3->length = ((int64_t) samples * 1000) / id3->frequency;
  94
  95     if (id3->length <= 0)
  96     {
  97         logf("mpc length invalid!");
  98         return false;
  99     }
 100
 101     id3->filesize = filesize(fd);
 102     id3->bitrate = id3->filesize * 8 / id3->length;
 103     return true;
 104 }