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  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19
  20 #include <string.h>
  21 #include <inttypes.h>
  22 #include "system.h"
  23 #include "id3.h"
  24 #include "metadata_common.h"
  25 #include "logf.h"
  26 #include "replaygain.h"
  27
  28 static int set_replaygain(struct mp3entry* id3, bool album, long value,
  29     long used)
  30 {
  31     long gain = (int16_t) ((value >> 16) & 0xffff);
  32     long peak = (uint16_t) (value & 0xffff);
  33
  34     /* We use a peak value of 0 to indicate a given gain type isn't used. */
  35     if (peak != 0)
  36     {
  37         /* Use the Xing TOC field to store ReplayGain strings for use in the
  38          * ID3 screen, since Musepack files shouldn't need to use it in any
  39          * other way.
  40          */
  41         used += parse_replaygain_int(album, gain * 512 / 100, peak << 9,
  42             id3, id3->toc + used, sizeof(id3->toc) - used);
  43     }
  44
  45     return used;
  46 }
  47
  48 bool get_musepack_metadata(int fd, struct mp3entry *id3)
  49 {
  50     const int32_t sfreqs_sv7[4] = { 44100, 48000, 37800, 32000 };
  51     uint32_t header[8];
  52     uint64_t samples = 0;
  53     int i;
  54
  55     if (!skip_id3v2(fd, id3))
  56         return false;
  57     if (read(fd, header, 4*8) != 4*8) return false;
  58     /* Musepack files are little endian, might need swapping */
  59     for (i = 1; i < 8; i++)
  60        header[i] = letoh32(header[i]);
  61     if (!memcmp(header, "MP+", 3)) { /* Compare to sig "MP+" */
  62         unsigned int streamversion;
  63
  64         header[0] = letoh32(header[0]);
  65         streamversion = (header[0] >> 24) & 15;
  66         if (streamversion >= 8) {
  67             return false; /* SV8 or higher don't exist yet, so no support */
  68         } else if (streamversion == 7) {
  69             unsigned int gapless = (header[5] >> 31) & 0x0001;
  70             unsigned int last_frame_samples = (header[5] >> 20) & 0x07ff;
  71             unsigned int bufused = 0;
  72
  73             id3->frequency = sfreqs_sv7[(header[2] >> 16) & 0x0003];
  74             samples = (uint64_t)header[1]*1152; /* 1152 is mpc frame size */
  75             if (gapless)
  76                 samples -= 1152 - last_frame_samples;
  77             else
  78                 samples -= 481; /* Musepack subband synth filter delay */
  79
  80             bufused = set_replaygain(id3, false, header[3], bufused);
  81             bufused = set_replaygain(id3, true, header[4], bufused);
  82         }
  83     } else {
  84         header[0] = letoh32(header[0]);
  85         unsigned int streamversion = (header[0] >> 11) & 0x03FF;
  86         if (streamversion != 4 && streamversion != 5 && streamversion != 6)
  87             return false;
  88         id3->frequency = 44100;
  89         id3->track_gain = 0;
  90         id3->track_peak = 0;
  91         id3->album_gain = 0;
  92         id3->album_peak = 0;
  93
  94         if (streamversion >= 5)
  95             samples = (uint64_t)header[1]*1152; // 32 bit
  96         else
  97             samples = (uint64_t)(header[1] >> 16)*1152; // 16 bit
  98
  99         samples -= 576;
 100         if (streamversion < 6)
 101             samples -= 1152;
 102     }
 103
 104     id3->vbr = true;
 105     /* Estimate bitrate, we should probably subtract the various header sizes
 106        here for super-accurate results */
 107     id3->length = ((int64_t) samples * 1000) / id3->frequency;
 108
 109     if (id3->length <= 0)
 110     {
 111         logf("mpc length invalid!");
 112         return false;
 113     }
 114
 115     id3->filesize = filesize(fd);
 116     id3->bitrate = id3->filesize * 8 / id3->length;
 117     return true;
 118 }