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 #include <stdio.h>
  20 #include <string.h>
  21 #include <stdlib.h>
  22 #include <ctype.h>
  23 #include <inttypes.h>
  24
  25 #include "system.h"
  26 #include "id3.h"
  27 #include "metadata_common.h"
  28 #include "logf.h"
  29 #include "replaygain.h"
  30
  31 bool get_musepack_metadata(int fd, struct mp3entry *id3)
  32 {
  33     const int32_t sfreqs_sv7[4] = { 44100, 48000, 37800, 32000 };
  34     uint32_t header[8];
  35     uint64_t samples = 0;
  36     int i;
  37
  38     if (!skip_id3v2(fd, id3))
  39         return false;
  40     if (read(fd, header, 4*8) != 4*8) return false;
  41     /* Musepack files are little endian, might need swapping */
  42     for (i = 1; i < 8; i++)
  43        header[i] = letoh32(header[i]);
  44     if (!memcmp(header, "MP+", 3)) { /* Compare to sig "MP+" */
  45         unsigned int streamversion;
  46
  47         header[0] = letoh32(header[0]);
  48         streamversion = (header[0] >> 24) & 15;
  49         if (streamversion >= 8) {
  50             return false; /* SV8 or higher don't exist yet, so no support */
  51         } else if (streamversion == 7) {
  52             unsigned int gapless = (header[5] >> 31) & 0x0001;
  53             unsigned int last_frame_samples = (header[5] >> 20) & 0x07ff;
  54             int track_gain, album_gain;
  55             unsigned int bufused;
  56
  57             id3->frequency = sfreqs_sv7[(header[2] >> 16) & 0x0003];
  58             samples = (uint64_t)header[1]*1152; /* 1152 is mpc frame size */
  59             if (gapless)
  60                 samples -= 1152 - last_frame_samples;
  61             else
  62                 samples -= 481; /* Musepack subband synth filter delay */
  63
  64             /* Extract ReplayGain data from header */
  65             track_gain = (int16_t)((header[3] >> 16) & 0xffff);
  66             id3->track_gain = get_replaygain_int(track_gain);
  67             id3->track_peak = ((uint16_t)(header[3] & 0xffff)) << 9;
  68
  69             album_gain = (int16_t)((header[4] >> 16) & 0xffff);
  70             id3->album_gain = get_replaygain_int(album_gain);
  71             id3->album_peak = ((uint16_t)(header[4] & 0xffff)) << 9;
  72
  73             /* Write replaygain values to strings for use in id3 screen. We use
  74                the XING header as buffer space since Musepack files shouldn't
  75                need to use it in any other way */
  76             id3->track_gain_string = (char *)id3->toc;
  77             bufused = snprintf(id3->track_gain_string, 45,
  78                                "%d.%d dB", track_gain/100, abs(track_gain)%100);
  79             id3->album_gain_string = (char *)id3->toc + bufused + 1;
  80             bufused = snprintf(id3->album_gain_string, 45,
  81                                "%d.%d dB", album_gain/100, abs(album_gain)%100);
  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 }