apps/metadata/wavpack.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2007 David Bryant
  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 #include <stdio.h>
  22 #include <string.h>
  23 #include <stdlib.h>
  24 #include <ctype.h>
  25 #include <inttypes.h>
  26
  27 #include "system.h"
  28 #include "metadata.h"
  29 #include "metadata_common.h"
  30 #include "metadata_parsers.h"
  31 #include "logf.h"
  32
  33 #define ID_UNIQUE               0x3f
  34 #define ID_LARGE                0x80
  35 #define ID_SAMPLE_RATE          0x27
  36
  37 #define MONO_FLAG       4
  38 #define HYBRID_FLAG     8
  39
  40 static const long wavpack_sample_rates [] =
  41 {
  42      6000,  8000,  9600, 11025, 12000, 16000,  22050, 24000,
  43     32000, 44100, 48000, 64000, 88200, 96000, 192000
  44 };
  45
  46 /* A simple parser to read basic information from a WavPack file. This
  47  * now works with self-extrating WavPack files and also will scan the
  48  * metadata for non-standard sampling rates. This no longer fails on
  49  * WavPack files containing floating-point audio data because these are
  50  * now converted to standard Rockbox format in the decoder.
  51  */
  52
  53 bool get_wavpack_metadata(int fd, struct mp3entry* id3)
  54 {
  55     /* Use the trackname part of the id3 structure as a temporary buffer */
  56     unsigned char* buf = (unsigned char *)id3->path;
  57     uint32_t totalsamples, blocksamples, flags;
  58     int i;
  59
  60     for (i = 0; i < 256; ++i) {
  61
  62         /* at every 256 bytes into file, try to read a WavPack header */
  63
  64         if ((lseek(fd, i * 256, SEEK_SET) < 0) || (read(fd, buf, 32) < 32))
  65             return false;
  66
  67         /* if valid WavPack 4 header version, break */
  68
  69         if (memcmp (buf, "wvpk", 4) == 0 && buf [9] == 4 &&
  70             (buf [8] >= 2 && buf [8] <= 0x10))
  71                 break;
  72     }
  73
  74     if (i == 256) {
  75         logf ("Not a WavPack file");
  76         return false;
  77     }
  78
  79     id3->vbr = true;   /* All WavPack files are VBR */
  80     id3->filesize = filesize (fd);
  81     totalsamples = get_long_le(&buf[12]);
  82     blocksamples = get_long_le(&buf[20]);
  83     flags = get_long_le(&buf[24]);
  84
  85     if (blocksamples) {
  86         int srindx = ((buf [26] >> 7) & 1) + ((buf [27] << 1) & 14);
  87
  88         if (srindx == 15) {
  89             uint32_t meta_bytes = buf [4] + (buf [5] << 8) + (buf [6] << 16) - 24;
  90             uint32_t meta_size;
  91
  92             id3->frequency = 44100;
  93
  94             while (meta_bytes >= 6) {
  95                 if (read(fd, buf, 2) < 2)
  96                     break;
  97
  98                 if (buf [0] & ID_LARGE) {
  99                     if (read(fd, buf + 2, 2) < 2)
 100                         break;
 101
 102                     meta_size = (buf [1] << 1) + (buf [2] << 9) + (buf [3] << 17);
 103                     meta_bytes -= meta_size + 4;
 104                 }
 105                 else {
 106                     meta_size = buf [1] << 1;
 107                     meta_bytes -= meta_size + 2;
 108
 109                     if ((buf [0] & ID_UNIQUE) == ID_SAMPLE_RATE) {
 110                         if (meta_size == 4 && read(fd, buf + 2, 4) == 4)
 111                             id3->frequency = buf [2] + (buf [3] << 8) + (buf [4] << 16);
 112
 113                         break;
 114                     }
 115                 }
 116
 117                 if (meta_size > 0 && lseek(fd, meta_size, SEEK_CUR) < 0)
 118                     break;
 119             }
 120         }
 121         else
 122             id3->frequency = wavpack_sample_rates[srindx];
 123
 124         /* if the total number of samples is unknown, make a guess on the high side (for now) */
 125
 126         if (totalsamples == (uint32_t) -1) {
 127             totalsamples = filesize (fd) * 3;
 128
 129             if (!(flags & HYBRID_FLAG))
 130                 totalsamples /= 2;
 131
 132             if (!(flags & MONO_FLAG))
 133                 totalsamples /= 2;
 134         }
 135
 136         id3->length = ((int64_t) totalsamples * 1000) / id3->frequency;
 137         id3->bitrate = filesize (fd) / (id3->length / 8);
 138
 139         return true;
 140     }
 141
 142     return false;
 143 }