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