apps/metadata/wave.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2005 Dave Chapman
  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
  29 bool get_wave_metadata(int fd, struct mp3entry* id3)
  30 {
  31     /* Use the trackname part of the id3 structure as a temporary buffer */
  32     unsigned char* buf = (unsigned char *)id3->path;
  33     unsigned long totalsamples = 0;
  34     unsigned long channels = 0;
  35     unsigned long bitspersample = 0;
  36     unsigned long numbytes = 0;
  37     int read_bytes;
  38     int i;
  39
  40     /* get RIFF chunk header */
  41     if ((lseek(fd, 0, SEEK_SET) < 0)
  42         || ((read_bytes = read(fd, buf, 12)) < 12))
  43     {
  44         return false;
  45     }
  46
  47     if ((memcmp(buf, "RIFF",4) != 0)
  48         || (memcmp(&buf[8], "WAVE", 4) !=0 ))
  49     {
  50         return false;
  51     }
  52
  53     /* iterate over WAVE chunks until 'data' chunk */
  54     while (true)
  55     {
  56         /* get chunk header */
  57         if ((read_bytes = read(fd, buf, 8)) < 8)
  58             return false;
  59
  60         /* chunkSize */
  61         i = get_long_le(&buf[4]);
  62
  63         if (memcmp(buf, "fmt ", 4) == 0)
  64         {
  65             /* get rest of chunk */
  66             if ((read_bytes = read(fd, buf, 16)) < 16)
  67                 return false;
  68
  69             i -= 16;
  70
  71             /* skipping wFormatTag */
  72             /* wChannels */
  73             channels = buf[2] | (buf[3] << 8);
  74             /* dwSamplesPerSec */
  75             id3->frequency = get_long_le(&buf[4]);
  76             /* dwAvgBytesPerSec */
  77             id3->bitrate = (get_long_le(&buf[8]) * 8) / 1000;
  78             /* skipping wBlockAlign */
  79             /* wBitsPerSample */
  80             bitspersample = buf[14] | (buf[15] << 8);
  81         }
  82         else if (memcmp(buf, "data", 4) == 0)
  83         {
  84             numbytes = i;
  85             break;
  86         }
  87         else if (memcmp(buf, "fact", 4) == 0)
  88         {
  89             /* dwSampleLength */
  90             if (i >= 4)
  91             {
  92                 /* get rest of chunk */
  93                 if ((read_bytes = read(fd, buf, 4)) < 4)
  94                     return false;
  95
  96                 i -= 4;
  97                 totalsamples = get_long_le(buf);
  98             }
  99         }
 100
 101         /* seek to next chunk (even chunk sizes must be padded) */
 102         if (i & 0x01)
 103             i++;
 104
 105         if(lseek(fd, i, SEEK_CUR) < 0)
 106             return false;
 107     }
 108
 109     if ((numbytes == 0) || (channels == 0))
 110     {
 111         return false;
 112     }
 113
 114     if (totalsamples == 0)
 115     {
 116         /* for PCM only */
 117         totalsamples = numbytes
 118             / ((((bitspersample - 1) / 8) + 1) * channels);
 119     }
 120
 121     id3->vbr = false;   /* All WAV files are CBR */
 122     id3->filesize = filesize(fd);
 123
 124     /* Calculate track length (in ms) and estimate the bitrate (in kbit/s) */
 125     id3->length = ((int64_t) totalsamples * 1000) / id3->frequency;
 126
 127     return true;
 128 }