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  * 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
  32 bool get_wave_metadata(int fd, struct mp3entry* id3)
  33 {
  34     /* Use the trackname part of the id3 structure as a temporary buffer */
  35     unsigned char* buf = (unsigned char *)id3->path;
  36     unsigned long totalsamples = 0;
  37     unsigned long channels = 0;
  38     unsigned long bitspersample = 0;
  39     unsigned long numbytes = 0;
  40     int read_bytes;
  41     int i;
  42
  43     /* get RIFF chunk header */
  44     if ((lseek(fd, 0, SEEK_SET) < 0)
  45         || ((read_bytes = read(fd, buf, 12)) < 12))
  46     {
  47         return false;
  48     }
  49
  50     if ((memcmp(buf, "RIFF",4) != 0)
  51         || (memcmp(&buf[8], "WAVE", 4) !=0 ))
  52     {
  53         return false;
  54     }
  55
  56     /* iterate over WAVE chunks until 'data' chunk */
  57     while (true)
  58     {
  59         /* get chunk header */
  60         if ((read_bytes = read(fd, buf, 8)) < 8)
  61             return false;
  62
  63         /* chunkSize */
  64         i = get_long_le(&buf[4]);
  65
  66         if (memcmp(buf, "fmt ", 4) == 0)
  67         {
  68             /* get rest of chunk */
  69             if ((read_bytes = read(fd, buf, 16)) < 16)
  70                 return false;
  71
  72             i -= 16;
  73
  74             /* skipping wFormatTag */
  75             /* wChannels */
  76             channels = buf[2] | (buf[3] << 8);
  77             /* dwSamplesPerSec */
  78             id3->frequency = get_long_le(&buf[4]);
  79             /* dwAvgBytesPerSec */
  80             id3->bitrate = (get_long_le(&buf[8]) * 8) / 1000;
  81             /* skipping wBlockAlign */
  82             /* wBitsPerSample */
  83             bitspersample = buf[14] | (buf[15] << 8);
  84         }
  85         else if (memcmp(buf, "data", 4) == 0)
  86         {
  87             numbytes = i;
  88             break;
  89         }
  90         else if (memcmp(buf, "fact", 4) == 0)
  91         {
  92             /* dwSampleLength */
  93             if (i >= 4)
  94             {
  95                 /* get rest of chunk */
  96                 if ((read_bytes = read(fd, buf, 4)) < 4)
  97                     return false;
  98
  99                 i -= 4;
 100                 totalsamples = get_long_le(buf);
 101             }
 102         }
 103
 104         /* seek to next chunk (even chunk sizes must be padded) */
 105         if (i & 0x01)
 106             i++;
 107
 108         if(lseek(fd, i, SEEK_CUR) < 0)
 109             return false;
 110     }
 111
 112     if ((numbytes == 0) || (channels == 0))
 113     {
 114         return false;
 115     }
 116
 117     if (totalsamples == 0)
 118     {
 119         /* for PCM only */
 120         totalsamples = numbytes
 121             / ((((bitspersample - 1) / 8) + 1) * channels);
 122     }
 123
 124     id3->vbr = false;   /* All WAV files are CBR */
 125     id3->filesize = filesize(fd);
 126
 127     /* Calculate track length (in ms) and estimate the bitrate (in kbit/s) */
 128     id3->length = ((int64_t) totalsamples * 1000) / id3->frequency;
 129
 130     return true;
 131 }