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 #include "metadata_parsers.h"
  29
  30 bool get_wave_metadata(int fd, struct mp3entry* id3)
  31 {
  32     /* Use the trackname part of the id3 structure as a temporary buffer */
  33     unsigned char* buf = (unsigned char *)id3->path;
  34     unsigned long totalsamples = 0;
  35     unsigned long channels = 0;
  36     unsigned long bitspersample = 0;
  37     unsigned long numbytes = 0;
  38     int read_bytes;
  39     int i;
  40
  41     /* get RIFF chunk header */
  42     if ((lseek(fd, 0, SEEK_SET) < 0)
  43         || ((read_bytes = read(fd, buf, 12)) < 12))
  44     {
  45         return false;
  46     }
  47
  48     if ((memcmp(buf, "RIFF",4) != 0)
  49         || (memcmp(&buf[8], "WAVE", 4) !=0 ))
  50     {
  51         return false;
  52     }
  53
  54     /* iterate over WAVE chunks until 'data' chunk */
  55     while (true)
  56     {
  57         /* get chunk header */
  58         if ((read_bytes = read(fd, buf, 8)) < 8)
  59             return false;
  60
  61         /* chunkSize */
  62         i = get_long_le(&buf[4]);
  63
  64         if (memcmp(buf, "fmt ", 4) == 0)
  65         {
  66             /* get rest of chunk */
  67             if ((read_bytes = read(fd, buf, 16)) < 16)
  68                 return false;
  69
  70             i -= 16;
  71
  72             /* skipping wFormatTag */
  73             /* wChannels */
  74             channels = buf[2] | (buf[3] << 8);
  75             /* dwSamplesPerSec */
  76             id3->frequency = get_long_le(&buf[4]);
  77             /* dwAvgBytesPerSec */
  78             id3->bitrate = (get_long_le(&buf[8]) * 8) / 1000;
  79             /* skipping wBlockAlign */
  80             /* wBitsPerSample */
  81             bitspersample = buf[14] | (buf[15] << 8);
  82         }
  83         else if (memcmp(buf, "data", 4) == 0)
  84         {
  85             numbytes = i;
  86             break;
  87         }
  88         else if (memcmp(buf, "fact", 4) == 0)
  89         {
  90             /* dwSampleLength */
  91             if (i >= 4)
  92             {
  93                 /* get rest of chunk */
  94                 if ((read_bytes = read(fd, buf, 4)) < 4)
  95                     return false;
  96
  97                 i -= 4;
  98                 totalsamples = get_long_le(buf);
  99             }
 100         }
 101
 102         /* seek to next chunk (even chunk sizes must be padded) */
 103         if (i & 0x01)
 104             i++;
 105
 106         if(lseek(fd, i, SEEK_CUR) < 0)
 107             return false;
 108     }
 109
 110     if ((numbytes == 0) || (channels == 0))
 111     {
 112         return false;
 113     }
 114
 115     if (totalsamples == 0)
 116     {
 117         /* for PCM only */
 118         totalsamples = numbytes
 119             / ((((bitspersample - 1) / 8) + 1) * channels);
 120     }
 121
 122     id3->vbr = false;   /* All WAV files are CBR */
 123     id3->filesize = filesize(fd);
 124
 125     /* Calculate track length (in ms) and estimate the bitrate (in kbit/s) */
 126     id3->length = ((int64_t) totalsamples * 1000) / id3->frequency;
 127
 128     return true;
 129 }