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2.2.3 File Conversion: Verification of Conversion to Raw
Section 2.2.3: Verification of Conversion

There are several ways to verify that your conversion has proceeded correctly, including listening to the audio data. Three procedures are outlined below.

SoX: Audio Playback

In order to listen to the file, SoX must be installed on your system. To listen to the file speech.raw, convert the file from raw format to .au format using SoX. Go to the directory:
    $ISIP_TUTORIAL/sections/s02/s02_02_p03/
Use the following syntax:
    sox -t .sw -r 16000 speech.raw -t .au speech.au
The command line entries for SoX are explained in Section 2.3.3.

Once conversion has been completed, listen to the file on a computer running the Sun Solaris operating system using the command:
    audioplay speech.au
Other software tools are available for display and audio playback, including display signal and CoolEdit.

File Size Comparison: Using "ls -l"

The NIST SPHERE header is typically 1024 bytes. Hence, we can use standard Unix commands to check if the output file is the correct size. Use the command:

    ls -l speech.*
The command will result in this output:

    -rw-rw-r-- 1 may isip 97486 Sep 10 15:19 speech.raw
    -rw-rw-r-- 1 may isip 98510 Sep 10 15:12 speech.sph
The fifth field contains the file size in bytes. We can see that speech.raw is exactly 1024 bytes smaller than speech.sph.

Octel Dump (od): Listing Values

From time to time it will be necessary to list the values of a file. A useful command for this is "od". Since speech.raw consists of two-byte signed integers, we can use the od command to list the numeric values of the samples:

    od -t d2 speech.raw
This results in the following display:

    0000000 4 3 4 3 4 3 3 3
    0000020 -1 6 3 4 5 1 3 4
    0000040 3 2 5 5 5 5 5 3
    0000060 5 4 3 6 2 6 3 4
    0000100 4 2 4 3 3 4 4 0
    0000120 6 3 4 3 2 4 1 3
    0000140 2 5 5 5 4 3 6 3
    0000160 1 5 5 5 5 5 5 5
    0000200 5 5 5 3 4 4 3 3
    0000220 6 3 3 5 2 5 5 3
    ...
Sample values are displayed as signed decimals using a format of 8 samples per row. The first column indicates the index of the starting byte in the file for the data from that row (in an octal format).
   
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