Ok, I FINALLY found the PDF file in the Wii SDK that had the documentation needed for correct operation of sndconv.exe
Below are quotes from the documentation needed to know how to completely operate sndconv.exe. Within these quote boxes, for any sections that include sample code, I've used code boxes, and if a graphic/table is used, I've uploaded uploaded a screencap to imgur, and embedded it here. The full PDF file is much longer, and has info on a lot more things than just sndconv.exe, so I've only included quotes from the sections involving the use of sndconv.exe.
2.2 Using sndconv.exe
2.2.1 The Command Line
From the command line, you can invoke the sndconv.exe program like so:
Code 2–1 sndconv Command Line Syntax
bash> sndconv <scriptfile> [-option]
Where:
<scriptfile>script file (required)
Options are:
-a Default output to ADPCM.
-w Default output to 16bit PCM.
-b Default output to 8bit PCM.
-h This help text.
The <scriptfile> argument in Code 2–1 is required and specifies a text file that contains commands for
sndconv.exe. These commands specify which sound files to convert and pack. These commands also
describe the various attributes of each file, and how they should be converted. For further details, see
“Data Abstraction and File Formats” on page 32.
The –a, –w, and –b options specify the default output format. The sndconv.exe tool uses these defaults
if the script file does not specify a desired output format for a given sound file.
If no option is specified, then sndconv.exe will use ADPCM as a default output format
Note that I have NOT quoted page 32 in this post, despite it being referenced in the above quote. That is because it just provides more technical information about how sound data is stored. This information would really only useful if you are writing your own program for processing sound data in the Wii audio file format. As with the above quote, all the quotes below are also specifically about sndconv.exe and the format of its script files.
2.2.2 Scripting
The sndconv.exe script file specifies which files to convert and how to convert them. An example is
shown in Code 2–2:
Code 2–2 Script File Example
;
; Text after a semicolon is ignored as commentary.
;
COMMENT
COMMENT This is a COMMENT field. Any text following a COMMENT
COMMENT command will be generated as a comment in the corresponding
COMMENT ‘C’ header file output. This is useful for annotating the
COMMENT header file from the script
COMMENT
;
; Set source path for sound files
;
PATH C:\sounds
INCLUDE other_script.txt
COMMENT *****************************************
COMMENT Explosion sounds!
COMMENT *****************************************
BEGIN BIG_EXPLOSION ; Identifier for sound effect
FILE big_exp_pcm16mono.wav ; Source filename – it’s a WAV file!
SAMPLERATE 22050 ; Source sample rate, in Hz
OUTPUT ADPCM ; Will be converted to ADPCM
END
BEGIN LITTLE_EXPLOSION ; Identifier for sound effect
FILE lil_exp_pcm16stereo.aif ; Source filename – it’s an AIFF file!
SAMPLERATE 22050 ; Source sample rate, in Hz
OUTPUT ADPCM ; Will be converted to ADPCM
END
COMMENT *****************************************
COMMENT Helicopter sounds!
COMMENT *****************************************
BEGIN CHOPPER ; Identifier for sound effect
FILE apache_pcm16mono.wav ; Source filename – it’s a WAV file!
SAMPLERATE 32000 ; Source sample rate, in Hz
OUTPUT 16BIT ; Output will be in 16bit PCM
LOOP 117 254 ; loop point start and end!
END
COMMENT *****************************************
COMMENT Whoosh sound
COMMENT *****************************************
BEGIN BIG_WHOOSH ; Identifier for sound effect
FILE bigwhoosh_pcm16stereo.aif ; Source filename – it’s an AIFF file
SAMPLERATE 32000 ; Source sample rate, in Hz
OUTPUT 16BIT ; Output will be 16bit also
LOOP 312 423 ; loop start and end points
MIX COMBINE ; Source sample is stereo, downmix to MONO
END
BEGIN LEFT_WHOOSH ; Identifier for sound effect
FILE bigwhoosh_pcm16stereo.aif ; Source filename – it’s an AIFF file
SAMPLERATE 32000 ; Source sample rate, in Hz
OUTPUT 16BIT ; Output will be 16bit also
LOOP 312 423 ; Loop start and end points
MIX LEFT ; Extract left channel only
END
BEGIN RIGHT_WHOOSH ; Identifier for sound effect
FILE bigwhoosh_pcm16stereo.aif ; Source filename – it’s an AIFF file
SAMPLERATE 32000 ; Source sample rate, in Hz
OUTPUT 16BIT ; Output will be 16bit also
LOOP 312 423 ; Loop start and end points
MIX RIGHT ; Extract left channel only
END
COMMENT *****************************************
COMMENT Beep sound
COMMENT *****************************************
BEGIN WARNING_BEEP ; Identifier for sound effect
FILE beep_pcm8stereo.aif ; Source filename – it’s an AIFF file
SAMPLERATE 11025 ; Source sample rate, in Hz
OUTPUT 16BIT ; Will be converter to 16bit
MIX COMBINE ; Source sample is stereo, downmix to MONO
END
2.2.2.1 Command syntax
Script files have the following basic structure:
Code 2–3 Basic Script Structure and Syntax
; Script comments!
;
;
PATH <path specification>
INCLUDE <other script file>
COMMENT <optional comment field>
BEGIN <sound effect name>
attribute1 <parameter>
attribute2 <parameter>
…
END
COMMENT <optional comment field>
BEGIN <another sound effect name>
attribute1 <parameter>
attribute2 <parameter>
…
END
…
(1) The INCLUDE Command
Code 2–4 The INCLUDE Command
The INCLUDE command specifies the path of another script file to be included for processing. The path
can be relative to the directory established by the last PATH command, if any, or it can be absolute.
This command is optional and can be issued at any point in the script (outside of BEGIN-END clauses).
(2) The PATH Command
Code 2–5 The PATH Command
PATH <path specification>
The PATH command specifies an absolute or relative path to the directory from which subsequent sound
files will be processed. You can issue multiple PATH commands in a script to change directories as
needed. PATH commands must exist outside of BEGIN…END clauses. The path must not contain spaces.
This command is optional. If omitted, sndconv.exe will use the directory from which the tool was invoked
as the current path.
(3) The Sound Effect Clause
Code 2–6 The Sound Effect Clause
BEGIN <sound effect name>
…
END
The BEGIN and END commands delimit a clause within which you define the attributes of a sound effect.
The field <sound effect name> must be a C-compatible symbol that uniquely identifies the sound
effect. When generating the header file, sndconv.exe will collect all sound effect names and automatically
enumerate them.
Note: Each sound effect name MUST be unique, otherwise the C header file will fail to compile. Also,
BEGIN-END clauses cannot be nested.
(4) The COMMENT Command in C Header Files and Script Files
Code 2–7 The Header File COMMENT Command
COMMENT <commentary text for C-header file>
The COMMENT command specifies text that must appear as a comment in the C header file. Everything on
the line after a COMMENT command will be preserved as text in the C header file (preceded by “//”).
Code 2–8 Script Comment
Everything after a semicolon (“;”) is ignored as script commentary.
2.2.2.2 Attributes
This section describes the keywords reserved for defining the attributes of a particular sound effect.
(1) The FILE attribute
Code 2–9 The FILE Attribute
Where <filename> specifies a file (in the current PATH) to be processed. The filename must not contain
any spaces.
The sndconv.exe tool will automatically determine the file type by examining the file itself. If the file is
neither WAV- nor AIFF-encoded data, the tool will generate an error message and ignore the sound file.
If sndconv.exe cannot find the file, it will issue a warning and continue processing the script.
By default, sndconv.exe will extract the following information from each sound file (depending on type):
Table 2–1 Intrinsic Attributes of Supported Sound File Formats

Note: WAV files do not support the encoding of loop-point information.
The FILE attribute is required.
(2) The SAMPLERATE Attribute
Code 2–10 The SAMPLERATE Attribute
SAMPLERATE <source sample rate>
Where <source sample rate> is an integer specifying the base sample rate of the sound effect, in
Hertz.
This attribute is optional. If omitted, sndconv.exe will use the sample rate encoded in the sound file.
(3) The LOOP Points Attribute
Code 2–11 The LOOP Points Attribute
LOOP <loop start> <loop end>
The LOOP attribute specifies the loop start and loop end points of a sample. The <loop start> parameter
specifies the first sample played within the loop. The <loop end> parameter specifies the very last
sample played within the loop.
Note: For these parameters, samples are counted starting from zero. For example, if a loop starts on the
14th sample in the file, then the <loop start> parameter must be set to 13.
The LOOP attribute is optional. If omitted, loop point information encoded within the sound file (if any) will
be used by default. Otherwise, the specified loop points will override the encoded data.
Note: This applies to AIFF files only, as WAV files do not support the encoding of loop point information.
(4) The MIX Attribute
Code 2–12 The MIX attribute
The MIX attribute specifies how to handle STEREO sound files. The following operations are supported:
Table 2–2 MIX Operations

This attribute is optional. If omitted, the tool will COMBINE stereo files by default.
(5) The OUTPUT Attribute
Code 2–13 The OUTPUT Attribute
OUTPUT <conversion operation>
The OUTPUT attribute specifies the output format of the sound data. The following conversions are supported:
Table 2–3 OUTPUT Arguments

This attribute is optional. If omitted, sndconv.exe will use the default output format specified by the -a,
-w, or -b command line options. If no command line option is specified, the default output format will be
ADPCM.
Note: Sound effects in an SPD file can have different output formats.
2.2.2.3 General Notes on Scripting
• White space is ignored. For example, “BEGIN BLAMMO_32KHZ” is the same as
“BEGIN BLAMMO_32KHZ”.
• Sound effect names are case-sensitive. Thus, “BEGIN BLAMMO_32KHZ” is unique from
“BEGIN Blammo_32KHz”.
• Text is parsed line-by-line and must end with a newline. Each line must be less than 255 characters in
length.
• Script comments begin with a semicolon and continue to the end of the line.