RiffX

RiffX is a simple utility that can be used to extract RIFF data streams embedded in other files.

It is useful e.g. for extracting audio clips from certain game files, e.g. Borderlands 2/TPS *.pck audio packages and others.

RIFFX IS NOT A RIFF PARSER!

It has no deeper knowledge about a RIFF file's inner structure and just indiscriminately dumps anything that even remotely looks like a RIFF chunk into a separate output file. You break it, you get to keep the pieces!

Usage

The general invocation looks like this:

riffx [-b] [-l] [-g] [-v] infile_0 [... infile_N] [out_dir]

Options shall be placed before any non-option arguments. Input files are processed in the order they are specified. If the last argument is not a readable input file, it is taken to be the name of the desired output directory. If no output directory name is specified, it defaults to 'output' in the current working directory. The output directory is created, if it does not already exist. CAVEAT: riffx will overwrite any existing file having the same name as a dump file, without asking for confirmation!

By default riffx creates a directory structure in the output directory that reflects the path(s) used to specify the input file(s). The -b option causes riffx to alternatively create a flat output directory, resulting in all generated files being placed directly in output, with a file number and the base name of the input file included in the dump file name to help disambiguate the files.

The -l option activates a primitive heuristic that tries to extract a text label from each RIFF chunk and include it in the dump file name. In the absence of a suitable label chunk it falls back to the default behavior of using solely the stream index count to create the output file name. This method is unreliable and may or may not give meaningful results depending on your input files.

With the -g option riffx can be instructed to ignore the respective size fields in the embedded RIFF chunks and instead assume that each chunk ends where the next one begins, or at the end of the input file. This is imprecise, but may help in certain cases where the RIFF size fields may contain bogus values.

To make riffx be a bit more verbose about its operation you can pass it the -v flag.

NOTE: The extracted raw RIFF streams will most likely require some form of post-processing to be useful. To turn e.g. the Audiokinetic Wwise RIFF/RIFX sound format into something any run-of-the-mill audio player can digest you should:

1. Run each individual RIFF file through the ww2ogg converter, cf. https://github.com/hcs64/ww2ogg

2. Fix up the resulting Ogg Vorbis files with revorb, cf. https://github.com/jonboydell/revorb-nix

Both mentioned third party projects are also referenced as Git submodules and can conveniently be cloned and built right in the riffx project tree. Please consult the documentation of each respective project for more information on how and under what conditions you may use it.

Example

The following is a simple example to demonstrate the extraction of and conversion to the Ogg Vorbis format of sound clips embedded in a file named audio_banks.pck:

  $ riffx -blv audio_banks.pck outdir
  $ for f in outdir/*.riff ; do ww2ogg $f ; done
  $ for f in outdir/*.ogg ; do revorb $f ; done

NOTE: It may turn out necessary to tweak the ww2ogg command line parameters in order to get satisfactory results, please refer to the ww2ogg documentation for details.

Build

Simply run make without any parameters to build all included tools and submodules, or make riffx to build only the riffx utility.

Alternatively just translate riffx.c using your C compiler of choice and hope for the best.

Porting

RiffX was written on Linux and makes use of some OS specific features, most prominently the POSIX mmap() function to make processing large files easy and efficient. Any effort to port riffx to another platform may entail:

• Replace open/mmap/creat/write with suitable ISO C functions (malloc, fopen, fread, fwrite), while taking extra care of chunk splitting on buffer boundaries.

• Port the mkdirp() function.

Helper

Another small utility named unriffle is included in this repository.

Again, this is not a real RIFF parser either, but it can dump the chunks of a RIFF/RIFX file to standard output and thereby help to get a rough idea on what kind of data it may contain. A tiny subset of chunk types known to be present in some RIFF audio formats is given special treatment to make their content more accessible to mere humans. This might help identify the format of the data stored in the file.

Unriffle is build automatically when calling make in the project directory. In contrast to riffx it is written entirely in portable ISO C99.

Alternatives

As riffx was written as a quick-and-dirty tool for a specific use case chances are high it might not work in your specific scenario. In this case you may want to check out other, more generalized, data extraction tools, like e.g. the QuickBMS tool developed by Luigi Auriemma.

License

RiffX is distributed under the 0BSD ("Zero-clause BSD") license. See LICENSE file for more information.

Each referenced third party submodule comes with its own license terms, please consult the respective project's documentation.

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