Csound

CSOUND UTILITIES

Csound comes bundled with a variety of additional utility applications. These are small programs that perform a single function, very often with a sound file, that might be useful just before or just after working with the main Csound program. Originally these were programs that were run from the command line but many of Csound front-ends now offer direct access to many of these utilities through their own utilities menus. It is useful to still have access to these programs via the command line though, if all else fails.

The standard syntax for using these programs from the command line is to type the name of the utility followed optionally by one or more command line flags which control various performance options of the program - all of these will have useable defaults anyway - and finally the name of the sound file upon which the utility will operate.

utility_name [flag(s)] [file_name(s)]

If we require some help or information about a utility and don't want to be bothered hunting through the Csound Manual we can just type the the utility's name with no additional arguments, hit enter and the commmand line response will give us some information about that utility and what command line flags it offers. We can also run the utility through Csound - perhaps useful if there are problems running the utility directly - by calling Csound with the -U flag. The -U flag will instruct Csound to run the utility and to interpret subsequent flags as those of the utility and not its own.

Csound -U utility_name [flag(s)] [file_name(s)]

sndinfo

As an example of invoking one of these utilities form the command line we shall look at the utility 'sndinfo' (sound information) which provides the user with some information about one or more sound files. 'sndinfo' is invoked and provided with a file name thus:

sndinfo /Users/iainmccurdy/sounds/mysound.wav

If you are unsure of the file address of your sound file you can always just drag and drop it into the terminal window. The output should be something like:

util sndinfo:
/Users/iainmccurdy/sounds/mysound.wav:
	srate 44100, stereo, 24 bit WAV, 3.335 seconds
	(147078 sample frames)

'sndinfo' will accept a list of file names and provide information on all of them in one go so it may prove more efficient gleaning the same information from a GUI based sample editor. We also have the advantage of begin able to copy and paste from the terminal window into a .csd file.

Analysis Utilities

Although many of Csound's opcodes already operate upon commonly encountered sound file formats such as 'wav' and 'aiff', a number of them require sound information in more specialised and pre-analysed formats and for this Csound provides the sound analysis utilities atsa, cvanal, hetro, lpanal and pvanal. By far the most commonly used of these is pvanal which, although originally written to provide analysis files for pvoc and its generation of opcodes, has now been extended to be able to generate files in the pvoc-ex (.pvx) format for use with the newer 'pvs' streaming pvoc opcodes.

This time as well as requiring an input sound file for analysis we will need to provide a name (and optionally the full address) for the output file. Using pvanal's command flags we can have full control over typical FFT conversion parameters such as FFT size, overlap, window type etc. as well as additional options that may prove useful such as the ability to select a fragment of a larger sound file for the analysis. In the following illustration we shall make use of just one flag, -s, for selecting which channel of the input sound file to analyse, all other flag values shall assume their default values which should work fine in most situations.

Ā pvanal -s1 mysound.wav myanalysis.pvx

pvanal will analyse the first (left if stereo) channel of the input sound file 'mysound.wav' (and in this case as no full address has been provided it will need to be in either the current working directory or SSDIR), and a name has been provided for the output file 'myanalysis.pvx', which, as no full address has been given, will be placed in the current working directory. While pvanal is running it will print a running momentary and finally inform us once the process is complete.

If you use CsoundQT you can have direct access to pvanal with all its options through the 'utilities' button in the toolbar. Once opened it will reveal a dialogue window looking something like this:


Especially helpful is the fact that we are also automatically provided with pvanal's manual page.

File Conversion Utilities

The next group of utilities, het_import, het_export, pvlook, pv_export, pv_import, sdif2ad and srconv facilitate file conversions between various types. Perhaps the most interesting of these are pvlook, which prints to the terminal a formatted text version of a pvanal file - useful to finding out exactly what is going on inside individual analysis bins, something that may be of use when working with the more advanced resynthesis opcodes such as pvadd or pvsbin. srconv can be used to convert the sample rate of a sound file.

Miscellaneous Utilities

A final grouping gathers together various unsorted utilities: cs, csb64enc, envext, extractor, makecsd, mixer, scale and mkdb. Most interesting of these are perhaps extractor which will extract a user defined fragment of a sound file which it will then write to a new file, mixer which mixes together any number of sound files and with gain control over each file and scale which will scale the amplitude of an individual sound file.

Conclusion

It has been seen that the Csound utilities offer a wealth of useful, but often overlooked, tools to augment our work with Csound. Whilst some of these utilities may seem redundant now that most of us have access to fully featured 3rd-party sound editing software, it should be borne in mind that many of these utilities were written in the 1980s and early 90s when such tools were less readily available.