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CSW2CDT by César Nicolas Gonzales, a windows utility to transfer Amstrad CPC tapes


The CSW2CDT tool suite is a set of three programs whose main purpose is the encoding of computer tapes used in the Sinclair ZX and the Amstrad CPC families during the Golden Age of European videogames (1982-1994), when tapes were the most popular distribution method of commercial software :

  • CSW0 is a command-line program that reads WAV audio sample files and writes CSW V1 packed samples
  • CSW2CDT is a command-line program that reads CSW1 V1 packed samples and writes CDT/TZX tape images
  • CSW2CDT-UI is a dialog-driven program whose graphical user interface simplifies the usage of the first two tools.

The general procedure is divided in several steps :

  • The tape must be sampled as an uncompressed WAV audio file whose quality should be at least 22050 Hz. Mono and 8 bits are preferred over stereo and 16 bits
  • The resulting WAV file must be fed to CSW0, that will measure all the square waves and produce a CSW V1 file. Optional flags can be used to perform band-pass filtering on the signal
  • This CSW V1 file will be handed to CSW2CDT, whose task is to scan the data blocks within and build a CDT/TZX image. Again, optional flags allow for increasingly complex processing of the contents
  • The CDT/TZX image ultimately needs to be tested then in an emulator that can play tape files back, such as CPCE and WinAPE for Amstrad CPC titles or FUSE and UnrealSpeccy for ZX Spectrum softwares

CSW2CDT-UI eases the procedure because its graphical user interface is more comfortable (although less flexible) than the command line : choosing the sample, generating the CSW V1 file, and encoding the CDT/TZX file can be performed by pushing buttons and choosing options. It also allows for the reverse procedure of playing back CDT/TZX images into CSW V1 files and WAV audio files with some few mouse clicks.

Dlfrsilver, loyal alphatester and main inspiration, wrote the French and English handbooks.

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