by Thomas Harte, 2004
Table of Contents
Introduction
Usage
Future Availability for non-Windows Users
Technical Aspects
| Introduction |
Welcome to the Windows GUI version of FreeUEF - a tool for releasing tape data stored in UEF files back into the wild via your soundcard or via conversion to .wav. FreeUEF fully supports all tape elements of the UEF 0.10 specification subject to the notes on internal counter sizes in the technical aspects section, which shouldn't affect any real world files. It is therefore the perfect complement to any files downloaded from Acorn Preservation or The Stairway to Hell. This is only v0.9 of FreeUEF. That reflects its current, relatively untested state. Please send bug reports to the email at the top of this document. |
| Usage |
Launch FreeUEF by double clicking its icon. You will be presented with a dialogue box in which the only changeable options are a small text line for 'Input File' and a tick box for 'Output to File'. Click the ellipsis ('...') button next to 'Input File' to bring up a standard Windows Open dialogue. Use this to locate the UEF you want to convert to free. Alternatively type the name of the UEF (including full path) into the text box to the left of the ellipsis button. It is also possible to complete this detail by draging and dropping UEF files into the FreeUEF window. If you merely wish to output the UEF through your computer speakers or sound output, now simply click 'Play' in the bottom right. The computer will output the UEF file and then stop. During this time, the progress bar at the bottom of the window will give a visual impression of FreeUEF's progression through the file. When you click 'Play', the 'Creator' box, below 'Input File' is filled in with the relevant detail. While the UEF is playing, the 'Play' button is disabled and the 'Stop' button enabled. Pressing 'Stop' at any time will cause FreeUEF to cease its output and return to the start of the file. To output to a .wav file instead of your computer's sound output, click the 'Output to File' box. The 'Output File' box immediately below will become highlighted. Use it in exactly the same way as 'Input File' to select a target .wav file. All other buttons will function in the same manner, but audio will be written to the selected .wav file rather than an audible output target. FreeUEF outputs mono 8bit audio at 44100Hz. This is an incredibly common format and should be supported by all computers capable of running Windows 95 or above. Be warned though that .wav files will be substantially larger than their UEF equivalents. For example, Chuckie Egg as encoded by MakeUEF 0.3 occupies 7.99kb as a UEF and lasts for just over two minutes, but grows to 5.24mb if converted to a .wav. The BBC Micro welcome tape as encoded by Greg Cook's kleen | bitparse | writeuef toolset occupies 51kb as a UEF and lasts for almost 20 minutes. When converted to .wav it occupies 50.4mb. |
| Future Availability for non-Windows Users |
FreeUEF uses a pre-release version of a new UEF media access library which I hope to make public in the short to medium term. Once this is complete it should be trivial to reproduce FreeUEF on any other platform. The desirability of MacOS and Linux/X ports is accepted. In the meantime, a java solution in UEFReader and jlGui is recommended for users of those platforms. |
| Technical Aspects |
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FreeUEF imposes some limits on the UEF files it can correctly reproduce. All internal time measurements are done according to a 2Mhz timer, and time counts for individual UEF encoded chunks are 32bit. Therefore, no individual chunk may exceed 35 minutes and 47 seconds in length. To put that in perspective, the Electron tape hardware can store over 251kb of data in that period.
The position within a UEF file is stored as a 64bit number. Therefore, the longest supported UEF file is just beyond 292 and 1/4 centuries. In that time the Electron tape hardware can store over 1,006 terrabytes of data. At present FreeUEF silently ignores any chunks within the UEF that appear malformed. It therefore probably has limited use as a tool for validity testing of UEFs, although the ability to visually check the output through .wav editors is helpful. An option for verbose reporting of any UEF errors will grow in a later version. |