Implementation of a DSP filter for hiss noise removal from audio streams

Active Sound Editor" <[login to view URL]> is an audio related ActiveX control providing sound editing capabilities. We need someone to develop a new audio filter for removing "Hiss noise" usually found when recording from old magnetic tapes; in this case there will be the need to define noise profiling. ## Deliverables Active Sound Editor" <[login to view URL]> is an audio related ActiveX control providing sound editing capabilities. We need someone to develop a new audio filter for removing "Hiss noise" usually found when recording from old magnetic tapes; in this case there will be the need to define noise profiling. The developed filter should be configurable with parameters and should act without damaging original voices and sound quality. Actually the component already comes with a similar DSP but its quality is not the one expected so we would like to develop a new one from scratch; the theory behind the actual filter is described on the link below: <[login to view URL]> If the new filter could be developed using the same theory, that would be better, but it's not mandatory. Requested filter should be implemented in the form of one dynamic link library (DLLs) developed using Visual C++ (better if Visual C++ 6) and MFC, the use of the Hungarian notation would be preferred and the source code should be documented at least in the most important portions. Finally, there would be the need to produce a small document describing the theory behind the filter and the meaning of all of parameters applied to the filters Some word about the way the DLL should be implemented: this control is predisposed to operate with custom DSP effects contained inside external dynamic link libraries (DLLs): the setup package of this control comes with a VB6 sample, named "SoundEditor", which allows interfacing with a couple of very simple external DSP effects (MyCustomDsp and (MyCustomDspWithUI) whose VC++ 6 source code is also installed. As you will see examining the code of these external DSP effects, the main function that the DLL needs to export is a callback function that will receive in input the WAV PCM format of the sound under editing and that will modify this PCM in order to implement the needed filter: neverthless to say that the DLL you will have to implement will have to follow the same schema of the previously mentioned (MyCustomDsp and (MyCustomDspWithUI) external DSP effects, so it should provide a callback function for the implemented filter and a set of exported functions for passing parameters needed by the filter's algorithm you will implement. The use of external DSP effects is documented on the link below: <[login to view URL]> The algorithm of the implemented filter should be as fast as possible in order to avoid bottlenecks and shouldn't make use of third-party components and/or libraries. If possible, all sound processing should be made within the callback and not during parameters definition: in this way it should be possible, at a later stage, applying the same filters during playback also and not only during offline editing: if this specific request should compromise the overall quality of the filters, it should be discussed with us. I hope to have provided enough information about the needs we have and how they should be implemented but feel free to ask if you should have any doubt.