Discussions for GoldWave plug-in development
7 posts • Page 1 of 1
I'm not a dev myself but here's an idea. I'm surprised it wasn't part of the normal GW package. Someone really should make a spectrogram display with cursor frequency indicator. That is, putting your mouse cursor over the spectrogram should should give a frequency readout in a small numerical display for where the tip of your mouse cursor is pointing. That way if you see a signal in the spectrogram you like, you can easilly find frequencies just above and below it so you know where to set the bandpass filter. Right now I have no way to know where to set the bandpass filter except by "trial and error". The default spectrogram display just shows the spectrogram image, and I don't know of any plugins that add an alternate version of the spectrogram as I've described. Someone really should make this, and quite frankly I think it should be part of the official Goldwave release.
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If you use the Spectrum Filter, you'll see the spectrum graph and you can click on the graph to set points to create a filter. Value are shown numerically, but you don't really need to know them because you can just do it visually. There is a time scroll bar below the graph to see the spectrum at different times within the file.
I know that, but that spectrum display only shows one point in time (is a fft spectrum, but NOT a spectrogram) and only shows in logarithmic frequencies, and only shows logarithmic amplitudes. As a ham radio / shortwave radio enthusiast, I'm used to my software using full spectrograms and a linear frequency and linear amplitude scale. My primary use of this software will be for processing sound recordings acquired from my all band radio receiver, prior to decoding signals such as images transmitted by SSTV or HF-FAX, or text transmitted by RTTY. No other software package offers the number of tools goldwave does so I have no intent to find a different package (which I'm sure will be your first suggestion), but from my use in radio reception, it is missing a couple key features. That is the purpose for my post here requesting a plugin as I've described. Spectrogram display, linear frequency scale, linear amplitude scale. x=time, y=frequency, brightness or color = amplitude. positioning the mouse cursor gives a frequency number readout for the pixel of the spectrogram touched by the cursor. optionally also an amplitude number in millivolts (actual signal voltage amplitude at line-in port on sound card) if possible for that given frequency at that specific time (for where the mouse cursor is touching).
In case it helps... Once you have selected the Spectrogram visual you can right-click it and choose "Properties...", then click the "Show axis" checkbox. That will give you a time scale along the bottom and a frequency scale (linear) on the side.
In a program called Argo Spectrogram http://www.sdradio.eu/weaksignals/argo/index.html you will notice that when you hover your cursor over the spectrogram it shouws the current frequency that your cursor is hovering over. This has an advantage in that you don't just have to approximate the frequency based on where it lies next to a displayed scale. The only downside to Argo is that it is limited to live audio streaming into the soundcard through a line-in or mic-in (or other input your soundcard has), while Goldwave actually works on saved audio files. If you could add this great "Argo feature" of having a frequency cursor into Goldwave it would be GREAT.