You can now enter commands at the cursor in the Command Window. Here’s what you see when you start the Windows GUI: It’s also convenient: I downloaded and ran the latest official Windows installer and had things up and running within moments. Out of the available options-including MATLAB-I ended up going with GNU Octave, which is free and open-source. However, I’ve since learned about some numerical computing environments and programming languages that can flexibly input and output both image and audio files while carrying out elaborate computations on them in between, and I decided to see if I could harness one of these as a substitute for ImageToSound. There are programs aplenty out there for converting pictures into audio, but virtually all of them treat source images spectrographically, as graphs of time against frequency- Photosounder is a prime example-rather than oscillographically, as graphs of time against amplitude. Nothing else of which I’m aware along the same lines is readily available for public use (PRISM, the software attached to IRENE, is not). AEO-Light is designed to convert digital images of optical film sound tracks into audio on roughly the same principle as ImageToSound, but it’s set up to assume there will be accompanying motion picture frames as a point of reference. Unfortunately, there haven’t been any convenient alternatives. Meanwhile, the ImageToSound software has some unfortunate quirks and limitations and is becoming increasingly challenging to run-I can still execute it successfully on my current Windows 10 laptop in Windows 98 compatibility mode, but others have told me they can’t get it to work. It can require a lot of time-consuming manual editing to clean up the area to either side of the trace and connect any breaks in it so that the paintbucket tool won’t “spill through” to the other side. More recently, it occurred to me that we could convert that result into a band of varying brightness in turn by reducing it to one pixel in height and then (optionally) re-expanding it-not particularly useful, I guess, but ImageToSound can handle it in that form just as well. But eight years ago, I realized that I could convert a wavy line into a bright band of varying width by filling the area above or below it with white using an ordinary Photoshop paintbucket tool, and that ImageToSound could then be used to convert it into audio. At first glance, this might not seem applicable to playing sources such as phonautograms. ImageToSound converts the sums of pixel luminance in each successive column in a source image file into successive audio samples in a target WAV file. In optical film sound tracks, the modulation of the audio signal is tied to how much light passes through a translucent strip that varies either in opacity (“variable density,” below left) or width (“variable area,” below right, with thanks to Iainf for the illustrations). In the past, I’ve relied on Andrew Jaremko’s ImageToSound, a piece of freeware designed to convert any 24-bit BMP into an 8-bit WAV file as though it were an image of an optical film sound track. Wouldn’t writing some software to do this be far easier and produce greater fidelity? It seems you used an extraordinary lengthy and convoluted process to generate barely audible sound. That method works, but a point raised by one reader is well taken: I’ve previously described a circuitous method of doing that here and here, as well as in my book Pictures of Sound. The question is how to convert that image into a playable audio file so we can listen to it. Or maybe it’s just a random squiggly line you want to treat as an audio waveform to find out what happens. Or maybe it’s an ink print on paper made from a gramophone disc a few decades later (converted, in this case, from a spiral into parallel lines by a polar-to-rectangular-coordinates transform). Maybe it’s a phonautogram from the 1850s or 1860s: a record of sound traced in soot on a moving paper sheet for visual analysis at a time when playback wasn’t yet on the table. Let’s say you have a digitized image of an audio waveform-a graph of the amplitude of sound vibrations as a function of time. It doesn’t have the friendliest of interfaces, but it’s relatively easy to get up and running, and it’s free (as in free beer, not free puppy), so the price is right. After years of trying to get existing software to do things it was never intended to do, I’ve finally written some code of my own for converting pictures of sound waves into playable audio.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |