On Thu, Feb 13, 2025 at 02:04:42AM +0000, John Dyson via Sox-users wrote: > About the DolbyA thing... ... > I do suggest that a compressor with general DolbyA characteristics > might be reasonable to do with SoX. Truly encoding/decoding DolbyA > materials is a totally different world. For which reason I plan to amend my documentation for Audir to point out that Audir probably cannot precisely decode an actual Dolby A analog recording. > Anyone really interested in emulating DolbyA behavior, feel free to > contact me, I lurk on Hoffman and Audiophile Style, where I blather > about my crazy processing project. It is probably very off topic for > this mailing list... Sadly my interest in Dolby for handling analog recordings would more involve Dolby B than Dolby A, as I have some old tapes from a Pioneer deck where I used Dolby B; but even more sadly, the Dolby settings were tweaked rather aggressively by a repairman, a move I was not expecting at the time; and I'm sure nothing out there would precisely match the results. The deck itself is long gone. My interest in Dolby A emulation is peculiar: I have a long-term real-time connection to a friend with ALS to help her communicate with staff, friends, etc.; and I find that her iPhone often cuts out her sounds when her fan turns on. I haven't tried yet, but I plan to find out if this effect can be used to make it easier to hear the letters and responses she tries to produce. (I very often use SoX in real-time sound processing arrangements.) > On Wednesday, February 12, 2025 at 06:01:43 PM EST, SoX NG > <sox_ng@xxxxxxxxxxxx> wrote: > On 12/02/25 20:56, Doug Lee wrote: > > I did, though, just write a small Python utility for scanning files > via sound very fast > > using a two-stage SoX pipe and 1-10ms tones on a 256-frequency range > to represent bytes > Do you mean a single tone that blips at one of 256 frequencies > according > to its value and > recognizing certain characteristic sequences? Interesting. Yes. My original (90s, 16-bit, now lost) implementation used a C-library or hardware tone generator and switched its frequency very fast without turning it off. That was cleaner than this because, for example, rows of zeros in a file came out as one tone, whereas in my SoX implementation they come out as something like that tone and a tone from my scan speed as if one modulates the other. I don't think I can emulate that via SoX unless I generate the wave form myself and just use SoX to play it in real time. The original tone generator made a square wave I think; so unless I get fancy, that might not be so hard to do if I ever get to it. > One of my passions is for log-frequency-axis spectrograms, which > translate sound from > the audio domain to the visual one - not a lot of use to you but maybe > for deaf people to > let them see speech and music - however there are inverse techniques to > turn a spectrogram > back into the original sound, or a best effort at it. Peter Zinovieff's > tried this in the 1960s > and in one of his notebooks describes scanning a picture of a flower > and > converting it into > sound as a particularly fascinating experiment. My own efforts in this > direction are documented > at [2]https://wikidelia.net/wiki/Spectrograms#Inverse_spectrograms > That suggests adding JPG and PNG as input and output formats to SoX > as synonyms for spectrograms without axes, presumably with the lower > and > upper frequencies and the pixel-columns-per-second and dynamic range > in image comments or as format parameters. I've played with the image-to-sound idea in various ways over many years but never with complete focus. The basic idea is to translate two or three spatial dimensions and the concept of color into corresponding parameters of sound. The trick, of course, is mapping the visual elements onto sound in a way that the brain can learn to interpret with similar speed and precision. For example, using time for the X axis, pitch for the Y axis, and volume for color works intuitively for most people but is far better at showing location than color, because the volume of one frequency among 45 can be very difficult to perceive with the ear. At one time, I thought of using 3-d sound technology for positioning so I'd have the full range of audible frequencies to represent color. I concluded that this approach would, like for a very young child, make motion more readily discernable than object appearance. But I don't think SoX will become a platform for research in this direction, because it will require a whole lot of real-time activity that is not representable as SoX effects. AI is also probably reducing the interest in this area a bit by textually describing images - unless, of course, I suddenly decide at 57 to become a solid blind Baseball contender... My signature quotes are randomly pulled from a set; but this one's applicability to this discussion amuses me! -- Doug Lee dgl@xxxxxxxx http://www.dlee.org "Determine that the thing can and shall be done, and then...find the way." - Abraham Lincoln _______________________________________________ Sox-users mailing list Sox-users@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/sox-users
