8/12/2023 0 Comments Get swifty soun byteIt is frustrating as anything that we can only memory map byte buffers and not double arrays nevertheless, we can use them with the appropriate accessor methods. Memory mapped files are somewhat supported in Java. It is not there yet, but it is getting there. Indeed, the work around is always evolving and I would not be shocked it it became almost as effective as a hand crafted memory management system in C++ but with the platform independence of Java. However, all is not lost as there is a usable work around. I tried, oh I tried so hard, to get a reliable way of estimating when the JVM was about to throw an out of memory exception but as far as I can tell, there is no fail-safe way of doing so. In a C++ based system (for example) we could intercept malloc and know, to the byte, the amount of memory being used from the heap. There are some forms of instrumentation which are supposed to tell us the amount of memory being used, but they are not very ‘real time’. Java has garbage collection which means we do not know how much memory is actually being used. Now we have some background to why managing audio data is such a challenge we are ready to see why Java is a bit of a catastrophe for managing memory. How Java Is Terrible At Memory Management (and approaching a solution): * final double getSampleCubic(double index) * the sample this will fall back to linear interpolation. Cubic interpolation uses two samples either side of the required point and so at the ends of * Returns a cubic interpolated sample based on the samples either side of the the passed index. Return ((index - s) * b + (e - index) * a) * final double getSampleLinear(double index) * Returns a linearly interpolated sample based on the samples either side of the the passed index. Public abstract double getSample(int index) Private static ThreadLocal pythonStack = new ThreadLocal() Protected final AtomicInteger referenceCount = new AtomicInteger(1) Private final static AtomicLong uniqueId = new AtomicLong(0) Public abstract class SFSignal implements AutoCloseable Basically, sound processing is memory lop sided compared to most other forms of processing. I could use a bigger machine and address say 128 Gig that would do for most music, but again, such a machine is likely to have more cores and the parallel memory use issue appears again. More complex and longer notes (especially in ambient music where notes can last a very long time) quickly exhaust the capacity of my machine. That is just to great a 10 second note which is relatively simple. Then we want to generate notes in multiple threads, for 8 threads that might be 8 notes at once which is 1.6 Gigabytes. Each of those sine waves in the trumpet sound might be 10 seconds long (about 5 megabytes) and there could be 40 harmonics, so that is 400 mega bytes. The reason being that sounds are made of sounds (as we saw before). I use a 16Gig machine and it would run out of memory very quickly if I used simple arrays. The simplest way would be to just use a Java array of doubles. You should have received a copy of the GNU Affero General Public License GNU Affero General Public License for more details. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. This program is distributed in the hope that it will be useful,īut WITHOUT ANY WARRANTY without even the implied warranty of License, or (at your option) any later version. Published by the Free Software Foundation, either version 3 of the It under the terms of the GNU Affero General Public License as This program is free software: you can redistribute it and/or modify Sonic Field Audio Processing And Synthesis ProgramĬopyright (C) 2012-2014 Dr Alexander J Turner We must understand this is an compromise and it brings with it a whole series of computational challenges of its own.Ī quick note on licensing: Sonic Field is free as freedom: Just like the samples that make up a video, one frame at a time, sound is generated and manipulated one sample at a time. Here we consider sounds as a series of samples.
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