If we ever so slightly increase the secondary level threshold constant in hopes of not detecting the false transients we no longer detect the second real transient at 0.How would you describe the tone and quality of your latest audio mix? If we use a constant secondary level threshold of 1.220 the algorithm detects false transients at 1.434 and 1.643 seconds: Time Note how the secondary level threshold value varies: TimeĪ constant secondary level threshold can't produce the same accurate results. This information comes directly from my transient detector command line tool (download information below). The table immediately below shows the time (in seconds) and the sample position of each transient along with the secondary level threshold (abbreviated "SL"). The transients are easy to detect by looking at the waveform and listening to the audio. It consists of two plucked guitar strings in quick succession, then a bit of a pause followed with a quieter plucked string. This enhancement is not only helpful to the user as they no longer have to guess the optimal secondary level threshold value, but can also provide better results than using a constant secondary level threshold. I made an enhancement to Gueorguieff's method by automatically calculating and scaling the secondary level threshold based on the average energy of previous windows.
The key is usually in choosing the right "secondary level threshold". This method seems to work pretty well in a lot of cases, but can fall short in other cases. (This "one-to-two times" level increase over the window before the previous window is what I call the "secondary level threshold"). A transient exists when the energy in the current window is greater than the previous window, and one-to-two times greater than the window before that. The method is pretty simple: Step through the audio in small windows (maybe 5-10 milliseconds in length) analyzing the energy increase between successive windows. I've implemented a straightforward transient detection method described in this paper by Lutshayzar Gueorguieff. There are a number research papers and even research papers that sum up the various research papers.
There's a lot of information out there on transient detection.
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