Le Thu, 07 Feb 2013 21:21:59 +0100, Kjetil Matheussen &lt;k.s.matheussen(a)notam02.no&gt; a écrit : This is not related to any of the software you mention, but what I am really missing in linux audio is the ability to plug-in my guitar (or another instrument), play some melody, and get the corresponding MIDI notes messages in real-time. As the timbre will differ from one instrument to another, and even from a player to another, such a tool should provide a visual way to setup the parameters, that in order to make it easily usable. Is is a few applications that claim to be able to do that. By example guitarix http://linuxaudio.org/mailarchive/lau/2011/1/7/177338 but in practice, it is total unusable. Quote: "Guitarix offers this, Given, you play with good intonation/a well tuned instrument, it works OK." I was never able to make it work even with a well tuned guitar. In the past, I done such a rt conversion on a dsp. It was working very well but need some parameters to be carefully chosen. The only way to chose those parameters are with a visual signal analysis. The timbre of an instrument is unique, vary with the time and with the play. I used a memory oscilloscope to do this analysis. I am a lazy bastard that also have a real life, so I never managed to learn enough C/C++ in order to translate my dsp56k program into a GNU/linux software. Some said this would be a piece of cake, but that's not to me. The algorithm is very simple. The incoming signal need to be rounded in order to reject the false maximums that can arise (look at the signal of a good simple humbuking microphone and you will show them) (this will reject the high frequencies and is very simple and fast to implement). This is done with a simple arithmetic mean on the successive input samples. 1 parameter here: the samples number. Another and obvious parameters is the input threshold level. In order to easily adjust those 2 parameters, a visualisation GUI is the best option. It have to show both the incoming signal and the same signal after the average operation. It would be best if it would work like a memory oscilloscope, that is define some threshold and time period the user want to acquire when some incoming signal is detected, acquire the samples into a ring buffer in a one shot way, and display them with the ability to change the x axis period and offset. As a bonus, this will be the best oscilloscope using an audio card on linux. At that point, 2 separated software can even be made. And yes, I am missing too a good memory oscilloscope using the audio card on linux. I know an audio card will never provide the sampling frequency of a LeCroy, but beside the sampling rate, a GNU/linux oscilloscope using the audio card is able to provide a lot of the, if not all, advanced features of a real memory oscilloscope. After the average is done, and concurrently to it, the program find 2 consecutive maximums of same sign of the signal. A simple comparison (> or < depending to the sign) of the consecutive samples is enough to do that. The period of the signal is represented by the number of samples that separate those 2 consecutive maximums. The program know the sampling frequency, so, a table can be made with the values of the MIDI notes for different sampling count intervals, and a simple read of this table from the number of samples between 2 consecutive maximums will give the corresponding MIDI note. The worst case scenario depend on the lowest note that will be played. The time to find the note = the period of the note + the time between 0 and the first maximum of the signal. I don't know any faster and simpler algorithm to do that. Dominique P.S.: If you wait for me to adapt this software to GNU/linux, you will wait much longer than if you, or someone else, do it. I try several times, but I never managed to get enough time, to learn the C, and like my life is going, both privately and professionally, this will unfortunately not append in a foreseeable future. -- "We have the heroes we deserve."