frequency

问题 I'm developing a simple audio player in java. The only advanced feature I need is a frequency filter. It's not necessarily a full-featured equalizer function, with different gains for specific frequency ranges: a low pass filter which cuts frequencies higher than a specified value would be enough. I studied jlGui which has an equalizer, but it only works with MP3 data, while the files I will be playing are OGG. Browsing through various answers I found that an ffmpeg wrapper like Xuggler or

问题 I'm experimenting with Android's LiveData. I just tried to push a lot of notifications to an observer that observes a LiveData object. I let a thread run in background and in a while-loop i constantly push random values via LiveData's postValue-method. The number of received notifications (number of onChanged()-callbacks) in the observer which observes the livedata is much less then the number of calls of postValue in the background thread. Can somebody explain what's the reason for this?

问题 I have 40 pairs of birds with each male and female in the pair scored for their colour. The colour score is a categorical variable with a value range of 1 to 9. I would like to create a table with the number of each combination (1/1, 1/2, 1/3, ... 9/7, 9/8, 9/9). My problem is that there are some combinations that do not exist in my data when I try to create the table (in these cases I would like zeros for the missing values). Below is the data and sample code. I am pretty sure the answer

问题 I'm having a little bit of programing and conversion trouble. I'm designing an AI to recognize notes played by instruments and need to extract the raw sound data from a wave file. My objective is to perform a FFT operation over chunks of time in the file for use by the AI. For this I need an amplitude list of the audio file, but I can't seem to find a conversion technique that will work. The files start as MP3's and then I convert them to wav file, but I always end up with a compressed file

问题 This question already has answers here : Counting existing permutations in R (2 answers) Closed 5 years ago . If I have this data: One <- c(rep("X",4),rep("Y",3),rep("Z",2)) Two <- c(rep("A",2),rep("B",6),rep("C",1)) df <- data.frame(One,Two) One Two 1 X A 2 X A 3 X B 4 X B 5 Y B 6 Y B 7 Y B 8 Z B 9 Z C I want to find the frequency of unique pairs (one,two). I know if I wanted to find the frequency of different elements in column One I would do table(df$one) . How about the frequency of

问题 I have a string s of length n . What is the most efficient data structure / algorithm to use for finding the most frequent character in range i..j ? The string doesn't change over time, I just need to repeat queries that ask for the most frequent char among s[i] , s[i + 1] , ... , s[j] . 回答1: An array in which you hold the number of occurences of each character. You increase the respective value while iterating throught the string once. While doing this, you can remember the current max in

问题 I have created two sine wave each with a different frequency. Time period for both waves is 2sec or 2000msecs. Code works well when i find correlation value for whole time period. Buth i want to get correlation values after every 200msec interval. That means i need an array that can store 10 correlation values for the whole 2000msecs. Here's the code how am i calculating correlation for time period of 2000msecs. delta=0.005; %200 hz Fs samples=200; t=0:delta:delta*(samples-1); % Time Samples

问题 I am trying to recreate the full range of a guitar only using 6 audio clips. I was thinking there would be a way to set frequency of an audio clip but audio.frequency only returns the frequency of the audio based on compression format and not the actual tone. I know I can read GetSpectrumData, but that solution is fairly complex and would require some Fourier Transform analysis or something of the kind. Affecting the pitch, it is easy to alter the tone so I can go up and down but is there a

问题 Find the nth most frequent number in array. (There is no limit on the range of the numbers) I think we can (i) store the occurence of every element using maps in C++ (ii) build a Max-heap in linear time of the occurences(or frequence) of element and then extract upto the N-th element, Each extraction takes log(n) time to heapify. (iii) we will get the frequency of the N-th most frequent number (iv) then we can linear search through the hash to find the element having this frequency. Time - O

问题 I'm extending the Linux kernel in order to control the frequency of some threads: when they are scheduled onto a core (any core!), the core's frequency is changed by writing the proper p-state to the register IA32_PERF_CTL , as suggested in Intel's manual. But when different threads with different "custom" frequencies are scheduled, it appears that the throughput of all the thread increases, as if all the cores run at the maximum set frequency. I did many trials and measurements in different