Python Tutorial : Converting sound wave bytes to integers

Key Takeaways

excellent effort you've imported the good-morning audio file and seen what it looks like in byte form now let's see if we can make those bytes even more useful to make our audio data more useful we're going to convert it from byte form to integers to do this we'll use numpy numpy is a numerical Python library full of helpful functions first we'll import it with the common alias NP to avoid typing numpy every time then the numpy method will use to convert our bytes to integers is from buffer from buffer turns a series of data into a one-dimensional array of a specified data type remember we save the goodmorning audio file bytes to the variable sound wave GM since this is an array of data we can pass it to from buffer as the first parameter and then we can set the D type parameter to the data type we'd like to get back there are multiple data types we could pass in but for our case in 16 is what we're after so if we wanted to see the first values of our sound wave in integer form what do they look like much better but we're only looking at the first 10 can you guess how long the whole array is remember how frequency is a measure of information per second our goodmorning sound wave has a frequency of 48 kilohertz a length of 2 seconds and thus 96 thousand pieces of information so this array only shows the first 10 of those 96 thousand ok we know our good morning sound wave as a frequency of 48 kilohertz but what if we didn't to find it we could divide the length of the wave object array by the duration of the sound wave in seconds but pythons wave module has a programmatic way get frame wait on a wave object will return its framerate let's use it on our good morning wave object excellent the method returns the number we were expecting 48 thousand or 48 kilohertz we can use this framerate variable for one more thing which will be handy for visualizing our sound waves later by dividing the number of items in the sound wave array by the framerate we can get the duration of our audio file with this value we can leverage num pies linspace method to figure out the timestamp where each sound wave value occurs the linspace method takes start/stop & num integers as parameters calling it will return num evenly-spaced values between start and stop let's try it with start as 1 stop as 10 and now is 10 as you can see it returns an array of evenly spaced numbers between 1 and 10 let's try it on our own values to get the time stance of pieces of information in our sound wave start will be 0 for the beginning of the audio file stop will be the length of our sound wave array over the frame rate or in other words the duration and num will be the length of our sound wave array since each item in the array is a sound wave value let's check out the first 10 timestamps each of these values is the time in seconds where each sound wave bite occurred we'll be able to use these timestamp values later to see what our sound wave looks like ok