So far I was using the Fast Fourier Transform (FFT) functionality of my “Arduino Audio Tools Library” for analyzing the audio. This week I spent some time to make sure that we also support the inverse FFT properly. The inverse FFT is generating audio samples in the time domain from the spektrum information. This functionality is executed automatically when we read the data from the fft source: The spektrum information can be set in the Read more…
When I was comparing the RP2040 with an ESP32 for audio filters quite some time ago , the ESP32 was winning by a big margin. The Rasperry Pico has been improved with the new RP2350 and I thought it would be interesting to have a comparision: I was using the default settings (for cpu speed and optimization) Type ESP32 RP2040 RP2350 ARM RP2350 RISC int32_t 318 ms 717 ms 380 ms 420 ms int64_t 788 Read more…
Yesterday, a user was proposing an Arduino Sketch for a Guitar Effects Pedal which is mixing the original input with an effect. Setting up a simple effect is easy, but I have never thought about how to mix the effect with the original input. He was proposing the following process chain (which I think is just ingenious): |-> AudioEffectStream –| I2SStream -copy-> MultiOutput -| |-> OutputMixer -> I2SStream |———————–| It took me quite some time Read more…
I was wondering if the Raperry Pico 2W can be used with my Arduino Snapclient Library. A related discussion was hinting that it is just not powerful enough. In the beginning was stuggeling quite a bit and the audio with Opus was just not working and I could bareliy make it work with PCM/WAV with a sample rate of only 8000. The solution was to split up the Wifi and the audio decoding to the Read more…
The starting point for writing audio data from USB to I2S using a Rasperry Pico (RP2040) Microcontroller is the speaker example sketch from my extended TinyUSB library. We would just do an i2s.write(data, len) in the callback: Unfortunately this did not work and this was locking up the output quite quickly. In the next trial, I was writing the data to a queue and do the i2s output in the loop(): still no success. The Read more…
Today I found the time to test some audio on the Rasperry Pico 2W Microcontroller. I tried out the standard Interenet Streaming sketch from the Audio Tools examples. Unfortunatly, I noticed that the regular WiFi login logic is quite unreliable, but using the WiFiMulti works each time. Here is the adapted version: #include “AudioTools.h” #include “AudioTools/AudioCodecs/CodecMP3Helix.h” #include <WiFiMulti.h> const char *ssid = “ssid”; const char *pwd = “password”; WiFiMulti wifiMulti; URLStream url; I2SStream i2s; // Read more…
In my Arduino AudioTools project I am providing many examples that show how to distribute audio over the network. One scenario that is easy to implement, is to write the data via http post. On the server side usually one of the following options is expected: the content length and we can just write the audio data to the stream after the http header no content length, adding transfer-encoding: chunked to the post header and Read more…
I am providing the untyped NumberFormatConverterStream class to convert between different signed bit sizes. This class is using the typed templated NumberFormatConverterStreamT do do the actual work. Currently there are also some Codecs that can also be used to convert the nubmer format: e.g. L8, L16 and Float. I decided to extend the functionality of NumberFormatConverterStreamT to potentially support any number type, so that we can also use unsigned data types for the conversion as Read more…
I had the issue that the 24 bit output via A2DP was not working, but the corresponding 32 bit example was just working fine. So I decided to double check the I2S output with the help of a logical analyzer. Checking 16 bits First I was double checking how the working 16 bit is showing up. So I used the following Arduino Sketch which was just outputting some unique numbers per byte: #include “AudioTools.h” AudioInfo Read more…
The Readme from the AudioTools project describes how to use the logger: AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Debug); You can log to any object that is a subclass of Print and valid log level values are: Debug, Info, Warning, Error. But only few peaple realize the power behind this! So let me give you a couple of ideas: you can log to a file you can use any other standard Arduino class that inherits from Print like Wire, Ethernet, Read more…