BirdNet-Pi: export audio recordings as video

Posting audio detection recordings for others can be tricky.

 

It seems that apps like Facebook don't support audio files.

So I was looking for an easy way around this issue.

BirdNet-Pi: USB audio module testing

I've bought a couple more modules

so thought I'd do some tests to compare performance.

This post concerns the use of USB audio modules in connection with miniature electret microphone capsules.

Insomniacs Bedside Radio: signal to noise ratio

Raspberry Pi audio projects can be prone to noise issues.

I don't use our bedside radio very often, but when I do, I notice background noise.

I've finally got around to doing something about it.

Electret Microphone Preamplifier

This design runs from a 5Volt USB supply and attempts to minimise electrical noise.

I wanted to create a simple preamp for an electret mic insert using components from my bits box.

So component values and transistor types are not critical.

BlissFlixx: Pi HDMI config.txt settings

I recently set up another Raspberry Pi as a BlissFlixx set-top box using an earlier post.

Although the system worked, I quickly realised that I'd missed a couple of config settings from my original post.

So this update includes those important settings.

Increasing the VOLUME in Linux

One annoying characteristic of Lubuntu in particular (and I suspect Linux in general) is that the playback volume is often too quiet, especially on laptops.

This problem is due to differences in audio recording levels, and is most noticeable when listening to audio via a web browser (e.g. watching a video).

Having put up with this for years, today is the day I feel I need to take some action.

Gambas Video Reverser

I recently needed to reverse a video clip, to make the action run backwards.

I couldn't find a Linux video editor with this feature built in, so I ran a series of command line instructions...

...then I decided it would be useful to wrap these instructions into a GUI application.

Raspberry Pi audio vs. Adafruit USB audio

Many people on the internet comment about the poor sound quality of the Raspberry Pi audio output when taken direct from the 3.5mm jack socket.

One alternative is the Adafruit USB audio adaptor, which provides a mic input and headphone output.

Both the Pi jack and Adafruit audio outputs sounded a little harsh to me, so I decided to do a few checks using sine waves and a scope.

The NJM2073D: an amp for the Pi

The NJM2073D is a low cost, easy to use, audio amplifier chip with a maximum power of about 2 Watts.

It can be used as a stereo amplifier for portable devices like a music player or a radio, and is available for just over £1.

I have a couple of Raspberry Pi applications that need audio, so this device looks like a good option.

The Adafruit USB Audio Adapter

This USB module is recommended for the Raspberry Pi, but one of the sales bullet points for this module says "Not recommended for Mic input"

Why would you buy it just for the audio output when the Pi already has an audio output?

Well I need it for the audio input, and for just £4.77 post free from The Pi Hut via Amazon, it was worth a punt.

Simple Video Editing with Avidemux

Avidemux is a relatively simple to use video editor. It is cross-platform, free open source software (FOSS), so you can use it on Linux, Windows or a MAC box.

Illustrations in this post are from Avidemux running on Lubuntu Linux.

Before we start, there are a few points which need clarification.