It can mix the audio from multiple applications together, so you can hear VLC at the same time as YouTube, and it allows the output to be moved around between different devices while it is playing. It’s a piece of software that sits as a layer between all the audio hardware and all the applications that send and receive audio, and it automatically routes everything to the right places. We’ve used a third-party library called bluez-alsa for a few years now, but it’s an additional piece of code to maintain and update, so this isn’t ideal. More significant is that ALSA doesn’t handle Bluetooth audio at all, so various other extensions and additional bits of software are required to even get audio into and out of Bluetooth devices on an ALSA-based system. These aren’t massive problems, but most modern operating systems do handle audio in a more flexible fashion. Similarly, if you want to switch the sound from your YouTube video from HDMI to a USB sound card, you can’t do it while the video is playing it won’t change until the sound stops.

So for example, if ALSA is being used by your web browser to play sound from a YouTube video to the HDMI output on your Raspberry Pi, nothing else can produce sound at the same time if you were to try playing a video or an audio file in VLC, you’d hear nothing but the audio from YouTube.

For example, it can only handle one input and one output at a time. This is a fairly reliable low-level audio interface - indeed, it is what Raspberry Pi OS has used up until now - but it has quite a lot of limitations and is starting to show its age. The most common audio interface, which lies underneath most Linux systems somewhere, is called ALSA, the Advanced Linux Sound Architecture. There are multiple different standards for handling audio input and output, and it does sometimes seem that what has happened, historically, is that whenever anyone wanted to use audio in Linux, they looked at the existing libraries and programs and went “Hmmm… I don’t like that, I’ll write something new and better.” This has resulted in a confused mass of competing and conflicting software, none of which quite works the way anyone wants it to! Audio on Linux is really quite complicated. Most websites have now stopped requiring Flash Player, so this hopefully isn’t something that anyone notices! PulseAudioįrom this release onwards, we are switching Raspberry Pi OS to use the PulseAudio sound server.įirst, a bit of background. Flash Player is being retired by Adobe at the end of the year, so this release will be the last that includes it. We’ve been shipping Adobe’s Flash Player as part of our Chromium install for several years now.

There’s one more thing to mention on the subject of web browsers.

Install pulseaudio raspberry pi