Recent Developments in the PulseAudio World Arun Raghavan - PowerPoint PPT Presentation

Recent Developments in the PulseAudio World Arun Raghavan Collabora

Feature-rich audio server Convenient client API

Some rough bumps early on

Lots of FUD afterwards

More and more people love us

Okay, fine More and more people don't hate us

Ubuntu, Fedora, OpenSUSE GNOME, maybe even KDE one day Wine(!)

The People

Colin Guthrie: maintainer; * Arun Raghavan: committer; * Tanu Kaskinen: committer-in-waiting; ALSA, misc David Henningson: ALSA, misc Maarten Bosmans: RTP, Win32, build, more Pierre-Louis Bossart: Power, performance, misc Lots of others

So we're alive and kicking

We did a 1.0 release

It took 2½ years

But it's awesome ;)

DBus protocol Source-ouput volumes Echo cancellation Windows, OS X ports Equalizer RTP improvements Passthrough Deferred volumes Optimisations

And there's more to come ...

Jack detection ALSA UCM Dynamic sample rate changes WebRTC echo canceller Drift compensation, AGC Module loader Configuration API Moar Orc Fixed rate resamplers

Exciting times ahead ...

A little more about passthrough

Problem: we'd like to use hardware audio decoders

Challenge: PulseAudio needs fixed bytes-to-ms conversion

Solution: Support only fixed bytes-to-ms conversion (IEC 61937)

Format negotiation ╭──────╮ ╭──────╮ │client│ ──▷ requested formats ──▷ │server│ ╰──────╯ ╰──────╯ ╭──────╮ ╭──────╮ │client│ ◁── selected format ◁── │server│ ╰──────╯ ╰──────╯

Notification on format change

Changes to GStreamer

baseaudiosink does payloading IEC 61937 payloading in pbutils

playbin2/playsink understands compressed sinks (go slomo!)

pulsesink now does AC3/DTS/MP3

to handle format changes pulseaudiosink is a new bin

AC3 sink ╭───────────────playbin2────────────────╮ │ │ │ ╭─pulseaudiosink─╮ │ │ ╭────────╮ │ ╭─────────╮ │ │ │ ...──▷│ac3parse│──▷│──▷│pulsesink│ │ │ │ ╰────────╯ │ ╰─────────╯ │ │ │ ╰────────────────╯ │ │ │ ╰───────────────────────────────────────╯

PCM sink ╭───────────────────────playbin2───────────────────────╮ │ │ │ ╭────────pulseaudiosink────────╮ │ │ ╭────────╮ │ ╭──────────╮ ╭─────────╮ │ │ │ ...──▷│ac3parse│──▷│──▷│decodebin2│──▷│pulsesink│ │ │ │ ╰────────╯ │ ╰──────────╯ ╰─────────╯ │ │ │ ╰──────────────────────────────╯ │ │ │ ╰──────────────────────────────────────────────────────╯

All this will be in the next gst-plugins-good (0.10.31)

GStreamer 1.0 will provide better upstream renegotiation

But we finally closed bug 331875 (took only 5 years :p)

Questions?

Thank you!