• Dynamic sample rate switching by Pierre-Louis Bossart: This makes PulseAudio even more power efficient.

• Jack detection by David Henningsson: Separate volumes for your laptop speakers and headphones, and more stuff coming soon.

• Major echo canceller improvements by me: Based on the WebRTC.org audio processing library, we now do better echo cancellation, remove the need to fiddle with the mic volume knob and have fixed AEC between laptop speakers and a USB webcam mic.

• A virtual surround module by Niels Ole Salscheider: Try it out for some virtual surround sound shininess!

• Support for Xen guests by Giorgos Boutsiouki: Should make audio virtualisation in guests more efficient.

Special thanks from me to Collabora for giving me some time for upstream work.

Packages are available on Gentoo, Arch, and probably soon on other distributions if they’re not already there.

I finally got around to actually figuring out the problem and fixing it, so if you have custom configuration to do all this, you should now be able to remove it after emerge’ing media-plugins/alsa-plugins-1.0.25-r1 or later with the pulseaudio USE flag. With the next PulseAudio bump, we’ll be depending on this to make the out-of-the-box experience a lot more seamless.

This took much longer to get done than it should have, but we’ve finally caught up. :)

[Props to Mart Raudsepp (leio) for prodding me into doing this.]

PulseAudio 1.1 is out. It’s mostly a bunch of bug fixes on top of 1.0. Most important of these are fixes for: a libpulse dependency on libsamplerate (if enabled) which would make our LGPL license invalid, broken Skype audio capture (because we changed from a 3 number version to 2 numbers), broken startup without a DBus session bus running, and not going crazy on USB disconnects.

This should be a very safe upgrade, so grab it while it’s hot!

Currently, PulseAudio runs all your devices at a default sample rate, which is set to 44.1 kHz on most systems (this can be configured). All streams running at different sample rates are resampled to this sample rate. Pierre’s patches add an alternate sample rate that we try to switch to under certain circumstances if it means that we can save on resampling cost. This would happen if the stream uses exactly the alternate sample rate, or some integral-or-so multiple of it.

The default value for the alternate sample rate is 48 kHz. So if you’re playing a movie off a DVD where the audio track is typically a 48 kHz stream, and your card supports it, we switch to 48 kHz and avoid resampling altogether. Similarly, while making voice calls, common sample rates are 8, 16, and 32 kHz. These can be resampled to 48 kHz much faster than to 44.1 kHz.

Now for the big caveat — this won’t work if there’s any other stream connected to your sink/source. So if your music player is playing (or even paused) when you get that voip call, we can’t update the rate. This situation can probably be improved by at least allowing corked streams have their sample rate change (so having some random stream connected but not playing — I’m looking at you, Flash! — won’t block rate updates altogether). Hopefully we’ll get this fixed before this feature is released in PulseAudio 2.0.

Thanks to Pierre for all his work on this, and to my company, Collabora, for giving me some time for upstream work!

A lot of people have contributed to this release and thanks to them all. Special props to Colin all the patch-herding, tireless help, and code ninjutsu!

p.s.: Gentoo packages are already available, of course. :)

p.s.: I was quite happy to see that the Google Talk plugin has proper PulseAudio support (thanks to the WebRTC née GIPS code, it looks like).

I’ll be presenting a talk titled DLNA in a GNOME 3 World, talking about Rygel and the work we’ve been doing on gupnp-dlna to make DLNA rock on GNOME.

If you’re in or around Bangalore and contribute to or are interested in contributing to GNOME, you really have no excuse to not attend (heck, entry’s free). This applies doubly to students who are looking for cool stuff to do for the Google Summer of Code this year. So, do drop by and say hello! :)

So Nirbheek Chauhan and I designed a couple of quick mockups that I think would work well. This doesn’t address customising behaviour with an external monitor, but I don’t feel nearly as strongly about that being hidden in dconf-editor as I do about the rest.

My mockup

Nirbheek's mockup

While Nirbheek’s version looks decidedly prettier, I think the meaning of the icons is not absolutely obvious. This might be solvable by some explanatory text above and mouse-overs.

While doing all this, though, it’s clear that it is really hard to design a UI that you think will please enough people, and really easy to make assumptions about what “people” want and how they use their computers. So kudos to the GNOME3 UI designers for taking up this difficult job and I hope they take all the feedback flying around in a positive spirit (even if the messages are often not quite positive-sounding ;) )

p.s.: This also adds to my count of Gentoo boxen. :)

That said, I still don’t like the idea of running a proprietary operating system on it (as beautiful as OS X is ;)), so I continue to happily use Gentoo. The standard amd64 install works just fine with some minor hiccups (keyboard doesn’t work on the LiveCD, kernel only shows a console with vesafb).

The one thing that did bother me is BIOS-emulation. For those coming from the PC world, Macs don’t have a BIOS. They run something called EFI which is significantly more advanced (though I think the jury’s out on quirkiness issues and Linus certainly doesn’t approve of the added complexity).

Anyway, in order to support booting other OSes (=> Windows) exactly as they would on PCs, Apple has added a BIOS emulation layer. This is how Ubuntu (at least as of 9.10) boots on Macbooks. Given that both the bootloader (be it Grub2 or elilo) and the Linux kernel support booting in an EFI environment, it rubbed me the wrong way to take the easy way out and just boot them in BIOS mode. There is a reasonable technical argument for this – I see no good reason to add one more layer of software (read bugs) when there is no need at all. After a lot of pain, I did manage do make Linux boot in EFI-only mode. There is not enough (accurate, easily-findable) documentation out there, so this is hard-won knowledge. :) I’m putting this up to help others avoid this pain.

Here’s what I did (I might be missing some stuff since this was done almost a month ago). The basic boot steps look something like this:

1. EFI firmware starts on boot
2. Starts rEFIt, a program that extends the default bootloader to provide a nice bootloader menu, shell, etc.
3. Scans FAT/HFS partitions (no ext* support, despite some claims on the Internet) for bootable partitions (i.e. having a /efi/… directory with valid boot images)
4. Runs the Grub2 EFI image from a FAT partition
5. Loads the Linux kernel (and initrd/initramfs if any) from /boot
6. Kernel boots normally with whatever your root partition is

Now you could use elilo instead of Grub2, but I found this it to not work well (or at all) for me, so I just used a Grub2 (1.97.1, with some minor modifications) (just adds an “efi” USE-flag to build with --with-platform=efi). While I could make /boot a FAT partition, this would break the installkernel script (it’s run by make install in your kernel source directory), which makes symlinks for your latest/previous kernel image.

Instructions for installing the Grub2 EFI image are here. Just ignore the “bless” instructions (that’s for OS X), and put the EFI image and other stuff in something like /efi/grub (the /efi is mandatory). You can create a basic config file using grub-mkconfig and then tweak it to taste. The Correct Way™ to do this, though, is to edit the files in /etc/grub.d/.

Of course, you need to enable EFI support in the kernel, but that’s it. With this, you’re all set for the (slightly obsessive-compulsive) satisfaction of not having to enable yet another layer to support yet another proprietary interface, neither of which you have visibility or control over.

As Srini had announced, Dec 5th was GNOME Day at FOSS.IN this year. We kicked the day off with Shreyas giving a developer’s introduction to GNOME 3.0. This was followed by another well-received talk by Srini on the Mobiln2 UI and Clutter.

By the end of lunch, it turned out our already packed schedule had got some new additions from the other enthusiastic GNOME folks around! The afternoon session was kicked off by Arun ‘vimzard’ Chaganty introducing what newbies need to know to dive into GNOME development. Tobias Mueller followed with a talk about GNOME Bugsquadding. Sayamindu and Dimitris then took the stage for a short L10n talk. Next up was a talk about Anjal by Puthali. Olivier then gave a hackers’ introduction to Empathy/Telepathy, Srinidhi and Bharath did a quick introduction to using the OpenSUSE Build Service.

Wait, I’m not done yet. :) The final session on GNOME Performance was a 4-hit combo with me giving a quick introduction to Sysprof, Lennart introducing mutrace, Krishnan giving a pretty wow introduction to using DTrace to profile GNOME, and Dhaval giving a short introduction to how cgroups could help make GNOME more responsive.

Phew! That was a long and awesome day, with some icing on the cake in the form of stickers and T-shirts. The last were possible thanks to the GNOME Foundation, so a huge thanks to them!

Sponsored by GNOME!

As some of you might already know, my next step, which has had me bouncing off the walls for the last month, is to join the great folks at Collabora Multimedia working on the PulseAudio sound server. I’ll be working from home here, in Bangalore (in your face, 1.5-hour commute!). It is incredibly exciting for me to be working with a talented bunch of folks and actively contributing to open source software as part of my work!

More updates as they happen. :)

In addition, pkgcore 0.4.4 has my patch to support HTTP proxies for rsync. This was a fun patch to write, small as it is. The code is beautiful, and Brian Harring (ferringb) and Patrick Lauer (bonsaikitten) walked me through a lot of it. Good stuff!

I’ve also been working on splitting the gnome-python* ebuilds to make the dependency trees for packages that use these bindings a lot saner. This has been longer and more painstaking that intended. It wouldn’t even have happened if Jim Ramsay (lack) hadn’t made an excellent start with the gnome-python-desktop split, since all subsequent work was based on that. Hope this is useful to someone, though. :-)

As I said, a good week.

[PMS is, from what I gather, a spec detailing the minimum portage API required to support the current ebuild ebuild tree]

Yet, hope springs eternal.

And if you haven’t already, emerge ferringb‘s awesome confcache for caching the autoconf stuff.

Does anybody know a good place to get high-quality CS GATE practise papers?