Steve's blog

Noodles kindly passed on the Linksys WMA11B Wireless Media Adapter that he'd promised me. This is a little ARM-based Linux box with wired and wireless network inputs and TV and audio outputs. With the software that comes with the little media box, you can play Windows media and MP3 audio and display a variety of image formats.

There's just one problem with this software - it claims to work only on Windows, needing a .Net runtime to serve both software and media files to the box. We don't have any Windows machines in the house any more, so that clearly wasn't going to wash!

Various Free Software hackers have acquired these boxes and played with them, and there's now a complete set of Free tools available (to play audio, at least):

Andy Wild has written wmaloader, a replacement program to download software to the WMA11B. I've packaged this for Debian.
James Pitts has written wmamp, an iTunes client that runs on the WMA11B. Simply replace the "squishguava" software image from the WMA11B CD with wmamp.img.
Alexander Oberdörster has written a free iTunes-compatible server called daapd that runs on Linux, serving up MP3 files. This is packaged in Debian too.

With this selection of excellent programs, I managed to get my WMA11B up and running a couple of weeks back without once using the supplied Windows software. I could play MP3 music through my new hi-fi, spooling the files directly off the network. Yay! Well, almost. The problem is that almost all the music I have is now in Ogg Vorbis format. :-(

I didn't want to re-rip and re-encode all of my CDs into an inferior, encumbered format, so I decided to extend the toolchain to support Ogg Vorbis. This turned out to be really quite easy, and after just a few hours of hacking at the weekend I have it working now.

There were a few issues and bugs to solve along the way:

daapd didn't know anything about Ogg at all. That was easily solved - add code to use libogg and libvorbis to extract header info from Ogg files.
daapd always sent music files as Content-Type: text/html, which seemed a little silly. I've fixed this so that it will now use audio/mpeg and application/ogg as appropriate.
Setting up an arm cross compiler. In the past I've spent many many hours doing this, so I was really impressed by the Debian toolchain-source package. It Just Worked first time.
wmamp would only play MP3 files; I've now extended it to recognise the Content-Type header and use either the original MP3 code or the new Ogg code as appropriate.
My first attempt to use libvorbis in wmamp almost worked, but playback was very jerky. The little Arm processor in the WMA11B doesn't have hardware floating-point support, and the normal libvorbis uses floating point for decoding. Noodles pointed me at Tremor, the simplified fixed-point Vorbis decoder. A few minutes more hacking and I was done.

My very first attempt to play Ogg files worked, just slowly. My first attempt at playback with the Tremor library worked perfectly. Monitoring the system using top, I can see it uses about 20-25% CPU when playing back Ogg files, leaving enough spare cycles to do other stuff.

To do:

At the moment I only have rudimentary Ogg playback working. I want to make all the remote control functions work (e.g. pausing playback).
Ogg Flac support should be quite easy to add too.
The MP3 decoder currently drives a visualiser - a simple spectrum analyser. The Ogg code should be able to do the same at least. In fact, I'd like to add more visualisation options, maybe using xmms-style plugins if I can.
I need to check that the changes I've made to daapd haven't broken support for existing iTunes clients.
Last, but not least: I need to push the changes I've made upstream!

Longer term, I'm thinking of hacking apart wmamp and essentially rewriting it. I've got several ideas on how I'd like it to look and behave. It's been a while since I've worked on GUI code, but I'll muddle through somehow.

I've had a great time so far hacking on the WMA11B. Plugging together the fruits of multiple projects has proven to me again just how powerful Free Software can be. I have a neat new toy to play with, and as I have source to all the main components I can customise and improve them as I see fit. How cool is that? :-)

01:26 :: # :: /wma :: 10 comments

Comments

Re: Ogg support on my WMA11B
Davyd wrote on Wed, 02 Feb 2005 05:37

The problem with daapd sending Content-Type: text/html, is from memory that's what the protocol actually does. It's like it's actually intent on breaking the ability to use other HTTP clients and instead relying on Quicktime's built in MIME detection to deal with it instead. What I would look at is getting the gstreamer architecture running on the thing. There are components to instantly wire up players, so you can put video on the TV and audio out the audio, with visualisations and movies, or whatever you're after. Not sure if it currently compiles on ARM however, or if your ARM would be powerful enough to handle it (I'm told there is little overhead in GStreamer however). Of course, you might have fun without floating point maths... Since DAAP in you only need the URL to stream a song, you could use an existing DAAP browser, then probably pass it off to an existing GStreamer HTTP streaming plugin, perhaps with some custom headers. Just some crazy thoughts.

Re: Re: Ogg support on my WMA11B
BigLew (Hacking CyberVirus) wrote on Mon, 21 Mar 2005 22:24

How much can we fit into a cramFS like I dunno a minilinux with X. Also is there any way to decompile the binaries into C / C++ and ASM this would be very cool as linksys have yet to offer GPL'd code for this product. Also Some page I read said this baby has a 400Mhz ARM core in it is this true because ARM this would mean the processor was more powerful than a PS2 thats crazy. I think it may be possible to do some very cool mods for this. I'm thinking Macromedia Flash, MPEG & MPEG 2 the possibilities are limitless if sum1 could post a howto solder a new flash chip into it say 1GB + or any future expansion mods for the HW memory etc I have about £150 to spend on this new toy lots of gadgets and gizmos and Hardware to interface as well as 3 13" SVGA LCD screens from thinkpad 560E. any mods like usb any mods at all please contact me I love Mods

Re: Re: Re: Ogg support on my WMA11B
Jim wrote on Wed, 06 Apr 2005 11:21

Linksys have finally released the GPL source to the wma11b. Although your comment comparing the PS2 Mips processor to the 400Mhz ARM are reasonable, the video processor in the wma11b is very poor indeed.

Re: Re: Re: Ogg support on my WMA11B
J. Buck wrote on Mon, 05 Dec 2005 07:01

Perhaps a pcmcia to cf card, and a cf 128 or more for memory? maybe even pcmcia to usb, then usb flash, wi-fi, whatever?

Then again, if you fill it with sand, it will make a nice doorstop.

Re: Re: Ogg support on my WMA11B
Steve wrote on Wed, 02 Feb 2005 20:57

Ick! You don't surprise me on the Content-Type front. Re gstreamer, I'm not convinced that would be a good plan - the box only has a very small amount of memory, 6.5 MB free after the kernel and ramdisk have taken their chunks. I will take a look, though - thanks for the pointer.

daapd patch - It does break iTunes compatibility
Ed Schouten wrote on Sun, 24 Apr 2005 21:28

Hi Steve, I tampered around with your patch a little and it does break iTunes compatibility. I patched daapd on my Gentoo box and it also shares ogg files now (though the time duration is set to 0:00). When I try to play ogg files with the Ogg module available at http://qtcomponents.sourceforge.net/, I only get a lot of garble

Re: Ogg support on my WMA11B
shane wrote on Tue, 14 Jun 2005 23:32

Re: Ogg support on my WMA11B
Wookey wrote on Thu, 07 Jul 2005 14:56

Good stuff steve. Just one point. Toolchain-source is now deprecated because it is not maintained and trying to keep it syned with all arches is/was a nightmare. Now the normal packages have been fixed to just cross-build properly themselves (which is what upstream intended anyway).

Info available at http://www.emdebian.org/tools/crossdev.html

This is now the 'right' (TM) way to build debian cross-toolchains. Pre-built ones are available from emdebian.org.

Cleaned up wmamp sources at MyTinker
Geert wrote on Mon, 13 Feb 2006 02:39

I have rigorously cleaned up the wmamp source and fixes lots of bugs and leaks and streamlined the whole thing.

http://groups.yahoo.com/group/mytinker/

Cleaned up wmamp sources at MyTinker
Geert wrote on Mon, 13 Feb 2006 02:39

I have rigorously cleaned up the wmamp source and fixes lots of bugs and leaks and streamlined the whole thing.

http://groups.yahoo.com/group/mytinker/

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