Well, my A2DP set got here today. Working nicely, so far. (Haven't even got the DSP SBC up yet, and it's already almost usable.)

A couple observations:

• The worst audio breaking comes from ordinary output (HSP) causing the headset to drop from A2DP for ~5 seconds. Screen and key sounds are especially bad. Solution? (Besides turning those two off...) Just mute the normal volume control.
• http://wiki.bluez.org/wiki/HOWTO/AudioDevices mentions two main methods of making A2DP work, as well as pointing out that some obsolete methods are obsolete. One is ALSA; main topic of this thread, and of most work. The other... gstreamer; isn't that what the built-in mediaplayer engine uses? I haven't heard of any work involving that on the tablets, which strikes me as surprising. If anyone knows of efforts that way, or reasons it won't work, pointers are welcome.

(And if it's been mentioned in this thread, feel free to call me an inobservant idiot; I think I've read the whole thing, keeping up with it.)

Hello Cybercowboy,

I am going to get my nokia bh-604 headphones pretty soon.... so is it possible for you to write a complete "How to" including setting up a2dp, using lardmans dsp encoder(or whatever) for a complete noob.
Also include minor things you found out of your experience which will allow for best audio. Please include instructions for streaming internet radio if possible and video also.

Thank you so much. I believe more and more people will try it out if there are complete instructions.

For those of you out there who A) use Canola and B) haven't figured out how to make it use mplayer so A2DP works, here's a very short set of instructions. First, the caveats:
If you mess up the "config" file Canola will not be happy. You may want to copy it to another location before making edits. Lastly, Canola with mplayer or at least Canola with A2DP + mplayer does not always work well. I've had problems where seeking around in a song will cause it to freeze mplayer and rapidly sequence through my playlist (Not playing anything). The only way to fix this is to exit Canola, kill the leftover /usr/bin/mplayer processes (there are usually two) or reboot your tablet, then start Canola again. If anybody has a great idea on how to fix this problem it would be nice.

1) Go to /home/user/.atabake (you'll need to do this from a SSH session or the X terminal since File Manager won't show hidden directories (names prefixed with a dot/period)
2) Edit the file called "config" (without the quotes)
2a) How you do this is up to you. I use vi.
3) On line 8 it should say "audio = (something other than mplayer)"
4) Change it to read "audio = mplayer"
5) Save and quit, you're done.
6) If you're in Canola you need to quit and go back in for the change to take effect



Larry

Sachin007,

The message you quoted wasn't mine, sorry. I intend to type up instructions myself but am still having some quirks that I want to work out, and attempt to get it working with 2 different headphones easily. After that no problem

Sorry about that. My bad. Waiting for your instructions.

Thanks

i GOT my brand new nokia bh 604 headphones and i tried the steps in thread 1 .... but i still get hsp sound which is crapppy. Can some one please help me. Thanks

Ok Guys success. i just had to unpair, reboot , re-pair and run the script.

It is pretty good. Now checking out the dsp stuff. Thanks

Yeah, it's still a bit clunky (no fault of johnx), the Bluez stuff seems to have a mind of its own unfortunately

I've recently installed a2dp packages on my N810 and that is working pretty good, unless I try to use anything else on the tablet at the same time. :( But even when the tablet was idle, I mean just Canola playing music, I've had quite frequent, short skips of 1-2 secs - really annoying.

Today I've installed dsp-sbc tough (great stuff, lardman!), CPU usage dropped to almost-zero, and to be honest there are significantly less drop-outs in the 'idle' mode, but then it seems like it's way more sensitive to any other activity - event sliding the keyboard up/down, or locking screen and keyboard with slide button results in drop. :-o (which is quite strange, as CPU is almost not busy at all, so such tasks should have no effect...)

The only thing I didn't do tough, is flashing that custom kernel image provided with dsp-sbc. I've read release notes and I know it gives the ability to tweak CPU/DSP speed, but are there any other improvements and/or changes than that?

No, the only change is to allow you to run the cpu at full speed (and the dsp at less than full speed). This was designed to allow video decoding to use the full cpu speed, but there is some sort of issue with video decoding - it produces very poor framerates when using the dsp task for sbc. I'm looking into this atm.

Regarding the drop outs using dsp-sbc, the ARM is is transferring 48000Hz x 2 channels x 16bit data to the DSP (512 bytes x 375 per second), which then transfers 78 x 375 bytes back per second. So we don't have a great deal of latency, if anything delays the transfer to or from the DSP we've only got ~1/375th of a second of audio left in the buffer.

Unfortunately this is what bluez provides (without major hacking), obviously a larger transfer buffer would be far better in terms of transfer overhead and delays. We'll have to see if bluez can be hacked a bit more to provide more than the 512 bytes per call it currently does (though I guess much more will start producing syncing problems, not that we have video working anyway though