Helmi WM6 A2DP BT Stereo Thread (5.2.1620 Build 18125.0.4.2)

[Cbones]

For those with severe skipping issues, try this:

1) HKLM\Software\Microsoft\Bluetooth\A2DP\Settings
Bitpool 58
MaxSupportedBitPool 128
UseJointStereo 2

Hint: write down old settings if you want to go back

2) Soft Reset
3) Make sure your headset is paired
4) Go into BT Settings then devices and press and hold on your Stereo headset device and choose "Set as Wireless Stereo"
5) If it still skips, go back into BT Settings and uncheck "Turn on Bluetooth", hit OK
6) Go back into BT settings again, and check "Turn on Bluetooth" (for some reason using Cycle BT or using the Comm manager to cycle the BT doesn't seem to work for me)
7) then do step 4 again.

It will usually be solid once you get no skipping, and it will last all day or until you pair a different BT headset.

Lastly, the BT and Wifi share the same antenna. There is no way as far as I know to have BT and Wifi on simultaneously without a skipping issue.

One more thing, this is not my work, I read it somewhere on another forum, and unfortunately I can't give the right person credit for the work, because I don't remember who figured it out

[Surfer]

Thanks. I'll give it a try.

I can confirm the WiFi/A2DP skipping.

For me, it happens 100% of the time if both are enabled.

-Surfer

[rjfranken]

Originally Posted by Surfer

Thanks. I'll give it a try.

I can confirm the WiFi/A2DP skipping.

For me, it happens 100% of the time if both are enabled.

-Surfer

Let's cover a little 2.4 GHz basics: WiFi uses 2.4, this divided into 11 channels; BT used 2.4 but BT uses the whole of the spectrum (2.40 - 2.49 GHz) so it will eventually have to fall upon a part of the WiFi's channel; it can't use that freq. so a skip is observed. It's not so much as using the same antenna as it is using the same frequency-which spells using the same antenna!

[semicharm]

Originally Posted by Cbones

For those with severe skipping issues, try this:
5) If it still skips, go back into BT Settings and uncheck "Turn on Bluetooth", hit OK
6) Go back into BT settings again, and check "Turn on Bluetooth" (for some reason using Cycle BT or using the Comm manager to cycle the BT doesn't seem to work for me)

I don't have WM6 yet, but that right there clears up almost all of my BT audio problems. I mean, not even a soft-reset will or re-pairing will do, but cycling that setting will. I can only figure that it must reset a corrupt setting in the BT stack that even persist after a soft-reset.

XV6700 with hacked A2DP stack and Motorola HT820

BTW, anyone try hemi's WM6 with a HT820?

[allanak]

Originally Posted by semicharm

BTW, anyone try hemi's WM6 with a HT820?

Just paired mine today and listened to about a half hour of music or so with very minimal skips...light years better than anything on any of the WM5 ROMs I was using. I didn't have to hack up anything, install any fixes, change any reg keys or anything at all - great right after the flash.

[mrmead2]

can someone try normal headphones on this rom i only get 1 side to work when plugging them in.
mike

[slightlyevolved]

I have the HT820's and Hemi's WM6. I'm sticking with it. All attempts with 3.3/3.5 have failed me and out of the box (in all fairness, I did just get this phone replaced in warranty after the radio died in my old one). A2DP is flawless with no skipping unless I have the CPU under heavy load.

Put it this way. I wasn't paying attention and my headset started skipping, quick look at the task manager showed that I had 17 programs running! A quick "Stop All" and I was skip free again.

I would like to get the bitrate a bit higher as "S"-es come out a bit distorted still and the highs are a bit lossy. Originally they were:
BitPool 30
MasSupportedBitPool 30
UseJointStereo 1

Based on some info I saw here, I've moved them to:
BitPool 56
MaxSupportedBitPool 128
UseJointStereo 2

But really, what increases the sound quality? I've seen JointStereo as 0,1,2; which is really stereo and which is joint?

I'd appreciate any info on that.

Also, thanks everyone who made WM6 possible on my 6700. It's the most stable and best performing ROM I've used yet.

[edufur]

For those that want to know, any setting other than 0 (zero) for the JointStereo, you are really combining both channels into each ear. Zero is true stereo separation. Picking 1 will combine the stereo tracks together, then plays both tracks in both ears... I have no idea why people think option 2 is a legit setting. Neither setting will improve the skipping problem... which I still have and am eager for a solution.

[edufur]

Update: BitPool and MaxSupportedBitPool seem to play a bigger role than I thought. Here is what I recently did after a lot of fiddling and resetting.

1. Paired with defaults of 30.
2. Refreshed the device.
3. Set BitPool to 37 and Max to 41.
4. Told device to use as Wireless Stereo Headset.

Minimal skipping now (after LOTS before), but the quality still isnt that good... even with this expensive headset. I think there are some driver issues with this ROM. Maybe this portion of the next rev needs some love.

My point: keep playing with the BitPool settings in single digit increments until you start to notice a change, then stay close to that range. If you want stereo, use JointStereo 0

[sethlo]

According to this article at ppc magazine, JointStereo = 1 retains stereo seperation in Windows mobile 6:

http://www.pocketpcmag.com/blogs/ind...&c=1&tb=1&pb=1

He basically says that all you need to do in WM6 is remove BitPool, MaxSupportedbitPool, and maybe add SampleRate 48000 if you think you need it. I think he is right.

I set JointStereo back to 1, deleted bp and msbp, then I added the SampleRate 48000 dword. So far it sounds great with zero skipping.

I am pretty sure I hear the separation in the Gorillaz "O Green World" on Demon Days album. I am still looking for a better sample song.

Also, I read this interesting article on Joint Stero: http://harmsy.freeuk.com/mostync/

Apparently, according to the article, the use of proper "Joint Stereo" does not eliminate stereo separation. Not exactly sure if this applies to A2DP bluetooth, but I suspect it is the same concepts.

edit: edited SampleRate 4800 to 48000 above