[MOD] Increase A2DP Bluetooth bitpool settings - Nexus 7 General

I've recently acquired a new car which has a built in stereo system (Renault Megane Estate 2012 Bose edition) which is able to receive CBR encoded A2DP streams. It works well, connects, music plays, even controls work.
Awesome!
Using catlog I can see that the bitpool that is negotiated is 51. While the sound isn't horrible, I believe the handsets (Samsung Galaxy SIII Int. and Nexus 7, both running CM10 nightly) are able to encode and transmit at a higher bitrate/bitpool then currently is set.
I've tried my best effort in changing this settings. I've built my own Ubuntu kitchen, followed all the guides and have from the looks of it compiled a successful ROM image. Sadly enough when I flash it, my tablet dies (black screen) and even CWM is destroyed. Using fastbood and USB I've been able to recover the tablet, so no problem there, but still, no working ROM. Even without changing something. But that is not what this thread is for, I'll figure that out eventually.
I am trying to recreate the results that are in the following topic : http://forum.xda-developers.com/showthread.php?t=1880298
Sadly, the files provided are not compatible with my CM10 devices and changing the source and then compiling it and replacing the files yields no result. Whatever I try, it stays at 51 (The bitpool it SENDS to the radio as max). There are several files which are connected to the settings, such as cbr.c , audio.a2dp.default.so, etc. but I don't really know what to change to get the desired results.
If anyone is able to help, that would be greatly appreciated. Point me to the right file where I can find the values to change, either in a compiled ROM or in the source so that I can compile it and change the files in
my running ROM using rootexplorer. Whatever works.
I would like to try settings as high as 125. But ideally, I would like to experiment what my headunit accepts, what it can be forced to, and thus finding the highest quality possible using my combination of equipment.
In this the Nexus 7 is the most important because that will be permanently located in the car.
update--
I have found a thread on bluez surrounding this topic.
http://www.spinics.net/lists/linux-bluetooth/msg23091.html
Could someone more knowledgeable then me please take a look at this for me and maybe change the file? Sadly that goes way beyond my programming knowledge, but I would really love to give it a try!
update--
Some extra information and a good explanation as to why I am looking for this (and maybe more people with me).
Bitpool values as high as 128 are possible on Windows Mobile devices (including mine), which means they are possible in A2DP. Such a high value is necessary for some genres of current music, which are highly
compressed (the problem was once discussed in one of Xiph Foundation's articles). SBC is unable to encode such material properly if it doesn't have enough bandwidth.
Click to expand...
Click to collapse
I've done some more tests editing and replacing files and I think I've actually gotten it to sync higher but it still displays it's at 51. The sound just sounds a lot better, but of course, that can always be a placebo effect. :silly:
So, anyone have any insight, or who can point me into the right direction of what needs to be changed and where? As said, I think I have reached the quality increase (bitpool 100) but the logs still display 51.... not quite there yet. And in light of people using the Nexus 7 in a cars a lot (which I also intend) and the borked headphones output I read everywhere, CD quality streaming over A2DP (It's possible) would be awesome!

Kitchen fixed
So I got my kitchen working and am cooking working ROM's.
Just getting the right files changed is giving me some problems.
I think I fixed most of it, but for some reason when I check the logs it still states that it's sending a max bitpool of 51. I believe in the background it's using the 128 as I stated in the source files, but still. I would like the logs to show the same, just to acknowledge I'm a not having a placebo effect.
The files I have changed are the following:
/android/system/external/bluetooth/bluez
a2dp.c
gsta2dpsink.c
gstscenc.c
liba2dp.c
pcm_bluetooth.c
I used the patch listed above on the pcm_bluetooth.c. And I do believe it overrides the settings and it's not set to 51 anymore but the 128 I put in all the files manually. Music sounds great, but it's hard to subjectively test.
Hopefully we can find some people who have a greater understanding of bluez.

Little kick
Little kick to see if someone wants to assist me on this or not. I think it could potentially benefit a lot of people making Bluetooth audio/A2DP go from barely adequate to High Fidelity!

I'd love to help you test this - I also find the A2DP quality to be lacking in a lot of more "active" or compressed music. Acoustic and softer music sounds great, but rock/metal tends to sound like a 128kbps mp3. It actually seems to sound better from my Galaxy Nexus than the 7 as well. I'm running a Bugless Beast ROM now but was running CM10.

Also, not sure if you've seen this but I found an article (soundexpert.org/news/-/blogs/bluetooth-audio-quality-a2dp, sorry can't post links yet) that shows the bitrate per bitpool value. At a bitpool value of 53, the bitrate is around 320kbps. A2DP itself supports a bitrate of up to 512kbps for stereo, but through other optionally-supported codecs. SBC however, in this profile, only seems to go to ~320. It might be worth checking out if your car stereo supports mp3 over A2DP - there is an option in /etc/bluetooth/audio.conf to set MPEG12Sources from 0 to 1 and SBCSources from 1 to 0.

ROM up for download
Hi there, thnx's for joining the cause.
I compiled a new daily today with settings set to bitpool 128. But I don't really hear much change, maybe the setting is too high, maybe something else is going wrong. As stated above, in the logs I can only see it sending 51 as max pool to the device and setteling with it. But since I'm using an edit pcm_bluetooth.c it should override that setting, say it's going to do 51 and then stream and the values I defined in the files.
.....in theory at least...... the only subjective evidence I have for this are my own ears.
So, I will provide you with access to the 128 version and am going to compile a 64 version while I'm at it.
Use an FTP client to connect to:
host: oss.quindorian.org
user: XDA
pass: ROMROM
Anyone is welcome to give it a try. I have put limits on the FTP site, so please beware of that. But I'll put ROM's there you can try and report back on. Tell me if you think it does nothing or if you think it makes it sound like a singing angel. Any feedback is appreciated.
As source I use the CM10 repository so I am basically building modded nightly builds. Today it allready has the 4.1.2 flavor with the newest drivers and everything included. Don't forget to flash gapps if you need them.

Understand
ChrisK15 said:
Also, not sure if you've seen this but I found an article (soundexpert.org/news/-/blogs/bluetooth-audio-quality-a2dp, sorry can't post links yet) that shows the bitrate per bitpool value. At a bitpool value of 53, the bitrate is around 320kbps. A2DP itself supports a bitrate of up to 512kbps for stereo, but through other optionally-supported codecs. SBC however, in this profile, only seems to go to ~320. It might be worth checking out if your car stereo supports mp3 over A2DP - there is an option in /etc/bluetooth/audio.conf to set MPEG12Sources from 0 to 1 and SBCSources from 1 to 0.
Click to expand...
Click to collapse
Yeah, I understand what that article says. But for me, the quality just isn't up to par to listening to a 320Kbit stream. Also, there is what A2DP officialy supports and there is what works. I'm shooting for the last type. If I can get a 1000Kbit stream between my device and my headunit, I will, even if it doens't add much above say 786Kbit, more is always better in this case. If it works that is, ofcourse.
Because I wish to use spotify, I believe my only choice is to use the SBC encoder. Spotify will never let you transfer it's source file to anywhere because of DRM. Alternativly, if we could enable an AAC stream or something (also supported I believe) we'd need less bitrate/bitpool for better quality! And from what I have read, the SBC encoder standard used it just quite crappy. So while a 320Kbit LAME encoded MP3 might sound great/perfect, using a sub-standard encoder can still give it artifacts and low quality. Thus the hunt for insane amounts of bitrate!

Awesome, I'll definitely give it a shot. If it's possible to exceed the Bluetooth standard spec then that'd be awesome. I'm more worried about our receivers not being able to support the higher bandwidth - my head unit is new but only supports SBC unfortunately.

Cool
ChrisK15 said:
Awesome, I'll definitely give it a shot. If it's possible to exceed the Bluetooth standard spec then that'd be awesome. I'm more worried about our receivers not being able to support the higher bandwidth - my head unit is new but only supports SBC unfortunately.
Click to expand...
Click to collapse
Cool, I just put the bitpool64 version there too. Tested it and I notice no real difference. Sadly the quality is still not great, it's not horrible.... but certainly not great so I still feel like my settings are maybe not having any effect whatsoever. As reflected by the logs using catlog. It sen bitpool 51 max and settles for that. For all the values I have changed in the files and that stay the same, I really do not understand. Wish I could fix that, but with my knowledge I have just run out of places where to look.
Let me know if in your case it makes any difference!

I just tried it out and to me it seems like there's an improvement. I normally stream Pandora One in my car, and that definitely seemed like it had more clarity. However Google Music streaming sounded the same, although it was already good to begin with. I would think that compressing more highly-compressed music from the start (Pandora) would have a worse effect on quality than less-compressed music, which seems to be the case. Or maybe I'm just hearing things
Thanks for looking into this, I've been trying to find a way to do this for a while!

Quindor said:
Hi there, thnx's for joining the cause.
I compiled a new daily today with settings set to bitpool 128. But I don't really hear much change, maybe the setting is too high, maybe something else is going wrong. As stated above, in the logs I can only see it sending 51 as max pool to the device and setteling with it. But since I'm using an edit pcm_bluetooth.c it should override that setting, say it's going to do 51 and then stream and the values I defined in the files.
.....in theory at least...... the only subjective evidence I have for this are my own ears.
(...) .
Click to expand...
Click to collapse
perhaps you can test if the patch does anything - by setting bitpool to some very LOW value ?

ChrisK15 said:
It might be worth checking out if your car stereo supports mp3 over A2DP - there is an option in /etc/bluetooth/audio.conf to set MPEG12Sources from 0 to 1 and SBCSources from 1 to 0.
Click to expand...
Click to collapse
On my CM12.1 official nightly ROM (2015/12/03) for my Samsung i9505, there is no file audio.conf
Does that mean I can simply create it with the two lines
MPEG12Sources=1
SBCSources=0
in order to test wether a bluetooth SNK device such as a car stereo or a headset supports mp3 over A2DP?

So does anyone have some actual logs or HCI captures showing bitpool above 53?

..

Related

A2DP skipping solution

Hi to all,
as pointed out many times in various XDA forums - there is a definite solution to the skipping problem with bluetooth stereo. The reason i post it again is that i never had the issue before, but it appeared with the latest ROMS 2.26 and beyond - probably due to more optimistic assumptions about the BT headset performances (i own a Jabra BT620S which i love, after i got rid of the Motorola HT820 because of terrific skipping that i could have probably solved!)
The solution:
set/change the registry BitPool (it is a DWORD in case you don't have it) by using TotalCommander or similar:
HKLM/SOFTWARE/Microsoft/Bluetooth/A2DP/Settings/BitPool=40
A value of 50 or so means heavy skipping, the lower it is the lower the bandwidth between your headset and the wizard. At 40, i can be the famous 10 m away without any skipping with a great audio quality. But at 50, i have essentially to keep the wizard nearby my ears....
Last comment on the quality: i don't notice any difference, probably because my WMA files are encoded at lower bandwidth anyway....BTW, MaxBitpool and SampleRate, experimentally, have no visible effect (probably depending onthe MS implementation of the BT stack).
All the precise information supporting this empirical evidence is available in (see for example pg. 22 and 71 for the bandwidth estimation)
http://www.bluetooth.com/NR/rdonlyres/800D10CD-DE3D-4D51-ABC0-726C8DF26151/921/A2DPspecv10.pdf
Enjoy the Wizard!
No Skipping at last.
It seems to work for me no skipping as long as I am not syning via bluetooth.
Thanks for posting this fix, as the skipping has been bothering me for a while.
I thought it was fixed
Sorry Buddy it still skips on me, do I have to reset the wiza after adding the registry setting?
wrongway2002 said:
Sorry Buddy it still skips on me, do I have to reset the wiza after adding the registry setting?
Click to expand...
Click to collapse
Absolutely yes, you have to soft reset your device (keep pressed the power button or use the stylus in the small hole on the right side).
I use resco registery editor and there is no file for settings or bitpool? I have cingular 8125 and jabra 620
same here, i have no settings/bitpool in my registry
i have hklm/software/ms/bt/a2dp/devices/1, 2, 3, 4
@pzucchel, which rom are you using?
bbobeckyj said:
same here, i have no settings/bitpool in my registry
i have hklm/software/ms/bt/a2dp/devices/1, 2, 3, 4
@pzucchel, which rom are you using?
Click to expand...
Click to collapse
And your roms are A2DP enabled? seems strange, though you could always add the settings, but God knows how many other keys you'll be missing.
masr1979 said:
And your roms are A2DP enabled? seems strange, though you could always add the settings, but God knows how many other keys you'll be missing.
Click to expand...
Click to collapse
I'm currently trying wm6 underground, in my first test the bt stereo semmed beetter than the others i tried - but i'll see how it survives the work commute today/
which are you using, my only requirements for a rom are -
1 working a2dp
2 fast i don't really care if vanilla or not
Just overclock mate!! No skipping at 260MHz
new2city said:
Just overclock mate!! No skipping at 260MHz
Click to expand...
Click to collapse
if only that worked
i am using phoneAlarm which seems to slow down every rom is use a lot, but overclocking does not work for me.
someone please tell me which rom they are using, that way i can try it, and if the sound still drops, i know it's my device/my loaded software
I'm using Core2.0 (as shown in my signature). But I got the hissing problem so I am using Axim Widcomm stack.. However, I still have to overclock to get rid of the skipping. The reason could be because I play aac+ files using TCPMP. I remember that there was no skipping in WM5 when I played MP3s.
bbobeckyj said:
I'm currently trying wm6 underground, in my first test the bt stereo semmed beetter than the others i tried - but i'll see how it survives the work commute today/
which are you using, my only requirements for a rom are -
1 working a2dp
2 fast i don't really care if vanilla or not
Click to expand...
Click to collapse
Well I'm using the stock T-Mobile now (I'm in between cooks, and messing around with the registry files, hopefully tomorrow I'll be flashing..... again) Have you tried Faria's roms? a2dp worked pretty well for me using an IOGear stereo headset. Skip's were far in between, that is if they were present at all; usually when I had a lot of apps running, or when the phone was connected or connecting to GPRS was the only way it would skip. Your milage may vary though, but it might be worth a shot.
so i flashed the core 2
edited the registry (set it to 20 hexadecimal, which gives 32 in brackets) (i really didn't find a2dp settings in any other rom i tried) and now it works, so thanks for all the help - it's easy when you have the right rom
I thought I would drop in my .02 cents. I have a Jabra 620 as well. I had previously used Molski 3.3 crossbow lookalike rom (WM5). With that one, auidio was good but was not in stereo.
Now today I had some free time so I decided to try a wm6 rom or 2. With Faria's rom, the sound quality was good. I think he sets the bitpool to 60. But the rom itself is buggy.
Next I tried crossbow reload 1.7. This rom is much less buggy. But the stereo bluetooth sucks. The sound quality is very tinny. Also, there is this constant background clanging that is very annoying. I have looked at the bitpool. Bitpool in reload is 30. I changed this to 60 but it may have only gotten slightly better. Sound quality still sucks. To note, I dont get any skipping, so Im happy about that.
EDIT: I decided to change the MaxBitPool value to greater than 30. At 35, all the clanging and general bad sound went away. I'm happy!
sorry for the missed replies!
....i have switched to the trinity due to a wizard failure!
...If you don't have the bitpool register, you should create it. And by the way, i had exactly the same problems with the trinity and the same jabra bt620s, and changing the bitpool value worked again!!!
all the best;
Piero
I now have the ingenetics rom dump flashed to my ppc (see my sig) and it is by far the best a2dp rom ever - without overclocking (i forgot to try it, so i'll be doing that soon, to see what improvements i can make)
pzucchel said:
....i have switched to the trinity due to a wizard failure!
Piero
Click to expand...
Click to collapse
OT - how is the trinity compared to a wiz? i asked in my local shop, but with all the rubbish from orange on it, it was actually a lot slower than my wiz. and they wouldn't even let me hard reset it and let me remove the extended rom they even said there was no other software to make it run faster! nor would i be able to remove the orange crp - funny how we know more about these things than the sellers
Thanks for this post. I know it's been a few months, but I just got myself a Jabra BT8010 and this change in the registry value made a difference in the audio quality. I don't have the drop outs I had with the other value. The problem I have now is that TCPMP doesn't play the video smoothly when using the headset despite overclocking. Any ideas to the setting that would help? Thanks.
Re Skipping
Hi All
I just got the 620,s , and Yes they sucked, found this fix , (post 1) tweaked my registry , soft reset......
And OH MY GOD !!!!!!!!
It works FLAWLESSLY,
hasent skipped now in 30 mins, walked away from phone 20 feet, not a skip in sight
You Guys , Totally Rock!!!
Kudos to the poster

Audio Quality on G1/Dream

Greetings:
Over the years I've owned many HTC devices and have always used them as a media player as its main secondary function, usually with CorePlayer as my main software. The one thing I noticed was that when it came to playback, all of my non-Dream phones were relatively quiet (very low noise/artifacts) when it came to music playback.
Ever since I got the G1 (running stock, no mods) I've noticed that there's a huge difference in the audio section-when using the wired adapter, I get lots of noise/artifacts (very noticeable with low playback volume) and I get an incredible amount of GSM chatter (which was rare in my other devices.)
Anyone else noticed this? Any fixes/workarounds? (I'm waiting for the Android port of CorePlayer, maybe that might fix some of the quality issues>)
Audio quality is something that the G1 lacks in my opinion right out of the box, compared to other mobile phones. If you have a rooted mobile though, I would have a look at the Meltus Audio mod (had a look at my signature).
The new V6 version of the audio mod increases audio, clarity and adds a bit of bass
wazmo said:
Greetings:
Over the years I've owned many HTC devices and have always used them as a media player as its main secondary function, usually with CorePlayer as my main software. The one thing I noticed was that when it came to playback, all of my non-Dream phones were relatively quiet (very low noise/artifacts) when it came to music playback.
Ever since I got the G1 (running stock, no mods) I've noticed that there's a huge difference in the audio section-when using the wired adapter, I get lots of noise/artifacts (very noticeable with low playback volume) and I get an incredible amount of GSM chatter (which was rare in my other devices.)
Anyone else noticed this? Any fixes/workarounds? (I'm waiting for the Android port of CorePlayer, maybe that might fix some of the quality issues>)
Click to expand...
Click to collapse
I've noticed it a lot as well. Unfortunately, this has been both out of the box (stock) and rooted with any firmware whatsoever. It's a lot more obvious in my Bose earbuds, since they're noise-canceling, but it's unavoidable all the same.
I haven't tried Meltus's full app yet, just the lite version on the website, but as we speak, I'm on the Market buying it :]. But I've heard it's nothing but amazing, so I would give that a shot too.
Along the same lines, when ripping CDs or converting audio files, what would the ideal bitrate be for use with stock headphones?
The reason I ask is I'm under the impression that if we encode at too high of a bitrate, it will do nothing to increase the sound quality but will suck up more of our limited phone memory (not sdcard space, but useable memory for running apps). Please correct me if I'm wrong about that.
blueheeler said:
Along the same lines, when ripping CDs or converting audio files, what would the ideal bitrate be for use with stock headphones?
The reason I ask is I'm under the impression that if we encode at too high of a bitrate, it will do nothing to increase the sound quality but will suck up more of our limited phone memory (not sdcard space, but useable memory for running apps). Please correct me if I'm wrong about that.
Click to expand...
Click to collapse
I use AAC-HE exclusively on phones-I find that using a 56 kbps conversion does a decent job regardless of the headset.
I have no knowledge of which encoding methods causes the greatest impact to running memory usage.

streaming bluetooth audio (AD2P) possible?

So I got a new car Ford Fusion with Microsoft Sync. Wanted to report to everyone that it is working 100% calls dialing, phonebook, etc - with one exception that I'd like to ask about. AD2P.
I'm not sure if our AD2P is even setup for our port of Android on the Vogue? Amazing to my ears, when I tried to stream AD2P of Droidlive over my Sync it actually plays! Only thing is it plays a second, skips a second, and so on
So does anyone know if AD2P is supported?
Thanks guys!
Congrats on the new car . I hear the Fusions Sync is quite nice.
AFAIK AD2P is very choppy currently.
I would love to know of a fix if anyone has one.
skipbarker said:
Congrats on the new car . I hear the Fusions Sync is quite nice.
AFAIK AD2P is very choppy currently.
I would love to know of a fix if anyone has one.
Click to expand...
Click to collapse
Thanks!
Yeah I was quite surprised that it even worked... It's a blessing because it's not one of the things that I expected, unexpected surprises are the best! AD2P seems to be so close to working on this that I wonder if there's something small I have to tweak. I googled it wondering if it was a problem with all Android + sync but couldn't find any helpful results.
berardi said:
AD2P seems to be so close to working on this that I wonder if there's something small I have to tweak.
Click to expand...
Click to collapse
Agreed. I've been searching around myself, I found this page. No fixes listed but at least some info about bluetooth issues in general.
I'd be happy to have AD2P functionality working on android as well! I hate to run cable in a car. That's what I have to do right now. Please, if anyone possibly can, fix choppiness. Then listening to Pandora in a car would be very simple!
From what I understand fixing this is part of the high speed serial bus that DZO and vilord have been working on. From what I know there's some clock issues that need to be worked out.
mssmison said:
From what I understand fixing this is part of the high speed serial bus that DZO and vilord have been working on. From what I know there's some clock issues that need to be worked out.
Click to expand...
Click to collapse
Good to know. Keep up the good work.
mssmison said:
From what I understand fixing this is part of the high speed serial bus that DZO and vilord have been working on. From what I know there's some clock issues that need to be worked out.
Click to expand...
Click to collapse
Great news... although totally over my head All I could do was Wikipedia "high speed serial bus" and I concluded that it's what helps the phone communicate with the the bluetooth hardware, so I guess right now the "high speed bus" is not in sync with the bluetooth hardware, or maybe vice versa? It's great to know that it's a possibility some day, AD2P is a nice thing.
This stuff you guys are doing is so impressive to me, so although I don't really understand it, I like to watch the development process. I haven't even seen dedicated, paid support teams for these companies do work this good, especially not in such short time frames. I'm a broken record but thanks again.
In addition to the high-speed serial bus, Android seems to be buggy with A2DP.
G1 thread on the subject:
http://forum.xda-developers.com/showthread.php?t=577128
Official Android bugreport:
http://code.google.com/p/android/issues/detail?id=2807
I just paired my headphones up a few minutes ago and was about to make a thread about the choppiness. Glad to know I'm not the only one....but damn I guess I need go buy that 1/8th-to-miniUSB cable to plug in my bluetooth headphones directly to the phone.
But Android is STILL worth it! Can't wait until they figure out AD2P!
polyrhythmic said:
In addition to the high-speed serial bus, Android seems to be buggy with A2DP.
G1 thread on the subject:
http://forum.xda-developers.com/showthread.php?t=577128
Official Android bugreport:
http://code.google.com/p/android/issues/detail?id=2807
Click to expand...
Click to collapse
Thanks for those links, I'm going to try playing around with unpairing, repairing, changing options to see if I can get it working. I'll report back with any results.
One thing I noticed was the posters don't seem to be having exactly the same issue I'm having. The music plays for about 1 second on 1 second off, intermittent consistently, repeatedly. The audio quality is perfect, just intermittent. There is no crackling as many describe. Not that it's any better, but at least it doesn't seem to be a hardware issue like some are describing. (Well obviously it's not since AD2P works in Winmo!)
slow88lx said:
I just paired my headphones up a few minutes ago and was about to make a thread about the choppiness. Glad to know I'm not the only one....but damn I guess I need go buy that 1/8th-to-miniUSB cable to plug in my bluetooth headphones directly to the phone.
But Android is STILL worth it! Can't wait until they figure out AD2P!
Click to expand...
Click to collapse
Thanks for sharing - I'm just curious, is your issue the play, stop, play around 1 second intervals?
Oh also, in the meantime here you go
http://www.amazon.com/OEM-3-5mm-Hea...2?ie=UTF8&s=electronics&qid=1266872487&sr=8-2
$4 This is the best one I've found that works without the left or right channel fading out. Annoying because it's bulky but it has a port for charging, in case you use it in the car also Let me know if you are brave and try other ones though
berardi said:
Thanks for those links, I'm going to try playing around with unpairing, repairing, changing options to see if I can get it working. I'll report back with any results.
One thing I noticed was the posters don't seem to be having exactly the same issue I'm having. The music plays for about 1 second on 1 second off, intermittent consistently, repeatedly. The audio quality is perfect, just intermittent. There is no crackling as many describe. Not that it's any better, but at least it doesn't seem to be a hardware issue like some are describing. (Well obviously it's not since AD2P works in Winmo!)
Click to expand...
Click to collapse
No, it's a kernel issue - we don't initialize a high speed serial port (ttyHS0) on the system. Just low speed (ttyMSM0). out of curiosity, does your audio play:
second 1 - pause - second 2
OR
second 1 - pause - second 3?
IF you play a super lo-fi file (maybe 16kbps mono mp3) does it play correctly? the speed limit on the low speed port is 115200 bps. think 14.4 modem.
mrkite38 said:
No, it's a kernel issue - we don't initialize a high speed serial port (ttyHS0) on the system. Just low speed (ttyMSM0). out of curiosity, does your audio play:
second 1 - pause - second 2
OR
second 1 - pause - second 3?
IF you play a super lo-fi file (maybe 16kbps mono mp3) does it play correctly? the speed limit on the low speed port is 115200 bps. think 14.4 modem.
Click to expand...
Click to collapse
I'll play with it more tonight, but I was using Droidlive to stream a 64 KB AAC+ stream. I also tried an mp3 file (sorry I can't remember the bit rate but it was at leat 92 kbps) and the result was identical, no better no worse.
As best as I can remember the result was one second of sound, one second of pause, one second of sound, and so on. Also of note, the audio was slowed, not chopped off. In other words: I was listening to an audiobook and if the sentence was "I am reading this sentence to you right now" it would output "I am" *pause* "reading this" *pause* "sentence to" *pause* "you right" *pause* "now".
I'll see what results I can produce tonight playing with settings and file formats. any idea where I can even find a 16kbps mono mp3?
mrkite38 said:
No, it's a kernel issue - we don't initialize a high speed serial port (ttyHS0) on the system. Just low speed (ttyMSM0). out of curiosity, does your audio play:
second 1 - pause - second 2
OR
second 1 - pause - second 3?
IF you play a super lo-fi file (maybe 16kbps mono mp3) does it play correctly? the speed limit on the low speed port is 115200 bps. think 14.4 modem.
Click to expand...
Click to collapse
Interesting. I'll try a lo-fi file and report back what happens tonight.
berardi said:
I'll play with it more tonight, but I was using Droidlive to stream a 64 KB AAC+ stream. I also tried an mp3 file (sorry I can't remember the bit rate but it was at leat 92 kbps) and the result was identical, no better no worse.
As best as I can remember the result was one second of sound, one second of pause, one second of sound, and so on. Also of note, the audio was slowed, not chopped off. In other words: I was listening to an audiobook and if the sentence was "I am reading this sentence to you right now" it would output "I am" *pause* "reading this" *pause* "sentence to" *pause* "you right" *pause* "now".
I'll see what results I can produce tonight playing with settings and file formats. any idea where I can even find a 16kbps mono mp3?
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Click to collapse
lol - i'll post one if someone else doesn't.
EDIT: ok, here's a few different samples, sorry for zip but mp3s aren't allowed, go figure
mrkite38 said:
lol - i'll post one if someone else doesn't.
EDIT: ok, here's a few different samples, sorry for zip but mp3s aren't allowed, go figure
Click to expand...
Click to collapse
thanks I'll try this in the morning. But yeah, it plays 1 sec skips 1 sec, and so on like I mentioned before. Will try the low bit rate and report back!
The high speed serial bus code is complete, it's just the clock, (we think) that needs to be worked out.
mssmison said:
The high speed serial bus code is complete, it's just the clock, (we think) that needs to be worked out.
Click to expand...
Click to collapse
Awesome!!!
mssmison said:
The high speed serial bus code is complete, it's just the clock, (we think) that needs to be worked out.
Click to expand...
Click to collapse
Woohoo!!!

Mate 10 Pro LDAC Playback Quality

Hi, got a Huawei Mate 10 Pro BLA-L29 8.0.0.136(C185) and a Shanling M0 as a Bluetooth receiver. When I get them connected using LDAC, there are two menu sections where I can set the audio quality to be fed to the M0. One is the Developer Options where, apart from selecting the BT codec itself, I can set sample rate at 44.1 to 96 kHz, bit depth of 16 to 32 bits per sample, and stream bitrate at 330 to 990 kbps. These settings behave in a weird manner, always reverting to default every time I disconnect the BT or even while it's connected. The other instance is the properties of an individual BT device where I can set the LDAC playback quality to either "Optimized for audio quality" or "Balanced audio and connection quality".
Problem: if the BT device is "Optimized for audio quality", I only get decent transmission if stream bitrate is set to 660 kbps or lower in the Developer Options. Inversely, if the latter is set to 990 kbps, it only works decently if the device-specific setting is "Balanced audio and connection quality". If both are set to maximum audio quality, the playback starts gagging violently, interruptions happening up to twice a second if the phone is active and like once every five to ten seconds if the screen is off (the two devices 5 inches away from each other with nothing but air between them).
I brought the Shanling M0 to the nearest Sony store and paired it with a demo phone with LDAC audio quality set to 32/96 at 990 kbps and it worked like a charm without a single hiccup.
Anyone else has this issue and/or aware of a fix?
I have been to a number of stores since the original post and was able to pair my Shanling M0 to various devices:
1. Huawei P20, Android 8.1, Bluetooth 4.2 - same problem.
2. Samsung Galaxy S9+, Android 8.0, Bluetooth 5.0 - no problem.
3. Samsung Galaxy A6, Android 8.0, Bluetooth 4.2 - no problem.
Apparently, Android version is not responsible for the malfunction, neither is Bluetooth version. It's the manufacturer.
Crap, crossing fingers about having this issue fixed. Have you reported it to Huawei customer service and Shanling's one ?
Thank you for the feedback. I'm interested in this small DAP (nostalgic for my beloved Sansa Clip), even if I'm quite sure I probably won't use the Shanling M0 as BT receiver.
Scalpos said:
I'm interested in this small DAP (nostalgic for my beloved Sansa Clip), even if I'm quite sure I probably won't use the Shanling M0 as BT receiver.
Click to expand...
Click to collapse
If you ask me, you should just grab your money and go get it, because it works fine with other phones than Huawei. Even with mine, if I set it to "Balanced audio and connection quality", it's doing great. Actually, the LDAC standard bitrate of 660 kbps is amply sufficient to deliver music from major streaming services like Google Play Music. Whatever the problem is, I don't believe it's Shanling's fault, because the intensity of gagging depends heavily on whether the phone screen is on or off, which has nothing to do with connection quality.
As to the DAP itself, I find its sound signature and stage presentation nothing short of amazing, at least on par with my favorite Hidizs AP100 and far better than vivo Xplay6 or anything else I tried. Sansa Clip+ is nowhere near. The way I feel right now, I'm far more likely to ditch the Huawei phone than the Shanling DAP, because there are reasonable alternatives to the former, but not the latter.
anton79ru said:
If you ask me, you should just grab your money and go get it, because it works fine with other phones than Huawei. Even with mine, if I set it to "Balanced audio and connection quality", it's doing great. Actually, the LDAC standard bitrate of 660 kbps is amply sufficient to deliver music from major streaming services like Google Play Music. Whatever the problem is, I don't believe it's Shanling's fault, because the intensity of gagging depends heavily on whether the phone screen is on or off, which has nothing to do with connection quality.
As to the DAP itself, I find its sound signature and stage presentation nothing short of amazing, at least on par with my favorite Hidizs AP100 and far better than vivo Xplay6 or anything else I tried. Sansa Clip+ is nowhere near. The way I feel right now, I'm far more likely to ditch the Huawei phone than the Shanling DAP, because there are reasonable alternatives to the former, but not the latter.
Click to expand...
Click to collapse
Indeed, I started following Head-fi.org's thread few weeks ago, this device looks great.
I currently own a Cowon Plenue D for more than 2 years, I'm quite happy with it: relatively small, great battery life and sound. But I'd like to have a smaller good DAP I can bring with me when I run, or simply don't want to suck smartphone's battery. I bought a Sansa Sport Clip+ (BT DAP) one year ago, crappiest DAP I ever met...
What's your battery life experience using BT head/earphones wiht this DAP ?
Hello there,
Just to share the using LDAC experience with a mate 10 pro (BLA-L29 145 (C432))
I have a Sony headsets (WH-1000XM2) and it works just fine, I'm able to use LDAC perfectly, sound is very good but you need to be close to the phone, 5m apart and it starts to break.
I know its not the same situation, but this is my experience.
Best regards.
And the volume?
Mine with my sennheiser 4.50 BT NC is very low..
Scalpos said:
What's your battery life experience using BT head/earphones wiht this DAP ?
Click to expand...
Click to collapse
I have no such experience, I only use M0 as a BT receiver with wired IEM connected to it. I never even bothered to measure battery life, since it's more than two days of my regular use, i connect it to a USB port earlier than I need to charge.
sartan said:
And the volume? Mine with my sennheiser 4.50 BT NC is very low.
Click to expand...
Click to collapse
If you want to control volume on your headphones, you need to set it to maximum on the DAP. The rest of it will be the responsibility of your headphones' integrated amp - if the volume's too low, then it's just not powerful enough, there is no way a bluetooth source can fix that, as it does not transmit loudness.
sadmam said:
Hello there,
Just to share the using LDAC experience with a mate 10 pro (BLA-L29 145 (C432))
I have a Sony headsets (WH-1000XM2) and it works just fine, I'm able to use LDAC perfectly, sound is very good but you need to be close to the phone, 5m apart and it starts to break.
I know its not the same situation, but this is my experience.
Best regards.
Click to expand...
Click to collapse
Thank you very much indeed, because that's exactly the diagnostic step that I missed. Need to try that to locate the problem more precisely. Are you sure that the LDAC playback quality setting in your bluetooth device options was at "Optimized for audio quality"?
anton79ru said:
I have no such experience, I only use M0 as a BT receiver with wired IEM connected to it. I never even bothered to measure battery life, since it's more than two days of my regular use, i connect it to a USB port earlier than I need to charge.
If you want to control volume on your headphones, you need to set it to maximum on the DAP. The rest of it will be the responsibility of your headphones' integrated amp - if the volume's too low, then it's just not powerful enough, there is no way a bluetooth source can fix that, as it does not transmit loudness.
Click to expand...
Click to collapse
With other smartphone is working perfectly and with strong volume.
Where is possible to maximize the volume on the DAP? Simply with volume buttons?
Thanks.
sartan said:
With other smartphone is working perfectly and with strong volume.
Where is possible to maximize the volume on the DAP? Simply with volume buttons?
Click to expand...
Click to collapse
I would suggest that you go to the Shanling M0 thread on head-fi, there's a company representative on that forum who's very cooperative, you should describe your issue to him. I wish I could give you a hand, but my experience is limited to operating the volume wheel on the DAP.
anton79ru said:
Thank you very much indeed, because that's exactly the diagnostic step that I missed. Need to try that to locate the problem more precisely. Are you sure that the LDAC playback quality setting in your bluetooth device options was at "Optimized for audio quality"?
Click to expand...
Click to collapse
Yes... it has to be... or it wont use LDAC at all... it will use APTX or something else... LDAC is only used on the setting "Optimised for audio quality".

Limit the max sample rate to 48kHz?

Hi, is there a way of limiting the sample rate to 48kHz in Android 10 (AOSP Rom)?
I'm using a USB-C to headphone dongle and according to the developer, Viper4Android doesn't support a sample rate greater than 48kHz, so my current driver status is abnormal. Note that my bluetooth headphones work fine.
In system/etc, I have a audio_policy.conf, but not an audio_policy_configuration.xml ( https://source.android.com/devices/audio/implement-policy )
Any alternative ways of limiting the sample rate would be much appreciated.
The mixer in Android downsamples everything to 44100Hz anyway, so that is probably not the issue.
It won't ever go past the above value other than the case where you use an application that creates a pass-through between the DAC (whether that is the internal one by Qualcomm or an external dongle one) and the output, thus offering bitperfect quality
Dariusdd said:
The mixer in Android downsamples everything to 44100Hz anyway, so that is probably not the issue.
It won't ever go past the above value other than the case where you use an application that creates a pass-through between the DAC (whether that is the internal one by Qualcomm or an external dongle one) and the output, thus offering bitperfect quality
Click to expand...
Click to collapse
Thanks for your response - do you have any other ideas why viper doesn't work?
Absolutely none, it's old and unmaintained as far as I remember. I am unsure of the compatibility of the newer fork of it as well. Good luck getting it to work
I mean you can try jdsp
Yeah James DSP does work actually, but it's missing a few features. It seems the only way of fixing this issue is using a passive headphone adapter, which aren't that common on amazon at least.

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