I'm interested in implementing a a2dp audio sink.
The framework of choice so far for me is the bluetooth classes of Qt's QtMobility. I also heard a2dp is using l2cap.
Where can I get any more detailed specifications?
You can get all the adopted bluetooth specifications here
https://www.bluetooth.org/Technical/Specifications/adopted.htm
A2DP is part of this list.
I am not sure if QT provide you with the necessary APIs on l2cap to implement an a2dp sink by yourself.
Related
i am new to Linux and Bluetooth. i know that the standard implementation of the bluetooth protocol stack is bluez. I know that alsa is not supporting bluez anymore and if you want to use audio over bluetooth, you need pulseaudio. so pulseaudio should support HSP/HFP since version 6 and bluez 5.x. Know i was wondering if i can connect a usb-dongle to my hardwareboard (raspberryPi) there is a serial connection to the board. is that right? so the Dongle has the BT-STack and you can use alsa audio over USB like an USB HEadset?
i hope someone can help me.
The answering this vast addressable question is not that easy. I have few hints which will help you to narrow down.
BlueZ is user layer stack to communicate or use the functionality of Linux Kernel Bluetooth subsystem and provides helpers to developers.
USB Dongle itself doesn't have any stack and I don't really understand your question in that sense. To brief, USB Bluetooth Dongle is just the hardware device with Bluetooth functionalities. To make it functional, you need Linux Kernel Bluetooth system support enabled and either you can directly make use of "socket" system calls to pair,connect etc., or use BlueZ to develop applications with API's
BlueZ itself doesn't provide API's for developers, instead it makes use of the DBus to provide methods, properties and signals with vast range functionalities. Check here
If you interested in Audio Playback using Bluetooth, then you should register your media player and audio sink with BlueZ with according media DBus Interfaces.
To add, I am currently developing a framework library to wrap the DBus functionality provided by BlueZ for friendly development of applications. Check this repo and it is currently in initial development phase.
I want to develop the application to input the voice from the microphone of the Bluetooth headset and to output into the Bluetooth speaker.
I think that use of HFP to input and A2DP to output.
The two profile can be used at the same time?
I'm interested in this as well. From what I can find, it sounds possible but I've yet to see many hardware vendors specifically market it as a feature.
Creative recently released their BT-W2 bluetooth dongle that supports what they're calling a "voice-back channel". Might be similar to what we're talking about but it's hard to find tech specs that confirm it.
Below is a link to some documentation I found on the Bluetooth SIG website that appears to support the fact that it's possible. Maybe it'll help you:
https://www.bluetooth.org/docman/handlers/DownloadDoc.ashx?doc_id=296662
I am trying to identify which android phones support Bluetooth Low Energy and I am a bit confused on whether or not a device with BTv4.0+ is BLE compatible.
To be more precise, I am looking at the device Samsung Galaxy J5. According to http://www.gsmarena.com/samsung_galaxy_j5-7184.php, the bluetooth version is 4.1 but it doesn't mention anything about BLE.
According to the bluetooth specification:
"Bluetooth Low Energy (LE) (also called Bluetooth Smart or Version 4.0+ of the Bluetooth specification) is the power- and application-friendly version of Bluetooth that was built for the Internet of Things (IoT).". According to this I would presume that 4.0+ is BLE.
However if you see the specs of Samsung Galaxy S6 (http://www.gsmarena.com/samsung_galaxy_s6-6849.php) it mentions that it supports both BTv4.1 and BLE. It therefore distinguishes the two BT specifications.
Any information would be very helpful
Edit
Additional reference information for interested parties:
from bluetooth.org: Two flavors of Bluetooth The two most prevalent implementations of the specification are Bluetooth Basic Rate/Enhanced Data Rate (BR/EDR), which was adopted as version 2.0/2.1, and Bluetooth with low energy (LE), which was adopted as version 4.0/4.1/4.2. Each implementation has different use cases and each implementation uses a different chipset to meet essential hardware requirements. Dual-mode chipsets are also available for applications that include both use cases. - See more at: https://www.bluetooth.com/specifications/bluetooth-core-specification#sthash.7X7IrtWy.dpuf
Instead of relying on gsmarena with unreliable information, you can refer to Bluetooth SIG's official information.
Based on this Bluetooth SIG's announcement and this one, BLE is a core specification of Bluetooth 4.0. Bluetooth 4.1 and 4.2 also adopt this core specification.
However, all this still depends on whether the manufacturers implement the firmware. To keep track of all this, Bluetooth SIG maintains a list of devices currently supporting any profile (for example GATT).
This crossed my mind myself as I saw it as a pointless advancement until I saw the low energy bLE (bluetooth low energy) side of it. In my pastime I tinker with various electronics and with various BLE 4.x modules and their pro's and cons are HUGE.
All in all, BLE is better as Bluetooth pretty much is battery drain on the most robust of phones.
I found a nice little writeup (pretty simple yet comprehensive) here: http://www.argenox.com/bluetooth-low-energy-ble-v4-0-development/library/a-guide-to-selecting-a-bluetooth-chipset/
Do cut my answer short, as the bag you linked shows it as being "NFC" compatible, then yet, it's BLE 4.x. (That's Near Field Communication i.e. similar to your your contactless bank card). The v4.1, A2DP which you mention is how one "audio device talks to another" via bluetooth. (dvanced Audio Distribution Profile).
If you're really bored, there's a long list of other profiles (other than A2D):
https://en.wikipedia.org/wiki/List_of_Bluetooth_profiles
Hope this helps!
Happy bluetoothing!
I'm working on university project that consists in audio speaker with bluetooth connected to mobile application.
I search a lot possibilities and bluetooth modules that comply my needs, but I have not found any module. I need a Bluetooth module that can receive audio and work in iOS and Android, but I see that a lot of modules with Classic Bluetooth (lowe than 3.0) do not work with iOS, but 3.0 and 4.0 version works with both but are not oriented in audio.
I'm looking for if someone can help me finding one kit with audio receive bluetooth for all plataforms intended for speaker and cheap. Or separately one bluetooth module receiver with 3.0 or upper version (because works in iOS), intended for audio streaming to an speaker, and with some UART pins (tx/rx for example) that can simplify the connection with a microcontroller. And one basic microcontroller oriented to bluetooth receives (with some bluetooth libraries) or simply to program with upp-level language. This microcontroller just receive the audio (bits) and send it to the speaker.
I read too that Smart Bluetooth or Bluetooth Low Energy works on iOS, but can't send audio, have small rate, but i think Smart Ready Bluetooth its possible, but not sure, I have just seen that supports Classic Bluetooth (oriented to audio) and Bluetooth Low Energy, it's possible sens audio with it?
In short, I'm looking for one module Bluetooth 3.o or 4.0 + EDR (that can send audio) for iOS and Android. I find HC05, CC2506X, or HC06 module, but I have read not works in iOS. And a basic microcontroller simply to program to receive this bluetooth audio to send in a speaker.
If someone know one basic kit, or useful information for me I would appreciate.
Thanks.
There is a bluetooth module BC127. it is available at Sparkfun. It dual mode. Means It can work as source and sink both.
Source means, It can Transmit Audio
Sink means, It can receive Audio
Here is link for https://learn.sparkfun.com/tutorials/understanding-the-bc127-bluetooth-module
Any Bluetooth module that acts as an A2DP Sink should work with both iOS and Android.
The specific Bluetooth version that the module implements is not important (as long as it's higher than 2.1), but it needs to be an A2DP Sink (which is only possible over classic Bluetooth)
I understand that Bluetooth profiles consist of other profiles and protocols. What I don't understand is exactly how Bluetooth devices interact with each other. For example, if you take any accessory that implements the A2DP profile and connect it to the iPad then the iPad will stream all audio output to it. This makes me believe that a profile is nothing more than a modular component in a well-defined eco-system. For instance, a web-browser can use any one of your choice of search-engines in the toolbar; would I be correct in saying that the iPad is the equivalent of the browser and the A2DP accessory is the equivalent of the search-engine? Would I also be correct in saying that the use of A2DP is entirely up to the device it's paired with? That is, Apple could have instead chosen (albeit unwisely) to make the iPad output only key-clicks and ring-tones to it, correct? So there's nothing inherent in the A2DP profile that says "All devices using the A2DP profile MUST output all audio to it" right?
I'm not 100% familiar with Bluetooth as a whole. I've been spending some time drafting a profile for BT Low-Energy, so someone might be able to provide insight on standard Bluetooth with a little more detail.
But, from what I understand, the profiles are essentially a large map of connected references. So the A2DP profile will have a list of attributes, or rather, a list of HEX values which point to attributes within the larger profile. These attribute are typically universally available to all profiles, but only implemented by the profile where they are needed. These attributes define some piece of information that is going to be transmitted. This profile needs to be on both device to communicate, because this allows to Bluetooth transmissions to be smaller by only referencing a commonly known definition of the data it is transmitting (rather than defining what the data is in every transmission like some communication types).
So for A2DP, the transmission might be something very simple like '0x1351458 0', which tails the device that whatever that profile attribute is, it's value is 0. So that attribute might be the "play" attribute, so setting to 0 might stop the music.
Again, this is how I understand Bluetooth profiles from the Low-Energy standpoint which tends to be more a transmission of state than actual data, so it might differ a bit with regular Bluetooth.
Bluetooth profiles are specifications of bluetooth protocols that are implemented on the host side in bluetooth protocol stack.
Following link by bluetooth.org will provide basics about bluetooth profiles
https://developer.bluetooth.org/TechnologyOverview/Pages/Profiles.aspx
Bluetooth Profiles are set of standard interoperable guidelines defined by bluetooth.org, to ensure interoperability between different bluetooth devices.
Bluetooth devices claiming to support bluetooth profiles, should get Bluetooth Qualification Board[BQB] certified for interoperability.
You can buy any device supporting A2DP and test with any tablet/computers[which has bluetooth A2DP profile supported].
A2DP is not specific to iPad. It is a generic profile that stands for Advanced Audio Distribution Profile for exchanging Audio between two bluetooth devices.