Stereo recording using 2 external mic? - android

I am new to android development. I am trying to record an audio file in stereo mode. I have connected two external mics using 3.5mm jack.
The only problem is that my recording is done in mono mode. Both speakers sounds same. I am using inbuilt recorder app in my phone. Is stereo recording possible in smartphones using external mic? If so, do I need to code for stereo recording? And what libraries should I use?

Speak two different words, one to each microphone and try to figure out if both speakers are getting a "blend" of both sides or if you're only getting one of the mics, then post the results to get a more accurate answer.
Take a look at this question where the topic is discussed, maybe it has to do with the configuration in your source code.

Related

Multichannel Audio recording in Android

I have a multichannel microphone connected to an android phone (pixel 3) through usb. I'm trying to use MediaRecorder API for recording audio. However, there doesn't seem to be a way to setup multichannel recording with MediaRecorder even though Android USB audio documentation seems to say it allows multichannel input. I know recording multi channel audio is possible, as there are apps that already do that (see ntrack). I'm trying to figure out how to do this and hoping it doesn't involve writing usb driver (like these developers).
If you can see your microphones as separate input devices using audioService.getDevices(AudioManager.GET_DEVICES_INPUTS) then you can use the AAudio API (preferably using Oboe library) to access each of these microphones by opening stream for each.

How to implement functionality in Android Such that i can record through bluetooth mic and play it on the phones speaker/headphones

I am trying to implement an IOT project for which I need to hear sound from a Bluetooth mic and play it on headphones paired to phone how could i achieve this functionality in Android Studio, also I need to save the media to perform an algorithmic research on it
[Solved] This functionality could easily be achieved using Android libraries AudioRecord and AudioTrack as they work on raw data, These libraries are mostly used for analysing real time data of audiostreams.

Android audio record external jack

I would like to record the sound of the jack entry of my android phone. I've been searching about the Audio Capture class in Android, and i've found this:
https://developer.android.com/guide/topics/media/audio-capture.html
In the settings of this class, there are many options to choose the rec default mic, as this:
Set the audio source using MediaRecorder.setAudioSource(). You will probably want to use MediaRecorder.AudioSource.MIC.
What should I use to get the sound of the jack entry? Is there any example?
Thank you!
The API you provided is the correct one.
Calling mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC) (assuming the correct initialization of MediaRecorder as described here https://developer.android.com/guide/topics/media/camera.html -> Capturing Videos) will behave like this:
When you launch your app and start recording without any Jacks connected, phone's default microphones will be used. As soon as Jack microphone pin has detected a microphone connected, the system will use the Jack mic pin as an audio imput. Hovewer, you need to know that even though the audio record will have two channels, they will be identical, as Jack microphone can only record mono stream.

Play music via android speakers

I want to make an app that makes it possible to connect an iPod or mp3 player to my Android device and let the Android speakers function as external speakers.
The ideal situation would be to actually read from speaker output so I can connect a stereo mini jack cable.
Is it possible to read from the headset output with the Android SDK?
A second option would be to use a mono mini jack instead. I could maybe directly read from microphone and output as a music player. Although, having to use a mono mini jack would be a huge disadvantage, because most people don't own such a cable.
UPDATE
For my second option I found this link that would let me take a special adapter onto a stereo cable so the iPod output can go into the mic input. It's a TRRS adapter. This works, but still isn't the ideal solution to me. http://www.techlife.net/2012/12/add-an-audio-input-to-android.html
ANOTHER UPDATE
I did a test with only a mono cable, but it seems that the mic is not recognized, so I really need the TRRS adapter to make sure that the mic is on. I found some apps that can help me with measuring input volume. I think I can achieve my goal for myself with the adapter, but reading from headset output would be nicer and could actually result in building an app.
You need to understand some basic things...
Audio output lets you "take audio out of your device".
It's not audio input that would let you "insert audio signal into your device".
So the concept that you've presented cannot work, because this socket is not able to receive audio signal through normal stereo jack cable (and connector).
You could try to make it work with a device that supports the headphones/mic set (it's a different kind of 3.5 mm jack connector). It's so called TRRS (four-conductor). But to use it in your project you probably would need some cable/socket soldering and maybe even some sort of microporcessor to help processing the signals.

Recording audio from many source/microphones

I'm curious if it's possible to record audio from many sources and if not, what's the limitation.
Many current devices have two internal microphones (basically for noise reduction). On top of that it's possible to plug additional external one using audiojack. You can as well have another audio stream via bluetooth headset.
You are allowed to specify AudioSource in android but is it possible to do recording from many sources at the same time? I'm also interested how the situation look like on the iOS devices.

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