I am trying to receive audio from headset's microphone using AudioRecord and playback the audio in real time to the Headphones using AudioTrack.I have implemented required code but the problem is that there is a disturbing Echo. I'm not using speakers and i'm using headphones. So,whats causing this echo? I used device's echocanceller which introduced in API level 11 and echo decreased but didn't go away.Im aware of audio latency in android devices but i can't understand how the delay may cause echo while i'm using headphones. Please guide me in the right direction.
I dont think there is a generic solution to this problem.
The reason are
1) the headphone quality may be bad, there may be internal coupling between the mic and headphones as the wires are very close in headphones
2) The echo canceler in android is not mandatory to be implemented by all devices. Try querying it first and settings. also the echo canceler implementation may vary from device to device
3) the latency affect the performance of the echo canceler a lot as the algorithm has to adapt to the delay and buffer that much audio.
4) lower versions of android have horrible delay problems acknowledged by google itself. You may want to move to higher android version as these things have been improved greatly.
In general any API that has some direct hardware access like mic and camera , the performance varies from device to device and performance cannot be guaranteed.
you may want to look at openSLES for better audio performance and easier integration to AEC library if you are thinking of integrating.
Please look at -
https://source.android.com/devices/latency_design.html
Low-latency audio playback on Android
https://www.youtube.com/watch?v=d3kfEeMZ65c
Hope this helps,
Regards,
Shrish
Related
The audio recorded by MediaRecorder in android App having so much noise.How can I use noise suppression to remove noice while recording.
I had the same problem of low audio quality while using MediaRecorder and finally figured out the correct working solution. Here are few modifications you need to do for good quality audio recordings:
save the file using .m4a extention.
and
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
mRecorder.setAudioEncoder(MediaRecorder.OutputFormat.AMR_NB);
mRecorder.setAudioEncodingBitRate(16*44100);
mRecorder.setAudioSamplingRate(44100);
Many solutions on stackoverflow would suggest .setAudioEncodingBiteRate(16) but 16 is too low to be considered meaningless .
Source: #Grant answer on stackoverflow very poor quality of audio recorded on my droidx using MediaRecorder, why?
Are you testing this with the emulator, or on an actual device (if so, which device)? The acoustic tuning (which includes gain control, noise reduction, etc) will be specific to a given platform and product, and is not something you can change.
Jellybean includes APIs to let applications apply certain acoustic filters on recordings, and a noise suppressor is one of those. However, by using that API you're limiting your app to only function correctly on devices running Jellybean or later (and not even all of those devices might actually implement this functionality).
Another possibility would be to include a noise suppressor in your app. I think e.g. Speex includes noise supressing functionality, but it's geared towards low-bitrate speech encoding.
https://developer.android.com/reference/android/media/audiofx/NoiseSuppressor.html
android voice recording - voice with background noice issue
Sending audio to the speaker for playback on Android is easy, but is it possible to get a copy of the actual final digital signal? Let's say I have 2 apps running "MyApp" and "SomeOtherApp". My app sends audio to the speaker, but so does "SomeOtherApp". "SomeOtherApp" is not my app - it's a 3rd party app. Is it possible to get a copy of the mixed audio signal which is played to the speaker by the OS? That is, the audio signal which is a mixture of the speaker signal from my app and the speaker signal from "SomeOtherApp".
To summarize: I am looking for a way to hook into the low-level audio path (HAL audio stream out - after mixing!) so I can get a copy of the "final" speaker signal (in real-time). Optimally, I would also like to hook into the low-level microphone path, but that's less of a concern right now.
Looks like the short answer is no.
Longer one is kinda. And sorta. But not really, as far as I know. Option 1: it might be a problem with respects to privacy. (not really a good option) Option 2: nobody thought it was needed, so did not build it into the system. Option 3: the amount of trouble shooting when programmers use the wrong source is just not worth it.
edit - You can, of course, record the input.
Checkthis one google example
Usage :
App will capture audio from android devices and playback on the same
device; the playback on speaker will be captured immediately
*
I wrote an app that records audio. Everything works. However, I am going to be using this app to record class room notes. How can I boost the input of the microphone to better capture all the noise? I wouldn't mind using root if I must. But wasn't sure if there was an API to do this.
Thanks all for reading!
If you are asking how to make the microphone more sensitive, I'm not sure. That would involve either operating the microphone at a higher voltage and/or hacking the drivers, neither of which are doable programatically, AFAIK. However, you could try amplifying the output by multiplying the output by some value (say 1.1 for 10% volume boost). Of course, the more you "amplify" the output, the more you will saturate the speaker (aka distort the audio). There are some signal processing techniques you can try to remove background noise and to isolate the paticular audio of interest, however, these things are merely processing improvements, not hardware upgrades. You can always try plugging in an external microphone into the headphone jack and using that to record the audio.
I know this isn't the answer you were hoping for, but I hope it helps.
I'm new to the android platform, and I wanted to develop an app that runs in the background and reads the microphone input, applies a transformation to it, and outputs the resulting audio to the speaker.
I'm wondering if there is any lag perceived by the user in this process, or if it's possible to do it in near-realtime so that the user can hear the transformed audio in sync with the ambient audio. Thanks!
Yes, users will hear a severe latency lag or echo with attempts at real-time audio on current unmodified Android devices using the provided APIs.
The summary is that Android devices are configured for fairly long audio buffers, which has been reported to be in the somewhere around the range of 100 to 400 milliseconds long, depending on the particular device and the Android OS version it is running. (Shorter buffers might be possible on Android devices on which one can build and install a modified custom build of the OS with your own custom audio drivers.)
(Humans hear echoes at somewhere around or above 25 mS. Audio buffers on iOS can be as short as 5.8 mS, so you may have better luck trying to develop your near-real-time audio processing on a different device platform.)
Audio processing on android isn't all the great, in fact to be honest, it sucks. The out-of-the-box latency on android devices for such things is pretty awful. You can however tinker with the NDK and try to put together something based on OpenSL ES which will have significantly low latency.
There is a similar StackOverflow question: Playing back sound coming from microphone in real-time
Some other helpful links:
http://arunraghavan.net/2012/01/pulseaudio-vs-audioflinger-fight/
http://www.musiquetactile.fr/android-is-far-behind-ios/
http://www.geardiary.com/2012/02/21/the-dismal-state-of-android-as-a-music-production-solution/
On the other side of the coin, android mic quality is way better than IOS quality. I have a galaxy s4 and a huawei very low end phone and both have a wonderful mic quality when recording.
I am trying to access, programatically, the data received from 2 microphones on Android devices.
This arises several questions:
Are there shipping Android devices with 2 microphones (e.g. for stereo recording)? I know there are devices with 2 microphones for echo cancellation / noise reduction, but as far as I could find they can be accessed as a single microphone for any programatic purpose.
Are there devices with a microphone / headphone socket supporting stereo external microphones?
Assuming any of the above is positive, is there a way to know what is the currently operating microphone setup?
I will appreciate any response!
Thanks,
Yoav
I only found out that e.g. once you plug in wired headset with microphone it doesn't matter what AudioSource you specify in you code - it always give you the audio stream form headset mic. I tried to get access to internal mic using AudioSource.CAMCORDER but without luck. I haven't tried with wireless (BT) headset though. However if I plugin headphones (w/o mic) it uses internal microphone. At least this is the outcome on my SGS2 with ICS 4.0. If somebody find a workaround I would be happy to hear as well.
I haven't tried yet, but maybe the Native Developement Tools can allow you to access any microphone you want from low level.
If you want to make things a bit simpler, you could consider using OpenSL ES for Android, although i have no idea if it provides low-level microphone control.