Develop Reference

Android screen AND audio record library

I need some way to record android screen AND audio. I have seen some libraries that record screen, but I need audio too. Does such a thing exists? Anybody knows any library to do that? I know something similar is available for iOS (ReplayKit), but seems that is not available for Android. Any alternative for Android?

The only thing in the Android SDK that allows you to record the screen are the media projection APIs. They do not include sound. However, there is nothing stopping you from recording sound yourself and attempting to merge the two. The problem is in getting the audio to accurately sync up with the video.

You can try looking into https://github.com/saki4510t/ScreenRecordingSample.
It does record the screen's video and audio from the microphone.

Audio quality issue when recorded with MediaRecorder

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

Recording audio with a mic on Android

I am developing an Android application which is supposed to capture audio with the built-in mic of the smartphone and save it.
For the further processing purposes I would like to have some control over the quality of audio captured. For instance, to my knowledge some smartphones have high-quality audio recording mode and I would like to make use of it, if that is possible.
I am aware of mediaRecorder, but I am not sure how to use its methods or input arguments to get the best quality of sound possible. I would be very grateful if somebody could point out that for me or provide references to other libraries that allow to adjust the quality of recorded sound.

Android audio and voice processing

I am new to android and presently doing android voice recording application. I want top know which format is best for saving audio file in android. (i.e RAW-AMR or 3gp or mp4).So rhat we can hear playback sound loudly in device.
Is there any alternative way to increase audio sound through voice processing in android.
Thanks in advance.

Question: Which bear is best? Answer: Black Bear
Seriously though, you would need to state your criteria for the audio file for us to make a codec recommendation. Does it need to be portable? Best compression? Highest fidelity?
The codec that you choose has no affect on the loudness of audio that will be played over the device, so this should not factor into your criteria.
Is there an alternative way to increase audio?
Yes, if you are recording audio from the microphone then you can amplify the audio data before you save it to a file.
Let an audio sample from the microphone be represented by the function:
f(t)
Amplification is achieved by multiplying the audio sample by some factor A
A * f(t)

You can use AGC(Automatic Gain Control) module from WebRTC to increase sound level.
I didn't find any simple Java API yet. You can use C++ API via JNI.
Have a look here, WebRTC AGC (Automatic Gain Control) .

I want top know which format is best for saving audio file in android.
To save voice audio on Android (or any other platform), take a look at Opus. It's a free, state-of-the-art audio codec that also supports voice mode.

Improve Android Audio Recording quality?

Is there any way to record audio in high quality?
And how can I read information that user is saying something? In Audio Recording application you can see such indicator (I don't know the right name for it).

At the moment, a big reason for poor audio quality recording on Android is the codec used by the MediaRecorder class (the AMR-NB codec). However, you can get access to uncompressed audio via the AudioRecord class, and record that into a file directly.
The Rehearsal Assistant app does this to save uncompressed audio into a WAV file - take a look at the RehearsalAudioRecord class source code.
The RehearsalAudioRecord class also provides a getMaxAmplitude method, which you can use to detect the maximum audio level since the last time you called the method (MediaRecorder also provides this method).

For recording and monitoring: You can use the sound recorder activity.
Here's a snippet of code:
Intent recordIntent = new Intent(
MediaStore.Audio.Media.RECORD_SOUND_ACTION);
startActivityForResult(recordIntent, REQUEST_CODE_RECORD);
For a perfect working example of how to record audio which includes an input monitor, download the open source Ringdroid project: https://github.com/google/ringdroid
Look at the screenshots and you'll see the monitor.
For making the audio higher quality, you'd need a better mic. The built in mic can only capture so much (which is not that good). Again, look at the ringdroid project, glean some info from there. At that point you could implement some normalization and amplification routines to improve the sound.

I give you a simple answer.
for samplerate, about the quality, 48000 is almost the same as 16000.
for bitrate, about the quality, 96Kbps is much better than 16Kbps.
you can try stereo(channelCount = 2), but make little change.
So, for android phones, just set the audio bit rate bigger, you will get the better quality.