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.
Related
I’m struggling since days trying to obtain a raw audio stream from the microphone. I am trying different ways: the low-level JNI way with Oboe Library (either AAudio and OpenSL ES implementations) and the Android’s AudioRecord Java classes.
The problem I am facing is that I am not able to retrieve amplitudes near -/+1.0 while being sure of saturating the microphone input with a calibrated pure tone with such a high amplitude.
I think that the problem is that I am not able to effectively disable the signal preprocessing from AndroidOS (Automatic Gain Control or Noise Cancelling).
AutomaticGainControl.create(id).setEnabled(false)
(not working!)
Also, it seems that it is not possible also to disable any additional microphone rather than the one "selected" (done that as selecting the setPreferredDevice on AudioRecord instance). Used as audio source: unprocessed, mic, voice_recognition.
Is there anyway doing this or am I missing something?
Thank you
Which audio source are you using for your recording? VOICE_RECOGNITION or UNPROCESSED are mandated to not have any pre-processing enabled by default (i.e. see https://source.android.com/compatibility/10/android-10-cdd#5_11_capture_for_unprocessed) and therefore would allow you to check your signal path.
I have a cross-platform(iOS and Android) app where I will record audio clips then send it to the server to do some machine learning operations. In my iOS app, I use AVAudioRecorder for recording the audio. In the Android app, I use MediaRecorder for recording the audio. In the mobile initially, I use m4a format because of size constrictions. After reaching the server I will convert it to wav format before using it in the ML operations.
My Problem is, in iOS the AVAudioRecorder by OS default does a factor of Amplification to the raw audio data before we the developer get access to the raw data. But in Android, the MediaRecorder doesn't provide any sort of default Amplification to the raw data. In other words, in iOS I will never get the raw audio stream from the microphone whereas in Android I will always only get the raw audio stream from the microphone. The distinction is clearly visible if you can record the same audio in both iPhone and Android phones side by side with a common audio source, then import the recorded audio in Audacity for visual representation. I have attached a sample representation screenshot below.
In the image, the first track is the Android recording and the second track is from the iOS recording. When I hear both the audio through headphones I can vaguely distinguish them but when I visualize the data points, you can clearly see the difference in the image. These distinctions are bad for ML operations.
Clearly in the iPhone, there is a certain amplification factor involved which I would like to implement in the Android also.
Is anyone aware of the amplification factor? OR are there any other possible alternatives?
It's quite possible that the difference is that the effect of Automatic Gain Control.
You can disable this in your app's AVAudioSession by setting its mode to AVAudioSessionModeMeasurement which you do once in your application - usually at startup. This disables a great deal of input signal processing.
Reading your problem description, you might be better off enabling AGC on Android.
If neither of these yields results, you might want to gain scale both signals so they are just below clipping.
let audioSession = AVAudioSession.sharedInstance()
audio.session.setMode(AVAudioSessionModeMeasurement)
I'm writing an android app that plays an audio file and records what the phone is outputting simultaneously. When the recording is done, it would compare the recording against the original audio played and return whether they match and to what certainty.
I searched a lot and I found some libraries for audio fingerprinting, but they're mostly for music identification purposes.
Is there any libraries out there that I could use for this purpose? Would it make sense to write a custom algorithm for this?
You could compare the sound waves sample to sample (as numbers), then compute maximal, minimal, average difference, etc..
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.
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.