I want to record human voice on my Android phone. I noticed that Android has two classes to do this: AudioRecord and MediaRecorder. Can someone tell me what’s the difference between the two and what are appropriate use cases for each?
I want to be able to analyse human speech in real-time to measure amplitude, etc. Am I correct in understanding that AudioRecord is better suited for this task?
I noticed on the official Android guide webpage for recording audio, they use MediaRecorder with no mention of AudioRecord.
If you want to do your analysis while recording is still in progress, you need to use
MediaRecorder automatically records into a file.
AudioRecord has the disadvantage, that after calling
startRecording() you need to poll the data yourself from the
AudioRecord instance. Also, you must read and process the data fast enough such that the internal buffer is not overrun (look in the logcat output,
AudioRecord will tell you when that happens).
As I understand
MediaRecorder is a black box which gives compressed audio file on the output and
AudioRecorder gives you just raw sound stream and you have to compress it by yourself.
MediaRecorder gives you the max amptitude from last call of
getMaxAmplitude() method so you can implement a sound visualizer for example.
So in most cases
MediaRecorder is the best choice except those in which you should make some complicated sound processing and you need access to the raw audio stream.
AudioRecorderer first saves data in minBuffer then it is copied from there to the temporary buffer, in MediaRecorder it is copied to files.
In AudioRecorder we need the api setRecordPosition() to copy the saved data at required position, whereas in MediaRecorder the file pointer is does this job to set the position of the marker.
AudioRecorder can be used to those apps which run on an emulator this can be done by providing low sample rate such as 8000, while using MediaRecorder the audio cannot be recorded using emulator.
In AudioRecord the screen sleep after sometime, while in MediaRecorder the screen does not sleep.