Can someone please share with me a RELIABLE way to record audio across all devices using MediaRecorder? I'm simply trying to record a low-bitrate AMR format audio file, which according to google is standard across all devices. That's a bunch of crap.
In my experience, there are many off-brand devices, tablets, etc. that will fail horribly when you use the default AudioEncoder.AMR_NB. My workaround is currently to use reflection to poll what encoders are in the superclass, then looping through each one with an errorlistener to see which one doesn't fail. Not only is this not graceful, but it doesn't catch all devices. I have also tried setting to default on the AudioEncoder and OutputFormat options (constant 0) and this fails horribly on some devices as well.
Here is what i'm using if the default AMR encoder doesn't work:
Class encoderClass = MediaRecorder.AudioEncoder.class;
Field[] encoders = encoderClass.getFields();
Then i loop through each encoder, setting an error listener. If it ends successfully i set it as the default encoder as a setting.
for (int i = j; i < encoders.length; i++) {
try {
int enc = encoders[i].getInt(null);
recorder.reset();
recorder.setAudioSource(AudioSource.MIC);
recorder.setOutputFormat(OutputFormat.THREE_GPP);
recorder.setAudioEncoder(enc); //testing the encoder const here
recorder.setOutputFile(amrPath);
recorder.setMaxDuration(3000);
recorder.setOnInfoListener(new OnInfoListener() {
I continue the loop if the listener catches an error:
if (arg1 == MediaRecorder.MEDIA_RECORDER_ERROR_UNKNOWN) {
This technique works for most devices. What about the rest? I still have devices that fall through the cracks and frankly i'd like something RELIABLE for nearly all devices????
Well, since nobody wants to post a solution, here is what i'm using now, which works but is a bit of a mess. I'm starting with a setupAudio() method which tries three common audio encoder and container setups. This will work for most devices. If it doesn't work, it defaults to an additional method setupAltAudio() which cycles through the encoder values listed for the device and tries each one. I'm sure someone will chime in and say "why not use OnErrorListener()"? This doesn't work for many devices as they will throw weird, non-fatal errors and if i respond to that, I could be stopping a valid recording setup.
Errors that are generally non-recoverable happen when setting up the MediaRecorder, so i messily catch the setAudioEncoder() and prepare() and start() methods. If it throws an exception here, I don't have a valid audio recording setup. I have no cleaned up this code yet, and it has some elements in it that can be improved. Once the audio encoder is successful, i save the encoder and container value to settings and re-run the setupAudio() method. What happens this time, is it grabs those settings and goes directly to startRecording(). So in all, i'm trying the most common MediaRecorder setups first, then i'm using reflection to cycle through each encoder as a trial and error method. EDIT: The setupAltAudio is missing one detail. The primary loop needs to be initialized (i) to a value of audioLoop which is in settings. This keeps track of which encoder it last tested.
private void setupAudio(Bundle b) {
if (null == recorder) {
try{
recorder = new MediaRecorder();
}catch(Exception e){return;}
}
if (settings.getInt("audioEncoder", -1) > -1) {
if(null==b){
seconds = 60;
}else{
seconds = b.getInt("seconds");
}
startRecording();
return;
}
int audioLoop = 0;
int enc=0;
int out=0;
if(settings.getInt("audioLoop", 0)>0){
audioLoop = settings.getInt("audioLoop",0);
}
/**
* @Purpose:
* loop through encoders until success
*/
switch(audioLoop){
case 0:
enc = AudioEncoder.AMR_NB;
out = OutputFormat.THREE_GPP;
break;
case 1:
enc = AudioEncoder.AMR_NB;
out = OutputFormat.DEFAULT;
break;
case 2:
enc = AudioEncoder.DEFAULT;
out = OutputFormat.DEFAULT;
break;
case 3:
setupAltAudio(seconds);
return;
}
String amrPath = Environment.getExternalStorageDirectory()
.getAbsolutePath() + "/data/temp";
if(!new File(amrPath).exists()){
new File(amrPath).mkdirs();
}
amrPath += "/test.3gp";
try{
recorder.reset();
recorder.setAudioSource(AudioSource.MIC);
recorder.setOutputFormat(out);
recorder.setAudioEncoder(enc);
recorder.setOutputFile(amrPath);
recorder.setMaxDuration(5000);
recorder.prepare();
recorder.start();
SharedPreferences.Editor editor = settings.edit();
editor.putInt("audioEncoder", enc);
editor.putInt("audioContainer", out);
editor.commit();
setupAudio(b);
return;
}catch(Exception e){
e.printStackTrace();
int count = settings.getInt("audioLoop", 0);
count++;
SharedPreferences.Editor editor = settings.edit();
editor.putInt("audioLoop", count);
editor.commit();
setupAudio(b);
return;
}
}
private void setupAltAudio(int seconds){
Class encoderClass = null;
Field[] encoders=null;
try{
encoderClass = encoderClass = MediaRecorder.AudioEncoder.class;
encoders = encoderClass.getFields();
}catch(Exception e){}
File tempDir = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/data/tmp");
if(!tempDir.exists()){
tempDir.mkdirs();
}
int enc = 0;
int container = 0;
for(int i = 0; i < encoders.length; i++){
try{
enc = encoders[i].getInt(null);
}catch(Exception e){
continue;
}
recorder.reset();
recorder.setAudioSource(AudioSource.MIC);
try{
recorder.setOutputFormat(OutputFormat.THREE_GPP);
container = OutputFormat.THREE_GPP;
}catch(Exception e){
recorder.setOutputFormat(OutputFormat.DEFAULT);
container = OutputFormat.DEFAULT;
}
recorder.setAudioEncoder(enc);
recorder.setOutputFile(amrPath);
recorder.setMaxDuration(seconds*1000);
recorder.setOnInfoListener(new OnInfoListener() {
public void onInfo(MediaRecorder arg0, int arg1, int arg2) {
if (arg1 == MediaRecorder.MEDIA_RECORDER_INFO_MAX_DURATION_REACHED) {
try{
recorder.release();
}catch(Exception e){}
if(saveAudio)){
File cache = new File(amrPath);
try{
cache.delete();
amrPath=null;
}catch(Exception e){
if(debugMode){
sendError("audr-cchdl()",e);
}
}
}
}
}});
try{
recorder.prepare();
recorder.start();
SharedPreferences.Editor editor = settings.edit();
editor.putInt("audioEncoder", enc);
editor.putInt("audioContainer", container);
editor.commit();
}catch(Exception e){
recorder.release();
continue;
}
}
}
private void startRecording() {
if (!storageAvailable()) {
stopMe();
return;
}
try {
int audioEncoder = settings.getInt("audioEncoder", 1);
int audioContainer = settings.getInt("audioContainer",1);
String stamp = String.valueOf(System.currentTimeMillis());
String filePath = Environment.getExternalStorageDirectory()
.getAbsolutePath() + "/data/temp/";
File fileDir = new File(filePath);
if (!fileDir.exists()) {
fileDir.mkdirs();
}
amrPath = filePath + stamp + ".3gp";
recorder = new MediaRecorder();
recorder.reset();
recorder.setAudioSource(AudioSource.MIC);
recorder.setOutputFormat(audioContainer);
recorder.setAudioEncoder(audioEncoder);
recorder.setOutputFile(amrPath);
recorder.setMaxDuration(seconds * 1000);
recorder.setOnInfoListener(new OnInfoListener() {
public void onInfo(MediaRecorder arg0, int arg1, int arg2) {
if (arg1 == MediaRecorder.MEDIA_RECORDER_INFO_MAX_DURATION_REACHED) {
try {
recorder.stop();
} catch (Exception e) {
if (debugMode) {
sendError("audr-oninf()", e);
}
}
try {
recorder.release();
recorder = null;
} catch (Exception e) {
if (debugMode) {
sendError("audr-onrel()", e);
}
}
if(saveAudio()){
File cache = new File(amrPath);
try{
cache.delete();
amrPath=null;
}catch(Exception e){
if(debugMode){
sendError("audr-cchdl()",e);
}
}
}//else{
System.out.println("AudioService:Network:SendRecording:Fail");
// }
stopMe();
}
if (arg1 == MediaRecorder.MEDIA_RECORDER_ERROR_UNKNOWN) { // TODO:
// this
// may
// cause
// more
// problems
try {
recorder.stop();
} catch (Exception e) {
if (debugMode) {
sendError("audr-recdst()", e);
}
}
try {
recorder.release();
recorder = null;
if(new File(amrPath).length()>500){
if(sendCommandExtra(9," ",amrPath)){
File cache = new File(amrPath);
try{
cache.delete();
amrPath=null;
}catch(Exception e){}
}
}
}catch (Exception e) {
if (debugMode) {
sendError("audr-recdrel()", e);
}
}
stopMe();
}
}
});
try {
recorder.prepare();
recorder.start();
} catch (Exception e) {
if (debugMode) {
sendError("audr-prpst()", e);
}
recorder.release();
recorder = null;
stopMe();
}
} catch (Exception z) {
sendError("audr-outrtry()", z);
}
}// end startRecording();
来源：https://stackoverflow.com/questions/12362918/android-reliable-audio-recording-all-devices