I am looking for a way to mix an audio into an already-playing mixed audio stream. For example, when a sound is being played half way through, I want to add in another sound to play together without interrupting the first sound to continue. I would also like to have an ability to withdraw a playing sound stream from the mixed playing stream. Going through Android's relevant document, I think that the only possible solution is to use native OpenSL ES via JNI to develop my own library where I can programmatically mix in/take out an audio stream from mixed audio streams. I would like to hear if anyone has a way to achieve it with less effort.
Thank you
Chris
Have you considered SoundPool?
http://developer.android.com/reference/android/media/SoundPool.html
Related
How can I play background audio, in Android, without interrupting the MediaPlayer playback, by either using MediaPlayer (preferred) or OpenSL ES?
I know SoundPool is able to play sound effects without interrupting any MediaPlayer playback, but the size is limited to 1M per effect, which is way to less. Not requesting audio focus, via AudioManager doesn't seem to work either, audio doesn't play at all in this case.
And in the case of OpenSL ES, all audio generally stops when I start to play a longer asset file. It's similar to the behaviour of SoundPool described above.
Edit from the comments:
I don't want to interrupt other music players, it's the background
audio of a game, which shall play without interrupting the, for
example, music of a player. Games like Subway Surfer, Clash Royale and
such seem to have this achieved somehow, but I could not achieve it
via OpenSL ES, or MediaPlayer.
In order to play sound in background you can use SoundPool, AudioTracks and OpenSlES.
Soundpool: Use small files and make a sequence. In my last project i use 148 sound files (all small) in different scenarios and played using soundpool. Make a list and play one by one or in parallel. Also in games usually you have a small set of sound for particular scenario and it loops. Best is soundpool for that. You can also perform some effects like rate change. Also ogg files are way small, so use them.
AudioTrack: You can use RAW PCM data in audio track. If you want you can extract pcm data using MediaExtractor from almost all formats and use it. But it will be a little work for you in your case, but it is really good (supports huge data, even live streaming).
OpenSLES: Apparently android uses opensles in background for all its purpose. So using it will help you a lot. But it's not easy to get everything done on it. You need to learn more for lesser work.
I have been deeply working on OpenSlES for about 20 days and still i will say for small purpose use soundpool, medium to high level implementation use AudioTracks and for kickass implementation use OpenSLES.
PS: It will be bad effect on your user if you play game sound in background while they are playing their music or their call. Personal experience.
Is there any way to intercept or just-read the audio output in android device?
I need to read the whole audio output in PCM from inside myActivity, including media player application in background, voice from calls, MediaPlayer istances inside myACtivity, etc., everything that's going to played by speakers. Actually, if it was possible to read them separately, would be great as well.
I tried with AudioRecord, giving it as audioSource parameter every constant found in MediaRecorder.AudioSource with no luck, should I try different audioSources?
Is it a so low-level task that has to be handled within native layer?
The visualizer class is helpful. I use it to playback immediately played audio here.
This audio comes in very low quality, however, so it's only really good for visualization.
I'm currently implementing a sound effect mixing on Android via OpenSL. I have an initial implementation going, but I've encountered some issues.
My implementation is as follows:
1) For each sound effect I create several AudioPlayer objects (one for each simultaneous sound) that uses an SLDataLocator_AndroidFD data source that in turn refers to an OGG file. For example, if I have a gun firing sound (lets call it gun.ogg) that is played in rapid succession, I use around 5 AudioPlayer objects that refer to the same gun.ogg audio source and also the same outputmix object.
2) When I need to play that sound effect, I search through all the AudioPlayer objects I created and find one that isn't currently in the SL_PLAYSTATE_PLAYING state and use it to play the effect.
3) Before playing a clip, I seek to the start of it using SLPlayItf::SetPosition.
This is working out alright so far, but there is some crackling noise that occurs when playing sounds in rapid succession. I read on the Android NDK newsgroup that OpenSL on Android has problems with switching data sources. Has anyone come across this issue?
I'm also wondering if anyone else seen or come up with a sound mixing approach for OpenSL on Android. If so, does your approach differ from mine? Any advice on the crackling noise?
I've scoured the internet for OpenSL documentation and example code, but there isn't much out there with regards to mixing (only loading which I've figured out already). Any help would be greatly appreciated.
This is probably not the best approach (creating many instances of audio players). Unfortunately the Android version (2.3) of OpenSL ES doesn't support SLDynamicSourceItf. Which would be similar to OpenAL's source binding interface. One approach would be to create multiple stream players. You would then search for a stream player that isn't currently playing and start streaming your sound effect to it from memory. It's not ideal but it's doable.
You should probably not use the ogg format for sound effects either. You're better off with WAV (PCM) as it won't need to be decoded.
Ogg is fine for streaming background music.
I'm building a buffering engine to play streams from url.. I need to buffering both mp3 and aac ( on device that can support it ) so I can't pass directly the url to MediaPlayer.. I tried this method: I have 2 synchronized thread, one that running creates some file with data from buffer and the second playing files created: the problem is that when mediaplayer switch from a file to another, there is a little gap... how can I remove it?? is very annoying...
Maybe my method is wrong, if so can anyone provide a working method without chopping sound??
Thank you very much in advance..
It seems you are trying to implement Gapless Playback. (Right ? )
Towards this you need to define level of Gapless Playback you want to achieve. Should it be across fileformats / codecs, audio attributes like sample rate, number of channels etc.
With your approach, you ll surely see gaps across different streams. (Fileformats , compression, audio attributes).
To achive true Gapless playback at application level (My Approach) you need to do the following
Implement custom stack, that would take the input files, decode it and produce pcm samples. This stack will have Parsers (MP3, AAC), and decoders (MP3, AAC..)
Pass pcm samples through resampler, to produce pcm samples having same sample rate.
Add buffering modules at input (File) and output (resampled pcm data).
Use AudioTrack class of Android SDK for playout.
If you stick to one fileformat, Codec and audio attributes, then at application level, you can concatenate all the files in the playlist and provide it to MediaPLayer for playback. (Since audio streams have less size, this solution can be practical. Only obstacle would be streams attributes. If the Audio OMX Components within Android Multimedia stack support dynamic reconfiguration, then this should be no issue at all)
Shash
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.