AudioMixer-android

A simple android library for processing audio and mixing multiple audios parallelly or sequentially, made with android native media APIs (MediaCodec, MediaFormat, MediaMuxer) and JAVA.

Features

• Mixing multple audios parallely or sequentially or processing single audio
• Trimming audio
• Adding an audio to another audio at specific time
• Changing sample-rate, bit-rate, channel(mono to stereo and vice versa) of audio
• Controlling volume of audio
• Making an audio file without any real audio data
• Making audio file by providing audio data
• Merging audios with video
• Fast transcoding to AAC
• Hardware accelerated

Requirements

• Minimum API level 18

Installation

Step 1. Add the JitPack repository to your build file

allprojects {
	repositories {
		...
		maven { url 'https://jitpack.io' }
	}
}

Step 2. Add the dependency

dependencies {
	        implementation 'com.github.ZeroOneZeroR:android_audio_mixer:v1.1'
	}

Sample Usage

            AudioInput input1 = new GeneralAudioInput(input1Path);
            input1.setVolume(0.5f); //Optional
            // It will produce a blank portion of 3 seconds between input1 and input2 if mixing type is sequential.
	    // But it will does nothing in parallel mixing.
            AudioInput blankInput = new BlankAudioInput(3000000); //
            AudioInput input2 = new GeneralAudioInput(context, input2Uri, null);
	    input2.setStartTimeUs(3000000); //Optional
            input2.setEndTimeUs(9000000); //Optional
	    input2.setStartOffsetUs(5000000); //Optional. It is needed to start mixing the input at a certain time.
            String outputPath = Environment.getDownloadCacheDirectory().getAbsolutePath()
            +"/" +"audio_mixer_output.mp3"; // for example
            final AudioMixer audioMixer = new AudioMixer(outputPath);
            audioMixer.addDataSource(input1);
            audioMixer.addDataSource(blankInput);
            audioMixer.addDataSource(input2);
            audioMixer.setSampleRate(44100); // Optional
            audioMixer.setBitRate(128000); // Optional
            audioMixer.setChannelCount(2); // Optional //1(mono) or 2(stereo)
	    
	    // Smaller audio inputs will be encoded from start-time again if it reaches end-time
            // It is only valid for parallel mixing
            //audioMixer.setLoopingEnabled(true);
            audioMixer.setMixingType(AudioMixer.MixingType.PARALLEL); // or AudioMixer.MixingType.SEQUENTIAL
            audioMixer.setProcessingListener(new AudioMixer.ProcessingListener() {
                @Override
                public void onProgress(final double progress) {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            progressDialog.setProgress((int) (progress * 100));
                        }
                    });
                }
                @Override
                public void onEnd() {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Toast.makeText(context, "Success!!!", Toast.LENGTH_SHORT).show();
                            audioMixer.release();
                        }
                    });
                }
            });
            
            
            //it is for setting up the all the things
            audioMixer.start();
            
            /* These getter methods must be called after calling 'start()'*/
            //audioMixer.getOutputSampleRate();
            //audioMixer.getOutputBitRate();
            //audioMixer.getOutputChannelCount();
            //audioMixer.getOutputDurationUs();
            
            //starting real processing
            audioMixer.processAsync();
            
            // We can stop the processing immediately by calling audioMixer.stop() when we want.
            
            // audioMixer.processSync() is generally not used.
            // We have to use this carefully.
            // Tt will do the processing in caller thread
            // And calling audioMixer.stop() from the same thread won't stop the processing

Merging audio with video and using external MediaMuxer

Also external MediaMuxer can be used for muxing through new AudioMixer(externalMediaMuxer). As for example, if we want to add audio with video, we have to pass the media-muxer which is currently being used for video muxing. MediaMuxer's starting, stopping, releasing must be handled externally. In this case, we must call AudioMixer.start() before MediaMuxer.start() and AudioMixer.processAsync() after MediaMuxer.start().

Custom AudioInput

You can implement AudioInput interface and make your own audio processing system.