MediaCodec decode && encode on-the-fly

Question

I want convert some audio tracks from video files from AAC 5.1 (not only but for starting) to AAC 2 (just because ac3 not supported by MediaMuxer and vorbis and opus encoders has not hardware support in Pixel 2) and use callbacks for MediaCodec. I wrote code like that:

mExtractor = new MediaExtractor();
mExtractor.setDataSource(source.getPath());
mExtractor.selectTrack(trackNumber);

MediaFormat sourceMf = mExtractor.getTrackFormat(trackNumber);
mDecoder = MediaCodec.createDecoderByType(sourceMf.getString(MediaFormat.KEY_MIME));
mDecoder.setCallback(createCallbackDecoder());
mDecoder.configure(sourceMf, null, null, 0);

MediaFormat wantedMediaFormat = MediaFormat.createAudioFormat(MediaFormat.MIMETYPE_AUDIO_AAC, 44100, 2);
mEncoder = MediaCodec.createEncoderByType(MediaFormat.MIMETYPE_AUDIO_AAC);
mEncoder.setCallback(createCallbackEncoder());
mEncoder.configure(wantedMediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);

mMuxer = new MediaMuxer(saveTo.getPath(), MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);

public void start() {
        mDecoder.start();

And callbacks

Decoder:

@Override
public void onInputBufferAvailable(@NonNull MediaCodec codec, int index) {
    ByteBuffer byteBuffer = codec.getInputBuffer(index);
    Log.i(TAG, "onInputBufferAvailable: byteBuffer b/f readSampleData (decoder): " + byteBuffer);
    if (byteBuffer != null) {
        int offset = 0;
        long presentationTimeUs = 0;
        int flags;
        int size;
        if ((size = mExtractor.readSampleData(byteBuffer, offset)) > -1) {
            presentationTimeUs = mExtractor.getSampleTime();
            flags = mExtractor.getSampleFlags();
            mExtractor.advance();
        } else {
            flags = MediaCodec.BUFFER_FLAG_END_OF_STREAM;
        }
        try {
            codec.queueInputBuffer(index, offset, size, presentationTimeUs, flags);
            Log.i(TAG, "onInputBufferAvailable (decoder): SUCCESS");
        } catch (Exception e) {
            Log.e(TAG, "EXCEPTION (decoder)!\nonInputBufferAvailable (decoder): ", e);
            throw e;
        }
    } else {
        Log.e(TAG, "onInputBufferAvailable = null");
    }
}

@Override
public void onOutputBufferAvailable(@NonNull MediaCodec codec, int index, @NonNull MediaCodec.BufferInfo info) {
    ByteBuffer byteBuffer = codec.getOutputBuffer(index);
    Log.i(TAG, "onOutputBufferAvailable: byteBuffer with data (decoder): " + byteBuffer);
    if (byteBuffer != null) {
        ByteBuffer buffer2 = ByteBuffer.allocate(info.size);
        Log.i(TAG, "onOutputBufferAvailable: allocated byteBuffer (decoder): " + buffer2);
        buffer2.put(byteBuffer);
        MediaCodec.BufferInfo info2 = new MediaCodec.BufferInfo();
        info2.flags = info.flags;
        info2.size = info.size;
        info2.presentationTimeUs = info.presentationTimeUs;
        info2.offset = info.offset;
        if (mQueue.add(new Pair<>(buffer2, info2))) {
            Log.i(TAG, String.format("onOutputBufferAvailable (decoder): added in queue: %s\n%s %s %s %s", buffer2,
                      info2.offset, info2.size, info2.presentationTimeUs, info2.flags));
            codec.releaseOutputBuffer(index, false);
        }
    } else {
        Log.e(TAG, "onOutputBufferAvailable = null");
    }
}

@Override
public void onOutputFormatChanged(@NonNull MediaCodec codec, @NonNull MediaFormat format) {
    Log.i(TAG, String.format("onOutputFormatChanged (decoder): OLD=%s NEW=%s", codec.getInputFormat(), format));
    mEncoder.start();
}

Encoder:

@Override
public void onInputBufferAvailable(@NonNull MediaCodec codec, int index) {
    Log.i(TAG, "onInputBufferAvailable (encoder): index=" + index);
    Pair<ByteBuffer, MediaCodec.BufferInfo> mediaChunk;
    if ((mediaChunk = mQueue.poll()) != null) {
        Log.i(TAG, "onInputBufferAvailable (encoder): queue poll != null");
        ByteBuffer byteBuffer = codec.getInputBuffer(index);
        Log.i(TAG, "onInputBufferAvailable: byteBuffer b/f queue (encoder): " + byteBuffer);
        if (byteBuffer != null) {
            int offset = mediaChunk.second.offset;
            int flags = mediaChunk.second.flags;
            long presentationTimeUs = mediaChunk.second.presentationTimeUs;
            int size = mediaChunk.second.size;
            byteBuffer.put(mediaChunk.first);
            try {
                Log.i(TAG, String.format("onInputBufferAvailable (encoder): %s\n%s %s %s %s", mediaChunk.first,
                    mediaChunk.second.offset,
                    mediaChunk.second.size,
                    mediaChunk.second.presentationTimeUs,
                    mediaChunk.second.flags));
                codec.queueInputBuffer(index, offset, size, presentationTimeUs, flags);
                Log.i(TAG, "queueInputBuffer (encoder): SUCCESS");
            } catch (Exception e) {
                Log.e(TAG, "EXCEPTION (encoder)!\nonInputBufferAvailable (encoder): ", e);
                throw e;
            }
        }
    } else {
        Log.e(TAG, "onInputBufferAvailable (encoder): empty queue");
    }
}

@Override
public void onOutputBufferAvailable(@NonNull MediaCodec codec, int index, @NonNull MediaCodec.BufferInfo info) {
    ByteBuffer byteBuffer = codec.getOutputBuffer(index);
    Log.i(TAG, "onOutputBufferAvailable: byteBuffer from codec with data (encoder): " + byteBuffer);
    if (byteBuffer != null) {
        mMuxer.writeSampleData(mTrackNumber, byteBuffer, info);
        Log.i(TAG, "onOutputBufferAvailable (encoder): muxer written");
        if (info.flags == MediaCodec.BUFFER_FLAG_END_OF_STREAM) {
            finish();
        } else {
            codec.releaseOutputBuffer(index, false);
        }
    } else {
        Log.e(TAG, "onOutputBufferAvailable (encoder): buffer = null");
    }
}

@Override
public void onOutputFormatChanged(@NonNull MediaCodec codec, @NonNull MediaFormat format) {
    Log.i(TAG, String.format("onOutputFormatChanged (encoder): OLD=%s NEW=%s", codec.getInputFormat(), format));
    mTrackNumber = mMuxer.addTrack(format);
    mMuxer.start();
}

But on executing I got exception:

I/MediaCodec: MediaCodec will operate in async mode
I/MediaCodec: MediaCodec will operate in async mode
I/Codec: onInputBufferAvailable: byteBuffer b/f readSampleData (decoder): java.nio.DirectByteBuffer[pos=0 lim=8192 cap=8192]
I/Codec: onInputBufferAvailable (decoder): SUCCESS
I/Codec: onInputBufferAvailable: byteBuffer b/f readSampleData (decoder): java.nio.DirectByteBuffer[pos=0 lim=8192 cap=8192]
I/Codec: onInputBufferAvailable (decoder): SUCCESS
I/Codec: onInputBufferAvailable: byteBuffer b/f readSampleData (decoder): java.nio.DirectByteBuffer[pos=0 lim=8192 cap=8192]
I/Codec: onInputBufferAvailable (decoder): SUCCESS
I/Codec: onInputBufferAvailable: byteBuffer b/f readSampleData (decoder): java.nio.DirectByteBuffer[pos=0 lim=8192 cap=8192]
I/Codec: onInputBufferAvailable (decoder): SUCCESS
I/Codec: onInputBufferAvailable: byteBuffer b/f readSampleData (decoder): java.nio.DirectByteBuffer[pos=0 lim=8192 cap=8192]
I/Codec: onInputBufferAvailable (decoder): SUCCESS
I/Codec: onInputBufferAvailable: byteBuffer b/f readSampleData (decoder): java.nio.DirectByteBuffer[pos=0 lim=8192 cap=8192]
I/Codec: onInputBufferAvailable (decoder): SUCCESS
I/Codec: onInputBufferAvailable: byteBuffer b/f readSampleData (decoder): java.nio.DirectByteBuffer[pos=0 lim=8192 cap=8192]
I/Codec: onInputBufferAvailable (decoder): SUCCESS
I/Codec: onOutputFormatChanged (decoder): OLD={sample-rate=44100, mime=audio/mp4a-latm, channel-count=1, bitrate=0} NEW={sample-rate=48000, pcm-encoding=2, mime=audio/raw, channel-count=6}
I/Codec: onOutputBufferAvailable: byteBuffer with data (decoder): java.nio.DirectByteBuffer[pos=0 lim=0 cap=32768]
I/Codec: onOutputBufferAvailable: allocated byteBuffer (decoder): java.nio.HeapByteBuffer[pos=0 lim=0 cap=0]
I/Codec: onOutputBufferAvailable (decoder): added in queue: java.nio.HeapByteBuffer[pos=0 lim=0 cap=0]
    0 0 0 0
I/Codec: onInputBufferAvailable: byteBuffer b/f readSampleData (decoder): java.nio.DirectByteBuffer[pos=0 lim=8192 cap=8192]
I/Codec: onInputBufferAvailable (decoder): SUCCESS
I/Codec: onOutputBufferAvailable: byteBuffer with data (decoder): java.nio.DirectByteBuffer[pos=0 lim=0 cap=32768]
I/Codec: onOutputBufferAvailable: allocated byteBuffer (decoder): java.nio.HeapByteBuffer[pos=0 lim=0 cap=0]
I/Codec: onOutputBufferAvailable (decoder): added in queue: java.nio.HeapByteBuffer[pos=0 lim=0 cap=0]
    0 0 21333 0
I/Codec: onInputBufferAvailable: byteBuffer b/f readSampleData (decoder): java.nio.DirectByteBuffer[pos=0 lim=8192 cap=8192]
I/Codec: onInputBufferAvailable (decoder): SUCCESS
I/Codec: onOutputBufferAvailable: byteBuffer with data (decoder): java.nio.DirectByteBuffer[pos=0 lim=12288 cap=32768]
I/Codec: onOutputBufferAvailable: allocated byteBuffer (decoder): java.nio.HeapByteBuffer[pos=0 lim=12288 cap=12288]
I/Codec: onOutputBufferAvailable (decoder): added in queue: java.nio.HeapByteBuffer[pos=12288 lim=12288 cap=12288]
    0 12288 42666 0
I/Codec: onInputBufferAvailable: byteBuffer b/f readSampleData (decoder): java.nio.DirectByteBuffer[pos=0 lim=8192 cap=8192]
I/Codec: onInputBufferAvailable (decoder): SUCCESS
I/Codec: onOutputBufferAvailable: byteBuffer with data (decoder): java.nio.DirectByteBuffer[pos=0 lim=12288 cap=32768]
I/Codec: onOutputBufferAvailable: allocated byteBuffer (decoder): java.nio.HeapByteBuffer[pos=0 lim=12288 cap=12288]
I/Codec: onOutputBufferAvailable (decoder): added in queue: java.nio.HeapByteBuffer[pos=12288 lim=12288 cap=12288]
    0 12288 64000 0
I/Codec: onInputBufferAvailable (encoder): index=0
I/Codec: onInputBufferAvailable (encoder): queue poll != null
I/Codec: onInputBufferAvailable: byteBuffer b/f queue (encoder): java.nio.DirectByteBuffer[pos=0 lim=4096 cap=4096]
I/Codec: onInputBufferAvailable (encoder): java.nio.HeapByteBuffer[pos=0 lim=0 cap=0]
    0 0 0 0
I/Codec: queueInputBuffer (encoder): SUCCESS
I/Codec: onInputBufferAvailable (encoder): index=1
I/Codec: onInputBufferAvailable (encoder): queue poll != null
I/Codec: onInputBufferAvailable: byteBuffer b/f queue (encoder): java.nio.DirectByteBuffer[pos=0 lim=4096 cap=4096]
I/Codec: onInputBufferAvailable (encoder): java.nio.HeapByteBuffer[pos=0 lim=0 cap=0]
    0 0 21333 0
I/Codec: queueInputBuffer (encoder): SUCCESS
I/Codec: onInputBufferAvailable (encoder): index=2
I/Codec: onInputBufferAvailable (encoder): queue poll != null
I/Codec: onInputBufferAvailable: byteBuffer b/f queue (encoder): java.nio.DirectByteBuffer[pos=0 lim=4096 cap=4096]
I/Codec: onInputBufferAvailable (encoder): java.nio.HeapByteBuffer[pos=12288 lim=12288 cap=12288]
    0 12288 42666 0
E/Codec: EXCEPTION (encoder)!
    onInputBufferAvailable (encoder): 
    java.lang.IllegalArgumentException
        at android.media.MediaCodec.native_queueInputBuffer(Native Method)
        at android.media.MediaCodec.queueInputBuffer(MediaCodec.java:2450)
        at opensource.umnik.media2media.codec.SyncCodec$2.onInputBufferAvailable(SyncCodec.java:149)
        at android.media.MediaCodec$EventHandler.handleCallback(MediaCodec.java:1738)
        at android.media.MediaCodec$EventHandler.handleMessage(MediaCodec.java:1696)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
D/AndroidRuntime: Shutting down VM

at android.media.MediaCodec.queueInputBuffer(MediaCodec.java:2450) ← this is encoder's buffer

What I did wrong?

UPD: code updated some times. UPD2: more logs

Answer 1

The cause of the IllegalArgumentException is ultimately that you have specified a size of 12288 bytes for an input ByteBuffer that only has a capacity of 4096 bytes.

Note that, for the first two calls to queueInputBuffer() (encoder), you are not putting in any data; they are both 0-byte writes, therefor they are trivial, and they succeed. (Personally, I'd just skip the 0-byte writes).

The 3rd iteration is the first time you actually have some data to encode. But your byteBuffer.put(mediaChunk.first) isn't actually doing anything, because mediaChunk.first is already "played out". It has 0 bytes remaining. You need to "rewind" it before you do the put():

mediaChunk.first.position(0)

Of course, now the problem is, you have 12288 bytes to write, but the destination can only fit 4096 bytes, so the put() will undoubtedly throw. You must write a smaller amount. This will avoid the IllegalArgumentException.

As I mentioned in a comment, your decoded audio contains 6 channels of 5.1 audio. (`1024 samples x 2 bytes per sample x 6 channels == 12288). Your encoder would like 2048 samples of audio (at 2 bytes per sample; I assume you have configured the encoder for 1 channel/2 bytes per sample). This may be a good time to decide how you'd like to do the "5.1 -> mono" audio conversion; that will help reduce the amount of decoded audio that needs to be copied into the encoder.