MediaCodec.Callback句柄来自MediaExtractor的IllegalStateException

Question

I am using MediaCodec in asynchronous mode to transcode a video based on the example by mstorsjo . With some video files I am getting IllegalStateException 's thrown when I call either MediaExtractor.advance() or MediaExtractor.getSampleTime() . Eg in my audio decoder:

MediaCodec decoder = MediaCodec.createDecoderByType(type);
decoder.setCallback(new MediaCodec.Callback() {
    public void onInputBufferAvailable(@NonNull MediaCodec codec, int index) {
        ByteBuffer decoderInputBuffer = codec.getInputBuffer(index);
        while (!mExtractorDone) {
            int size = mExtractor.readSampleData(decoderInputBuffer, 0);
            long presentationTimeUs = mExtractor.getSampleTime();
            boolean queuedInputBuffer = false;
            if (size >= 0) {
                codec.queueInputBuffer(
                        index,
                        0,
                        size,
                        presentationTimeUs,
                        mExtractor.getSampleFlags());
                queuedInputBuffer = true;
            }
            mExtractorDone = !mExtractor.advance();
            if (mExtractorDone) {
                queueEOS();
            }
            if (queuedInputBuffer) {
                    break;
            }
        }
    }
    ...
});
decoder.configure(inputFormat, null, null, 0);
decoder.start();

And similarly in my video decoder, which is run in a separate HandlerThread .

Is there a way I can catch all exceptions thrown in the MediaCodec.Callback and pass them back to the main awaitEncode function, so I can close everything and exit nicely? Should I be putting try catch s around every callback and then notify the main processing thread?

It would be great to figure out what is causing the original IllegalStateException , but I would also feel more comfortable knowing all problems with my video transcoder were being caught and explained to the user.

Answer 1

My best solution so far is to just wrap everything in a try catch block. I use a utility class that extends MediaCodec.Callback :

public abstract class SafeMediaCodecCallback extends MediaCodec.Callback {

    private final OnExceptionListener exceptionListener;

    public SafeMediaCodecCallback(OnExceptionListener exceptionListener) {
        this.exceptionListener = exceptionListener;
    }

    @Override
    public final void onInputBufferAvailable(@NonNull MediaCodec mediaCodec, int i) {
        try {
            onInputBufferAvailableSafe(mediaCodec, i);
        } catch (Exception exception) {
            handleException(exception);
        }
    }

    @Override
    public final void onOutputBufferAvailable(@NonNull MediaCodec mediaCodec, int i, @NonNull MediaCodec.BufferInfo bufferInfo) {
        try {
            onOutputBufferAvailableSafe(mediaCodec, i, bufferInfo);
        } catch (Exception exception) {
            handleException(exception);
        }
    }

    @Override
    public final void onError(@NonNull MediaCodec mediaCodec, @NonNull MediaCodec.CodecException e) {
        handleException(e);
    }

    @Override
    public final void onOutputFormatChanged(@NonNull MediaCodec mediaCodec, @NonNull MediaFormat mediaFormat) {
        try {
            onOutputFormatChangedSafe(mediaCodec, mediaFormat);
        } catch (Exception exception) {
            handleException(exception);
        }
    }

    private void handleException(Exception e) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            if (e instanceof CodecException) {
                CodecException codecExc = (CodecException) e;

                if (codecExc.isTransient()) {
                    // We'll let transient exceptions go
                    return;
                }
            }
        }

        exceptionListener.onException(e);
    }

    public abstract void onInputBufferAvailableSafe(@NonNull MediaCodec mediaCodec, int i);

    public abstract void onOutputBufferAvailableSafe(@NonNull MediaCodec mediaCodec, int i, @NonNull MediaCodec.BufferInfo bufferInfo);

    public abstract void onOutputFormatChangedSafe(@NonNull MediaCodec mediaCodec, @NonNull MediaFormat mediaFormat);

}

And then I can bubble exceptions back up to the top thread, and if we can't recover, kill all the threads, tidy up, and throw the original Exception .