I'm joining audio only files.

the release() was called by:
release:208, DefaultDataSource (com.otaliastudios.transcoder.source)
release:62, FilePathDataSource (com.otaliastudios.transcoder.source)
releaseTrack:202, DefaultDataSource (com.otaliastudios.transcoder.source)
closeCurrentStep:203, Engine (com.otaliastudios.transcoder.engine)
getCurrentTrackTranscoder:216, Engine (com.otaliastudios.transcoder.engine)
transcode:371, Engine (com.otaliastudios.transcoder.engine)
call:150, Transcoder$1 (com.otaliastudios.transcoder)
call:140, Transcoder$1 (com.otaliastudios.transcoder)
run:237, FutureTask (java.util.concurrent)
runWorker:1112, ThreadPoolExecutor (java.util.concurrent)
run:587, ThreadPoolExecutor$Worker (java.util.concurrent)
run:818, Thread (java.lang)

then mExtractor and mMetadata were used later and IllegalStateException throw from android native

mMetadataApplied and mExtractorApplied should be updated when release.

protected void release() {
try {
mExtractor.release();
} catch (Exception e) {
LOG.w("Could not release extractor:", e);
}
try {
mMetadata.release();
} catch (Exception e) {
LOG.w("Could not release metadata:", e);
}
}