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POTrying to build "Hello, world!" media player activity using Jelly Beans new low-level media API
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  1. POTrying to build "Hello, world!" media player activity using Jelly Beans new low-level media API
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    copied!<p>I'm trying to test the new low-level media API feautures, MediaExtractor and MediaCodec. I am following this guide:</p> <p><a href="http://dpsm.wordpress.com/2012/07/28/android-mediacodec-decoded/" rel="nofollow">http://dpsm.wordpress.com/2012/07/28/android-mediacodec-decoded/</a></p> <p>I put together this function, where <code>songsList.get(songIndex).get("songPath")</code> is a path to an mp3 file given by another function. </p> <pre><code> /** * Attempts at API level 16 implementation * * MediaExtractor, MediaCodec and AudioTrack to play audiofiles * * */ public void JBPlay(int songIndex) { String LOG_TAG="JB"; //AssetFileDescriptor sampleFD = getResources().openRawResourceFd(R.raw.sample); //AssetFileDescriptor sampleFD = getAssets().openFd(songsList.get(songIndex).get("songPath")); // getResources().openRawResourceFD(songsList.get(songIndex).get("songPath")); //Log.d("FD: ", sampleFD.toString()); MediaExtractor extractor; MediaCodec codec; ByteBuffer[] codecInputBuffers; ByteBuffer[] codecOutputBuffers; extractor = new MediaExtractor(); extractor.setDataSource(songsList.get(songIndex).get("songPath")); //extractor.setDataSource(sampleFD.getFileDescriptor(), // sampleFD.getStartOffset(), sampleFD.getLength()); Log.d(LOG_TAG, String.format("TRACKS #: %d", extractor.getTrackCount())); MediaFormat format = extractor.getTrackFormat(0); String mime = format.getString(MediaFormat.KEY_MIME); Log.d(LOG_TAG, String.format("MIME TYPE: %s", mime)); codec = MediaCodec.createDecoderByType(mime); codec.configure(format, null /* surface */, null /* crypto */, 0 /* flags */); codec.start(); codecInputBuffers = codec.getInputBuffers(); codecOutputBuffers = codec.getOutputBuffers(); extractor.selectTrack(0); // &lt;= You must select a track. You will read samples from the media from this track! boolean sawInputEOS=false; int inputBufIndex = codec.dequeueInputBuffer(1000);//1 second timeout ??? if (inputBufIndex &gt;= 0) { ByteBuffer dstBuf = codecInputBuffers[inputBufIndex]; int sampleSize = extractor.readSampleData(dstBuf, 0); long presentationTimeUs = 0; if (sampleSize &lt; 0) { sawInputEOS = true; sampleSize = 0; } else { presentationTimeUs = extractor.getSampleTime(); } codec.queueInputBuffer(inputBufIndex, 0, //offset sampleSize, presentationTimeUs,0); //sawInputEOS ? MediaCodec.BUFFER_FLAG_END_OF_STREAM : 0); if (!sawInputEOS) { extractor.advance(); } } AudioTrack audioTrack = null; BufferInfo info = null; Boolean sawOutputEOS=false; final int res = codec.dequeueOutputBuffer(info, 1000); if (res &gt;= 0) { int outputBufIndex = res; ByteBuffer buf = codecOutputBuffers[outputBufIndex]; final byte[] chunk = new byte[info.size]; buf.get(chunk); // Read the buffer all at once buf.clear(); // ** MUST DO!!! OTHERWISE THE NEXT TIME YOU GET THIS SAME BUFFER BAD THINGS WILL HAPPEN if (chunk.length &gt; 0) { audioTrack.write(chunk, 0, chunk.length); } codec.releaseOutputBuffer(outputBufIndex, false /* render */); if ((info.flags &amp; MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) { sawOutputEOS = true; } } else if (res == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) { codecOutputBuffers = codec.getOutputBuffers(); } else if (res == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) { final MediaFormat oformat = codec.getOutputFormat(); Log.d(LOG_TAG, "Output format has changed to " + oformat); audioTrack.setPlaybackRate(oformat.getInteger(MediaFormat.KEY_SAMPLE_RATE)); } // EDIT nov. 16: addition of play() causes crash! //audioTrack.play() } </code></pre> <p>It doesn't seem to throw off any major errors, but there's no sound and in the log there is a message for "libwvm.so not found" and "OMX_getExtensionIndex failed". Maybe someone has some ideas before I try to flod to code with logs. I'm running AVD with Jelly Bean version 4.1.2 and I can't debug from Eclipse, so I'm only using the logs to catch errors.</p> <p>EDIT nov. 16: I forgot the obvious audioTrack.play() function but this causes a crash, so it is commented out again.</p>
 

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