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andeoid硬件解码学习 （二）
Finally, I must say, finally, we get low-level media APIs in Android, the Android hardware decoding and encoding APIs are finally available. It was a thing since Android 4.1 in Google IO 2012, but until now, when a new Android version 4.2 has been released, those low-level APIs are still too hard to use. There‘re so many Android vendors, we can‘t even get the same results from all Google‘s Nexus devices.
Despite the annoyings, I still tried these APIs and prayed them to get better in next Android release, and next Android release would swallow market quikly.
I just finished a simple video player with the combination of MediaExtractor and MediaCodec, you may find the full project from my Github.
private MediaExtractor extractor;private MediaCodec decoder;private Surface surface;public void run() { extractor = new MediaExtractor(); extractor.setDataSource(SAMPLE); for (int i = 0; i < extractor.getTrackCount(); i++) { MediaFormat format = extractor.getTrackFormat(i); String mime = format.getString(MediaFormat.KEY_MIME); if (mime.startsWith("video/")) { extractor.selectTrack(i); decoder = MediaCodec.createDecoderByType(mime); decoder.configure(format, surface, null, 0); break; } } if (decoder == null) { Log.e("DecodeActivity", "Can‘t find video info!"); return; } decoder.start(); ByteBuffer[] inputBuffers = decoder.getInputBuffers(); ByteBuffer[] outputBuffers = decoder.getOutputBuffers(); BufferInfo info = new BufferInfo(); boolean isEOS = false; long startMs = System.currentTimeMillis(); while (!Thread.interrupted()) { if (!isEOS) { int inIndex = decoder.dequeueInputBuffer(10000); if (inIndex >= 0) { ByteBuffer buffer = inputBuffers[inIndex]; int sampleSize = extractor.readSampleData(buffer, 0); if (sampleSize < 0) { Log.d("DecodeActivity", "InputBuffer BUFFER_FLAG_END_OF_STREAM"); decoder.queueInputBuffer(inIndex, 0, 0, 0, MediaCodec.BUFFER_FLAG_END_OF_STREAM); isEOS = true; } else { decoder.queueInputBuffer(inIndex, 0, sampleSize, extractor.getSampleTime(), 0); extractor.advance(); } } } int outIndex = decoder.dequeueOutputBuffer(info, 10000); switch (outIndex) { case MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED: Log.d("DecodeActivity", "INFO_OUTPUT_BUFFERS_CHANGED"); outputBuffers = decoder.getOutputBuffers(); break; case MediaCodec.INFO_OUTPUT_FORMAT_CHANGED: Log.d("DecodeActivity", "New format " + decoder.getOutputFormat()); break; case MediaCodec.INFO_TRY_AGAIN_LATER: Log.d("DecodeActivity", "dequeueOutputBuffer timed out!"); break; default: ByteBuffer buffer = outputBuffers[outIndex]; Log.v("DecodeActivity", "We can‘t use this buffer but render it due to the API limit, " + buffer); // We use a very simple clock to keep the video FPS, or the video // playback will be too fast while (info.presentationTimeUs / 1000 > System.currentTimeMillis() - startMs) { try { sleep(10); } catch (InterruptedException e) { e.printStackTrace(); break; } } decoder.releaseOutputBuffer(outIndex, true); break; } if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) { Log.d("DecodeActivity", "OutputBuffer BUFFER_FLAG_END_OF_STREAM"); break; } } decoder.stop(); decoder.release(); extractor.release();}andeoid硬件解码学习 （二）
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