talk/app/webrtc/java/src/org/webrtc/MediaCodecVideoDecoder.java - platform/external/webrtc - Git at Google

 /*
  * libjingle
  * Copyright 2014 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
  *     this list of conditions and the following disclaimer in the documentation
  *     and/or other materials provided with the distribution.
  *  3. The name of the author may not be used to endorse or promote products
  *     derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 package org.webrtc;

 import android.media.MediaCodec;
 import android.media.MediaCodecInfo;
 import android.media.MediaCodecInfo.CodecCapabilities;
 import android.media.MediaCodecList;
 import android.media.MediaFormat;
 import android.os.Build;
 import android.view.Surface;

 import org.webrtc.Logging;

 import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.TimeUnit;

 // Java-side of peerconnection_jni.cc:MediaCodecVideoDecoder.
 // This class is an implementation detail of the Java PeerConnection API.
 // MediaCodec is thread-hostile so this class must be operated on a single
 // thread.
 public class MediaCodecVideoDecoder {
   // This class is constructed, operated, and destroyed by its C++ incarnation,
   // so the class and its methods have non-public visibility.  The API this
   // class exposes aims to mimic the webrtc::VideoDecoder API as closely as
   // possibly to minimize the amount of translation work necessary.

   private static final String TAG = "MediaCodecVideoDecoder";

   // Tracks webrtc::VideoCodecType.
   public enum VideoCodecType {
     VIDEO_CODEC_VP8,
     VIDEO_CODEC_VP9,
     VIDEO_CODEC_H264
   }

   private static final int DEQUEUE_INPUT_TIMEOUT = 500000;  // 500 ms timeout.
   private static MediaCodecVideoDecoder instance;
   private Thread mediaCodecThread;
   private MediaCodec mediaCodec;
   private ByteBuffer[] inputBuffers;
   private ByteBuffer[] outputBuffers;
   private static final String VP8_MIME_TYPE = "video/x-vnd.on2.vp8";
   private static final String H264_MIME_TYPE = "video/avc";
   // List of supported HW VP8 decoders.
   private static final String[] supportedVp8HwCodecPrefixes =
     {"OMX.qcom.", "OMX.Nvidia.", "OMX.Exynos.", "OMX.Intel." };
   // List of supported HW H.264 decoders.
   private static final String[] supportedH264HwCodecPrefixes =
     {"OMX.qcom.", "OMX.Intel." };
   // NV12 color format supported by QCOM codec, but not declared in MediaCodec -
   // see /hardware/qcom/media/mm-core/inc/OMX_QCOMExtns.h
   private static final int
     COLOR_QCOM_FORMATYUV420PackedSemiPlanar32m = 0x7FA30C04;
   // Allowable color formats supported by codec - in order of preference.
   private static final List<Integer> supportedColorList = Arrays.asList(
     CodecCapabilities.COLOR_FormatYUV420Planar,
     CodecCapabilities.COLOR_FormatYUV420SemiPlanar,
     CodecCapabilities.COLOR_QCOM_FormatYUV420SemiPlanar,
     COLOR_QCOM_FORMATYUV420PackedSemiPlanar32m);
   private int colorFormat;
   private int width;
   private int height;
   private int stride;
   private int sliceHeight;
   private boolean useSurface;
   // |isWaitingForTexture| is true when waiting for the transition:
   // MediaCodec.releaseOutputBuffer() -> onTextureFrameAvailable().
   private boolean isWaitingForTexture = false;
   private TextureListener textureListener;
   private Surface surface = null;

   private MediaCodecVideoDecoder() {
     instance = this;
   }

   // Helper struct for findVp8Decoder() below.
   private static class DecoderProperties {
     public DecoderProperties(String codecName, int colorFormat) {
       this.codecName = codecName;
       this.colorFormat = colorFormat;
     }
     public final String codecName; // OpenMax component name for VP8 codec.
     public final int colorFormat;  // Color format supported by codec.
   }

   private static DecoderProperties findDecoder(
       String mime, String[] supportedCodecPrefixes) {
     if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {
       return null; // MediaCodec.setParameters is missing.
     }
     for (int i = 0; i < MediaCodecList.getCodecCount(); ++i) {
       MediaCodecInfo info = MediaCodecList.getCodecInfoAt(i);
       if (info.isEncoder()) {
         continue;
       }
       String name = null;
       for (String mimeType : info.getSupportedTypes()) {
         if (mimeType.equals(mime)) {
           name = info.getName();
           break;
         }
       }
       if (name == null) {
         continue;  // No HW support in this codec; try the next one.
       }
       Logging.v(TAG, "Found candidate decoder " + name);

       // Check if this is supported decoder.
       boolean supportedCodec = false;
       for (String codecPrefix : supportedCodecPrefixes) {
         if (name.startsWith(codecPrefix)) {
           supportedCodec = true;
           break;
         }
       }
       if (!supportedCodec) {
         continue;
       }

       // Check if codec supports either yuv420 or nv12.
       CodecCapabilities capabilities =
           info.getCapabilitiesForType(mime);
       for (int colorFormat : capabilities.colorFormats) {
         Logging.v(TAG, "   Color: 0x" + Integer.toHexString(colorFormat));
       }
       for (int supportedColorFormat : supportedColorList) {
         for (int codecColorFormat : capabilities.colorFormats) {
           if (codecColorFormat == supportedColorFormat) {
             // Found supported HW decoder.
             Logging.d(TAG, "Found target decoder " + name +
                 ". Color: 0x" + Integer.toHexString(codecColorFormat));
             return new DecoderProperties(name, codecColorFormat);
           }
         }
       }
     }
     return null;  // No HW decoder.
   }

   public static boolean isVp8HwSupported() {
     return findDecoder(VP8_MIME_TYPE, supportedVp8HwCodecPrefixes) != null;
   }

   public static boolean isH264HwSupported() {
     return findDecoder(H264_MIME_TYPE, supportedH264HwCodecPrefixes) != null;
   }

   public static void printStackTrace() {
     if (instance != null && instance.mediaCodecThread != null) {
       StackTraceElement[] mediaCodecStackTraces = instance.mediaCodecThread.getStackTrace();
       if (mediaCodecStackTraces.length > 0) {
         Logging.d(TAG, "MediaCodecVideoDecoder stacks trace:");
         for (StackTraceElement stackTrace : mediaCodecStackTraces) {
           Logging.d(TAG, stackTrace.toString());
         }
       }
     }
   }

   private void checkOnMediaCodecThread() throws IllegalStateException {
     if (mediaCodecThread.getId() != Thread.currentThread().getId()) {
       throw new IllegalStateException(
           "MediaCodecVideoDecoder previously operated on " + mediaCodecThread +
           " but is now called on " + Thread.currentThread());
     }
   }

   // Pass null in |surfaceTextureHelper| to configure the codec for ByteBuffer output.
   private boolean initDecode(
       VideoCodecType type, int width, int height, SurfaceTextureHelper surfaceTextureHelper) {
     if (mediaCodecThread != null) {
       throw new RuntimeException("Forgot to release()?");
     }
     useSurface = (surfaceTextureHelper != null);
     String mime = null;
     String[] supportedCodecPrefixes = null;
     if (type == VideoCodecType.VIDEO_CODEC_VP8) {
       mime = VP8_MIME_TYPE;
       supportedCodecPrefixes = supportedVp8HwCodecPrefixes;
     } else if (type == VideoCodecType.VIDEO_CODEC_H264) {
       mime = H264_MIME_TYPE;
       supportedCodecPrefixes = supportedH264HwCodecPrefixes;
     } else {
       throw new RuntimeException("Non supported codec " + type);
     }
     DecoderProperties properties = findDecoder(mime, supportedCodecPrefixes);
     if (properties == null) {
       throw new RuntimeException("Cannot find HW decoder for " + type);
     }
     Logging.d(TAG, "Java initDecode: " + type + " : "+ width + " x " + height +
         ". Color: 0x" + Integer.toHexString(properties.colorFormat) +
         ". Use Surface: " + useSurface);
     mediaCodecThread = Thread.currentThread();
     try {
       this.width = width;
       this.height = height;
       stride = width;
       sliceHeight = height;

       if (useSurface) {
         textureListener = new TextureListener(surfaceTextureHelper);
         surface = new Surface(surfaceTextureHelper.getSurfaceTexture());
       }

       MediaFormat format = MediaFormat.createVideoFormat(mime, width, height);
       if (!useSurface) {
         format.setInteger(MediaFormat.KEY_COLOR_FORMAT, properties.colorFormat);
       }
       Logging.d(TAG, "  Format: " + format);
       mediaCodec =
           MediaCodecVideoEncoder.createByCodecName(properties.codecName);
       if (mediaCodec == null) {
         Logging.e(TAG, "Can not create media decoder");
         return false;
       }
       mediaCodec.configure(format, surface, null, 0);
       mediaCodec.start();
       colorFormat = properties.colorFormat;
       outputBuffers = mediaCodec.getOutputBuffers();
       inputBuffers = mediaCodec.getInputBuffers();
       Logging.d(TAG, "Input buffers: " + inputBuffers.length +
           ". Output buffers: " + outputBuffers.length);
       return true;
     } catch (IllegalStateException e) {
       Logging.e(TAG, "initDecode failed", e);
       return false;
     }
   }

   private void release() {
     Logging.d(TAG, "Java releaseDecoder");
     checkOnMediaCodecThread();
     try {
       mediaCodec.stop();
       mediaCodec.release();
     } catch (IllegalStateException e) {
       Logging.e(TAG, "release failed", e);
     }
     mediaCodec = null;
     mediaCodecThread = null;
     instance = null;
     if (useSurface) {
       surface.release();
       surface = null;
       textureListener.release();
     }
     Logging.d(TAG, "Java releaseDecoder done");
   }

   // Dequeue an input buffer and return its index, -1 if no input buffer is
   // available, or -2 if the codec is no longer operative.
   private int dequeueInputBuffer() {
     checkOnMediaCodecThread();
     try {
       return mediaCodec.dequeueInputBuffer(DEQUEUE_INPUT_TIMEOUT);
     } catch (IllegalStateException e) {
       Logging.e(TAG, "dequeueIntputBuffer failed", e);
       return -2;
     }
   }

   private boolean queueInputBuffer(
       int inputBufferIndex, int size, long timestampUs) {
     checkOnMediaCodecThread();
     try {
       inputBuffers[inputBufferIndex].position(0);
       inputBuffers[inputBufferIndex].limit(size);
       mediaCodec.queueInputBuffer(inputBufferIndex, 0, size, timestampUs, 0);
       return true;
     }
     catch (IllegalStateException e) {
       Logging.e(TAG, "decode failed", e);
       return false;
     }
   }

   // Helper structs for dequeueOutputBuffer() below.
   private static class DecodedByteBuffer {
     public DecodedByteBuffer(int index, int offset, int size, long presentationTimestampUs) {
       this.index = index;
       this.offset = offset;
       this.size = size;
       this.presentationTimestampUs = presentationTimestampUs;
     }

     private final int index;
     private final int offset;
     private final int size;
     private final long presentationTimestampUs;
   }

   private static class DecodedTextureBuffer {
     private final int textureID;
     private final float[] transformMatrix;
     private final long timestampNs;

     public DecodedTextureBuffer(int textureID, float[] transformMatrix, long timestampNs) {
       this.textureID = textureID;
       this.transformMatrix = transformMatrix;
       this.timestampNs = timestampNs;
     }
   }

   // Poll based texture listener.
   private static class TextureListener
       implements SurfaceTextureHelper.OnTextureFrameAvailableListener {
     private final SurfaceTextureHelper surfaceTextureHelper;
     private DecodedTextureBuffer textureBuffer;
     // |newFrameLock| is used to synchronize arrival of new frames with wait()/notifyAll().
     private final Object newFrameLock = new Object();

     public TextureListener(SurfaceTextureHelper surfaceTextureHelper) {
       this.surfaceTextureHelper = surfaceTextureHelper;
       surfaceTextureHelper.setListener(this);
     }

     // Callback from |surfaceTextureHelper|. May be called on an arbitrary thread.
     @Override
     public void onTextureFrameAvailable(
         int oesTextureId, float[] transformMatrix, long timestampNs) {
       synchronized (newFrameLock) {
         if (textureBuffer != null) {
           Logging.e(TAG,
               "Unexpected onTextureFrameAvailable() called while already holding a texture.");
           throw new IllegalStateException("Already holding a texture.");
         }
         textureBuffer = new DecodedTextureBuffer(oesTextureId, transformMatrix, timestampNs);
         newFrameLock.notifyAll();
       }
     }

     // Dequeues and returns a texture buffer if available, or null otherwise.
     public DecodedTextureBuffer dequeueTextureFrame(int timeoutMs) {
       synchronized (newFrameLock) {
         if (textureBuffer == null && timeoutMs > 0) {
           try {
             newFrameLock.wait(timeoutMs);
           } catch(InterruptedException e) {
             // Restore the interrupted status by reinterrupting the thread.
             Thread.currentThread().interrupt();
           }
         }
         final DecodedTextureBuffer textureBuffer = this.textureBuffer;
         this.textureBuffer = null;
         return textureBuffer;
       }
     }

     public void release() {
       // SurfaceTextureHelper.disconnect() will block until any onTextureFrameAvailable() in
       // progress is done. Therefore, the call to disconnect() must be outside any synchronized
       // statement that is also used in the onTextureFrameAvailable() above to avoid deadlocks.
       surfaceTextureHelper.disconnect();
       synchronized (newFrameLock) {
         if (textureBuffer != null) {
           surfaceTextureHelper.returnTextureFrame();
           textureBuffer = null;
         }
       }
     }
   }

   // Returns null if no decoded buffer is available, and otherwise either a DecodedByteBuffer or
   // DecodedTexturebuffer depending on |useSurface| configuration.
   // Throws IllegalStateException if call is made on the wrong thread, if color format changes to an
   // unsupported format, or if |mediaCodec| is not in the Executing state. Throws CodecException
   // upon codec error.
   private Object dequeueOutputBuffer(int dequeueTimeoutMs)
       throws IllegalStateException, MediaCodec.CodecException {
     checkOnMediaCodecThread();
     // Calling multiple MediaCodec.releaseOutputBuffer() with render=true in a row will result in
     // dropped texture frames. Therefore, wait for any pending onTextureFrameAvailable() before
     // proceeding.
     if (isWaitingForTexture) {
       final DecodedTextureBuffer textureBuffer =
           textureListener.dequeueTextureFrame(dequeueTimeoutMs);
       isWaitingForTexture = (textureBuffer == null);
       return textureBuffer;
     }

     // Drain the decoder until receiving a decoded buffer or hitting
     // MediaCodec.INFO_TRY_AGAIN_LATER.
     final MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();
     while (true) {
       final int result = mediaCodec.dequeueOutputBuffer(
           info, TimeUnit.MILLISECONDS.toMicros(dequeueTimeoutMs));
       switch (result) {
         case MediaCodec.INFO_TRY_AGAIN_LATER:
           return null;
         case MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED:
           outputBuffers = mediaCodec.getOutputBuffers();
           Logging.d(TAG, "Decoder output buffers changed: " + outputBuffers.length);
           break;
         case MediaCodec.INFO_OUTPUT_FORMAT_CHANGED:
           MediaFormat format = mediaCodec.getOutputFormat();
           Logging.d(TAG, "Decoder format changed: " + format.toString());
           width = format.getInteger(MediaFormat.KEY_WIDTH);
           height = format.getInteger(MediaFormat.KEY_HEIGHT);
           if (!useSurface && format.containsKey(MediaFormat.KEY_COLOR_FORMAT)) {
             colorFormat = format.getInteger(MediaFormat.KEY_COLOR_FORMAT);
             Logging.d(TAG, "Color: 0x" + Integer.toHexString(colorFormat));
             if (!supportedColorList.contains(colorFormat)) {
               throw new IllegalStateException("Non supported color format: " + colorFormat);
             }
           }
           if (format.containsKey("stride")) {
             stride = format.getInteger("stride");
           }
           if (format.containsKey("slice-height")) {
             sliceHeight = format.getInteger("slice-height");
           }
           Logging.d(TAG, "Frame stride and slice height: " + stride + " x " + sliceHeight);
           stride = Math.max(width, stride);
           sliceHeight = Math.max(height, sliceHeight);
           break;
         default:
           // Output buffer decoded.
           if (useSurface) {
             mediaCodec.releaseOutputBuffer(result, true /* render */);
             final DecodedTextureBuffer textureBuffer =
                 textureListener.dequeueTextureFrame(dequeueTimeoutMs);
             isWaitingForTexture = (textureBuffer == null);
             return textureBuffer;
           } else {
             return new DecodedByteBuffer(result, info.offset, info.size, info.presentationTimeUs);
           }
       }
     }
   }

   // Release a dequeued output byte buffer back to the codec for re-use. Should only be called for
   // non-surface decoding.
   // Throws IllegalStateException if the call is made on the wrong thread, if codec is configured
   // for surface decoding, or if |mediaCodec| is not in the Executing state. Throws
   // MediaCodec.CodecException upon codec error.
   private void returnDecodedByteBuffer(int index)
       throws IllegalStateException, MediaCodec.CodecException {
     checkOnMediaCodecThread();
     if (useSurface) {
       throw new IllegalStateException("returnDecodedByteBuffer() called for surface decoding.");
     }
     mediaCodec.releaseOutputBuffer(index, false /* render */);
   }
 }
	/*
	* libjingle
	* Copyright 2014 Google Inc.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	*
	* 1. Redistributions of source code must retain the above copyright notice,
	* this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright notice,
	* this list of conditions and the following disclaimer in the documentation
	* and/or other materials provided with the distribution.
	* 3. The name of the author may not be used to endorse or promote products
	* derived from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
	* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
	* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
	* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
	* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	package org.webrtc;

	import android.media.MediaCodec;
	import android.media.MediaCodecInfo;
	import android.media.MediaCodecInfo.CodecCapabilities;
	import android.media.MediaCodecList;
	import android.media.MediaFormat;
	import android.os.Build;
	import android.view.Surface;

	import org.webrtc.Logging;

	import java.nio.ByteBuffer;
	import java.util.Arrays;
	import java.util.List;
	import java.util.concurrent.TimeUnit;

	// Java-side of peerconnection_jni.cc:MediaCodecVideoDecoder.
	// This class is an implementation detail of the Java PeerConnection API.
	// MediaCodec is thread-hostile so this class must be operated on a single
	// thread.
	public class MediaCodecVideoDecoder {
	// This class is constructed, operated, and destroyed by its C++ incarnation,
	// so the class and its methods have non-public visibility. The API this
	// class exposes aims to mimic the webrtc::VideoDecoder API as closely as
	// possibly to minimize the amount of translation work necessary.

	private static final String TAG = "MediaCodecVideoDecoder";

	// Tracks webrtc::VideoCodecType.
	public enum VideoCodecType {
	VIDEO_CODEC_VP8,
	VIDEO_CODEC_VP9,
	VIDEO_CODEC_H264
	}

	private static final int DEQUEUE_INPUT_TIMEOUT = 500000; // 500 ms timeout.
	private static MediaCodecVideoDecoder instance;
	private Thread mediaCodecThread;
	private MediaCodec mediaCodec;
	private ByteBuffer[] inputBuffers;
	private ByteBuffer[] outputBuffers;
	private static final String VP8_MIME_TYPE = "video/x-vnd.on2.vp8";
	private static final String H264_MIME_TYPE = "video/avc";
	// List of supported HW VP8 decoders.
	private static final String[] supportedVp8HwCodecPrefixes =
	{"OMX.qcom.", "OMX.Nvidia.", "OMX.Exynos.", "OMX.Intel." };
	// List of supported HW H.264 decoders.
	private static final String[] supportedH264HwCodecPrefixes =
	{"OMX.qcom.", "OMX.Intel." };
	// NV12 color format supported by QCOM codec, but not declared in MediaCodec -
	// see /hardware/qcom/media/mm-core/inc/OMX_QCOMExtns.h
	private static final int
	COLOR_QCOM_FORMATYUV420PackedSemiPlanar32m = 0x7FA30C04;
	// Allowable color formats supported by codec - in order of preference.
	private static final List<Integer> supportedColorList = Arrays.asList(
	CodecCapabilities.COLOR_FormatYUV420Planar,
	CodecCapabilities.COLOR_FormatYUV420SemiPlanar,
	CodecCapabilities.COLOR_QCOM_FormatYUV420SemiPlanar,
	COLOR_QCOM_FORMATYUV420PackedSemiPlanar32m);
	private int colorFormat;
	private int width;
	private int height;
	private int stride;
	private int sliceHeight;
	private boolean useSurface;
	// \|isWaitingForTexture\| is true when waiting for the transition:
	// MediaCodec.releaseOutputBuffer() -> onTextureFrameAvailable().
	private boolean isWaitingForTexture = false;
	private TextureListener textureListener;
	private Surface surface = null;

	private MediaCodecVideoDecoder() {
	instance = this;
	}

	// Helper struct for findVp8Decoder() below.
	private static class DecoderProperties {
	public DecoderProperties(String codecName, int colorFormat) {
	this.codecName = codecName;
	this.colorFormat = colorFormat;
	}
	public final String codecName; // OpenMax component name for VP8 codec.
	public final int colorFormat; // Color format supported by codec.
	}

	private static DecoderProperties findDecoder(
	String mime, String[] supportedCodecPrefixes) {
	if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {
	return null; // MediaCodec.setParameters is missing.
	}
	for (int i = 0; i < MediaCodecList.getCodecCount(); ++i) {
	MediaCodecInfo info = MediaCodecList.getCodecInfoAt(i);
	if (info.isEncoder()) {
	continue;
	}
	String name = null;
	for (String mimeType : info.getSupportedTypes()) {
	if (mimeType.equals(mime)) {
	name = info.getName();
	break;
	}
	}
	if (name == null) {
	continue; // No HW support in this codec; try the next one.
	}
	Logging.v(TAG, "Found candidate decoder " + name);

	// Check if this is supported decoder.
	boolean supportedCodec = false;
	for (String codecPrefix : supportedCodecPrefixes) {
	if (name.startsWith(codecPrefix)) {
	supportedCodec = true;
	break;
	}
	}
	if (!supportedCodec) {
	continue;
	}

	// Check if codec supports either yuv420 or nv12.
	CodecCapabilities capabilities =
	info.getCapabilitiesForType(mime);
	for (int colorFormat : capabilities.colorFormats) {
	Logging.v(TAG, " Color: 0x" + Integer.toHexString(colorFormat));
	}
	for (int supportedColorFormat : supportedColorList) {
	for (int codecColorFormat : capabilities.colorFormats) {
	if (codecColorFormat == supportedColorFormat) {
	// Found supported HW decoder.
	Logging.d(TAG, "Found target decoder " + name +
	". Color: 0x" + Integer.toHexString(codecColorFormat));
	return new DecoderProperties(name, codecColorFormat);
	}
	}
	}
	}
	return null; // No HW decoder.
	}

	public static boolean isVp8HwSupported() {
	return findDecoder(VP8_MIME_TYPE, supportedVp8HwCodecPrefixes) != null;
	}

	public static boolean isH264HwSupported() {
	return findDecoder(H264_MIME_TYPE, supportedH264HwCodecPrefixes) != null;
	}

	public static void printStackTrace() {
	if (instance != null && instance.mediaCodecThread != null) {
	StackTraceElement[] mediaCodecStackTraces = instance.mediaCodecThread.getStackTrace();
	if (mediaCodecStackTraces.length > 0) {
	Logging.d(TAG, "MediaCodecVideoDecoder stacks trace:");
	for (StackTraceElement stackTrace : mediaCodecStackTraces) {
	Logging.d(TAG, stackTrace.toString());
	}
	}
	}
	}

	private void checkOnMediaCodecThread() throws IllegalStateException {
	if (mediaCodecThread.getId() != Thread.currentThread().getId()) {
	throw new IllegalStateException(
	"MediaCodecVideoDecoder previously operated on " + mediaCodecThread +
	" but is now called on " + Thread.currentThread());
	}
	}

	// Pass null in \|surfaceTextureHelper\| to configure the codec for ByteBuffer output.
	private boolean initDecode(
	VideoCodecType type, int width, int height, SurfaceTextureHelper surfaceTextureHelper) {
	if (mediaCodecThread != null) {
	throw new RuntimeException("Forgot to release()?");
	}
	useSurface = (surfaceTextureHelper != null);
	String mime = null;
	String[] supportedCodecPrefixes = null;
	if (type == VideoCodecType.VIDEO_CODEC_VP8) {
	mime = VP8_MIME_TYPE;
	supportedCodecPrefixes = supportedVp8HwCodecPrefixes;
	} else if (type == VideoCodecType.VIDEO_CODEC_H264) {
	mime = H264_MIME_TYPE;
	supportedCodecPrefixes = supportedH264HwCodecPrefixes;
	} else {
	throw new RuntimeException("Non supported codec " + type);
	}
	DecoderProperties properties = findDecoder(mime, supportedCodecPrefixes);
	if (properties == null) {
	throw new RuntimeException("Cannot find HW decoder for " + type);
	}
	Logging.d(TAG, "Java initDecode: " + type + " : "+ width + " x " + height +
	". Color: 0x" + Integer.toHexString(properties.colorFormat) +
	". Use Surface: " + useSurface);
	mediaCodecThread = Thread.currentThread();
	try {
	this.width = width;
	this.height = height;
	stride = width;
	sliceHeight = height;

	if (useSurface) {
	textureListener = new TextureListener(surfaceTextureHelper);
	surface = new Surface(surfaceTextureHelper.getSurfaceTexture());
	}

	MediaFormat format = MediaFormat.createVideoFormat(mime, width, height);
	if (!useSurface) {
	format.setInteger(MediaFormat.KEY_COLOR_FORMAT, properties.colorFormat);
	}
	Logging.d(TAG, " Format: " + format);
	mediaCodec =
	MediaCodecVideoEncoder.createByCodecName(properties.codecName);
	if (mediaCodec == null) {
	Logging.e(TAG, "Can not create media decoder");
	return false;
	}
	mediaCodec.configure(format, surface, null, 0);
	mediaCodec.start();
	colorFormat = properties.colorFormat;
	outputBuffers = mediaCodec.getOutputBuffers();
	inputBuffers = mediaCodec.getInputBuffers();
	Logging.d(TAG, "Input buffers: " + inputBuffers.length +
	". Output buffers: " + outputBuffers.length);
	return true;
	} catch (IllegalStateException e) {
	Logging.e(TAG, "initDecode failed", e);
	return false;
	}
	}

	private void release() {
	Logging.d(TAG, "Java releaseDecoder");
	checkOnMediaCodecThread();
	try {
	mediaCodec.stop();
	mediaCodec.release();
	} catch (IllegalStateException e) {
	Logging.e(TAG, "release failed", e);
	}
	mediaCodec = null;
	mediaCodecThread = null;
	instance = null;
	if (useSurface) {
	surface.release();
	surface = null;
	textureListener.release();
	}
	Logging.d(TAG, "Java releaseDecoder done");
	}

	// Dequeue an input buffer and return its index, -1 if no input buffer is
	// available, or -2 if the codec is no longer operative.
	private int dequeueInputBuffer() {
	checkOnMediaCodecThread();
	try {
	return mediaCodec.dequeueInputBuffer(DEQUEUE_INPUT_TIMEOUT);
	} catch (IllegalStateException e) {
	Logging.e(TAG, "dequeueIntputBuffer failed", e);
	return -2;
	}
	}

	private boolean queueInputBuffer(
	int inputBufferIndex, int size, long timestampUs) {
	checkOnMediaCodecThread();
	try {
	inputBuffers[inputBufferIndex].position(0);
	inputBuffers[inputBufferIndex].limit(size);
	mediaCodec.queueInputBuffer(inputBufferIndex, 0, size, timestampUs, 0);
	return true;
	}
	catch (IllegalStateException e) {
	Logging.e(TAG, "decode failed", e);
	return false;
	}
	}

	// Helper structs for dequeueOutputBuffer() below.
	private static class DecodedByteBuffer {
	public DecodedByteBuffer(int index, int offset, int size, long presentationTimestampUs) {
	this.index = index;
	this.offset = offset;
	this.size = size;
	this.presentationTimestampUs = presentationTimestampUs;
	}

	private final int index;
	private final int offset;
	private final int size;
	private final long presentationTimestampUs;
	}

	private static class DecodedTextureBuffer {
	private final int textureID;
	private final float[] transformMatrix;
	private final long timestampNs;

	public DecodedTextureBuffer(int textureID, float[] transformMatrix, long timestampNs) {
	this.textureID = textureID;
	this.transformMatrix = transformMatrix;
	this.timestampNs = timestampNs;
	}
	}

	// Poll based texture listener.
	private static class TextureListener
	implements SurfaceTextureHelper.OnTextureFrameAvailableListener {
	private final SurfaceTextureHelper surfaceTextureHelper;
	private DecodedTextureBuffer textureBuffer;
	// \|newFrameLock\| is used to synchronize arrival of new frames with wait()/notifyAll().
	private final Object newFrameLock = new Object();

	public TextureListener(SurfaceTextureHelper surfaceTextureHelper) {
	this.surfaceTextureHelper = surfaceTextureHelper;
	surfaceTextureHelper.setListener(this);
	}

	// Callback from \|surfaceTextureHelper\|. May be called on an arbitrary thread.
	@Override
	public void onTextureFrameAvailable(
	int oesTextureId, float[] transformMatrix, long timestampNs) {
	synchronized (newFrameLock) {
	if (textureBuffer != null) {
	Logging.e(TAG,
	"Unexpected onTextureFrameAvailable() called while already holding a texture.");
	throw new IllegalStateException("Already holding a texture.");
	}
	textureBuffer = new DecodedTextureBuffer(oesTextureId, transformMatrix, timestampNs);
	newFrameLock.notifyAll();
	}
	}

	// Dequeues and returns a texture buffer if available, or null otherwise.
	public DecodedTextureBuffer dequeueTextureFrame(int timeoutMs) {
	synchronized (newFrameLock) {
	if (textureBuffer == null && timeoutMs > 0) {
	try {
	newFrameLock.wait(timeoutMs);
	} catch(InterruptedException e) {
	// Restore the interrupted status by reinterrupting the thread.
	Thread.currentThread().interrupt();
	}
	}
	final DecodedTextureBuffer textureBuffer = this.textureBuffer;
	this.textureBuffer = null;
	return textureBuffer;
	}
	}

	public void release() {
	// SurfaceTextureHelper.disconnect() will block until any onTextureFrameAvailable() in
	// progress is done. Therefore, the call to disconnect() must be outside any synchronized
	// statement that is also used in the onTextureFrameAvailable() above to avoid deadlocks.
	surfaceTextureHelper.disconnect();
	synchronized (newFrameLock) {
	if (textureBuffer != null) {
	surfaceTextureHelper.returnTextureFrame();
	textureBuffer = null;
	}
	}
	}
	}

	// Returns null if no decoded buffer is available, and otherwise either a DecodedByteBuffer or
	// DecodedTexturebuffer depending on \|useSurface\| configuration.
	// Throws IllegalStateException if call is made on the wrong thread, if color format changes to an
	// unsupported format, or if \|mediaCodec\| is not in the Executing state. Throws CodecException
	// upon codec error.
	private Object dequeueOutputBuffer(int dequeueTimeoutMs)
	throws IllegalStateException, MediaCodec.CodecException {
	checkOnMediaCodecThread();
	// Calling multiple MediaCodec.releaseOutputBuffer() with render=true in a row will result in
	// dropped texture frames. Therefore, wait for any pending onTextureFrameAvailable() before
	// proceeding.
	if (isWaitingForTexture) {
	final DecodedTextureBuffer textureBuffer =
	textureListener.dequeueTextureFrame(dequeueTimeoutMs);
	isWaitingForTexture = (textureBuffer == null);
	return textureBuffer;
	}

	// Drain the decoder until receiving a decoded buffer or hitting
	// MediaCodec.INFO_TRY_AGAIN_LATER.
	final MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();
	while (true) {
	final int result = mediaCodec.dequeueOutputBuffer(
	info, TimeUnit.MILLISECONDS.toMicros(dequeueTimeoutMs));
	switch (result) {
	case MediaCodec.INFO_TRY_AGAIN_LATER:
	return null;
	case MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED:
	outputBuffers = mediaCodec.getOutputBuffers();
	Logging.d(TAG, "Decoder output buffers changed: " + outputBuffers.length);
	break;
	case MediaCodec.INFO_OUTPUT_FORMAT_CHANGED:
	MediaFormat format = mediaCodec.getOutputFormat();
	Logging.d(TAG, "Decoder format changed: " + format.toString());
	width = format.getInteger(MediaFormat.KEY_WIDTH);
	height = format.getInteger(MediaFormat.KEY_HEIGHT);
	if (!useSurface && format.containsKey(MediaFormat.KEY_COLOR_FORMAT)) {
	colorFormat = format.getInteger(MediaFormat.KEY_COLOR_FORMAT);
	Logging.d(TAG, "Color: 0x" + Integer.toHexString(colorFormat));
	if (!supportedColorList.contains(colorFormat)) {
	throw new IllegalStateException("Non supported color format: " + colorFormat);
	}
	}
	if (format.containsKey("stride")) {
	stride = format.getInteger("stride");
	}
	if (format.containsKey("slice-height")) {
	sliceHeight = format.getInteger("slice-height");
	}
	Logging.d(TAG, "Frame stride and slice height: " + stride + " x " + sliceHeight);
	stride = Math.max(width, stride);
	sliceHeight = Math.max(height, sliceHeight);
	break;
	default:
	// Output buffer decoded.
	if (useSurface) {
	mediaCodec.releaseOutputBuffer(result, true /* render */);
	final DecodedTextureBuffer textureBuffer =
	textureListener.dequeueTextureFrame(dequeueTimeoutMs);
	isWaitingForTexture = (textureBuffer == null);
	return textureBuffer;
	} else {
	return new DecodedByteBuffer(result, info.offset, info.size, info.presentationTimeUs);
	}
	}
	}
	}

	// Release a dequeued output byte buffer back to the codec for re-use. Should only be called for
	// non-surface decoding.
	// Throws IllegalStateException if the call is made on the wrong thread, if codec is configured
	// for surface decoding, or if \|mediaCodec\| is not in the Executing state. Throws
	// MediaCodec.CodecException upon codec error.
	private void returnDecodedByteBuffer(int index)
	throws IllegalStateException, MediaCodec.CodecException {
	checkOnMediaCodecThread();
	if (useSurface) {
	throw new IllegalStateException("returnDecodedByteBuffer() called for surface decoding.");
	}
	mediaCodec.releaseOutputBuffer(index, false /* render */);
	}
	}