Restrict output format, abort if no transcoding necessary

Fixes ypresto#6

Author: ypresto

lib/build.gradle

@@ -40,5 +40,6 @@ publish {
 }
 
 dependencies {
+    compile 'org.jcodec:jcodec:0.1.9'
     compile fileTree(dir: 'libs', include: ['*.jar'])
 }

lib/src/main/java/net/ypresto/androidtranscoder/MediaTranscoder.java

@@ -68,7 +68,7 @@ public static MediaTranscoder getInstance() {
      * @param inFileDescriptor FileDescriptor for input.
      * @param outPath          File path for output.
      * @param listener         Listener instance for callback.
-     * @deprecated Use {@link #transcodeVideo(java.io.FileDescriptor, String, net.ypresto.androidtranscoder.format.MediaFormatStrategy, net.ypresto.androidtranscoder.MediaTranscoder.Listener)} which accepts output video format.
+     * @deprecated Use {@link #transcodeVideo(FileDescriptor, String, MediaFormatStrategy, MediaTranscoder.Listener)} which accepts output video format.
      */
     @Deprecated
     public void transcodeVideo(final FileDescriptor inFileDescriptor, final String outPath, final Listener listener) {
@@ -177,7 +177,7 @@ public void run() {
                             + " or could not open output file ('" + outPath + "') .", e);
                     caughtException = e;
                 } catch (RuntimeException e) {
-                    Log.e(TAG, "Fatal error while transcoding, this might be invalid output format or bug in engine or Android.", e);
+                    Log.e(TAG, "Fatal error while transcoding, this might be invalid format or bug in engine or Android.", e);
                     caughtException = e;
                 }
 
@@ -212,8 +212,8 @@ public interface Listener {
         /**
          * Called when transcode failed.
          *
-         * @param exception Exception caused failure. Note that it IS NOT {@link java.lang.Throwable}.
-         *                  This means {@link java.lang.Error} won't be caught.
+         * @param exception Exception thrown from {@link MediaTranscoderEngine#transcodeVideo(String, MediaFormatStrategy)}.
+         *                  Note that it IS NOT {@link java.lang.Throwable}. This means {@link java.lang.Error} won't be caught.
          */
         void onTranscodeFailed(Exception exception);
     }

lib/src/main/java/net/ypresto/androidtranscoder/engine/InvalidOutputFormatException.java

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2015 Yuya Tanaka
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.ypresto.androidtranscoder.engine;
+
+public class InvalidOutputFormatException extends RuntimeException {
+    public InvalidOutputFormatException(String detailMessage) {
+        super(detailMessage);
+    }
+}

lib/src/main/java/net/ypresto/androidtranscoder/engine/MediaFormatValidator.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2015 Yuya Tanaka
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.ypresto.androidtranscoder.engine;
+
+import android.media.MediaFormat;
+
+import net.ypresto.androidtranscoder.format.MediaFormatExtraConstants;
+import net.ypresto.androidtranscoder.utils.AvcCsdUtils;
+
+import org.jcodec.codecs.h264.H264Utils;
+import org.jcodec.codecs.h264.io.model.SeqParameterSet;
+
+import java.nio.ByteBuffer;
+
+class MediaFormatValidator {
+    // Refer: http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Profiles
+    private static final int PROFILE_IDC_BASELINE = 66;
+
+    public static void validateVideoOutputFormat(MediaFormat format) {
+        String mime = format.getString(MediaFormat.KEY_MIME);
+        // Refer: http://developer.android.com/guide/appendix/media-formats.html#core
+        // Refer: http://en.wikipedia.org/wiki/MPEG-4_Part_14#Data_streams
+        if (!MediaFormatExtraConstants.MIMETYPE_VIDEO_AVC.equals(mime)) {
+            throw new InvalidOutputFormatException("Video codecs other than AVC is not supported, actual mime type: " + mime);
+        }
+        ByteBuffer spsBuffer = AvcCsdUtils.getSpsBuffer(format);
+        SeqParameterSet sps = H264Utils.readSPS(spsBuffer);
+        if (sps.profile_idc != PROFILE_IDC_BASELINE) {
+            throw new InvalidOutputFormatException("Non-baseline AVC video profile is not supported by Android OS, actual profile_idc: " + sps.profile_idc);
+        }
+    }
+
+    public static void validateAudioOutputFormat(MediaFormat format) {
+        String mime = format.getString(MediaFormat.KEY_MIME);
+        if (!MediaFormatExtraConstants.MIMETYPE_AUDIO_AAC.equals(mime)) {
+            throw new InvalidOutputFormatException("Audio codecs other than AAC is not supported, actual mime type: " + mime);
+        }
+    }
+}

lib/src/main/java/net/ypresto/androidtranscoder/engine/MediaTranscoderEngine.java

@@ -77,6 +77,7 @@ public double getProgress() {
      * @param outputPath     File path to output transcoded video file.
      * @param formatStrategy Output format strategy.
      * @throws IOException when input or output file could not be opened.
+     * @throws InvalidOutputFormatException when output format is not supported.
      */
     public void transcodeVideo(String outputPath, MediaFormatStrategy formatStrategy) throws IOException {
         if (outputPath == null) {
@@ -152,6 +153,10 @@ private void setupTrackTranscoders(MediaFormatStrategy formatStrategy) {
         MediaExtractorUtils.TrackResult trackResult = MediaExtractorUtils.getFirstVideoAndAudioTrack(mExtractor);
         MediaFormat videoOutputFormat = formatStrategy.createVideoOutputFormat(trackResult.mVideoTrackFormat);
         MediaFormat audioOutputFormat = formatStrategy.createAudioOutputFormat(trackResult.mAudioTrackFormat);
+        if (videoOutputFormat == null && audioOutputFormat == null) {
+            throw new InvalidOutputFormatException("MediaFormatStrategy returned pass-through for both video and audio. No transcoding is necessary.");
+        }
+
         if (videoOutputFormat == null) {
             mVideoTrackTranscoder = new PassThroughTrackTranscoder(mExtractor, trackResult.mVideoTrackIndex, mMuxer);
         } else {
@@ -166,6 +171,8 @@ private void setupTrackTranscoders(MediaFormatStrategy formatStrategy) {
         mAudioTrackTranscoder.setup();
         mVideoTrackTranscoder.determineFormat();
         mAudioTrackTranscoder.determineFormat();
+        MediaFormatValidator.validateVideoOutputFormat(mVideoTrackTranscoder.getDeterminedFormat());
+        MediaFormatValidator.validateAudioOutputFormat(mAudioTrackTranscoder.getDeterminedFormat());
         mVideoTrackTranscoder.addTrackToMuxer();
         mAudioTrackTranscoder.addTrackToMuxer();
         mExtractor.selectTrack(trackResult.mVideoTrackIndex);

lib/src/main/java/net/ypresto/androidtranscoder/engine/VideoTrackTranscoder.java

@@ -21,6 +21,8 @@
 import android.media.MediaMuxer;
 import android.util.Log;
 
+import net.ypresto.androidtranscoder.format.MediaFormatExtraConstants;
+
 import java.io.IOException;
 import java.nio.ByteBuffer;
 
@@ -77,11 +79,11 @@ public void setup() {
         mEncoderOutputBuffers = mEncoder.getOutputBuffers();
 
         MediaFormat inputFormat = mExtractor.getTrackFormat(mTrackIndex);
-        if (inputFormat.containsKey("rotation-degrees")) {
+        if (inputFormat.containsKey(MediaFormatExtraConstants.KEY_ROTATION_DEGREES)) {
             // Decoded video is rotated automatically in Android 5.0 lollipop.
             // Turn off here because we don't want to encode rotated one.
             // refer: https://android.googlesource.com/platform/frameworks/av/+blame/lollipop-release/media/libstagefright/Utils.cpp
-            inputFormat.setInteger("rotation-degrees", 0);
+            inputFormat.setInteger(MediaFormatExtraConstants.KEY_ROTATION_DEGREES, 0);
         }
         mDecoderOutputSurfaceWrapper = new OutputSurface();
         try {

lib/src/main/java/net/ypresto/androidtranscoder/format/Android720pFormatStrategy.java

@@ -20,7 +20,7 @@
 import android.util.Log;
 
 class Android720pFormatStrategy implements MediaFormatStrategy {
-    private static final String TAG = "Android720pFormatStrategy";
+    private static final String TAG = "720pFormatStrategy";
     private static final int LONGER_LENGTH = 1280;
     private static final int SHORTER_LENGTH = 720;
     private static final int DEFAULT_BITRATE = 8000 * 1000; // From Nexus 4 Camera in 720p

lib/src/main/java/net/ypresto/androidtranscoder/format/MediaFormatExtraConstants.java

@@ -16,10 +16,41 @@
 package net.ypresto.androidtranscoder.format;
 
 public class MediaFormatExtraConstants {
-    // from API level >= 21, but might be usable in older APIs as native code implementation exists.
-    public static final String KEY_PROFILE = "profile"; // MediaCodecInfo.CodecProfileLevel
-    // from (ANDROID ROOT)/media/libstagefright/ACodec.cpp
-    public static final String KEY_LEVEL = "level"; // MediaCodecInfo.CodecProfileLevel
+    // from MediaFormat of API level >= 21, but might be usable in older APIs as native code implementation exists.
+    // https://android.googlesource.com/platform/frameworks/av/+/lollipop-release/media/libstagefright/ACodec.cpp#2621
+    // NOTE: native code enforces baseline profile.
+    // https://android.googlesource.com/platform/frameworks/av/+/lollipop-release/media/libstagefright/ACodec.cpp#2638
+    /** For encoder parameter. Use value of MediaCodecInfo.CodecProfileLevel.AVCProfile* . */
+    public static final String KEY_PROFILE = "profile";
+
+    // from https://android.googlesource.com/platform/frameworks/av/+/lollipop-release/media/libstagefright/ACodec.cpp#2623
+    /** For encoder parameter. Use value of MediaCodecInfo.CodecProfileLevel.AVCLevel* . */
+    public static final String KEY_LEVEL = "level";
+
+    // from https://android.googlesource.com/platform/frameworks/av/+/lollipop-release/media/libstagefright/MediaCodec.cpp#2197
+    /** Included in MediaFormat from {@link android.media.MediaExtractor#getTrackFormat(int)}. Value is {@link java.nio.ByteBuffer}. */
+    public static final String KEY_AVC_SPS = "csd-0";
+    /** Included in MediaFormat from {@link android.media.MediaExtractor#getTrackFormat(int)}. Value is {@link java.nio.ByteBuffer}. */
+    public static final String KEY_AVC_PPS = "csd-1";
+
+    /**
+     * For decoder parameter and included in MediaFormat from {@link android.media.MediaExtractor#getTrackFormat(int)}.
+     * Decoder rotates specified degrees before rendering video to surface.
+     * NOTE: Only included in track format of API >= 21.
+     */
+    public static final String KEY_ROTATION_DEGREES = "rotation-degrees";
+
+    // Video formats
+    // from MediaFormat of API level >= 21
+    public static final String MIMETYPE_VIDEO_AVC = "video/avc";
+    public static final String MIMETYPE_VIDEO_H263 = "video/3gpp";
+    public static final String MIMETYPE_VIDEO_VP8 = "video/x-vnd.on2.vp8";
+
+    // Audio formats
+    // from MediaFormat of API level >= 21
+    public static final String MIMETYPE_AUDIO_AAC = "audio/mp4a-latm";
+
     private MediaFormatExtraConstants() {
+        throw new RuntimeException();
     }
 }

lib/src/main/java/net/ypresto/androidtranscoder/format/MediaFormatStrategyPresets.java

@@ -25,6 +25,7 @@ public class MediaFormatStrategyPresets {
     /**
      * Preset based on Nexus 4 camera recording with 720p quality.
      * This preset is ensured to work on any Android >=4.3 devices by Android CTS (if codec is available).
+     * Default bitrate is 8Mbps. {@link #createAndroid720pStrategy(int)} to specify bitrate.
      */
     public static MediaFormatStrategy createAndroid720pStrategy() {
         return new Android720pFormatStrategy();

lib/src/main/java/net/ypresto/androidtranscoder/utils/AvcCsdUtils.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2015 Yuya Tanaka
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.ypresto.androidtranscoder.utils;
+
+import android.media.MediaFormat;
+
+import net.ypresto.androidtranscoder.format.MediaFormatExtraConstants;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+
+public class AvcCsdUtils {
+    // Refer: https://android.googlesource.com/platform/frameworks/av/+/lollipop-release/media/libstagefright/MediaCodec.cpp#2198
+    private static final byte[] AVC_CSD_PREFIX = {0x00, 0x00, 0x00, 0x01};
+    // Refer: http://www.cardinalpeak.com/blog/the-h-264-sequence-parameter-set/
+    private static final byte AVC_SPS_NAL = 103; // 0<<7 + 3<<5 + 7<<0
+
+    public static ByteBuffer getSpsBuffer(MediaFormat format) {
+        ByteBuffer prefixedSpsBuffer = format.getByteBuffer(MediaFormatExtraConstants.KEY_AVC_SPS).asReadOnlyBuffer();
+        byte[] csdPrefix = new byte[4];
+        prefixedSpsBuffer.get(csdPrefix);
+        if (!Arrays.equals(csdPrefix, AVC_CSD_PREFIX)) {
+            throw new IllegalStateException("Wrong csd-0 prefix.");
+        }
+        if (prefixedSpsBuffer.get() != AVC_SPS_NAL) {
+            throw new IllegalStateException("Got non SPS NAL data.");
+        }
+        return prefixedSpsBuffer.slice();
+    }
+
+    private AvcCsdUtils() {
+        throw new RuntimeException();
+    }
+}