Allow video with no audio stream present to be transcoded

Author: Cory Thompson

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

@@ -160,7 +160,12 @@ private void setupTrackTranscoders(MediaFormatStrategy formatStrategy) {
             @Override
             public void onDetermineOutputFormat() {
                 MediaFormatValidator.validateVideoOutputFormat(mVideoTrackTranscoder.getDeterminedFormat());
-                MediaFormatValidator.validateAudioOutputFormat(mAudioTrackTranscoder.getDeterminedFormat());
+
+                // If there is an audio track, validate the output is correct.
+                MediaFormat audioFormat = mAudioTrackTranscoder.getDeterminedFormat();
+                if (audioFormat != null) {
+                    MediaFormatValidator.validateAudioOutputFormat(audioFormat);
+                }
             }
         });
 
@@ -170,14 +175,18 @@ public void onDetermineOutputFormat() {
             mVideoTrackTranscoder = new VideoTrackTranscoder(mExtractor, trackResult.mVideoTrackIndex, videoOutputFormat, queuedMuxer);
         }
         mVideoTrackTranscoder.setup();
+        mExtractor.selectTrack(trackResult.mVideoTrackIndex);
+
         if (audioOutputFormat == null) {
             mAudioTrackTranscoder = new PassThroughTrackTranscoder(mExtractor, trackResult.mAudioTrackIndex, queuedMuxer, QueuedMuxer.SampleType.AUDIO);
         } else {
             mAudioTrackTranscoder = new AudioTrackTranscoder(mExtractor, trackResult.mAudioTrackIndex, audioOutputFormat, queuedMuxer);
         }
+
+        if (trackResult.mAudioTrackIndex >= 0) {
+            mExtractor.selectTrack(trackResult.mAudioTrackIndex);
+        }
         mAudioTrackTranscoder.setup();
-        mExtractor.selectTrack(trackResult.mVideoTrackIndex);
-        mExtractor.selectTrack(trackResult.mAudioTrackIndex);
     }
 
     private void runPipelines() {

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

@@ -42,10 +42,19 @@ public PassThroughTrackTranscoder(MediaExtractor extractor, int trackIndex,
         mMuxer = muxer;
         mSampleType = sampleType;
 
-        mActualOutputFormat = mExtractor.getTrackFormat(mTrackIndex);
-        mMuxer.setOutputFormat(mSampleType, mActualOutputFormat);
-        mBufferSize = mActualOutputFormat.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE);
-        mBuffer = ByteBuffer.allocateDirect(mBufferSize).order(ByteOrder.nativeOrder());
+        if (trackIndex >= 0) {
+            mActualOutputFormat = mExtractor.getTrackFormat(mTrackIndex);
+            mMuxer.setOutputFormat(mSampleType, mActualOutputFormat);
+            mBufferSize = mActualOutputFormat.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE);
+            mBuffer = ByteBuffer.allocateDirect(mBufferSize).order(ByteOrder.nativeOrder());
+        } else {
+            // track has no audio. Passthrough should also exclude the track.
+            mMuxer.setOutputFormat(mSampleType, null);
+
+            // Nothing to do. EOS and report it took us 0 ms.
+            mIsEOS = true;
+            mWrittenPresentationTimeUs = 0;
+        }
     }
 
     @Override

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

@@ -30,6 +30,7 @@
  */
 public class QueuedMuxer {
     private static final String TAG = "QueuedMuxer";
+    private static final int EXCLUDE_TRACK_INDEX = -1;
     private static final int BUFFER_SIZE = 64 * 1024; // I have no idea whether this value is appropriate or not...
     private final MediaMuxer mMuxer;
     private final Listener mListener;
@@ -54,6 +55,11 @@ public void setOutputFormat(SampleType sampleType, MediaFormat format) {
                 break;
             case AUDIO:
                 mAudioFormat = format;
+
+                if(format == null) {
+                    // Tell the muxer we do not require audio.
+                    mAudioTrackIndex = EXCLUDE_TRACK_INDEX;
+                }
                 break;
             default:
                 throw new AssertionError();
@@ -62,13 +68,17 @@ public void setOutputFormat(SampleType sampleType, MediaFormat format) {
     }
 
     private void onSetOutputFormat() {
-        if (mVideoFormat == null || mAudioFormat == null) return;
+        if (mVideoFormat == null || (mAudioFormat == null && mAudioTrackIndex != EXCLUDE_TRACK_INDEX)) return;
         mListener.onDetermineOutputFormat();
 
         mVideoTrackIndex = mMuxer.addTrack(mVideoFormat);
         Log.v(TAG, "Added track #" + mVideoTrackIndex + " with " + mVideoFormat.getString(MediaFormat.KEY_MIME) + " to muxer");
-        mAudioTrackIndex = mMuxer.addTrack(mAudioFormat);
-        Log.v(TAG, "Added track #" + mAudioTrackIndex + " with " + mAudioFormat.getString(MediaFormat.KEY_MIME) + " to muxer");
+
+        if(mAudioFormat != null) {
+            mAudioTrackIndex = mMuxer.addTrack(mAudioFormat);
+            Log.v(TAG, "Added track #" + mAudioTrackIndex + " with " + mAudioFormat.getString(MediaFormat.KEY_MIME) + " to muxer");
+        }
+
         mMuxer.start();
         mStarted = true;
 

lib/src/main/java/net/ypresto/androidtranscoder/format/Android16By9FormatStrategy.java

@@ -61,10 +61,14 @@ public MediaFormat createVideoOutputFormat(MediaFormat inputFormat) {
         if (longer * 9 != shorter * 16) {
             throw new OutputFormatUnavailableException("This video is not 16:9, and is not able to transcode. (" + width + "x" + height + ")");
         }
+
+        /*
+        I've commented this out because its unsafe to assume the user wants to bypass compression if resolution is equal.
         if (shorter <= targetShorter) {
             Log.d(TAG, "This video's height is less or equal to " + targetShorter + ", pass-through. (" + width + "x" + height + ")");
             return null;
-        }
+        }*/
+
         MediaFormat format = MediaFormat.createVideoFormat("video/avc", outWidth, outHeight);
         // From Nexus 4 Camera in 720p
         format.setInteger(MediaFormat.KEY_BIT_RATE, mVideoBitrate);
@@ -76,7 +80,7 @@ public MediaFormat createVideoOutputFormat(MediaFormat inputFormat) {
 
     @Override
     public MediaFormat createAudioOutputFormat(MediaFormat inputFormat) {
-        if (mAudioBitrate == AUDIO_BITRATE_AS_IS || mAudioChannels == AUDIO_CHANNELS_AS_IS) return null;
+        if (inputFormat == null || mAudioBitrate == AUDIO_BITRATE_AS_IS || mAudioChannels == AUDIO_CHANNELS_AS_IS) return null;
 
         // Use original sample rate, as resampling is not supported yet.
         final MediaFormat format = MediaFormat.createAudioFormat(MediaFormatExtraConstants.MIMETYPE_AUDIO_AAC,

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

@@ -63,10 +63,13 @@ public MediaFormat createVideoOutputFormat(MediaFormat inputFormat) {
         if (longer * 9 != shorter * 16) {
             throw new OutputFormatUnavailableException("This video is not 16:9, and is not able to transcode. (" + width + "x" + height + ")");
         }
+
+        /*
+        I've commented this out because its unsafe to assume the user wants to bypass compression if resolution is equal.
         if (shorter <= SHORTER_LENGTH) {
             Log.d(TAG, "This video is less or equal to 720p, pass-through. (" + width + "x" + height + ")");
             return null;
-        }
+        }*/
         MediaFormat format = MediaFormat.createVideoFormat("video/avc", outWidth, outHeight);
         // From Nexus 4 Camera in 720p
         format.setInteger(MediaFormat.KEY_BIT_RATE, mVideoBitrate);
@@ -78,7 +81,7 @@ public MediaFormat createVideoOutputFormat(MediaFormat inputFormat) {
 
     @Override
     public MediaFormat createAudioOutputFormat(MediaFormat inputFormat) {
-        if (mAudioBitrate == AUDIO_BITRATE_AS_IS || mAudioChannels == AUDIO_CHANNELS_AS_IS) return null;
+        if (inputFormat == null || mAudioBitrate == AUDIO_BITRATE_AS_IS || mAudioChannels == AUDIO_CHANNELS_AS_IS) return null;
 
         // Use original sample rate, as resampling is not supported yet.
         final MediaFormat format = MediaFormat.createAudioFormat(MediaFormatExtraConstants.MIMETYPE_AUDIO_AAC,

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

@@ -55,8 +55,8 @@ public static TrackResult getFirstVideoAndAudioTrack(MediaExtractor extractor) {
             }
             if (trackResult.mVideoTrackIndex >= 0 && trackResult.mAudioTrackIndex >= 0) break;
         }
-        if (trackResult.mVideoTrackIndex < 0 || trackResult.mAudioTrackIndex < 0) {
-            throw new IllegalArgumentException("extractor does not contain video and/or audio tracks.");
+        if (trackResult.mVideoTrackIndex < 0) {
+            throw new IllegalArgumentException("extractor does not contain video tracks.");
         }
         return trackResult;
     }