fix resource leak(s) on exception

amethyst/src/main/java/com/vitorpamplona/amethyst/service/uploads/MetadataStripper.kt

@@ -141,9 +141,12 @@ class MetadataStripper {
             val tempOutputFile = File.createTempFile("stripped_video_", ".mp4", context.cacheDir)
 
             val extractor = MediaExtractor()
+            var muxer: MediaMuxer? = null
+            var muxerStarted = false
+            try {
                 extractor.setDataSource(tempInputFile.absolutePath)
 
-            val muxer = MediaMuxer(tempOutputFile.absolutePath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4)
+                muxer = MediaMuxer(tempOutputFile.absolutePath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4)
 
                 val trackIndexMap = mutableMapOf<Int, Int>()
                 for (i in 0 until extractor.trackCount) {
@@ -153,6 +156,7 @@ class MetadataStripper {
                 }
 
                 muxer.start()
+                muxerStarted = true
 
                 val bufferSize = 1024 * 1024
                 val buffer = java.nio.ByteBuffer.allocate(bufferSize)
@@ -179,9 +183,13 @@ class MetadataStripper {
                 }
 
                 muxer.stop()
-            muxer.release()
+                muxerStarted = false
+            } finally {
+                if (muxerStarted) runCatching { muxer?.stop() }
+                muxer?.release()
                 extractor.release()
                 tempInputFile.delete()
+            }
 
             Log.d("MetadataStripper", "Stripped metadata from video")
             tempOutputFile.toUri()