Call Looper.prepareMainLooper() to avoid exception

Some devices internally create a Handler when creating an input Surface,
causing an exception:

> Surface: java.lang.RuntimeException: Can't create handler inside
> thread that has not called Looper.prepare()

As a workaround, call Looper.prepareMainLooper() beforehand.

Fixes:
 - <https://github.com/Genymobile/scrcpy/issues/240>
 - <https://github.com/Genymobile/scrcpy/issues/921>

Signed-off-by: Romain Vimont <rom@rom1v.com>

app/src/recorder.c

@@ -174,9 +174,14 @@ recorder_open(struct recorder *recorder, const AVCodec *input_codec) {
 
 void
 recorder_close(struct recorder *recorder) {
-    int ret = av_write_trailer(recorder->ctx);
+    if (recorder->header_written) {
-    if (ret < 0) {
+        int ret = av_write_trailer(recorder->ctx);
-        LOGE("Failed to write trailer to %s", recorder->filename);
+        if (ret < 0) {
+            LOGE("Failed to write trailer to %s", recorder->filename);
+            recorder->failed = true;
+        }
+    } else {
+        // the recorded file is empty
         recorder->failed = true;
     }
     avio_close(recorder->ctx->pb);

server/src/main/java/com/genymobile/scrcpy/ScreenEncoder.java

@@ -7,6 +7,7 @@ import android.media.MediaCodec;
 import android.media.MediaCodecInfo;
 import android.media.MediaFormat;
 import android.os.IBinder;
+import android.os.Looper;
 import android.view.Surface;
 
 import java.io.FileDescriptor;
@@ -54,6 +55,11 @@ public class ScreenEncoder implements Device.RotationListener {
     }
 
     public void streamScreen(Device device, FileDescriptor fd) throws IOException {
+        // Some devices internally create a Handler when creating an input Surface, causing an exception:
+        // "Can't create handler inside thread that has not called Looper.prepare()"
+        // <https://github.com/Genymobile/scrcpy/issues/240>
+        Looper.prepareMainLooper();
+
         MediaFormat format = createFormat(bitRate, frameRate, iFrameInterval);
         device.setRotationListener(this);
         boolean alive;