limit video transcoding to api >= 18 and other api 16 fixes

src/main/java/eu/siacs/conversations/persistance/FileBackend.java

@@ -19,6 +19,7 @@ import android.os.Environment;
 import android.os.ParcelFileDescriptor;
 import android.provider.MediaStore;
 import android.provider.OpenableColumns;
+import android.support.annotation.RequiresApi;
 import android.support.v4.content.FileProvider;
 import android.system.Os;
 import android.system.StructStat;
@@ -299,7 +300,12 @@ public class FileBackend {
         if (dimensions != null) {
             return dimensions;
         }
-        int rotation = extractRotationFromMediaRetriever(metadataRetriever);
+        final int rotation;
+        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN_MR1) {
+            rotation = extractRotationFromMediaRetriever(metadataRetriever);
+        } else {
+            rotation = 0;
+        }
         boolean rotated = rotation == 90 || rotation == 270;
         int height;
         try {
@@ -320,6 +326,7 @@ public class FileBackend {
         return rotated ? new Dimensions(width, height) : new Dimensions(height, width);
     }
 
+    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR1)
     private static int extractRotationFromMediaRetriever(MediaMetadataRetriever metadataRetriever) {
         String r = metadataRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_ROTATION);
         try {

src/main/java/eu/siacs/conversations/services/AttachFileToConversationRunnable.java

@@ -5,6 +5,7 @@ import android.net.Uri;
 import android.os.Build;
 import android.os.ParcelFileDescriptor;
 import android.preference.PreferenceManager;
+import android.support.annotation.RequiresApi;
 import android.util.Log;
 
 import net.ypresto.androidtranscoder.MediaTranscoder;
@@ -88,6 +89,7 @@ public class AttachFileToConversationRunnable implements Runnable, MediaTranscod
 		}
 	}
 
+	@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR2)
 	private void processAsVideo() throws FileNotFoundException {
 		Log.d(Config.LOGTAG,"processing file as video");
 		mXmppConnectionService.startForcingForegroundNotification();
@@ -158,7 +160,7 @@ public class AttachFileToConversationRunnable implements Runnable, MediaTranscod
 
 	@Override
 	public void run() {
-		if (isVideoMessage) {
+		if (isVideoMessage && Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
 			try {
 				processAsVideo();
 			} catch (FileNotFoundException e) {

src/main/java/eu/siacs/conversations/ui/ConversationFragment.java

@@ -1522,7 +1522,9 @@ public class ConversationFragment extends XmppFragment implements EditMessage.Ke
             switch (attachmentChoice) {
                 case ATTACHMENT_CHOICE_CHOOSE_IMAGE:
                     intent.setAction(Intent.ACTION_GET_CONTENT);
+                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
                         intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
+                    }
                     intent.setType("image/*");
                     chooser = true;
                     break;
@@ -1540,7 +1542,9 @@ public class ConversationFragment extends XmppFragment implements EditMessage.Ke
                 case ATTACHMENT_CHOICE_CHOOSE_FILE:
                     chooser = true;
                     intent.setType("*/*");
+                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
                         intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
+                    }
                     intent.addCategory(Intent.CATEGORY_OPENABLE);
                     intent.setAction(Intent.ACTION_GET_CONTENT);
                     break;

src/main/java/eu/siacs/conversations/ui/ConversationsActivity.java

@@ -41,10 +41,12 @@ import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.databinding.DataBindingUtil;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Bundle;
 import android.provider.Settings;
 import android.support.annotation.IdRes;
 import android.support.annotation.NonNull;
+import android.support.annotation.RequiresApi;
 import android.support.v7.app.ActionBar;
 import android.support.v7.app.AlertDialog;
 import android.support.v7.widget.Toolbar;
@@ -218,6 +220,7 @@ public class ConversationsActivity extends XmppActivity implements OnConversatio
     private void openBatteryOptimizationDialogIfNeeded() {
         if (hasAccountWithoutPush()
                 && isOptimizingBattery()
+                && android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M
                 && getPreferences().getBoolean(getBatteryOptimizationPreferenceKey(), true)) {
             AlertDialog.Builder builder = new AlertDialog.Builder(this);
             builder.setTitle(R.string.battery_optimizations_enabled);

src/main/java/eu/siacs/conversations/ui/EditAccountActivity.java

@@ -1143,7 +1143,7 @@ public class EditAccountActivity extends OmemoActivity implements OnAccountUpdat
 
     private void showOsOptimizationWarning(boolean showBatteryWarning, boolean showDataSaverWarning) {
         this.binding.osOptimization.setVisibility(showBatteryWarning || showDataSaverWarning ? View.VISIBLE : View.GONE);
-        if (showDataSaverWarning) {
+        if (showDataSaverWarning && android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.N) {
             this.binding.osOptimizationHeadline.setText(R.string.data_saver_enabled);
             this.binding.osOptimizationBody.setText(R.string.data_saver_enabled_explained);
             this.binding.osOptimizationDisable.setText(R.string.allow);
@@ -1157,7 +1157,7 @@ public class EditAccountActivity extends OmemoActivity implements OnAccountUpdat
                     Toast.makeText(EditAccountActivity.this, R.string.device_does_not_support_data_saver, Toast.LENGTH_SHORT).show();
                 }
             });
-        } else if (showBatteryWarning) {
+        } else if (showBatteryWarning && android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
             this.binding.osOptimizationDisable.setText(R.string.disable);
             this.binding.osOptimizationHeadline.setText(R.string.battery_optimizations_enabled);
             this.binding.osOptimizationBody.setText(R.string.battery_optimizations_enabled_explained);

src/main/java/eu/siacs/conversations/utils/Android360pFormatStrategy.java

@@ -2,6 +2,8 @@ package eu.siacs.conversations.utils;
 
 import android.media.MediaCodecInfo;
 import android.media.MediaFormat;
+import android.os.Build;
+import android.support.annotation.RequiresApi;
 import android.util.Log;
 
 import net.ypresto.androidtranscoder.format.MediaFormatExtraConstants;
@@ -26,6 +28,7 @@ public class Android360pFormatStrategy implements MediaFormatStrategy {
         mAudioChannels = 2;
     }
 
+    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR2)
     @Override
     public MediaFormat createVideoOutputFormat(MediaFormat inputFormat) {
         int width = inputFormat.getInteger(MediaFormat.KEY_WIDTH);

src/main/java/eu/siacs/conversations/utils/Android720pFormatStrategy.java

@@ -2,6 +2,8 @@ package eu.siacs.conversations.utils;
 
 import android.media.MediaCodecInfo;
 import android.media.MediaFormat;
+import android.os.Build;
+import android.support.annotation.RequiresApi;
 import android.util.Log;
 
 import net.ypresto.androidtranscoder.format.MediaFormatExtraConstants;
@@ -26,6 +28,7 @@ public class Android720pFormatStrategy implements MediaFormatStrategy {
         mAudioChannels = 2;
     }
 
+    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR2)
     @Override
     public MediaFormat createVideoOutputFormat(MediaFormat inputFormat) {
         int width = inputFormat.getInteger(MediaFormat.KEY_WIDTH);