diff --git a/app/src/main/java/app/fedilab/android/helper/Helper.java b/app/src/main/java/app/fedilab/android/helper/Helper.java
index a6c9f0b72..14e1540ba 100644
--- a/app/src/main/java/app/fedilab/android/helper/Helper.java
+++ b/app/src/main/java/app/fedilab/android/helper/Helper.java
@@ -1319,9 +1319,9 @@ public class Helper {
 
                 MimeTypeMap mime = MimeTypeMap.getSingleton();
                 String extension = mime.getExtensionFromMimeType(cR.getType(uri));
-                if (uri.toString().endsWith("fedilab_recorded_audio.wav")) {
-                    extension = "wav";
-                    attachment.mimeType = "audio/x-wav";
+                if (uri.toString().endsWith("fedilab_recorded_audio.m4a")) {
+                    extension = ".m4a";
+                    attachment.mimeType = "audio/mp4";
                 }
                 SimpleDateFormat formatter = new SimpleDateFormat("yyyy_MM_dd_HH_mm_ss_" + counter, Locale.getDefault());
                 counter++;
diff --git a/app/src/main/java/app/fedilab/android/helper/MediaHelper.java b/app/src/main/java/app/fedilab/android/helper/MediaHelper.java
index 08daff5e2..5000226f6 100644
--- a/app/src/main/java/app/fedilab/android/helper/MediaHelper.java
+++ b/app/src/main/java/app/fedilab/android/helper/MediaHelper.java
@@ -24,7 +24,6 @@ import android.content.Intent;
 import android.content.SharedPreferences;
 import android.graphics.BitmapFactory;
 import android.graphics.drawable.Drawable;
-import android.media.AudioFormat;
 import android.media.MediaRecorder;
 import android.net.Uri;
 import android.os.Build;
@@ -282,7 +281,7 @@ public class MediaHelper {
      * @param listener ActionRecord
      */
     public static void recordAudio(Activity activity, ActionRecord listener) {
-        String filePath = activity.getCacheDir() + "/fedilab_recorded_audio.wav";
+        String filePath = activity.getCacheDir() + "/fedilab_recorded_audio.m4a";
         AudioRecorder mAudioRecorder = AudioRecorder.getInstance();
         File mAudioFile = new File(filePath);
         PopupRecordBinding binding = PopupRecordBinding.inflate(activity.getLayoutInflater());
@@ -322,9 +321,7 @@ public class MediaHelper {
             listener.onRecorded(filePath);
         });
         mAudioRecorder.prepareRecord(MediaRecorder.AudioSource.MIC,
-                AudioFormat.ENCODING_PCM_16BIT, MediaRecorder.AudioEncoder.AAC,
-                48000,
-                128000,
+                MediaRecorder.OutputFormat.MPEG_4, MediaRecorder.AudioEncoder.AAC,
                 mAudioFile);
         mAudioRecorder.startRecord();
     }
diff --git a/app/src/main/java/app/fedilab/android/services/PostMessageService.java b/app/src/main/java/app/fedilab/android/services/PostMessageService.java
index b6bf5d66c..18a34af9b 100644
--- a/app/src/main/java/app/fedilab/android/services/PostMessageService.java
+++ b/app/src/main/java/app/fedilab/android/services/PostMessageService.java
@@ -212,12 +212,13 @@ public class PostMessageService extends IntentService {
                             attachmentIds.add(attachment.id);
                         } else {
                             MultipartBody.Part fileMultipartBody;
-                            if (watermark && attachment.mimeType.contains("image")) {
+                            if (watermark && attachment.mimeType != null && attachment.mimeType.contains("image")) {
                                 fileMultipartBody = Helper.getMultipartBodyWithWM(PostMessageService.this, watermarkText, "file", attachment);
                             } else {
                                 fileMultipartBody = Helper.getMultipartBody("file", attachment);
                             }
                             Call<Attachment> attachmentCall = mastodonStatusesService.postMedia(token, fileMultipartBody, null, attachment.description, null);
+
                             if (attachmentCall != null) {
                                 try {
                                     Response<Attachment> attachmentResponse = attachmentCall.execute();