Report call status from AudioSource::start() to file writer

Change-Id: I5109dc87a92170dede4eaa58b039efe6d8b7c330
related-to-bug: 5514288

Author: James Dong

media/libstagefright/codecs/amrnb/enc/AMRNBEncoder.cpp

@@ -82,7 +82,11 @@ status_t AMRNBEncoder::start(MetaData *params) {
                 &mEncState, &mSidState, false /* dtx_enable */),
              0);
 
-    mSource->start(params);
+    status_t err = mSource->start(params);
+    if (err != OK) {
+        LOGE("AudioSource is not available");
+        return err;
+    }
 
     mAnchorTimeUs = 0;
     mNumFramesOutput = 0;

media/libstagefright/codecs/amrwbenc/AMRWBEncoder.cpp

@@ -137,8 +137,12 @@ status_t AMRWBEncoder::start(MetaData *params) {
     CHECK_EQ(OK, initCheck());
 
     mNumFramesOutput = 0;
-    mSource->start(params);
 
+    status_t err = mSource->start(params);
+    if (err != OK) {
+        LOGE("AudioSource is not available");
+        return err;
+    }
     mStarted = true;
 
     return OK;