Add read and write option in opening file for output in the writers

Change-Id: Ibfba0aacd3c8587c04a2e903b636de337cc30104
diff --git a/media/libstagefright/AMRWriter.cpp b/media/libstagefright/AMRWriter.cpp
index 69846eb..b10d52c 100644
--- a/media/libstagefright/AMRWriter.cpp
+++ b/media/libstagefright/AMRWriter.cpp
@@ -37,7 +37,7 @@
       mPaused(false),
       mResumed(false) {
 
-    mFd = open(filename, O_CREAT | O_LARGEFILE | O_TRUNC);
+    mFd = open(filename, O_CREAT | O_LARGEFILE | O_TRUNC | O_RDWR);
     if (mFd >= 0) {
         mInitCheck = OK;
     }
diff --git a/media/libstagefright/MPEG4Writer.cpp b/media/libstagefright/MPEG4Writer.cpp
index edf76b5..e13b67e 100644
--- a/media/libstagefright/MPEG4Writer.cpp
+++ b/media/libstagefright/MPEG4Writer.cpp
@@ -232,7 +232,7 @@
       mEstimatedMoovBoxSize(0),
       mInterleaveDurationUs(1000000) {
 
-    mFd = open(filename, O_CREAT | O_LARGEFILE | O_TRUNC);
+    mFd = open(filename, O_CREAT | O_LARGEFILE | O_TRUNC | O_RDWR);
     if (mFd >= 0) {
         mInitCheck = OK;
     }