diff --git a/media/libmediaplayerservice/MediaPlayerService.cpp b/media/libmediaplayerservice/MediaPlayerService.cpp
index b4fc035..50dad33 100644
--- a/media/libmediaplayerservice/MediaPlayerService.cpp
+++ b/media/libmediaplayerservice/MediaPlayerService.cpp
@@ -1614,6 +1614,8 @@
     size_t actualSize = (*me->mCallback)(
             me, buffer->raw, buffer->size, me->mCallbackCookie);
 
+    buffer->size = actualSize;
+
     if (actualSize > 0) {
         me->snoopWrite(buffer->raw, actualSize);
     }